backports: add signature verification code

Uh, this was awful. Because the crypto/ things are completely
impossible to backport, I've actually implemented this by using
mbedtls and embedding the relevant functions it has...

The mbedtls code is taken from mbedtls version 2.6.0 and only
minimally modified (mostly to remove <string.h> and similar).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 672 insertions, 0 deletions

diff --git a/backport/compat/verification/mbedtls/rsa.h b/backport/compat/verification/mbedtls/rsa.h
new file mode 100644
index 00000000..9683520c
--- /dev/null
+++ b/backport/compat/verification/mbedtls/rsa.h
@@ -0,0 +1,672 @@
+/**
+ * \file rsa.h
+ *
+ * \brief The RSA public-key cryptosystem
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: GPL-2.0
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+#ifndef MBEDTLS_RSA_H
+#define MBEDTLS_RSA_H
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#include "bignum.h"
+#include "md.h"
+
+#if defined(MBEDTLS_THREADING_C)
+#include "threading.h"
+#endif
+
+/*
+ * RSA Error codes
+ */
+#define MBEDTLS_ERR_RSA_BAD_INPUT_DATA                    -0x4080  /**< Bad input parameters to function. */
+#define MBEDTLS_ERR_RSA_INVALID_PADDING                   -0x4100  /**< Input data contains invalid padding and is rejected. */
+#define MBEDTLS_ERR_RSA_KEY_GEN_FAILED                    -0x4180  /**< Something failed during generation of a key. */
+#define MBEDTLS_ERR_RSA_KEY_CHECK_FAILED                  -0x4200  /**< Key failed to pass the library's validity check. */
+#define MBEDTLS_ERR_RSA_PUBLIC_FAILED                     -0x4280  /**< The public key operation failed. */
+#define MBEDTLS_ERR_RSA_PRIVATE_FAILED                    -0x4300  /**< The private key operation failed. */
+#define MBEDTLS_ERR_RSA_VERIFY_FAILED                     -0x4380  /**< The PKCS#1 verification failed. */
+#define MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE                  -0x4400  /**< The output buffer for decryption is not large enough. */
+#define MBEDTLS_ERR_RSA_RNG_FAILED                        -0x4480  /**< The random generator failed to generate non-zeros. */
+
+/*
+ * RSA constants
+ */
+#define MBEDTLS_RSA_PUBLIC      0
+#define MBEDTLS_RSA_PRIVATE     1
+
+#define MBEDTLS_RSA_PKCS_V15    0
+#define MBEDTLS_RSA_PKCS_V21    1
+
+#define MBEDTLS_RSA_SIGN        1
+#define MBEDTLS_RSA_CRYPT       2
+
+#define MBEDTLS_RSA_SALT_LEN_ANY    -1
+
+/*
+ * The above constants may be used even if the RSA module is compile out,
+ * eg for alternative (PKCS#11) RSA implemenations in the PK layers.
+ */
+#if defined(MBEDTLS_RSA_C)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief          RSA context structure
+ */
+typedef struct
+{
+    int ver;                    /*!<  always 0          */
+    size_t len;                 /*!<  size(N) in chars  */
+
+    mbedtls_mpi N;                      /*!<  public modulus    */
+    mbedtls_mpi E;                      /*!<  public exponent   */
+
+    mbedtls_mpi D;                      /*!<  private exponent  */
+    mbedtls_mpi P;                      /*!<  1st prime factor  */
+    mbedtls_mpi Q;                      /*!<  2nd prime factor  */
+    mbedtls_mpi DP;                     /*!<  D % (P - 1)       */
+    mbedtls_mpi DQ;                     /*!<  D % (Q - 1)       */
+    mbedtls_mpi QP;                     /*!<  1 / (Q % P)       */
+
+    mbedtls_mpi RN;                     /*!<  cached R^2 mod N  */
+    mbedtls_mpi RP;                     /*!<  cached R^2 mod P  */
+    mbedtls_mpi RQ;                     /*!<  cached R^2 mod Q  */
+
+    mbedtls_mpi Vi;                     /*!<  cached blinding value     */
+    mbedtls_mpi Vf;                     /*!<  cached un-blinding value  */
+
+    int padding;                /*!<  MBEDTLS_RSA_PKCS_V15 for 1.5 padding and
+                                      MBEDTLS_RSA_PKCS_v21 for OAEP/PSS         */
+    int hash_id;                /*!<  Hash identifier of mbedtls_md_type_t as
+                                      specified in the mbedtls_md.h header file
+                                      for the EME-OAEP and EMSA-PSS
+                                      encoding                          */
+#if defined(MBEDTLS_THREADING_C)
+    mbedtls_threading_mutex_t mutex;    /*!<  Thread-safety mutex       */
+#endif
+}
+mbedtls_rsa_context;
+
+/**
+ * \brief          Initialize an RSA context
+ *
+ *                 Note: Set padding to MBEDTLS_RSA_PKCS_V21 for the RSAES-OAEP
+ *                 encryption scheme and the RSASSA-PSS signature scheme.
