Squashed 'lib/mbedtls/external/mbedtls/' content from commit 2ca6c285a0dd

git-subtree-dir: lib/mbedtls/external/mbedtls
git-subtree-split: 2ca6c285a0dd3f33982dd57299012dacab1ff206

1 files changed, 773 insertions, 0 deletions

diff --git a/library/pkcs7.c b/library/pkcs7.c
new file mode 100644
index 00000000000..3aac662ba69
--- /dev/null
+++ b/library/pkcs7.c
@@ -0,0 +1,773 @@
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+#include "common.h"
+
+#include "mbedtls/build_info.h"
+#if defined(MBEDTLS_PKCS7_C)
+#include "mbedtls/pkcs7.h"
+#include "x509_internal.h"
+#include "mbedtls/asn1.h"
+#include "mbedtls/x509_crt.h"
+#include "mbedtls/x509_crl.h"
+#include "mbedtls/oid.h"
+#include "mbedtls/error.h"
+
+#if defined(MBEDTLS_FS_IO)
+#include <sys/types.h>
+#include <sys/stat.h>
+#endif
+
+#include "mbedtls/platform.h"
+#include "mbedtls/platform_util.h"
+
+#if defined(MBEDTLS_HAVE_TIME)
+#include "mbedtls/platform_time.h"
+#endif
+#if defined(MBEDTLS_HAVE_TIME_DATE)
+#include <time.h>
+#endif
+
+/**
+ * Initializes the mbedtls_pkcs7 structure.
+ */
+void mbedtls_pkcs7_init(mbedtls_pkcs7 *pkcs7)
+{
+    memset(pkcs7, 0, sizeof(*pkcs7));
+}
+
+static int pkcs7_get_next_content_len(unsigned char **p, unsigned char *end,
+                                      size_t *len)
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+    ret = mbedtls_asn1_get_tag(p, end, len, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_CONTEXT_SPECIFIC);
+    if (ret != 0) {
+        ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret);
+    } else if ((size_t) (end - *p) != *len) {
+        ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO,
+                                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
+    }
+
+    return ret;
+}
+
+/**
+ * version Version
+ * Version ::= INTEGER
+ **/
+static int pkcs7_get_version(unsigned char **p, unsigned char *end, int *ver)
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+    ret = mbedtls_asn1_get_int(p, end, ver);
+    if (ret != 0) {
+        ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_VERSION, ret);
+    }
+
+    /* If version != 1, return invalid version */
+    if (*ver != MBEDTLS_PKCS7_SUPPORTED_VERSION) {
+        ret = MBEDTLS_ERR_PKCS7_INVALID_VERSION;
+    }
+
+    return ret;
+}
+
+/**
+ * ContentInfo ::= SEQUENCE {
+ *      contentType ContentType,
+ *      content
+ *              [0] EXPLICIT ANY DEFINED BY contentType OPTIONAL }
+ **/
+static int pkcs7_get_content_info_type(unsigned char **p, unsigned char *end,
+                                       unsigned char **seq_end,
+                                       mbedtls_pkcs7_buf *pkcs7)
+{
+    size_t len = 0;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    unsigned char *start = *p;
+
+    ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_SEQUENCE);
+    if (ret != 0) {
+        *p = start;
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret);
+    }
+    *seq_end = *p + len;
+    ret = mbedtls_asn1_get_tag(p, *seq_end, &len, MBEDTLS_ASN1_OID);
+    if (ret != 0) {
+        *p = start;
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret);
+    }
+
+    pkcs7->tag = MBEDTLS_ASN1_OID;
+    pkcs7->len = len;
+    pkcs7->p = *p;
+    *p += len;
+
+    return ret;
+}
+
+/**
+ * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
+ *
+ * This is from x509.h
+ **/
+static int pkcs7_get_digest_algorithm(unsigned char **p, unsigned char *end,
+                                      mbedtls_x509_buf *alg)
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+    if ((ret = mbedtls_asn1_get_alg_null(p, end, alg)) != 0) {
+        ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_ALG, ret);
+    }
+
+    return ret;
+}
+
+/**
+ * DigestAlgorithmIdentifiers :: SET of DigestAlgorithmIdentifier
+ **/
+static int pkcs7_get_digest_algorithm_set(unsigned char **p,
+                                          unsigned char *end,
+                                          mbedtls_x509_buf *alg)
+{
+    size_t len = 0;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+    ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_SET);
+    if (ret != 0) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_ALG, ret);
+    }
+
+    end = *p + len;
+
+    ret = mbedtls_asn1_get_alg_null(p, end, alg);
+    if (ret != 0) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_ALG, ret);
+    }
+
+    /** For now, it assumes there is only one digest algorithm specified **/
+    if (*p != end) {
+        return MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE;
+    }
+
+    return 0;
+}
+
+/**
+ * certificates :: SET OF ExtendedCertificateOrCertificate,
+ * ExtendedCertificateOrCertificate ::= CHOICE {
+ *      certificate Certificate -- x509,
+ *      extendedCertificate[0] IMPLICIT ExtendedCertificate }
+ * Return number of certificates added to the signed data,
+ * 0 or higher is valid.
