diff options
| author | Tom Rini <trini@konsulko.com> | 2024-10-08 13:56:50 -0600 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2024-10-08 13:56:50 -0600 |
| commit | 0344c602eadc0802776b65ff90f0a02c856cf53c (patch) | |
| tree | 236a705740939b84ff37d68ae650061dd14c3449 /library/rsa.c | |
Squashed 'lib/mbedtls/external/mbedtls/' content from commit 2ca6c285a0dd
git-subtree-dir: lib/mbedtls/external/mbedtls
git-subtree-split: 2ca6c285a0dd3f33982dd57299012dacab1ff206
Diffstat (limited to 'library/rsa.c')
| -rw-r--r-- | library/rsa.c | 3065 |
1 files changed, 3065 insertions, 0 deletions
diff --git a/library/rsa.c b/library/rsa.c new file mode 100644 index 00000000000..7eb4a259ea8 --- /dev/null +++ b/library/rsa.c @@ -0,0 +1,3065 @@ +/* + * The RSA public-key cryptosystem + * + * Copyright The Mbed TLS Contributors + * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later + */ + +/* + * The following sources were referenced in the design of this implementation + * of the RSA algorithm: + * + * [1] A method for obtaining digital signatures and public-key cryptosystems + * R Rivest, A Shamir, and L Adleman + * http://people.csail.mit.edu/rivest/pubs.html#RSA78 + * + * [2] Handbook of Applied Cryptography - 1997, Chapter 8 + * Menezes, van Oorschot and Vanstone + * + * [3] Malware Guard Extension: Using SGX to Conceal Cache Attacks + * Michael Schwarz, Samuel Weiser, Daniel Gruss, Clémentine Maurice and + * Stefan Mangard + * https://arxiv.org/abs/1702.08719v2 + * + */ + +#include "common.h" + +#if defined(MBEDTLS_RSA_C) + +#include "mbedtls/rsa.h" +#include "bignum_core.h" +#include "rsa_alt_helpers.h" +#include "rsa_internal.h" +#include "mbedtls/oid.h" +#include "mbedtls/asn1write.h" +#include "mbedtls/platform_util.h" +#include "mbedtls/error.h" +#include "constant_time_internal.h" +#include "mbedtls/constant_time.h" +#include "md_psa.h" + +#include <string.h> + +#if defined(MBEDTLS_PKCS1_V15) && !defined(__OpenBSD__) && !defined(__NetBSD__) +#include <stdlib.h> +#endif + +#include "mbedtls/platform.h" + +/* + * Wrapper around mbedtls_asn1_get_mpi() that rejects zero. + * + * The value zero is: + * - never a valid value for an RSA parameter + * - interpreted as "omitted, please reconstruct" by mbedtls_rsa_complete(). + * + * Since values can't be omitted in PKCS#1, passing a zero value to + * rsa_complete() would be incorrect, so reject zero values early. + */ +static int asn1_get_nonzero_mpi(unsigned char **p, + const unsigned char *end, + mbedtls_mpi *X) +{ + int ret; + + ret = mbedtls_asn1_get_mpi(p, end, X); + if (ret != 0) { + return ret; + } + + if (mbedtls_mpi_cmp_int(X, 0) == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + return 0; +} + +int mbedtls_rsa_parse_key(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen) +{ + int ret, version; + size_t len; + unsigned char *p, *end; + + mbedtls_mpi T; + mbedtls_mpi_init(&T); + + p = (unsigned char *) key; + end = p + keylen; + + /* + * This function parses the RSAPrivateKey (PKCS#1) + * + * RSAPrivateKey ::= SEQUENCE { + * version Version, + * modulus INTEGER, -- n + * publicExponent INTEGER, -- e + * privateExponent INTEGER, -- d + * prime1 INTEGER, -- p + * prime2 INTEGER, -- q + * exponent1 INTEGER, -- d mod (p-1) + * exponent2 INTEGER, -- d mod (q-1) + * coefficient INTEGER, -- (inverse of q) mod p + * otherPrimeInfos OtherPrimeInfos OPTIONAL + * } + */ + if ((ret = mbedtls_asn1_get_tag(&p, end, &len, + MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) { + return ret; + } + + if (end != p + len) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) { + return ret; + } + + if (version != 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* Import N */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_rsa_import(rsa, &T, NULL, NULL, + NULL, NULL)) != 0) { + goto cleanup; + } + + /* Import E */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL, + NULL, &T)) != 0) { + goto cleanup; + } + + /* Import D */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_rsa_import(rsa, NULL, NULL, NULL, + &T, NULL)) != 0) { + goto cleanup; + } + + /* Import P */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_rsa_import(rsa, NULL, &T, NULL, + NULL, NULL)) != 0) { + goto cleanup; + } + + /* Import Q */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_rsa_import(rsa, NULL, NULL, &T, + NULL, NULL)) != 0) { + goto cleanup; + } + +#if !defined(MBEDTLS_RSA_NO_CRT) && !defined(MBEDTLS_RSA_ALT) + /* + * The RSA CRT parameters DP, DQ and QP are nominally redundant, in + * that they can be easily recomputed from D, P and Q. However by + * parsing them from the PKCS1 structure it is possible to avoid + * recalculating them which both reduces the overhead of loading + * RSA private keys into memory and also avoids side channels which + * can arise when computing those values, since all of D, P, and Q + * are secret. See https://eprint.iacr.org/2020/055 for a + * description of one such attack. + */ + + /* Import DP */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_mpi_copy(&rsa->DP, &T)) != 0) { + goto cleanup; + } + + /* Import DQ */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_mpi_copy(&rsa->DQ, &T)) != 0) { + goto cleanup; + } + + /* Import QP */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = mbedtls_mpi_copy(&rsa->QP, &T)) != 0) { + goto cleanup; + } + +#else + /* Verify existence of the CRT params */ + if ((ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0 || + (ret = asn1_get_nonzero_mpi(&p, end, &T)) != 0) { + goto cleanup; + } +#endif + + /* rsa_complete() doesn't complete anything with the default + * implementation but is still called: + * - for the benefit of alternative implementation that may want to + * pre-compute stuff beyond what's provided (eg Montgomery factors) + * - as is also sanity-checks the key + * + * Furthermore, we also check the public part for consistency with + * mbedtls_pk_parse_pubkey(), as it includes size minima for example. + */ + if ((ret = mbedtls_rsa_complete(rsa)) != 0 || + (ret = mbedtls_rsa_check_pubkey(rsa)) != 0) { + goto cleanup; + } + + if (p != end) { + ret = MBEDTLS_ERR_ASN1_LENGTH_MISMATCH; + } + +cleanup: + + mbedtls_mpi_free(&T); + + if (ret != 0) { + mbedtls_rsa_free(rsa); + } + + return ret; +} + +int mbedtls_rsa_parse_pubkey(mbedtls_rsa_context *rsa, const unsigned char *key, size_t keylen) +{ + unsigned char *p = (unsigned char *) key; + unsigned char *end = (unsigned char *) (key + keylen); + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t len; + + /* + * RSAPublicKey ::= SEQUENCE { + * modulus INTEGER, -- n + * publicExponent INTEGER -- e + * } + */ + + if ((ret = mbedtls_asn1_get_tag(&p, end, &len, + MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) != 0) { + return ret; + } + + if (end != p + len) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* Import N */ + if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) { + return ret; + } + + if ((ret = mbedtls_rsa_import_raw(rsa, p, len, NULL, 0, NULL, 0, + NULL, 0, NULL, 0)) != 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + p += len; + + /* Import E */ + if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) { + return ret; + } + + if ((ret = mbedtls_rsa_import_raw(rsa, NULL, 0, NULL, 0, NULL, 0, + NULL, 0, p, len)) != 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + p += len; + + if (mbedtls_rsa_complete(rsa) != 0 || + mbedtls_rsa_check_pubkey(rsa) != 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (p != end) { + return MBEDTLS_ERR_ASN1_LENGTH_MISMATCH; + } + + return 0; +} + +int mbedtls_rsa_write_key(const mbedtls_rsa_context *rsa, unsigned char *start, + unsigned char **p) +{ + size_t len = 0; + int ret; + + mbedtls_mpi T; /* Temporary holding the exported parameters */ + + /* + * Export the parameters one after another to avoid simultaneous copies. + */ + + mbedtls_mpi_init(&T); + + /* Export QP */ + if ((ret = mbedtls_rsa_export_crt(rsa, NULL, NULL, &T)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export DQ */ + if ((ret = mbedtls_rsa_export_crt(rsa, NULL, &T, NULL)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export DP */ + if ((ret = mbedtls_rsa_export_crt(rsa, &T, NULL, NULL)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export Q */ + if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, &T, NULL, NULL)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export P */ + if ((ret = mbedtls_rsa_export(rsa, NULL, &T, NULL, NULL, NULL)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export D */ + if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, &T, NULL)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export E */ + if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export N */ + if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + +end_of_export: + + mbedtls_mpi_free(&T); + if (ret < 0) { + return ret; + } + + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_int(p, start, 0)); + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, + MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SEQUENCE)); + + return (int) len; +} + +/* + * RSAPublicKey ::= SEQUENCE { + * modulus INTEGER, -- n + * publicExponent INTEGER -- e + * } + */ +int mbedtls_rsa_write_pubkey(const mbedtls_rsa_context *rsa, unsigned char *start, + unsigned char **p) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t len = 0; + mbedtls_mpi T; + + mbedtls_mpi_init(&T); + + /* Export E */ + if ((ret = mbedtls_rsa_export(rsa, NULL, NULL, NULL, NULL, &T)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + + /* Export N */ + if ((ret = mbedtls_rsa_export(rsa, &T, NULL, NULL, NULL, NULL)) != 0 || + (ret = mbedtls_asn1_write_mpi(p, start, &T)) < 0) { + goto end_of_export; + } + len += ret; + +end_of_export: + + mbedtls_mpi_free(&T); + if (ret < 0) { + return ret; + } + + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len)); + MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_CONSTRUCTED | + MBEDTLS_ASN1_SEQUENCE)); + + return (int) len; +} + +#if defined(MBEDTLS_PKCS1_V15) && defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_RSA_ALT) + +/** This function performs the unpadding part of a PKCS#1 v1.5 decryption + * operation (EME-PKCS1-v1_5 decoding). + * + * \note The return value from this function is a sensitive value + * (this is unusual). #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE shouldn't happen + * in a well-written application, but 0 vs #MBEDTLS_ERR_RSA_INVALID_PADDING + * is often a situation that an attacker can provoke and leaking which + * one is the result is precisely the information the attacker wants. + * + * \param input The input buffer which is the payload inside PKCS#1v1.5 + * encryption padding, called the "encoded message EM" + * by the terminology. + * \param ilen The length of the payload in the \p input buffer. + * \param output The buffer for the payload, called "message M" by the + * PKCS#1 terminology. This must be a writable buffer of + * length \p output_max_len bytes. + * \param olen The address at which to store the length of + * the payload. This must not be \c NULL. + * \param output_max_len The length in bytes of the output buffer \p output. + * + * \return \c 0 on success. + * \return #MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE + * The output buffer is too small for the unpadded payload. + * \return #MBEDTLS_ERR_RSA_INVALID_PADDING + * The input doesn't contain properly formatted padding. + */ +static int mbedtls_ct_rsaes_pkcs1_v15_unpadding(unsigned char *input, + size_t ilen, + unsigned char *output, + size_t output_max_len, + size_t *olen) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t i, plaintext_max_size; + + /* The following variables take sensitive values: their value must + * not leak into the observable behavior of the function other than + * the designated outputs (output, olen, return value). Otherwise + * this would open the execution of the function to + * side-channel-based variants of the Bleichenbacher padding oracle + * attack. Potential side channels include overall timing, memory + * access patterns (especially visible to an adversary who has access + * to a shared memory cache), and branches (especially visible to + * an adversary who has access to a shared code cache or to a shared + * branch predictor). */ + size_t pad_count = 0; + mbedtls_ct_condition_t bad; + mbedtls_ct_condition_t pad_done; + size_t plaintext_size = 0; + mbedtls_ct_condition_t output_too_large; + + plaintext_max_size = (output_max_len > ilen - 11) ? ilen - 11 + : output_max_len; + + /* Check and get padding length in constant time and constant + * memory trace. The first byte must be 0. */ + bad = mbedtls_ct_bool(input[0]); + + + /* Decode EME-PKCS1-v1_5 padding: 0x00 || 0x02 || PS || 0x00 + * where PS must be at least 8 nonzero bytes. */ + bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_ne(input[1], MBEDTLS_RSA_CRYPT)); + + /* Read the whole buffer. Set pad_done to nonzero if we find + * the 0x00 byte and remember the padding length in pad_count. */ + pad_done = MBEDTLS_CT_FALSE; + for (i = 2; i < ilen; i++) { + mbedtls_ct_condition_t found = mbedtls_ct_uint_eq(input[i], 0); + pad_done = mbedtls_ct_bool_or(pad_done, found); + pad_count += mbedtls_ct_uint_if_else_0(mbedtls_ct_bool_not(pad_done), 1); + } + + /* If pad_done is still zero, there's no data, only unfinished padding. */ + bad = mbedtls_ct_bool_or(bad, mbedtls_ct_bool_not(pad_done)); + + /* There must be at least 8 bytes of padding. */ + bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_gt(8, pad_count)); + + /* If the padding is valid, set plaintext_size to the number of + * remaining bytes after stripping the padding. If the padding + * is invalid, avoid leaking this fact through the size of the + * output: use the maximum message size that fits in the output + * buffer. Do it without branches to avoid leaking the padding + * validity through timing. RSA keys are small enough that all the + * size_t values involved fit in unsigned int. */ + plaintext_size = mbedtls_ct_uint_if( + bad, (unsigned) plaintext_max_size, + (unsigned) (ilen - pad_count - 3)); + + /* Set output_too_large to 0 if the plaintext fits in the output + * buffer and to 1 otherwise. */ + output_too_large = mbedtls_ct_uint_gt(plaintext_size, + plaintext_max_size); + + /* Set ret without branches to avoid timing attacks. Return: + * - INVALID_PADDING if the padding is bad (bad != 0). + * - OUTPUT_TOO_LARGE if the padding is good but the decrypted + * plaintext does not fit in the output buffer. + * - 0 if the padding is correct. */ + ret = mbedtls_ct_error_if( + bad, + MBEDTLS_ERR_RSA_INVALID_PADDING, + mbedtls_ct_error_if_else_0(output_too_large, MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE) + ); + + /* If the padding is bad or the plaintext is too large, zero the + * data that we're about to copy to the output buffer. + * We need to copy the same amount of data + * from the same buffer whether the padding is good or not to + * avoid leaking the padding validity through overall timing or + * through memory or cache access patterns. */ + mbedtls_ct_zeroize_if(mbedtls_ct_bool_or(bad, output_too_large), input + 11, ilen - 11); + + /* If the plaintext is too large, truncate it to the buffer size. + * Copy anyway to avoid revealing the length through timing, because + * revealing the length is as bad as revealing the padding validity + * for a Bleichenbacher attack. */ + plaintext_size = mbedtls_ct_uint_if(output_too_large, + (unsigned) plaintext_max_size, + (unsigned) plaintext_size); + + /* Move the plaintext to the leftmost position where it can start in + * the working buffer, i.e. make it start plaintext_max_size from + * the end of the buffer. Do this with a memory access trace that + * does not depend on the plaintext size. After this move, the + * starting location of the plaintext is no longer sensitive + * information. */ + mbedtls_ct_memmove_left(input + ilen - plaintext_max_size, + plaintext_max_size, + plaintext_max_size - plaintext_size); + + /* Finally copy the decrypted plaintext plus trailing zeros into the output + * buffer. If output_max_len is 0, then output may be an invalid pointer + * and the result of memcpy() would be undefined; prevent undefined + * behavior making sure to depend only on output_max_len (the size of the + * user-provided output buffer), which is independent from plaintext + * length, validity of padding, success of the decryption, and other + * secrets. */ + if (output_max_len != 0) { + memcpy(output, input + ilen - plaintext_max_size, plaintext_max_size); + } + + /* Report the amount of data we copied to the output buffer. In case + * of errors (bad padding or output too large), the value of *olen + * when this function returns is not specified. Making it equivalent + * to the good case limits the risks of leaking the padding validity. */ + *olen = plaintext_size; + + return ret; +} + +#endif /* MBEDTLS_PKCS1_V15 && MBEDTLS_RSA_C && ! MBEDTLS_RSA_ALT */ + +#if !defined(MBEDTLS_RSA_ALT) + +int mbedtls_rsa_import(mbedtls_rsa_context *ctx, + const mbedtls_mpi *N, + const mbedtls_mpi *P, const mbedtls_mpi *Q, + const mbedtls_mpi *D, const mbedtls_mpi *E) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + if ((N != NULL && (ret = mbedtls_mpi_copy(&ctx->N, N)) != 0) || + (P != NULL && (ret = mbedtls_mpi_copy(&ctx->P, P)) != 0) || + (Q != NULL && (ret = mbedtls_mpi_copy(&ctx->Q, Q)) != 0) || + (D != NULL && (ret = mbedtls_mpi_copy(&ctx->D, D)) != 0) || + (E != NULL && (ret = mbedtls_mpi_copy(&ctx->E, E)) != 0)) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } + + if (N != NULL) { + ctx->len = mbedtls_mpi_size(&ctx->N); + } + + return 0; +} + +int mbedtls_rsa_import_raw(mbedtls_rsa_context *ctx, + unsigned char const *N, size_t N_len, + unsigned char const *P, size_t P_len, + unsigned char const *Q, size_t Q_len, + unsigned char const *D, size_t D_len, + unsigned char const *E, size_t E_len) +{ + int ret = 0; + + if (N != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->N, N, N_len)); + ctx->len = mbedtls_mpi_size(&ctx->N); + } + + if (P != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->P, P, P_len)); + } + + if (Q != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->Q, Q, Q_len)); + } + + if (D != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->D, D, D_len)); + } + + if (E != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&ctx->E, E, E_len)); + } + +cleanup: + + if (ret != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } + + return 0; +} + +/* + * Checks whether the context fields are set in such a way + * that the RSA primitives will be able to execute without error. + * It does *not* make guarantees for consistency of the parameters. + */ +static int rsa_check_context(mbedtls_rsa_context const *ctx, int is_priv, + int blinding_needed) +{ +#if !defined(MBEDTLS_RSA_NO_CRT) + /* blinding_needed is only used for NO_CRT to decide whether + * P,Q need to be present or not. */ + ((void) blinding_needed); +#endif + + if (ctx->len != mbedtls_mpi_size(&ctx->N) || + ctx->len > MBEDTLS_MPI_MAX_SIZE) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* + * 1. Modular exponentiation needs positive, odd moduli. + */ + + /* Modular exponentiation wrt. N is always used for + * RSA public key operations. */ + if (mbedtls_mpi_cmp_int(&ctx->N, 0) <= 0 || + mbedtls_mpi_get_bit(&ctx->N, 0) == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + +#if !defined(MBEDTLS_RSA_NO_CRT) + /* Modular exponentiation for P and Q is only + * used for private key operations and if CRT + * is used. */ + if (is_priv && + (mbedtls_mpi_cmp_int(&ctx->P, 0) <= 0 || + mbedtls_mpi_get_bit(&ctx->P, 0) == 0 || + mbedtls_mpi_cmp_int(&ctx->Q, 0) <= 0 || + mbedtls_mpi_get_bit(&ctx->Q, 0) == 0)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } +#endif /* !MBEDTLS_RSA_NO_CRT */ + + /* + * 2. Exponents must be positive + */ + + /* Always need E for public key operations */ + if (mbedtls_mpi_cmp_int(&ctx->E, 0) <= 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + +#if defined(MBEDTLS_RSA_NO_CRT) + /* For private key operations, use D or DP & DQ + * as (unblinded) exponents. */ + if (is_priv && mbedtls_mpi_cmp_int(&ctx->D, 0) <= 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } +#else + if (is_priv && + (mbedtls_mpi_cmp_int(&ctx->DP, 0) <= 0 || + mbedtls_mpi_cmp_int(&ctx->DQ, 0) <= 0)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } +#endif /* MBEDTLS_RSA_NO_CRT */ + + /* Blinding shouldn't make exponents negative either, + * so check that P, Q >= 1 if that hasn't yet been + * done as part of 1. */ +#if defined(MBEDTLS_RSA_NO_CRT) + if (is_priv && blinding_needed && + (mbedtls_mpi_cmp_int(&ctx->P, 0) <= 0 || + mbedtls_mpi_cmp_int(&ctx->Q, 0) <= 0)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } +#endif + + /* It wouldn't lead to an error if it wasn't satisfied, + * but check for QP >= 1 nonetheless. */ +#if !defined(MBEDTLS_RSA_NO_CRT) + if (is_priv && + mbedtls_mpi_cmp_int(&ctx->QP, 0) <= 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } +#endif + + return 0; +} + +int mbedtls_rsa_complete(mbedtls_rsa_context *ctx) +{ + int ret = 0; + int have_N, have_P, have_Q, have_D, have_E; +#if !defined(MBEDTLS_RSA_NO_CRT) + int have_DP, have_DQ, have_QP; +#endif + int n_missing, pq_missing, d_missing, is_pub, is_priv; + + have_N = (mbedtls_mpi_cmp_int(&ctx->N, 0) != 0); + have_P = (mbedtls_mpi_cmp_int(&ctx->P, 0) != 0); + have_Q = (mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0); + have_D = (mbedtls_mpi_cmp_int(&ctx->D, 0) != 0); + have_E = (mbedtls_mpi_cmp_int(&ctx->E, 0) != 0); + +#if !defined(MBEDTLS_RSA_NO_CRT) + have_DP = (mbedtls_mpi_cmp_int(&ctx->DP, 0) != 0); + have_DQ = (mbedtls_mpi_cmp_int(&ctx->DQ, 0) != 0); + have_QP = (mbedtls_mpi_cmp_int(&ctx->QP, 0) != 0); +#endif + + /* + * Check whether provided parameters are enough + * to deduce all others. The following incomplete + * parameter sets for private keys are supported: + * + * (1) P, Q missing. + * (2) D and potentially N missing. + * + */ + + n_missing = have_P && have_Q && have_D && have_E; + pq_missing = have_N && !have_P && !have_Q && have_D && have_E; + d_missing = have_P && have_Q && !have_D && have_E; + is_pub = have_N && !have_P && !have_Q && !have_D && have_E; + + /* These three alternatives are mutually exclusive */ + is_priv = n_missing || pq_missing || d_missing; + + if (!is_priv && !is_pub) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* + * Step 1: Deduce N if P, Q are provided. + */ + + if (!have_N && have_P && have_Q) { + if ((ret = mbedtls_mpi_mul_mpi(&ctx->N, &ctx->P, + &ctx->Q)) != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } + + ctx->len = mbedtls_mpi_size(&ctx->N); + } + + /* + * Step 2: Deduce and verify all remaining core parameters. + */ + + if (pq_missing) { + ret = mbedtls_rsa_deduce_primes(&ctx->N, &ctx->E, &ctx->D, + &ctx->P, &ctx->Q); + if (ret != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } + + } else if (d_missing) { + if ((ret = mbedtls_rsa_deduce_private_exponent(&ctx->P, + &ctx->Q, + &ctx->E, + &ctx->D)) != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } + } + + /* + * Step 3: Deduce all additional parameters specific + * to our current RSA implementation. + */ + +#if !defined(MBEDTLS_RSA_NO_CRT) + if (is_priv && !(have_DP && have_DQ && have_QP)) { + ret = mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D, + &ctx->DP, &ctx->DQ, &ctx->QP); + if (ret != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } + } +#endif /* MBEDTLS_RSA_NO_CRT */ + + /* + * Step 3: Basic sanity checks + */ + + return rsa_check_context(ctx, is_priv, 1); +} + +int mbedtls_rsa_export_raw(const mbedtls_rsa_context *ctx, + unsigned char *N, size_t N_len, + unsigned char *P, size_t P_len, + unsigned char *Q, size_t Q_len, + unsigned char *D, size_t D_len, + unsigned char *E, size_t E_len) +{ + int ret = 0; + int is_priv; + + /* Check if key is private or public */ + is_priv = + mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->E, 0) != 0; + + if (!is_priv) { + /* If we're trying to export private parameters for a public key, + * something must be wrong. */ + if (P != NULL || Q != NULL || D != NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + } + + if (N != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->N, N, N_len)); + } + + if (P != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->P, P, P_len)); + } + + if (Q != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->Q, Q, Q_len)); + } + + if (D != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->D, D, D_len)); + } + + if (E != NULL) { + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&ctx->E, E, E_len)); + } + +cleanup: + + return ret; +} + +int mbedtls_rsa_export(const mbedtls_rsa_context *ctx, + mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q, + mbedtls_mpi *D, mbedtls_mpi *E) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + int is_priv; + + /* Check if key is private or public */ + is_priv = + mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->E, 0) != 0; + + if (!is_priv) { + /* If we're trying to export private parameters for a public key, + * something must be wrong. */ + if (P != NULL || Q != NULL || D != NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + } + + /* Export all requested core parameters. */ + + if ((N != NULL && (ret = mbedtls_mpi_copy(N, &ctx->N)) != 0) || + (P != NULL && (ret = mbedtls_mpi_copy(P, &ctx->P)) != 0) || + (Q != NULL && (ret = mbedtls_mpi_copy(Q, &ctx->Q)) != 0) || + (D != NULL && (ret = mbedtls_mpi_copy(D, &ctx->D)) != 0) || + (E != NULL && (ret = mbedtls_mpi_copy(E, &ctx->E)) != 0)) { + return ret; + } + + return 0; +} + +/* + * Export CRT parameters + * This must also be implemented if CRT is not used, for being able to + * write DER encoded RSA keys. The helper function mbedtls_rsa_deduce_crt + * can be used in this case. + */ +int mbedtls_rsa_export_crt(const mbedtls_rsa_context *ctx, + mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + int is_priv; + + /* Check if key is private or public */ + is_priv = + mbedtls_mpi_cmp_int(&ctx->N, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->P, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->Q, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->D, 0) != 0 && + mbedtls_mpi_cmp_int(&ctx->E, 0) != 0; + + if (!is_priv) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + +#if !defined(MBEDTLS_RSA_NO_CRT) + /* Export all requested blinding parameters. */ + if ((DP != NULL && (ret = mbedtls_mpi_copy(DP, &ctx->DP)) != 0) || + (DQ != NULL && (ret = mbedtls_mpi_copy(DQ, &ctx->DQ)) != 0) || + (QP != NULL && (ret = mbedtls_mpi_copy(QP, &ctx->QP)) != 0)) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } +#else + if ((ret = mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D, + DP, DQ, QP)) != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret); + } +#endif + + return 0; +} + +/* + * Initialize an RSA context + */ +void mbedtls_rsa_init(mbedtls_rsa_context *ctx) +{ + memset(ctx, 0, sizeof(mbedtls_rsa_context)); + + ctx->padding = MBEDTLS_RSA_PKCS_V15; + ctx->hash_id = MBEDTLS_MD_NONE; + +#if defined(MBEDTLS_THREADING_C) + /* Set ctx->ver to nonzero to indicate that the mutex has been + * initialized and will need to be freed. */ + ctx->ver = 1; + mbedtls_mutex_init(&ctx->mutex); +#endif +} + +/* + * Set padding for an existing RSA context + */ +int mbedtls_rsa_set_padding(mbedtls_rsa_context *ctx, int padding, + mbedtls_md_type_t hash_id) +{ + switch (padding) { +#if defined(MBEDTLS_PKCS1_V15) + case MBEDTLS_RSA_PKCS_V15: + break; +#endif + +#if defined(MBEDTLS_PKCS1_V21) + case MBEDTLS_RSA_PKCS_V21: + break; +#endif + default: + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } + +#if defined(MBEDTLS_PKCS1_V21) + if ((padding == MBEDTLS_RSA_PKCS_V21) && + (hash_id != MBEDTLS_MD_NONE)) { + /* Just make sure this hash is supported in this build. */ + if (mbedtls_md_info_from_type(hash_id) == NULL) { + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } + } +#endif /* MBEDTLS_PKCS1_V21 */ + + ctx->padding = padding; + ctx->hash_id = hash_id; + + return 0; +} + +/* + * Get padding mode of initialized RSA context + */ +int mbedtls_rsa_get_padding_mode(const mbedtls_rsa_context *ctx) +{ + return ctx->padding; +} + +/* + * Get hash identifier of mbedtls_md_type_t type + */ +int mbedtls_rsa_get_md_alg(const mbedtls_rsa_context *ctx) +{ + return ctx->hash_id; +} + +/* + * Get length in bits of RSA modulus + */ +size_t mbedtls_rsa_get_bitlen(const mbedtls_rsa_context *ctx) +{ + return mbedtls_mpi_bitlen(&ctx->N); +} + +/* + * Get length in bytes of RSA modulus + */ +size_t mbedtls_rsa_get_len(const mbedtls_rsa_context *ctx) +{ + return ctx->len; +} + +#if defined(MBEDTLS_GENPRIME) + +/* + * Generate an RSA keypair + * + * This generation method follows the RSA key pair generation procedure of + * FIPS 186-4 if 2^16 < exponent < 2^256 and nbits = 2048 or nbits = 3072. + */ +int mbedtls_rsa_gen_key(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + unsigned int nbits, int exponent) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + mbedtls_mpi H, G, L; + int prime_quality = 0; + + /* + * If the modulus is 1024 bit long or shorter, then the security strength of + * the RSA algorithm is less than or equal to 80 bits and therefore an error + * rate of 2^-80 is sufficient. + */ + if (nbits > 1024) { + prime_quality = MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR; + } + + mbedtls_mpi_init(&H); + mbedtls_mpi_init(&G); + mbedtls_mpi_init(&L); + + if (exponent < 3 || nbits % 2 != 0) { + ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + goto cleanup; + } + + if (nbits < MBEDTLS_RSA_GEN_KEY_MIN_BITS) { + ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + goto cleanup; + } + + /* + * find primes P and Q with Q < P so that: + * 1. |P-Q| > 2^( nbits / 2 - 100 ) + * 2. GCD( E, (P-1)*(Q-1) ) == 