+ *
+ * \param ctx      RSA context to be initialized
+ * \param padding  MBEDTLS_RSA_PKCS_V15 or MBEDTLS_RSA_PKCS_V21
+ * \param hash_id  MBEDTLS_RSA_PKCS_V21 hash identifier
+ *
+ * \note           The hash_id parameter is actually ignored
+ *                 when using MBEDTLS_RSA_PKCS_V15 padding.
+ *
+ * \note           Choice of padding mode is strictly enforced for private key
+ *                 operations, since there might be security concerns in
+ *                 mixing padding modes. For public key operations it's merely
+ *                 a default value, which can be overriden by calling specific
+ *                 rsa_rsaes_xxx or rsa_rsassa_xxx functions.
+ *
+ * \note           The chosen hash is always used for OEAP encryption.
+ *                 For PSS signatures, it's always used for making signatures,
+ *                 but can be overriden (and always is, if set to
+ *                 MBEDTLS_MD_NONE) for verifying them.
+ */
+void mbedtls_rsa_init( mbedtls_rsa_context *ctx,
+               int padding,
+               int hash_id);
+
+/**
+ * \brief          Set padding for an already initialized RSA context
+ *                 See \c mbedtls_rsa_init() for details.
+ *
+ * \param ctx      RSA context to be set
+ * \param padding  MBEDTLS_RSA_PKCS_V15 or MBEDTLS_RSA_PKCS_V21
+ * \param hash_id  MBEDTLS_RSA_PKCS_V21 hash identifier
+ */
+void mbedtls_rsa_set_padding( mbedtls_rsa_context *ctx, int padding, int hash_id);
+
+/**
+ * \brief          Generate an RSA keypair
+ *
+ * \param ctx      RSA context that will hold the key
+ * \param f_rng    RNG function
+ * \param p_rng    RNG parameter
+ * \param nbits    size of the public key in bits
+ * \param exponent public exponent (e.g., 65537)
+ *
+ * \note           mbedtls_rsa_init() must be called beforehand to setup
+ *                 the RSA context.
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ */
+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 );
+
+/**
+ * \brief          Check a public RSA key
+ *
+ * \param ctx      RSA context to be checked
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ */
+int mbedtls_rsa_check_pubkey( const mbedtls_rsa_context *ctx );
+
+/**
+ * \brief          Check a private RSA key
+ *
+ * \param ctx      RSA context to be checked
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ */
+int mbedtls_rsa_check_privkey( const mbedtls_rsa_context *ctx );
+
+/**
+ * \brief          Check a public-private RSA key pair.
+ *                 Check each of the contexts, and make sure they match.
+ *
+ * \param pub      RSA context holding the public key
+ * \param prv      RSA context holding the private key
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ */
+int mbedtls_rsa_check_pub_priv( const mbedtls_rsa_context *pub, const mbedtls_rsa_context *prv );
+
+/**
+ * \brief          Do an RSA public key operation
+ *
+ * \param ctx      RSA context
+ * \param input    input buffer
+ * \param output   output buffer
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           This function does NOT take care of message
+ *                 padding. Also, be sure to set input[0] = 0 or ensure that
+ *                 input is smaller than N.
+ *
+ * \note           The input and output buffers must be large
+ *                 enough (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_public( mbedtls_rsa_context *ctx,
+                const unsigned char *input,
+                unsigned char *output );
+
+/**
+ * \brief          Do an RSA private key operation
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Needed for blinding)
+ * \param p_rng    RNG parameter
+ * \param input    input buffer
+ * \param output   output buffer
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The input and output buffers must be large
+ *                 enough (eg. 128 bytes if RSA-1024 is used).
+ */
+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 );
+
+/**
+ * \brief          Generic wrapper to perform a PKCS#1 encryption using the
+ *                 mode from the context. Add the message padding, then do an
+ *                 RSA operation.