+ * Return negative error code for failure.
+ **/
+static int pkcs7_get_certificates(unsigned char **p, unsigned char *end,
+                                  mbedtls_x509_crt *certs)
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    size_t len1 = 0;
+    size_t len2 = 0;
+    unsigned char *end_set, *end_cert, *start;
+
+    ret = mbedtls_asn1_get_tag(p, end, &len1, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_CONTEXT_SPECIFIC);
+    if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
+        return 0;
+    }
+    if (ret != 0) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_FORMAT, ret);
+    }
+    start = *p;
+    end_set = *p + len1;
+
+    ret = mbedtls_asn1_get_tag(p, end_set, &len2, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_SEQUENCE);
+    if (ret != 0) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CERT, ret);
+    }
+
+    end_cert = *p + len2;
+
+    /*
+     * This is to verify that there is only one signer certificate. It seems it is
+     * not easy to differentiate between the chain vs different signer's certificate.
+     * So, we support only the root certificate and the single signer.
+     * The behaviour would be improved with addition of multiple signer support.
+     */
+    if (end_cert != end_set) {
+        return MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE;
+    }
+
+    if ((ret = mbedtls_x509_crt_parse_der(certs, start, len1)) < 0) {
+        return MBEDTLS_ERR_PKCS7_INVALID_CERT;
+    }
+
+    *p = end_cert;
+
+    /*
+     * Since in this version we strictly support single certificate, and reaching
+     * here implies we have parsed successfully, we return 1.
+     */
+    return 1;
+}
+
+/**
+ * EncryptedDigest ::= OCTET STRING
+ **/
+static int pkcs7_get_signature(unsigned char **p, unsigned char *end,
+                               mbedtls_pkcs7_buf *signature)
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    size_t len = 0;
+
+    ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
+    if (ret != 0) {
+        return ret;
+    }
+
+    signature->tag = MBEDTLS_ASN1_OCTET_STRING;
+    signature->len = len;
+    signature->p = *p;
+
+    *p = *p + len;
+
+    return 0;
+}
+
+static void pkcs7_free_signer_info(mbedtls_pkcs7_signer_info *signer)
+{
+    mbedtls_x509_name *name_cur;
+    mbedtls_x509_name *name_prv;
+
+    if (signer == NULL) {
+        return;
+    }
+
+    name_cur = signer->issuer.next;
+    while (name_cur != NULL) {
+        name_prv = name_cur;
+        name_cur = name_cur->next;
+        mbedtls_free(name_prv);
+    }
+    signer->issuer.next = NULL;
+}
+
+/**
+ * SignerInfo ::= SEQUENCE {
+ *      version Version;
+ *      issuerAndSerialNumber   IssuerAndSerialNumber,
+ *      digestAlgorithm DigestAlgorithmIdentifier,
+ *      authenticatedAttributes
+ *              [0] IMPLICIT Attributes OPTIONAL,
+ *      digestEncryptionAlgorithm DigestEncryptionAlgorithmIdentifier,
+ *      encryptedDigest EncryptedDigest,
+ *      unauthenticatedAttributes
+ *              [1] IMPLICIT Attributes OPTIONAL,
+ * Returns 0 if the signerInfo is valid.
+ * Return negative error code for failure.
+ * Structure must not contain vales for authenticatedAttributes
+ * and unauthenticatedAttributes.