1 + * 3. E^-1 mod LCM(P-1, Q-1) > 2^( nbits / 2 ) + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_lset(&ctx->E, exponent)); + + do { + MBEDTLS_MPI_CHK(mbedtls_mpi_gen_prime(&ctx->P, nbits >> 1, + prime_quality, f_rng, p_rng)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_gen_prime(&ctx->Q, nbits >> 1, + prime_quality, f_rng, p_rng)); + + /* make sure the difference between p and q is not too small (FIPS 186-4 §B.3.3 step 5.4) */ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&H, &ctx->P, &ctx->Q)); + if (mbedtls_mpi_bitlen(&H) <= ((nbits >= 200) ? ((nbits >> 1) - 99) : 0)) { + continue; + } + + /* not required by any standards, but some users rely on the fact that P > Q */ + if (H.s < 0) { + mbedtls_mpi_swap(&ctx->P, &ctx->Q); + } + + /* Temporarily replace P,Q by P-1, Q-1 */ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&ctx->P, &ctx->P, 1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&ctx->Q, &ctx->Q, 1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&H, &ctx->P, &ctx->Q)); + + /* check GCD( E, (P-1)*(Q-1) ) == 1 (FIPS 186-4 §B.3.1 criterion 2(a)) */ + MBEDTLS_MPI_CHK(mbedtls_mpi_gcd(&G, &ctx->E, &H)); + if (mbedtls_mpi_cmp_int(&G, 1) != 0) { + continue; + } + + /* compute smallest possible D = E^-1 mod LCM(P-1, Q-1) (FIPS 186-4 §B.3.1 criterion 3(b)) */ + MBEDTLS_MPI_CHK(mbedtls_mpi_gcd(&G, &ctx->P, &ctx->Q)); + MBEDTLS_MPI_CHK(mbedtls_mpi_div_mpi(&L, NULL, &H, &G)); + MBEDTLS_MPI_CHK(mbedtls_mpi_inv_mod(&ctx->D, &ctx->E, &L)); + + if (mbedtls_mpi_bitlen(&ctx->D) <= ((nbits + 1) / 2)) { // (FIPS 186-4 §B.3.1 criterion 3(a)) + continue; + } + + break; + } while (1); + + /* Restore P,Q */ + MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&ctx->P, &ctx->P, 1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&ctx->Q, &ctx->Q, 1)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->N, &ctx->P, &ctx->Q)); + + ctx->len = mbedtls_mpi_size(&ctx->N); + +#if !defined(MBEDTLS_RSA_NO_CRT) + /* + * DP = D mod (P - 1) + * DQ = D mod (Q - 1) + * QP = Q^-1 mod P + */ + MBEDTLS_MPI_CHK(mbedtls_rsa_deduce_crt(&ctx->P, &ctx->Q, &ctx->D, + &ctx->DP, &ctx->DQ, &ctx->QP)); +#endif /* MBEDTLS_RSA_NO_CRT */ + + /* Double-check */ + MBEDTLS_MPI_CHK(mbedtls_rsa_check_privkey(ctx)); + +cleanup: + + mbedtls_mpi_free(&H); + mbedtls_mpi_free(&G); + mbedtls_mpi_free(&L); + + if (ret != 0) { + mbedtls_rsa_free(ctx); + + if ((-ret & ~0x7f) == 0) { + ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_KEY_GEN_FAILED, ret); + } + return ret; + } + + return 0; +} + +#endif /* MBEDTLS_GENPRIME */ + +/* + * Check a public RSA key + */ +int mbedtls_rsa_check_pubkey(const mbedtls_rsa_context *ctx) +{ + if (rsa_check_context(ctx, 0 /* public */, 0 /* no blinding */) != 0) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } + + if (mbedtls_mpi_bitlen(&ctx->N) < 128) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } + + if (mbedtls_mpi_get_bit(&ctx->E, 0) == 0 || + mbedtls_mpi_bitlen(&ctx->E) < 2 || + mbedtls_mpi_cmp_mpi(&ctx->E, &ctx->N) >= 0) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } + + return 0; +} + +/* + * Check for the consistency of all fields in an RSA private key context + */ +int mbedtls_rsa_check_privkey(const mbedtls_rsa_context *ctx) +{ + if (mbedtls_rsa_check_pubkey(ctx) != 0 || + rsa_check_context(ctx, 1 /* private */, 1 /* blinding */) != 0) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } + + if (mbedtls_rsa_validate_params(&ctx->N, &ctx->P, &ctx->Q, + &ctx->D, &ctx->E, NULL, NULL) != 0) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } + +#if !defined(MBEDTLS_RSA_NO_CRT) + else if (mbedtls_rsa_validate_crt(&ctx->P, &ctx->Q, &ctx->D, + &ctx->DP, &ctx->DQ, &ctx->QP) != 0) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } +#endif + + return 0; +} + +/* + * Check if contexts holding a public and private key match + */ +int mbedtls_rsa_check_pub_priv(const mbedtls_rsa_context *pub, + const mbedtls_rsa_context *prv) +{ + if (mbedtls_rsa_check_pubkey(pub) != 0 || + mbedtls_rsa_check_privkey(prv) != 0) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } + + if (mbedtls_mpi_cmp_mpi(&pub->N, &prv->N) != 0 || + mbedtls_mpi_cmp_mpi(&pub->E, &prv->E) != 0) { + return MBEDTLS_ERR_RSA_KEY_CHECK_FAILED; + } + + return 0; +} + +/* + * Do an RSA public key operation + */ +int mbedtls_rsa_public(mbedtls_rsa_context *ctx, + const unsigned char *input, + unsigned char *output) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t olen; + mbedtls_mpi T; + + if (rsa_check_context(ctx, 0 /* public */, 0 /* no blinding */)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + mbedtls_mpi_init(&T); + +#if defined(MBEDTLS_THREADING_C) + if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) { + return ret; + } +#endif + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&T, input, ctx->len)); + + if (mbedtls_mpi_cmp_mpi(&T, &ctx->N) >= 0) { + ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; + goto cleanup; + } + + olen = ctx->len; + MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&T, &T, &ctx->E, &ctx->N, &ctx->RN)); + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&T, output, olen)); + +cleanup: +#if defined(MBEDTLS_THREADING_C) + if (mbedtls_mutex_unlock(&ctx->mutex) != 0) { + return MBEDTLS_ERR_THREADING_MUTEX_ERROR; + } +#endif + + mbedtls_mpi_free(&T); + + if (ret != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_PUBLIC_FAILED, ret); + } + + return 0; +} + +/* + * Generate or update blinding values, see section 10 of: + * KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA, + * DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer + * Berlin Heidelberg, 1996. p. 104-113. + */ +static int rsa_prepare_blinding(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), void *p_rng) +{ + int ret, count = 0; + mbedtls_mpi R; + + mbedtls_mpi_init(&R); + + if (ctx->Vf.p != NULL) { + /* We already have blinding values, just update them by squaring */ + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vi, &ctx->Vi)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vf, &ctx->Vf, &ctx->Vf)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vf, &ctx->Vf, &ctx->N)); + + goto cleanup; + } + + /* Unblinding value: Vf = random number, invertible mod N */ + do { + if (count++ > 10) { + ret = MBEDTLS_ERR_RSA_RNG_FAILED; + goto cleanup; + } + + MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&ctx->Vf, ctx->len - 1, f_rng, p_rng)); + + /* Compute Vf^-1 as R * (R Vf)^-1 to avoid leaks from inv_mod. */ + MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, ctx->len - 1, f_rng, p_rng)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vf, &R)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N)); + + /* At this point, Vi is invertible mod N if and only if both Vf and R + * are invertible mod N. If one of them isn't, we don't need to know + * which one, we just loop and choose new values for both of them. + * (Each iteration succeeds with overwhelming probability.) */ + ret = mbedtls_mpi_inv_mod(&ctx->Vi, &ctx->Vi, &ctx->N); + if (ret != 0 && ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE) { + goto cleanup; + } + + } while (ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE); + + /* Finish the computation of Vf^-1 = R * (R Vf)^-1 */ + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&ctx->Vi, &ctx->Vi, &R)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&ctx->Vi, &ctx->Vi, &ctx->N)); + + /* Blinding value: Vi = Vf^(-e) mod N + * (Vi already contains Vf^-1 at this point) */ + MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN)); + + +cleanup: + mbedtls_mpi_free(&R); + + return ret; +} + +/* + * Unblind + * T = T * Vf mod N + */ +static int rsa_unblind(mbedtls_mpi *T, mbedtls_mpi *Vf, const mbedtls_mpi *N) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + const mbedtls_mpi_uint mm = mbedtls_mpi_core_montmul_init(N->p); + const size_t nlimbs = N->n; + const size_t tlimbs = mbedtls_mpi_core_montmul_working_limbs(nlimbs); + mbedtls_mpi RR, M_T; + + mbedtls_mpi_init(&RR); + mbedtls_mpi_init(&M_T); + + MBEDTLS_MPI_CHK(mbedtls_mpi_core_get_mont_r2_unsafe(&RR, N)); + MBEDTLS_MPI_CHK(mbedtls_mpi_grow(&M_T, tlimbs)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_grow(T, nlimbs)); + MBEDTLS_MPI_CHK(mbedtls_mpi_grow(Vf, nlimbs)); + + /* T = T * Vf mod N + * Reminder: montmul(A, B, N) = A * B * R^-1 mod N + * Usually both operands are multiplied by R mod N beforehand (by calling + * `to_mont_rep()` on them), yielding a result that's also * R mod N (aka + * "in the Montgomery domain"). Here we only multiply one operand by R mod + * N, so the result is directly what we want - no need to call + * `from_mont_rep()` on it. */ + mbedtls_mpi_core_to_mont_rep(T->p, T->p, N->p, nlimbs, mm, RR.p, M_T.p); + mbedtls_mpi_core_montmul(T->p, T->p, Vf->p, nlimbs, N->p, nlimbs, mm, M_T.p); + +cleanup: + + mbedtls_mpi_free(&RR); + mbedtls_mpi_free(&M_T); + + return ret; +} + +/* + * Exponent blinding supposed to prevent side-channel attacks using multiple + * traces of measurements to recover the RSA key. The more collisions are there, + * the more bits of the key can be recovered. See [3]. + * + * Collecting n collisions with m bit long blinding value requires 2^(m-m/n) + * observations on average. + * + * For example with 28 byte blinding to achieve 2 collisions the adversary has + * to make 2^112 observations on average. + * + * (With the currently (as of 2017 April) known best algorithms breaking 2048 + * bit RSA requires approximately as much time as trying out 2^112 random keys. + * Thus in this sense with 28 byte blinding the security is not reduced by + * side-channel attacks like the one in [3]) + * + * This countermeasure does not help if the key recovery is possible with a + * single trace. + */ +#define RSA_EXPONENT_BLINDING 28 + +/* + * Do an RSA private key operation + */ +int mbedtls_rsa_private(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + const unsigned char *input, + unsigned char *output) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t olen; + + /* Temporary holding the result */ + mbedtls_mpi T; + + /* Temporaries holding P-1, Q-1 and the + * exponent blinding factor, respectively. */ + mbedtls_mpi P1, Q1, R; + +#if !defined(MBEDTLS_RSA_NO_CRT) + /* Temporaries holding the results mod p resp. mod q. */ + mbedtls_mpi TP, TQ; + + /* Temporaries holding the blinded exponents for + * the mod p resp. mod q computation (if used). */ + mbedtls_mpi DP_blind, DQ_blind; +#else + /* Temporary holding the blinded exponent (if used). */ + mbedtls_mpi D_blind; +#endif /* MBEDTLS_RSA_NO_CRT */ + + /* Temporaries holding the initial input and the double + * checked result; should be the same in the end. */ + mbedtls_mpi input_blinded, check_result_blinded; + + if (f_rng == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (rsa_check_context(ctx, 1 /* private key checks */, + 1 /* blinding on */) != 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + +#if defined(MBEDTLS_THREADING_C) + if ((ret = mbedtls_mutex_lock(&ctx->mutex)) != 0) { + return ret; + } +#endif + + /* MPI Initialization */ + mbedtls_mpi_init(&T); + + mbedtls_mpi_init(&P1); + mbedtls_mpi_init(&Q1); + mbedtls_mpi_init(&R); + +#if defined(MBEDTLS_RSA_NO_CRT) + mbedtls_mpi_init(&D_blind); +#else + mbedtls_mpi_init(&DP_blind); + mbedtls_mpi_init(&DQ_blind); +#endif + +#if !defined(MBEDTLS_RSA_NO_CRT) + mbedtls_mpi_init(&TP); mbedtls_mpi_init(&TQ); +#endif + + mbedtls_mpi_init(&input_blinded); + mbedtls_mpi_init(&check_result_blinded); + + /* End of MPI initialization */ + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&T, input, ctx->len)); + if (mbedtls_mpi_cmp_mpi(&T, &ctx->N) >= 0) { + ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; + goto cleanup; + } + + /* + * Blinding + * T = T * Vi mod N + */ + MBEDTLS_MPI_CHK(rsa_prepare_blinding(ctx, f_rng, p_rng)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&T, &T, &ctx->Vi)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&T, &T, &ctx->N)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&input_blinded, &T)); + + /* + * Exponent blinding + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&P1, &ctx->P, 1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&Q1, &ctx->Q, 1)); + +#if defined(MBEDTLS_RSA_NO_CRT) + /* + * D_blind = ( P - 1 ) * ( Q - 1 ) * R + D + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING, + f_rng, p_rng)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&D_blind, &P1, &Q1)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&D_blind, &D_blind, &R)); + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&D_blind, &D_blind, &ctx->D)); +#else + /* + * DP_blind = ( P - 1 ) * R + DP + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING, + f_rng, p_rng)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&DP_blind, &P1, &R)); + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&DP_blind, &DP_blind, + &ctx->DP)); + + /* + * DQ_blind = ( Q - 1 ) * R + DQ + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_fill_random(&R, RSA_EXPONENT_BLINDING, + f_rng, p_rng)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&DQ_blind, &Q1, &R)); + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&DQ_blind, &DQ_blind, + &ctx->DQ)); +#endif /* MBEDTLS_RSA_NO_CRT */ + +#if defined(MBEDTLS_RSA_NO_CRT) + MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&T, &T, &D_blind, &ctx->N, &ctx->RN)); +#else + /* + * Faster decryption using the CRT + * + * TP = input ^ dP mod P + * TQ = input ^ dQ mod Q + */ + + MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&TP, &T, &DP_blind, &ctx->P, &ctx->RP)); + MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&TQ, &T, &DQ_blind, &ctx->Q, &ctx->RQ)); + + /* + * T = (TP - TQ) * (Q^-1 mod P) mod P + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_sub_mpi(&T, &TP, &TQ)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&TP, &T, &ctx->QP)); + MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&T, &TP, &ctx->P)); + + /* + * T = TQ + T * Q + */ + MBEDTLS_MPI_CHK(mbedtls_mpi_mul_mpi(&TP, &T, &ctx->Q)); + MBEDTLS_MPI_CHK(mbedtls_mpi_add_mpi(&T, &TQ, &TP)); +#endif /* MBEDTLS_RSA_NO_CRT */ + + /* Verify the result to prevent glitching attacks. */ + MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&check_result_blinded, &T, &ctx->E, + &ctx->N, &ctx->RN)); + if (mbedtls_mpi_cmp_mpi(&check_result_blinded, &input_blinded) != 0) { + ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; + goto cleanup; + } + + /* + * Unblind + * T = T * Vf mod N + */ + MBEDTLS_MPI_CHK(rsa_unblind(&T, &ctx->Vf, &ctx->N)); + + olen = ctx->len; + MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&T, output, olen)); + +cleanup: +#if defined(MBEDTLS_THREADING_C) + if (mbedtls_mutex_unlock(&ctx->mutex) != 0) { + return MBEDTLS_ERR_THREADING_MUTEX_ERROR; + } +#endif + + mbedtls_mpi_free(&P1); + mbedtls_mpi_free(&Q1); + mbedtls_mpi_free(&R); + +#if defined(MBEDTLS_RSA_NO_CRT) + mbedtls_mpi_free(&D_blind); +#else + mbedtls_mpi_free(&DP_blind); + mbedtls_mpi_free(&DQ_blind); +#endif + + mbedtls_mpi_free(&T); + +#if !defined(MBEDTLS_RSA_NO_CRT) + mbedtls_mpi_free(&TP); mbedtls_mpi_free(&TQ); +#endif + + mbedtls_mpi_free(&check_result_blinded); + mbedtls_mpi_free(&input_blinded); + + if (ret != 0 && ret >= -0x007f) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_PRIVATE_FAILED, ret); + } + + return ret; +} + +#if defined(MBEDTLS_PKCS1_V21) +/** + * Generate and apply the MGF1 operation (from PKCS#1 v2.1) to a buffer. + * + * \param dst buffer to mask + * \param dlen length of destination buffer + * \param src source of the mask generation + * \param slen length of the source buffer + * \param md_alg message digest to use + */ +static int mgf_mask(unsigned char *dst, size_t dlen, unsigned char *src, + size_t slen, mbedtls_md_type_t md_alg) +{ + unsigned char counter[4]; + unsigned char *p; + unsigned int hlen; + size_t i, use_len; + unsigned char mask[MBEDTLS_MD_MAX_SIZE]; + int ret = 0; + const mbedtls_md_info_t *md_info; + mbedtls_md_context_t md_ctx; + + mbedtls_md_init(&md_ctx); + md_info = mbedtls_md_info_from_type(md_alg); + if (md_info == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + mbedtls_md_init(&md_ctx); + if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0) { + goto exit; + } + + hlen = mbedtls_md_get_size(md_info); + + memset(mask, 0, sizeof(mask)); + memset(counter, 0, 4); + + /* Generate and apply dbMask */ + p = dst; + + while (dlen > 0) { + use_len = hlen; + if (dlen < hlen) { + use_len = dlen; + } + + if ((ret = mbedtls_md_starts(&md_ctx)) != 0) { + goto exit; + } + if ((ret = mbedtls_md_update(&md_ctx, src, slen)) != 0) { + goto exit; + } + if ((ret = mbedtls_md_update(&md_ctx, counter, 4)) != 0) { + goto exit; + } + if ((ret = mbedtls_md_finish(&md_ctx, mask)) != 0) { + goto exit; + } + + for (i = 0; i < use_len; ++i) { + *p++ ^= mask[i]; + } + + counter[3]++; + + dlen -= use_len; + } + +exit: + mbedtls_platform_zeroize(mask, sizeof(mask)); + mbedtls_md_free(&md_ctx); + + return ret; +} + +/** + * Generate Hash(M') as in RFC 8017 page 43 points 5 and 6. + * + * \param hash the input hash + * \param hlen length of the input hash + * \param salt the input salt + * \param slen length of the input salt + * \param out the output buffer - must be large enough for \p md_alg + * \param md_alg message digest to use + */ +static int hash_mprime(const unsigned char *hash, size_t hlen, + const unsigned char *salt, size_t slen, + unsigned char *out, mbedtls_md_type_t md_alg) +{ + const unsigned char zeros[8] = { 0, 0, 0, 0, 0, 0, 0, 0 }; + + mbedtls_md_context_t md_ctx; + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(md_alg); + if (md_info == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + mbedtls_md_init(&md_ctx); + if ((ret = mbedtls_md_setup(&md_ctx, md_info, 0)) != 0) { + goto exit; + } + if ((ret = mbedtls_md_starts(&md_ctx)) != 0) { + goto exit; + } + if ((ret = mbedtls_md_update(&md_ctx, zeros, sizeof(zeros))) != 0) { + goto exit; + } + if ((ret = mbedtls_md_update(&md_ctx, hash, hlen)) != 0) { + goto exit; + } + if ((ret = mbedtls_md_update(&md_ctx, salt, slen)) != 0) { + goto exit; + } + if ((ret = mbedtls_md_finish(&md_ctx, out)) != 0) { + goto exit; + } + +exit: + mbedtls_md_free(&md_ctx); + + return ret; +} + +/** + * Compute a hash. + * + * \param md_alg algorithm to use + * \param input input message to hash + * \param ilen input length + * \param output the output buffer - must be large enough for \p md_alg + */ +static int compute_hash(mbedtls_md_type_t md_alg, + const unsigned char *input, size_t ilen, + unsigned char *output) +{ + const mbedtls_md_info_t *md_info; + + md_info = mbedtls_md_info_from_type(md_alg); + if (md_info == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + return mbedtls_md(md_info, input, ilen, output); +} +#endif /* MBEDTLS_PKCS1_V21 */ + +#if defined(MBEDTLS_PKCS1_V21) +/* + * Implementation of the PKCS#1 v2.1 RSAES-OAEP-ENCRYPT function + */ +int mbedtls_rsa_rsaes_oaep_encrypt(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + const unsigned char *label, size_t label_len, + size_t ilen, + const unsigned char *input, + unsigned char *output) +{ + size_t olen; + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *p = output; + unsigned int hlen; + + if (f_rng == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + hlen = mbedtls_md_get_size_from_type((mbedtls_md_type_t) ctx->hash_id); + if (hlen == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + olen = ctx->len; + + /* first comparison checks for overflow */ + if (ilen + 2 * hlen + 2 < ilen || olen < ilen + 2 * hlen + 2) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + memset(output, 0, olen); + + *p++ = 0; + + /* Generate a random octet string seed */ + if ((ret = f_rng(p_rng, p, hlen)) != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret); + } + + p += hlen; + + /* Construct DB */ + ret = compute_hash((mbedtls_md_type_t) ctx->hash_id, label, label_len, p); + if (ret != 0) { + return ret; + } + p += hlen; + p += olen - 2 * hlen - 2 - ilen; + *p++ = 1; + if (ilen != 0) { + memcpy(p, input, ilen); + } + + /* maskedDB: Apply dbMask to DB */ + if ((ret = mgf_mask(output + hlen + 1, olen - hlen - 1, output + 1, hlen, + (mbedtls_md_type_t) ctx->hash_id)) != 0) { + return ret; + } + + /* maskedSeed: Apply seedMask to seed */ + if ((ret = mgf_mask(output + 1, hlen, output + hlen + 1, olen - hlen - 1, + (mbedtls_md_type_t) ctx->hash_id)) != 0) { + return ret; + } + + return mbedtls_rsa_public(ctx, output, output); +} +#endif /* MBEDTLS_PKCS1_V21 */ + +#if defined(MBEDTLS_PKCS1_V15) +/* + * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-ENCRYPT function + */ +int mbedtls_rsa_rsaes_pkcs1_v15_encrypt(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, size_t ilen, + const unsigned char *input, + unsigned char *output) +{ + size_t nb_pad, olen; + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *p = output; + + olen = ctx->len; + + /* first comparison checks for overflow */ + if (ilen + 11 < ilen || olen < ilen + 11) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + nb_pad = olen - 3 - ilen; + + *p++ = 0; + + if (f_rng == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + *p++ = MBEDTLS_RSA_CRYPT; + + while (nb_pad-- > 0) { + int rng_dl = 100; + + do { + ret = f_rng(p_rng, p, 1); + } while (*p == 0 && --rng_dl && ret == 0); + + /* Check if RNG failed to generate data */ + if (rng_dl == 0 || ret != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret); + } + + p++; + } + + *p++ = 0; + if (ilen != 0) { + memcpy(p, input, ilen); + } + + return mbedtls_rsa_public(ctx, output, output); +} +#endif /* MBEDTLS_PKCS1_V15 */ + +/* + * Add the message padding, then do an RSA operation + */ +int mbedtls_rsa_pkcs1_encrypt(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + size_t ilen, + const unsigned char *input, + unsigned char *output) +{ + switch (ctx->padding) { +#if defined(MBEDTLS_PKCS1_V15) + case MBEDTLS_RSA_PKCS_V15: + return mbedtls_rsa_rsaes_pkcs1_v15_encrypt(ctx, f_rng, p_rng, + ilen, input, output); +#endif + +#if defined(MBEDTLS_PKCS1_V21) + case MBEDTLS_RSA_PKCS_V21: + return mbedtls_rsa_rsaes_oaep_encrypt(ctx, f_rng, p_rng, NULL, 0, + ilen, input, output); +#endif + + default: + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } +} + +#if defined(MBEDTLS_PKCS1_V21) +/* + * Implementation of the PKCS#1 v2.1 RSAES-OAEP-DECRYPT function + */ +int mbedtls_rsa_rsaes_oaep_decrypt(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + const unsigned char *label, size_t label_len, + size_t *olen, + const unsigned char *input, + unsigned char *output, + size_t output_max_len) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t ilen, i, pad_len; + unsigned char *p; + mbedtls_ct_condition_t bad, in_padding; + unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; + unsigned char lhash[MBEDTLS_MD_MAX_SIZE]; + unsigned int hlen; + + /* + * Parameters sanity checks + */ + if (ctx->padding != MBEDTLS_RSA_PKCS_V21) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + ilen = ctx->len; + + if (ilen < 16 || ilen > sizeof(buf)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + hlen = mbedtls_md_get_size_from_type((mbedtls_md_type_t) ctx->hash_id); + if (hlen == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + // checking for integer underflow + if (2 * hlen + 2 > ilen) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* + * RSA operation + */ + ret = mbedtls_rsa_private(ctx, f_rng, p_rng, input, buf); + + if (ret != 0) { + goto cleanup; + } + + /* + * Unmask data and generate lHash + */ + /* seed: Apply seedMask to maskedSeed */ + if ((ret = mgf_mask(buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1, + (mbedtls_md_type_t) ctx->hash_id)) != 0 || + /* DB: Apply dbMask to maskedDB */ + (ret = mgf_mask(buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen, + (mbedtls_md_type_t) ctx->hash_id)) != 0) { + goto cleanup; + } + + /* Generate lHash */ + ret = compute_hash((mbedtls_md_type_t) ctx->hash_id, + label, label_len, lhash); + if (ret != 0) { + goto cleanup; + } + + /* + * Check contents, in "constant-time" + */ + p = buf; + + bad = mbedtls_ct_bool(*p++); /* First byte must be 0 */ + + p += hlen; /* Skip seed */ + + /* Check lHash */ + bad = mbedtls_ct_bool_or(bad, mbedtls_ct_bool(mbedtls_ct_memcmp(lhash, p, hlen))); + p += hlen; + + /* Get zero-padding len, but always read till end of buffer + * (minus one, for the 01 byte) */ + pad_len = 0; + in_padding = MBEDTLS_CT_TRUE; + for (i = 0; i < ilen - 2 * hlen - 2; i++) { + in_padding = mbedtls_ct_bool_and(in_padding, mbedtls_ct_uint_eq(p[i], 0)); + pad_len += mbedtls_ct_uint_if_else_0(in_padding, 1); + } + + p += pad_len; + bad = mbedtls_ct_bool_or(bad, mbedtls_ct_uint_ne(*p++, 0x01)); + + /* + * The only information "leaked" is whether the padding was correct or not + * (eg, no data is copied if it was not correct). This meets the + * recommendations in PKCS#1 v2.2: an opponent cannot distinguish between + * the different error conditions. + */ + if (bad != MBEDTLS_CT_FALSE) { + ret = MBEDTLS_ERR_RSA_INVALID_PADDING; + goto cleanup; + } + + if (ilen - ((size_t) (p - buf)) > output_max_len) { + ret = MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE; + goto cleanup; + } + + *olen = ilen - ((size_t) (p - buf)); + if (*olen != 0) { + memcpy(output, p, *olen); + } + ret = 0; + +cleanup: + mbedtls_platform_zeroize(buf, sizeof(buf)); + mbedtls_platform_zeroize(lhash, sizeof(lhash)); + + return ret; +} +#endif /* MBEDTLS_PKCS1_V21 */ + +#if defined(MBEDTLS_PKCS1_V15) +/* + * Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-DECRYPT function + */ +int mbedtls_rsa_rsaes_pkcs1_v15_decrypt(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + size_t *olen, + const unsigned char *input, + unsigned char *output, + size_t output_max_len) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t ilen; + unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; + + ilen = ctx->len; + + if (ctx->padding != MBEDTLS_RSA_PKCS_V15) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (ilen < 16 || ilen > sizeof(buf)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + ret = mbedtls_rsa_private(ctx, f_rng, p_rng, input, buf); + + if (ret != 0) { + goto cleanup; + } + + ret = mbedtls_ct_rsaes_pkcs1_v15_unpadding(buf, ilen, + output, output_max_len, olen); + +cleanup: + mbedtls_platform_zeroize(buf, sizeof(buf)); + + return ret; +} +#endif /* MBEDTLS_PKCS1_V15 */ + +/* + * Do an RSA operation, then remove the message padding + */ +int mbedtls_rsa_pkcs1_decrypt(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + size_t *olen, + const unsigned char *input, + unsigned char *output, + size_t output_max_len) +{ + switch (ctx->padding) { +#if defined(MBEDTLS_PKCS1_V15) + case MBEDTLS_RSA_PKCS_V15: + return mbedtls_rsa_rsaes_pkcs1_v15_decrypt(ctx, f_rng, p_rng, olen, + input, output, output_max_len); +#endif + +#if defined(MBEDTLS_PKCS1_V21) + case MBEDTLS_RSA_PKCS_V21: + return mbedtls_rsa_rsaes_oaep_decrypt(ctx, f_rng, p_rng, NULL, 0, + olen, input, output, + output_max_len); +#endif + + default: + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } +} + +#if defined(MBEDTLS_PKCS1_V21) +static int rsa_rsassa_pss_sign_no_mode_check(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + int saltlen, + unsigned char *sig) +{ + size_t olen; + unsigned char *p = sig; + unsigned char *salt = NULL; + size_t slen, min_slen, hlen, offset = 0; + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t msb; + mbedtls_md_type_t hash_id; + + if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (f_rng == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + olen = ctx->len; + + if (md_alg != MBEDTLS_MD_NONE) { + /* Gather length of hash to sign */ + size_t exp_hashlen = mbedtls_md_get_size_from_type(md_alg); + if (exp_hashlen == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (hashlen != exp_hashlen) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + } + + hash_id = (mbedtls_md_type_t) ctx->hash_id; + if (hash_id == MBEDTLS_MD_NONE) { + hash_id = md_alg; + } + hlen = mbedtls_md_get_size_from_type(hash_id); + if (hlen == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (saltlen == MBEDTLS_RSA_SALT_LEN_ANY) { + /* Calculate the largest possible salt length, up to the hash size. + * Normally this is the hash length, which is the maximum salt length + * according to FIPS 185-4 §5.5 (e) and common practice. If there is not + * enough room, use the maximum salt length that fits. The constraint is + * that the hash length plus the salt length plus 2 bytes must be at most + * the key length. This complies with FIPS 186-4 §5.5 (e) and RFC 8017 + * (PKCS#1 v2.2) §9.1.1 step 3. */ + min_slen = hlen - 2; + if (olen < hlen + min_slen + 2) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } else if (olen >= hlen + hlen + 2) { + slen = hlen; + } else { + slen = olen - hlen - 2; + } + } else if ((saltlen < 0) || (saltlen + hlen + 2 > olen)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } else { + slen = (size_t) saltlen; + } + + memset(sig, 0, olen); + + /* Note: EMSA-PSS encoding is over the length of N - 1 bits */ + msb = mbedtls_mpi_bitlen(&ctx->N) - 1; + p += olen - hlen - slen - 2; + *p++ = 0x01; + + /* Generate salt of length slen in place in the encoded message */ + salt = p; + if ((ret = f_rng(p_rng, salt, slen)) != 0) { + return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_RSA_RNG_FAILED, ret); + } + + p += slen; + + /* Generate H = Hash( M' ) */ + ret = hash_mprime(hash, hashlen, salt, slen, p, hash_id); + if (ret != 0) { + return ret; + } + + /* Compensate for boundary condition when applying mask */ + if (msb % 8 == 0) { + offset = 1; + } + + /* maskedDB: Apply dbMask to DB */ + ret = mgf_mask(sig + offset, olen - hlen - 1 - offset, p, hlen, hash_id); + if (ret != 0) { + return ret; + } + + msb = mbedtls_mpi_bitlen(&ctx->N) - 1; + sig[0] &= 0xFF >> (olen * 8 - msb); + + p += hlen; + *p++ = 0xBC; + + return mbedtls_rsa_private(ctx, f_rng, p_rng, sig, sig); +} + +static int rsa_rsassa_pss_sign(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + int saltlen, + unsigned char *sig) +{ + if (ctx->padding != MBEDTLS_RSA_PKCS_V21) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + if ((ctx->hash_id == MBEDTLS_MD_NONE) && (md_alg == MBEDTLS_MD_NONE)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + return rsa_rsassa_pss_sign_no_mode_check(ctx, f_rng, p_rng, md_alg, hashlen, hash, saltlen, + sig); +} + +int mbedtls_rsa_rsassa_pss_sign_no_mode_check(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + unsigned char *sig) +{ + return rsa_rsassa_pss_sign_no_mode_check(ctx, f_rng, p_rng, md_alg, + hashlen, hash, MBEDTLS_RSA_SALT_LEN_ANY, sig); +} + +/* + * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function with + * the option to pass in the salt length. + */ +int mbedtls_rsa_rsassa_pss_sign_ext(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + int saltlen, + unsigned char *sig) +{ + return rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg, + hashlen, hash, saltlen, sig); +} + +/* + * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function + */ +int mbedtls_rsa_rsassa_pss_sign(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + unsigned char *sig) +{ + return rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg, + hashlen, hash, MBEDTLS_RSA_SALT_LEN_ANY, sig); +} +#endif /* MBEDTLS_PKCS1_V21 */ + +#if defined(MBEDTLS_PKCS1_V15) +/* + * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-V1_5-SIGN function + */ + +/* Construct a PKCS v1.5 encoding of a hashed message + * + * This is used both for signature generation and verification. + * + * Parameters: + * - md_alg: Identifies the hash algorithm used to generate the given hash; + * MBEDTLS_MD_NONE if raw data is signed. + * - hashlen: Length of hash. Must match md_alg if that's not NONE. + * - hash: Buffer containing the hashed message or the raw data. + * - dst_len: Length of the encoded message. + * - dst: Buffer to hold the encoded message. + * + * Assumptions: + * - hash has size hashlen. + * - dst points to a buffer of size at least dst_len. + * + */ +static int rsa_rsassa_pkcs1_v15_encode(mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + size_t dst_len, + unsigned char *dst) +{ + size_t oid_size = 0; + size_t nb_pad = dst_len; + unsigned char *p = dst; + const char *oid = NULL; + + /* Are we signing hashed or raw data? */ + if (md_alg != MBEDTLS_MD_NONE) { + unsigned char md_size = mbedtls_md_get_size_from_type(md_alg); + if (md_size == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (mbedtls_oid_get_oid_by_md(md_alg, &oid, &oid_size) != 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (hashlen != md_size) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* Double-check that 8 + hashlen + oid_size can be used as a + * 1-byte ASN.1 length encoding and that there's no overflow. */ + if (8 + hashlen + oid_size >= 0x80 || + 10 + hashlen < hashlen || + 10 + hashlen + oid_size < 10 + hashlen) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* + * Static bounds check: + * - Need 10 bytes for five tag-length pairs. + * (Insist on 1-byte length encodings to protect against variants of + * Bleichenbacher's forgery attack against lax PKCS#1v1.5 verification) + * - Need hashlen bytes for hash + * - Need oid_size bytes for hash alg OID. + */ + if (nb_pad < 10 + hashlen + oid_size) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + nb_pad -= 10 + hashlen + oid_size; + } else { + if (nb_pad < hashlen) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + nb_pad -= hashlen; + } + + /* Need space for signature header and padding delimiter (3 bytes), + * and 8 bytes for the minimal padding */ + if (nb_pad < 3 + 8) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + nb_pad -= 3; + + /* Now nb_pad is the amount of memory to be filled + * with padding, and at least 8 bytes long. */ + + /* Write signature header and padding */ + *p++ = 0; + *p++ = MBEDTLS_RSA_SIGN; + memset(p, 0xFF, nb_pad); + p += nb_pad; + *p++ = 0; + + /* Are we signing raw data? */ + if (md_alg == MBEDTLS_MD_NONE) { + memcpy(p, hash, hashlen); + return 0; + } + + /* Signing hashed data, add corresponding ASN.1 structure + * + * DigestInfo ::= SEQUENCE { + * digestAlgorithm DigestAlgorithmIdentifier, + * digest Digest } + * DigestAlgorithmIdentifier ::= AlgorithmIdentifier + * Digest ::= OCTET STRING + * + * Schematic: + * TAG-SEQ + LEN [ TAG-SEQ + LEN [ TAG-OID + LEN [ OID ] + * TAG-NULL + LEN [ NULL ] ] + * TAG-OCTET + LEN [ HASH ] ] + */ + *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED; + *p++ = (unsigned char) (0x08 + oid_size + hashlen); + *p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED; + *p++ = (unsigned char) (0x04 + oid_size); + *p++ = MBEDTLS_ASN1_OID; + *p++ = (unsigned char) oid_size; + memcpy(p, oid, oid_size); + p += oid_size; + *p++ = MBEDTLS_ASN1_NULL; + *p++ = 0x00; + *p++ = MBEDTLS_ASN1_OCTET_STRING; + *p++ = (unsigned char) hashlen; + memcpy(p, hash, hashlen); + p += hashlen; + + /* Just a sanity-check, should be automatic + * after the initial bounds check. */ + if (p != dst + dst_len) { + mbedtls_platform_zeroize(dst, dst_len); + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + return 0; +} + +/* + * Do an RSA operation to sign the message digest + */ +int mbedtls_rsa_rsassa_pkcs1_v15_sign(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + unsigned char *sig) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + unsigned char *sig_try = NULL, *verif = NULL; + + if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (ctx->padding != MBEDTLS_RSA_PKCS_V15) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* + * Prepare PKCS1-v1.5 encoding (padding and hash identifier) + */ + + if ((ret = rsa_rsassa_pkcs1_v15_encode(md_alg, hashlen, hash, + ctx->len, sig)) != 0) { + return ret; + } + + /* Private key operation + * + * In order to prevent Lenstra's attack, make the signature in a + * temporary buffer and check it before returning it. + */ + + sig_try = mbedtls_calloc(1, ctx->len); + if (sig_try == NULL) { + return MBEDTLS_ERR_MPI_ALLOC_FAILED; + } + + verif = mbedtls_calloc(1, ctx->len); + if (verif == NULL) { + mbedtls_free(sig_try); + return MBEDTLS_ERR_MPI_ALLOC_FAILED; + } + + MBEDTLS_MPI_CHK(mbedtls_rsa_private(ctx, f_rng, p_rng, sig, sig_try)); + MBEDTLS_MPI_CHK(mbedtls_rsa_public(ctx, sig_try, verif)); + + if (mbedtls_ct_memcmp(verif, sig, ctx->len) != 0) { + ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED; + goto cleanup; + } + + memcpy(sig, sig_try, ctx->len); + +cleanup: + mbedtls_zeroize_and_free(sig_try, ctx->len); + mbedtls_zeroize_and_free(verif, ctx->len); + + if (ret != 0) { + memset(sig, '!', ctx->len); + } + return ret; +} +#endif /* MBEDTLS_PKCS1_V15 */ + +/* + * Do an RSA operation to sign the message digest + */ +int mbedtls_rsa_pkcs1_sign(mbedtls_rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + unsigned char *sig) +{ + if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + switch (ctx->padding) { +#if defined(MBEDTLS_PKCS1_V15) + case MBEDTLS_RSA_PKCS_V15: + return mbedtls_rsa_rsassa_pkcs1_v15_sign(ctx, f_rng, p_rng, + md_alg, hashlen, hash, sig); +#endif + +#if defined(MBEDTLS_PKCS1_V21) + case MBEDTLS_RSA_PKCS_V21: + return mbedtls_rsa_rsassa_pss_sign(ctx, f_rng, p_rng, md_alg, + hashlen, hash, sig); +#endif + + default: + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } +} + +#if defined(MBEDTLS_PKCS1_V21) +/* + * Implementation of the PKCS#1 v2.1 RSASSA-PSS-VERIFY function + */ +int mbedtls_rsa_rsassa_pss_verify_ext(mbedtls_rsa_context *ctx, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + mbedtls_md_type_t mgf1_hash_id, + int expected_salt_len, + const unsigned char *sig) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t siglen; + unsigned char *p; + unsigned char *hash_start; + unsigned char result[MBEDTLS_MD_MAX_SIZE]; + unsigned int hlen; + size_t observed_salt_len, msb; + unsigned char buf[MBEDTLS_MPI_MAX_SIZE] = { 0 }; + + if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + siglen = ctx->len; + + if (siglen < 16 || siglen > sizeof(buf)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + ret = mbedtls_rsa_public(ctx, sig, buf); + + if (ret != 0) { + return ret; + } + + p = buf; + + if (buf[siglen - 1] != 0xBC) { + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } + + if (md_alg != MBEDTLS_MD_NONE) { + /* Gather length of hash to sign */ + size_t exp_hashlen = mbedtls_md_get_size_from_type(md_alg); + if (exp_hashlen == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + if (hashlen != exp_hashlen) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + } + + hlen = mbedtls_md_get_size_from_type(mgf1_hash_id); + if (hlen == 0) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* + * Note: EMSA-PSS verification is over the length of N - 1 bits + */ + msb = mbedtls_mpi_bitlen(&ctx->N) - 1; + + if (buf[0] >> (8 - siglen * 8 + msb)) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + /* Compensate for boundary condition when applying mask */ + if (msb % 8 == 0) { + p++; + siglen -= 1; + } + + if (siglen < hlen + 2) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + hash_start = p + siglen - hlen - 1; + + ret = mgf_mask(p, siglen - hlen - 1, hash_start, hlen, mgf1_hash_id); + if (ret != 0) { + return ret; + } + + buf[0] &= 0xFF >> (siglen * 8 - msb); + + while (p < hash_start - 1 && *p == 0) { + p++; + } + + if (*p++ != 0x01) { + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } + + observed_salt_len = (size_t) (hash_start - p); + + if (expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY && + observed_salt_len != (size_t) expected_salt_len) { + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } + + /* + * Generate H = Hash( M' ) + */ + ret = hash_mprime(hash, hashlen, p, observed_salt_len, + result, mgf1_hash_id); + if (ret != 0) { + return ret; + } + + if (memcmp(hash_start, result, hlen) != 0) { + return MBEDTLS_ERR_RSA_VERIFY_FAILED; + } + + return 0; +} + +/* + * Simplified PKCS#1 v2.1 RSASSA-PSS-VERIFY function + */ +int mbedtls_rsa_rsassa_pss_verify(mbedtls_rsa_context *ctx, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + const unsigned char *sig) +{ + mbedtls_md_type_t mgf1_hash_id; + if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + mgf1_hash_id = (ctx->hash_id != MBEDTLS_MD_NONE) + ? (mbedtls_md_type_t) ctx->hash_id + : md_alg; + + return mbedtls_rsa_rsassa_pss_verify_ext(ctx, + md_alg, hashlen, hash, + mgf1_hash_id, + MBEDTLS_RSA_SALT_LEN_ANY, + sig); + +} +#endif /* MBEDTLS_PKCS1_V21 */ + +#if defined(MBEDTLS_PKCS1_V15) +/* + * Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-v1_5-VERIFY function + */ +int mbedtls_rsa_rsassa_pkcs1_v15_verify(mbedtls_rsa_context *ctx, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + const unsigned char *sig) +{ + int ret = 0; + size_t sig_len; + unsigned char *encoded = NULL, *encoded_expected = NULL; + + if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + sig_len = ctx->len; + + /* + * Prepare expected PKCS1 v1.5 encoding of hash. + */ + + if ((encoded = mbedtls_calloc(1, sig_len)) == NULL || + (encoded_expected = mbedtls_calloc(1, sig_len)) == NULL) { + ret = MBEDTLS_ERR_MPI_ALLOC_FAILED; + goto cleanup; + } + + if ((ret = rsa_rsassa_pkcs1_v15_encode(md_alg, hashlen, hash, sig_len, + encoded_expected)) != 0) { + goto cleanup; + } + + /* + * Apply RSA primitive to get what should be PKCS1 encoded hash. + */ + + ret = mbedtls_rsa_public(ctx, sig, encoded); + if (ret != 0) { + goto cleanup; + } + + /* + * Compare + */ + + if ((ret = mbedtls_ct_memcmp(encoded, encoded_expected, + sig_len)) != 0) { + ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; + goto cleanup; + } + +cleanup: + + if (encoded != NULL) { + mbedtls_zeroize_and_free(encoded, sig_len); + } + + if (encoded_expected != NULL) { + mbedtls_zeroize_and_free(encoded_expected, sig_len); + } + + return ret; +} +#endif /* MBEDTLS_PKCS1_V15 */ + +/* + * Do an RSA operation and check the message digest + */ +int mbedtls_rsa_pkcs1_verify(mbedtls_rsa_context *ctx, + mbedtls_md_type_t md_alg, + unsigned int hashlen, + const unsigned char *hash, + const unsigned char *sig) +{ + if ((md_alg != MBEDTLS_MD_NONE || hashlen != 0) && hash == NULL) { + return MBEDTLS_ERR_RSA_BAD_INPUT_DATA; + } + + switch (ctx->padding) { +#if defined(MBEDTLS_PKCS1_V15) + case MBEDTLS_RSA_PKCS_V15: + return mbedtls_rsa_rsassa_pkcs1_v15_verify(ctx, md_alg, + hashlen, hash, sig); +#endif + +#if defined(MBEDTLS_PKCS1_V21) + case MBEDTLS_RSA_PKCS_V21: + return mbedtls_rsa_rsassa_pss_verify(ctx, md_alg, + hashlen, hash, sig); +#endif + + default: + return MBEDTLS_ERR_RSA_INVALID_PADDING; + } +} + +/* + * Copy the components of an RSA key + */ +int mbedtls_rsa_copy(mbedtls_rsa_context *dst, const mbedtls_rsa_context *src) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + + dst->len = src->len; + + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->N, &src->N)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->E, &src->E)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->D, &src->D)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->P, &src->P)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Q, &src->Q)); + +#if !defined(MBEDTLS_RSA_NO_CRT) + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->DP, &src->DP)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->DQ, &src->DQ)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->QP, &src->QP)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RP, &src->RP)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RQ, &src->RQ)); +#endif + + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->RN, &src->RN)); + + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Vi, &src->Vi)); + MBEDTLS_MPI_CHK(mbedtls_mpi_copy(&dst->Vf, &src->Vf)); + + dst->padding = src->padding; + dst->hash_id = src->hash_id; + +cleanup: + if (ret != 0) { + mbedtls_rsa_free(dst); + } + + return ret; +} + +/* + * Free the components of an RSA key + */ +void mbedtls_rsa_free(mbedtls_rsa_context *ctx) +{ + if (ctx == NULL) { + return; + } + + mbedtls_mpi_free(&ctx->Vi); + mbedtls_mpi_free(&ctx->Vf); + mbedtls_mpi_free(&ctx->RN); + mbedtls_mpi_free(&ctx->D); + mbedtls_mpi_free(&ctx->Q); + mbedtls_mpi_free(&ctx->P); + mbedtls_mpi_free(&ctx->E); + mbedtls_mpi_free(&ctx->N); + +#if !defined(MBEDTLS_RSA_NO_CRT) + mbedtls_mpi_free(&ctx->RQ); + mbedtls_mpi_free(&ctx->RP); + mbedtls_mpi_free(&ctx->QP); + mbedtls_mpi_free(&ctx->DQ); + mbedtls_mpi_free(&ctx->DP); +#endif /* MBEDTLS_RSA_NO_CRT */ + +#if defined(MBEDTLS_THREADING_C) + /* Free the mutex, but only if it hasn't been freed already. */ + if (ctx->ver != 0) { + mbedtls_mutex_free(&ctx->mutex); + ctx->ver = 0; + } +#endif +} + +#endif /* !MBEDTLS_RSA_ALT */ + +#if defined(MBEDTLS_SELF_TEST) + + +/* + * Example RSA-1024 keypair, for test purposes + */ +#define KEY_LEN 128 + +#define RSA_N "9292758453063D803DD603D5E777D788" \ + "8ED1D5BF35786190FA2F23EBC0848AEA" \ + "DDA92CA6C3D80B32C4D109BE0F36D6AE" \ + "7130B9CED7ACDF54CFC7555AC14EEBAB" \ + "93A89813FBF3C4F8066D2D800F7C38A8" \ + "1AE31942917403FF4946B0A83D3D3E05" \ + "EE57C6F5F5606FB5D4BC6CD34EE0801A" \ + "5E94BB77B07507233A0BC7BAC8F90F79" + +#define RSA_E "10001" + +#define RSA_D "24BF6185468786FDD303083D25E64EFC" \ + "66CA472BC44D253102F8B4A9D3BFA750" \ + "91386C0077937FE33FA3252D28855837" \ + "AE1B484A8A9A45F7EE8C0C634F99E8CD" \ + "DF79C5CE07EE72C7F123142198164234" \ + "CABB724CF78B8173B9F880FC86322407" \ + "AF1FEDFDDE2BEB674CA15F3E81A1521E" \ + "071513A1E85B5DFA031F21ECAE91A34D" + +#define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \ + "2C01CAD19EA484A87EA4377637E75500" \ + "FCB2005C5C7DD6EC4AC023CDA285D796" \ + "C3D9E75E1EFC42488BB4F1D13AC30A57" + +#define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \ + "E211C2B9E5DB1ED0BF61D0D9899620F4" \ + "910E4168387E3C30AA1E00C339A79508" \ + "8452DD96A9A5EA5D9DCA68DA636032AF" + +#define PT_LEN 24 +#define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \ + "\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD" + +#if defined(MBEDTLS_PKCS1_V15) +static int myrand(void *rng_state, unsigned char *output, size_t len) +{ +#if !defined(__OpenBSD__) && !defined(__NetBSD__) + size_t i; + + if (rng_state != NULL) { + rng_state = NULL; + } + + for (i = 0; i < len; ++i) { + output[i] = rand(); + } +#else + if (rng_state != NULL) { + rng_state = NULL; + } + + arc4random_buf(output, len); +#endif /* !OpenBSD && !NetBSD */ + + return 0; +} +#endif /* MBEDTLS_PKCS1_V15 */ + +/* + * Checkup routine + */ +int mbedtls_rsa_self_test(int verbose) +{ + int ret = 0; +#if defined(MBEDTLS_PKCS1_V15) + size_t len; + mbedtls_rsa_context rsa; + unsigned char rsa_plaintext[PT_LEN]; + unsigned char rsa_decrypted[PT_LEN]; + unsigned char rsa_ciphertext[KEY_LEN]; +#if defined(MBEDTLS_MD_CAN_SHA1) + unsigned char sha1sum[20]; +#endif + + mbedtls_mpi K; + + mbedtls_mpi_init(&K); + mbedtls_rsa_init(&rsa); + + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_N)); + MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, &K, NULL, NULL, NULL, NULL)); + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_P)); + MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, &K, NULL, NULL, NULL)); + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_Q)); + MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, &K, NULL, NULL)); + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_D)); + MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, NULL, &K, NULL)); + MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&K, 16, RSA_E)); + MBEDTLS_MPI_CHK(mbedtls_rsa_import(&rsa, NULL, NULL, NULL, NULL, &K)); + + MBEDTLS_MPI_CHK(mbedtls_rsa_complete(&rsa)); + + if (verbose != 0) { + mbedtls_printf(" RSA key validation: "); + } + + if (mbedtls_rsa_check_pubkey(&rsa) != 0 || + mbedtls_rsa_check_privkey(&rsa) != 0) { + if (verbose != 0) { + mbedtls_printf("failed\n"); + } + + ret = 1; + goto cleanup; + } + + if (verbose != 0) { + mbedtls_printf("passed\n PKCS#1 encryption : "); + } + + memcpy(rsa_plaintext, RSA_PT, PT_LEN); + + if (mbedtls_rsa_pkcs1_encrypt(&rsa, myrand, NULL, + PT_LEN, rsa_plaintext, + rsa_ciphertext) != 0) { + if (verbose != 0) { + mbedtls_printf("failed\n"); + } + + ret = 1; + goto cleanup; + } + + if (verbose != 0) { + mbedtls_printf("passed\n PKCS#1 decryption : "); + } + + if (mbedtls_rsa_pkcs1_decrypt(&rsa, myrand, NULL, + &len, rsa_ciphertext, rsa_decrypted, + sizeof(rsa_decrypted)) != 0) { + if (verbose != 0) { + mbedtls_printf("failed\n"); + } + + ret = 1; + goto cleanup; + } + + if (memcmp(rsa_decrypted, rsa_plaintext, len) != 0) { + if (verbose != 0) { + mbedtls_printf("failed\n"); + } + + ret = 1; + goto cleanup; + } + + if (verbose != 0) { + mbedtls_printf("passed\n"); + } + +#if defined(MBEDTLS_MD_CAN_SHA1) + if (verbose != 0) { + mbedtls_printf(" PKCS#1 data sign : "); + } + + if (mbedtls_md(mbedtls_md_info_from_type(MBEDTLS_MD_SHA1), + rsa_plaintext, PT_LEN, sha1sum) != 0) { + if (verbose != 0) { + mbedtls_printf("failed\n"); + } + + return 1; + } + + if (mbedtls_rsa_pkcs1_sign(&rsa, myrand, NULL, + MBEDTLS_MD_SHA1, 20, + sha1sum, rsa_ciphertext) != 0) { + if (verbose != 0) { + mbedtls_printf("failed\n"); + } + + ret = 1; + goto cleanup; + } + + if (verbose != 0) { + mbedtls_printf("passed\n PKCS#1 sig. verify: "); + } + + if (mbedtls_rsa_pkcs1_verify(&rsa, MBEDTLS_MD_SHA1, 20, + sha1sum, rsa_ciphertext) != 0) { + if (verbose != 0) { + mbedtls_printf("failed\n"); + } + + ret = 1; + goto cleanup; + } + + if (verbose != 0) { + mbedtls_printf("passed\n"); + } +#endif /* MBEDTLS_MD_CAN_SHA1 */ + + if (verbose != 0) { + mbedtls_printf("\n"); + } + +cleanup: + mbedtls_mpi_free(&K); + mbedtls_rsa_free(&rsa); +#else /* MBEDTLS_PKCS1_V15 */ + ((void) verbose); +#endif /* MBEDTLS_PKCS1_V15 */ + return ret; +} + +#endif /* MBEDTLS_SELF_TEST */ + +#endif /* MBEDTLS_RSA_C */ |