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Needed for padding and PKCS#1 v2.1 encoding
+ *                               and MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param ilen     contains the plaintext length
+ * \param input    buffer holding the data to be encrypted
+ * \param output   buffer that will hold the ciphertext
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The output buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_pkcs1_encrypt( mbedtls_rsa_context *ctx,
+                       int (*f_rng)(void *, unsigned char *, size_t),
+                       void *p_rng,
+                       int mode, size_t ilen,
+                       const unsigned char *input,
+                       unsigned char *output );
+
+/**
+ * \brief          Perform a PKCS#1 v1.5 encryption (RSAES-PKCS1-v1_5-ENCRYPT)
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Needed for padding and MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param ilen     contains the plaintext length
+ * \param input    buffer holding the data to be encrypted
+ * \param output   buffer that will hold the ciphertext
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The output buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx,
+                                 int (*f_rng)(void *, unsigned char *, size_t),
+                                 void *p_rng,
+                                 int mode, size_t ilen,
+                                 const unsigned char *input,
+                                 unsigned char *output );
+
+/**
+ * \brief          Perform a PKCS#1 v2.1 OAEP encryption (RSAES-OAEP-ENCRYPT)
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Needed for padding and PKCS#1 v2.1 encoding
+ *                               and MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param label    buffer holding the custom label to use
+ * \param label_len contains the label length
+ * \param ilen     contains the plaintext length
+ * \param input    buffer holding the data to be encrypted
+ * \param output   buffer that will hold the ciphertext
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The output buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_rsaes_oaep_encrypt( mbedtls_rsa_context *ctx,
+                            int (*f_rng)(void *, unsigned char *, size_t),
+                            void *p_rng,
+                            int mode,
+                            const unsigned char *label, size_t label_len,
+                            size_t ilen,
+                            const unsigned char *input,
+                            unsigned char *output );
+
+/**
+ * \brief          Generic wrapper to perform a PKCS#1 decryption using the
+ *                 mode from the context. Do an RSA operation, then remove
+ *                 the message padding
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param olen     will contain the plaintext length
+ * \param input    buffer holding the encrypted data
+ * \param output   buffer that will hold the plaintext
+ * \param output_max_len    maximum length of the output buffer
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The output buffer length \c output_max_len should be
+ *                 as large as the size ctx->len of ctx->N (eg. 128 bytes
+ *                 if RSA-1024 is used) to be able to hold an arbitrary
+ *                 decrypted message. If it is not large enough to hold
+ *                 the decryption of the particular ciphertext provided, 
+ *                 the function will return MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.
+ *
+ * \note           The input buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_pkcs1_decrypt( mbedtls_rsa_context *ctx,
+                       int (*f_rng)(void *, unsigned char *, size_t),
+                       void *p_rng,
+                       int mode, size_t *olen,
+                       const unsigned char *input,
+                       unsigned char *output,
+                       size_t output_max_len );
+
+/**
+ * \brief          Perform a PKCS#1 v1.5 decryption (RSAES-PKCS1-v1_5-DECRYPT)
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param olen     will contain the plaintext length
+ * \param input    buffer holding the encrypted data
+ * \param output   buffer that will hold the plaintext
+ * \param output_max_len    maximum length of the output buffer
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The output buffer length \c output_max_len should be
+ *                 as large as the size ctx->len of ctx->N (eg. 128 bytes
+ *                 if RSA-1024 is used) to be able to hold an arbitrary
+ *                 decrypted message. If it is not large enough to hold
+ *                 the decryption of the particular ciphertext provided, 
+ *                 the function will return MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.
+ *
+ * \note           The input buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_rsaes_pkcs1_v15_decrypt( mbedtls_rsa_context *ctx,
+                                 int (*f_rng)(void *, unsigned char *, size_t),
+                                 void *p_rng,
+                                 int mode, size_t *olen,
+                                 const unsigned char *input,
+                                 unsigned char *output,
+                                 size_t output_max_len );
+
+/**
+ * \brief          Perform a PKCS#1 v2.1 OAEP decryption (RSAES-OAEP-DECRYPT)
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param label    buffer holding the custom label to use
+ * \param label_len contains the label length
+ * \param olen     will contain the plaintext length
+ * \param input    buffer holding the encrypted data
+ * \param output   buffer that will hold the plaintext
+ * \param output_max_len    maximum length of the output buffer
+ *
+ * \return         0 if successful, or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The output buffer length \c output_max_len should be
+ *                 as large as the size ctx->len of ctx->N (eg. 128 bytes
+ *                 if RSA-1024 is used) to be able to hold an arbitrary
+ *                 decrypted message. If it is not large enough to hold
+ *                 the decryption of the particular ciphertext provided, 
+ *                 the function will return MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE.