+ **/
+static int pkcs7_get_signer_info(unsigned char **p, unsigned char *end,
+                                 mbedtls_pkcs7_signer_info *signer,
+                                 mbedtls_x509_buf *alg)
+{
+    unsigned char *end_signer, *end_issuer_and_sn;
+    int asn1_ret = 0, ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    size_t len = 0;
+
+    asn1_ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
+                                    | MBEDTLS_ASN1_SEQUENCE);
+    if (asn1_ret != 0) {
+        goto out;
+    }
+
+    end_signer = *p + len;
+
+    ret = pkcs7_get_version(p, end_signer, &signer->version);
+    if (ret != 0) {
+        goto out;
+    }
+
+    asn1_ret = mbedtls_asn1_get_tag(p, end_signer, &len,
+                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
+    if (asn1_ret != 0) {
+        goto out;
+    }
+
+    end_issuer_and_sn = *p + len;
+    /* Parsing IssuerAndSerialNumber */
+    signer->issuer_raw.p = *p;
+
+    asn1_ret = mbedtls_asn1_get_tag(p, end_issuer_and_sn, &len,
+                                    MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
+    if (asn1_ret != 0) {
+        goto out;
+    }
+
+    ret  = mbedtls_x509_get_name(p, *p + len, &signer->issuer);
+    if (ret != 0) {
+        goto out;
+    }
+
+    signer->issuer_raw.len =  (size_t) (*p - signer->issuer_raw.p);
+
+    ret = mbedtls_x509_get_serial(p, end_issuer_and_sn, &signer->serial);
+    if (ret != 0) {
+        goto out;
+    }
+
+    /* ensure no extra or missing bytes */
+    if (*p != end_issuer_and_sn) {
+        ret = MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO;
+        goto out;
+    }
+
+    ret = pkcs7_get_digest_algorithm(p, end_signer, &signer->alg_identifier);
+    if (ret != 0) {
+        goto out;
+    }
+
+    /* Check that the digest algorithm used matches the one provided earlier */
+    if (signer->alg_identifier.tag != alg->tag ||
+        signer->alg_identifier.len != alg->len ||
+        memcmp(signer->alg_identifier.p, alg->p, alg->len) != 0) {
+        ret = MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO;
+        goto out;
+    }
+
+    /* Assume authenticatedAttributes is nonexistent */
+    ret = pkcs7_get_digest_algorithm(p, end_signer, &signer->sig_alg_identifier);
+    if (ret != 0) {
+        goto out;
+    }
+
+    ret = pkcs7_get_signature(p, end_signer, &signer->sig);
+    if (ret != 0) {
+        goto out;
+    }
+
+    /* Do not permit any unauthenticated attributes */
+    if (*p != end_signer) {
+        ret = MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO;
+    }
+
+out:
+    if (asn1_ret != 0 || ret != 0) {
+        pkcs7_free_signer_info(signer);
+        ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO,
+                                asn1_ret);
+    }
+
+    return ret;
+}
+
+/**
+ * SignerInfos ::= SET of SignerInfo
+ * Return number of signers added to the signed data,
+ * 0 or higher is valid.
+ * Return negative error code for failure.