+ *
+ * \note           The input buffer must be as large as the size 
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx,
+                            int (*f_rng)(void *, unsigned char *, size_t),
+                            void *p_rng,
+                            int mode,
+                            const unsigned char *label, size_t label_len,
+                            size_t *olen,
+                            const unsigned char *input,
+                            unsigned char *output,
+                            size_t output_max_len );
+
+/**
+ * \brief          Generic wrapper to perform a PKCS#1 signature using the
+ *                 mode from the context. Do a private RSA operation to sign
+ *                 a message digest
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Needed for PKCS#1 v2.1 encoding and for
+ *                               MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param md_alg   a MBEDTLS_MD_XXX (use MBEDTLS_MD_NONE for signing raw data)
+ * \param hashlen  message digest length (for MBEDTLS_MD_NONE only)
+ * \param hash     buffer holding the message digest
+ * \param sig      buffer that will hold the ciphertext
+ *
+ * \return         0 if the signing operation was successful,
+ *                 or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The "sig" buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ *
+ * \note           In case of PKCS#1 v2.1 encoding, see comments on
+ * \note           \c mbedtls_rsa_rsassa_pss_sign() for details on md_alg and hash_id.
+ */
+int mbedtls_rsa_pkcs1_sign( mbedtls_rsa_context *ctx,
+                    int (*f_rng)(void *, unsigned char *, size_t),
+                    void *p_rng,
+                    int mode,
+                    mbedtls_md_type_t md_alg,
+                    unsigned int hashlen,
+                    const unsigned char *hash,
+                    unsigned char *sig );
+
+/**
+ * \brief          Perform a PKCS#1 v1.5 signature (RSASSA-PKCS1-v1_5-SIGN)
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param md_alg   a MBEDTLS_MD_XXX (use MBEDTLS_MD_NONE for signing raw data)
+ * \param hashlen  message digest length (for MBEDTLS_MD_NONE only)
+ * \param hash     buffer holding the message digest
+ * \param sig      buffer that will hold the ciphertext
+ *
+ * \return         0 if the signing operation was successful,
+ *                 or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The "sig" buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *ctx,
+                               int (*f_rng)(void *, unsigned char *, size_t),
+                               void *p_rng,
+                               int mode,
+                               mbedtls_md_type_t md_alg,
+                               unsigned int hashlen,
+                               const unsigned char *hash,
+                               unsigned char *sig );
+
+/**
+ * \brief          Perform a PKCS#1 v2.1 PSS signature (RSASSA-PSS-SIGN)
+ *
+ * \param ctx      RSA context
+ * \param f_rng    RNG function (Needed for PKCS#1 v2.1 encoding and for
+ *                               MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param md_alg   a MBEDTLS_MD_XXX (use MBEDTLS_MD_NONE for signing raw data)
+ * \param hashlen  message digest length (for MBEDTLS_MD_NONE only)
+ * \param hash     buffer holding the message digest
+ * \param sig      buffer that will hold the ciphertext
+ *
+ * \return         0 if the signing operation was successful,
+ *                 or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The "sig" buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ *
+ * \note           The hash_id in the RSA context is the one used for the
+ *                 encoding. md_alg in the function call is the type of hash
+ *                 that is encoded. According to RFC 3447 it is advised to
+ *                 keep both hashes the same.
+ */
+int mbedtls_rsa_rsassa_pss_sign( mbedtls_rsa_context *ctx,
+                         int (*f_rng)(void *, unsigned char *, size_t),
+                         void *p_rng,
+                         int mode,
+                         mbedtls_md_type_t md_alg,
+                         unsigned int hashlen,
+                         const unsigned char *hash,
+                         unsigned char *sig );
+
+/**
+ * \brief          Generic wrapper to perform a PKCS#1 verification using the
+ *                 mode from the context. Do a public RSA operation and check
+ *                 the message digest
+ *
+ * \param ctx      points to an RSA public key
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param md_alg   a MBEDTLS_MD_XXX (use MBEDTLS_MD_NONE for signing raw data)
+ * \param hashlen  message digest length (for MBEDTLS_MD_NONE only)
+ * \param hash     buffer holding the message digest
+ * \param sig      buffer holding the ciphertext
+ *
+ * \return         0 if the verify operation was successful,
+ *                 or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The "sig" buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ *
+ * \note           In case of PKCS#1 v2.1 encoding, see comments on
+ *                 \c mbedtls_rsa_rsassa_pss_verify() about md_alg and hash_id.
+ */
+int mbedtls_rsa_pkcs1_verify( mbedtls_rsa_context *ctx,
+                      int (*f_rng)(void *, unsigned char *, size_t),
+                      void *p_rng,
+                      int mode,
+                      mbedtls_md_type_t md_alg,
+                      unsigned int hashlen,
+                      const unsigned char *hash,
+                      const unsigned char *sig );
+
+/**
+ * \brief          Perform a PKCS#1 v1.5 verification (RSASSA-PKCS1-v1_5-VERIFY)
+ *
+ * \param ctx      points to an RSA public key
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param md_alg   a MBEDTLS_MD_XXX (use MBEDTLS_MD_NONE for signing raw data)
+ * \param hashlen  message digest length (for MBEDTLS_MD_NONE only)
+ * \param hash     buffer holding the message digest
+ * \param sig      buffer holding the ciphertext
+ *
+ * \return         0 if the verify operation was successful,
+ *                 or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The "sig" buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ */
+int mbedtls_rsa_rsassa_pkcs1_v15_verify( mbedtls_rsa_context *ctx,
+                                 int (*f_rng)(void *, unsigned char *, size_t),
+                                 void *p_rng,
+                                 int mode,
+                                 mbedtls_md_type_t md_alg,
+                                 unsigned int hashlen,
+                                 const unsigned char *hash,
+                                 const unsigned char *sig );
+
+/**
+ * \brief          Perform a PKCS#1 v2.1 PSS verification (RSASSA-PSS-VERIFY)
+ *                 (This is the "simple" version.)
+ *
+ * \param ctx      points to an RSA public key
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param md_alg   a MBEDTLS_MD_XXX (use MBEDTLS_MD_NONE for signing raw data)
+ * \param hashlen  message digest length (for MBEDTLS_MD_NONE only)
+ * \param hash     buffer holding the message digest
+ * \param sig      buffer holding the ciphertext
+ *
+ * \return         0 if the verify operation was successful,
+ *                 or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The "sig" buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ *
+ * \note           The hash_id in the RSA context is the one used for the
+ *                 verification. md_alg in the function call is the type of
+ *                 hash that is verified. According to RFC 3447 it is advised to
+ *                 keep both hashes the same. If hash_id in the RSA context is
+ *                 unset, the md_alg from the function call is used.
+ */
+int mbedtls_rsa_rsassa_pss_verify( mbedtls_rsa_context *ctx,
+                           int (*f_rng)(void *, unsigned char *, size_t),
+                           void *p_rng,
+                           int mode,
+                           mbedtls_md_type_t md_alg,
+                           unsigned int hashlen,
+                           const unsigned char *hash,
+                           const unsigned char *sig );
+
+/**
+ * \brief          Perform a PKCS#1 v2.1 PSS verification (RSASSA-PSS-VERIFY)
+ *                 (This is the version with "full" options.)
+ *
+ * \param ctx      points to an RSA public key
+ * \param f_rng    RNG function (Only needed for MBEDTLS_RSA_PRIVATE)
+ * \param p_rng    RNG parameter
+ * \param mode     MBEDTLS_RSA_PUBLIC or MBEDTLS_RSA_PRIVATE
+ * \param md_alg   a MBEDTLS_MD_XXX (use MBEDTLS_MD_NONE for signing raw data)
+ * \param hashlen  message digest length (for MBEDTLS_MD_NONE only)
+ * \param hash     buffer holding the message digest
+ * \param mgf1_hash_id message digest used for mask generation
+ * \param expected_salt_len Length of the salt used in padding, use
+ *                 MBEDTLS_RSA_SALT_LEN_ANY to accept any salt length
+ * \param sig      buffer holding the ciphertext
+ *
+ * \return         0 if the verify operation was successful,
+ *                 or an MBEDTLS_ERR_RSA_XXX error code
+ *
+ * \note           The "sig" buffer must be as large as the size
+ *                 of ctx->N (eg. 128 bytes if RSA-1024 is used).
+ *
+ * \note           The hash_id in the RSA context is ignored.
+ */
+int mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_rsa_context *ctx,
+                               int (*f_rng)(void *, unsigned char *, size_t),
+                               void *p_rng,
+                               int mode,
+                               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 );
+
+/**
+ * \brief          Copy the components of an RSA context
+ *
+ * \param dst      Destination context
+ * \param src      Source context
+ *
+ * \return         0 on success,
+ *                 MBEDTLS_ERR_MPI_ALLOC_FAILED on memory allocation failure
+ */
+int mbedtls_rsa_copy( mbedtls_rsa_context *dst, const mbedtls_rsa_context *src );
+
+/**
+ * \brief          Free the components of an RSA key
+ *
+ * \param ctx      RSA Context to free
+ */
+void mbedtls_rsa_free( mbedtls_rsa_context *ctx );
+
+/**
+ * \brief          Checkup routine
+ *
+ * \return         0 if successful, or 1 if the test failed
+ */
+int mbedtls_rsa_self_test( int verbose );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MBEDTLS_RSA_C */
+
+#endif /* rsa.h */