+ **/
+static int pkcs7_get_signers_info_set(unsigned char **p, unsigned char *end,
+                                      mbedtls_pkcs7_signer_info *signers_set,
+                                      mbedtls_x509_buf *digest_alg)
+{
+    unsigned char *end_set;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    int count = 0;
+    size_t len = 0;
+
+    ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_SET);
+    if (ret != 0) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO, ret);
+    }
+
+    /* Detect zero signers */
+    if (len == 0) {
+        return 0;
+    }
+
+    end_set = *p + len;
+
+    ret = pkcs7_get_signer_info(p, end_set, signers_set, digest_alg);
+    if (ret != 0) {
+        return ret;
+    }
+    count++;
+
+    mbedtls_pkcs7_signer_info *prev = signers_set;
+    while (*p != end_set) {
+        mbedtls_pkcs7_signer_info *signer =
+            mbedtls_calloc(1, sizeof(mbedtls_pkcs7_signer_info));
+        if (!signer) {
+            ret = MBEDTLS_ERR_PKCS7_ALLOC_FAILED;
+            goto cleanup;
+        }
+
+        ret = pkcs7_get_signer_info(p, end_set, signer, digest_alg);
+        if (ret != 0) {
+            mbedtls_free(signer);
+            goto cleanup;
+        }
+        prev->next = signer;
+        prev = signer;
+        count++;
+    }
+
+    return count;
+
+cleanup:
+    pkcs7_free_signer_info(signers_set);
+    mbedtls_pkcs7_signer_info *signer = signers_set->next;
+    while (signer != NULL) {
+        prev = signer;
+        signer = signer->next;
+        pkcs7_free_signer_info(prev);
+        mbedtls_free(prev);
+    }
+    signers_set->next = NULL;
+    return ret;
+}
+
+/**
+ * SignedData ::= SEQUENCE {
+ *      version Version,
+ *      digestAlgorithms DigestAlgorithmIdentifiers,
+ *      contentInfo ContentInfo,
+ *      certificates
+ *              [0] IMPLICIT ExtendedCertificatesAndCertificates
+ *                  OPTIONAL,
+ *      crls
+ *              [0] IMPLICIT CertificateRevocationLists OPTIONAL,
+ *      signerInfos SignerInfos }
+ */
+static int pkcs7_get_signed_data(unsigned char *buf, size_t buflen,
+                                 mbedtls_pkcs7_signed_data *signed_data)
+{
+    unsigned char *p = buf;
+    unsigned char *end = buf + buflen;
+    unsigned char *end_content_info = NULL;
+    size_t len = 0;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    mbedtls_md_type_t md_alg;
+
+    ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_SEQUENCE);
+    if (ret != 0) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_FORMAT, ret);
+    }
+
+    if (p + len != end) {
+        return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_FORMAT,
+                                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
+    }
+
+    /* Get version of signed data */
+    ret = pkcs7_get_version(&p, end, &signed_data->version);
+    if (ret != 0) {
+        return ret;
+    }
+
+    /* Get digest algorithm */
+    ret = pkcs7_get_digest_algorithm_set(&p, end,
+                                         &signed_data->digest_alg_identifiers);
+    if (ret != 0) {
+        return ret;
+    }
+
+    ret = mbedtls_oid_get_md_alg(&signed_data->digest_alg_identifiers, &md_alg);
+    if (ret != 0) {
+        return MBEDTLS_ERR_PKCS7_INVALID_ALG;
+    }
+
+    mbedtls_pkcs7_buf content_type;
+    memset(&content_type, 0, sizeof(content_type));
+    ret = pkcs7_get_content_info_type(&p, end, &end_content_info, &content_type);
+    if (ret != 0) {
+        return ret;
+    }
+    if (MBEDTLS_OID_CMP(MBEDTLS_OID_PKCS7_DATA, &content_type)) {
+        return MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO;
+    }
+
+    if (p != end_content_info) {
+        /* Determine if valid content is present */
+        ret = mbedtls_asn1_get_tag(&p,
+                                   end_content_info,
+                                   &len,
+                                   MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC);
+        if (ret != 0) {
+            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret);
+        }
+        p += len;
+        if (p != end_content_info) {
+            return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO, ret);
+        }
+        /* Valid content is present - this is not supported */
+        return MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE;
+    }
+
+    /* Look for certificates, there may or may not be any */
+    mbedtls_x509_crt_init(&signed_data->certs);
+    ret = pkcs7_get_certificates(&p, end, &signed_data->certs);
+    if (ret < 0) {
+        return ret;
+    }
+
+    signed_data->no_of_certs = ret;
+
+    /*
+     * Currently CRLs are not supported. If CRL exist, the parsing will fail
+     * at next step of getting signers info and return error as invalid
+     * signer info.
+     */
+
+    signed_data->no_of_crls = 0;
+
+    /* Get signers info */
+    ret = pkcs7_get_signers_info_set(&p,
+                                     end,
+                                     &signed_data->signers,
+                                     &signed_data->digest_alg_identifiers);
+    if (ret < 0) {
+        return ret;
+    }
+
+    signed_data->no_of_signers = ret;
+
+    /* Don't permit trailing data */
+    if (p != end) {
+        return MBEDTLS_ERR_PKCS7_INVALID_FORMAT;
+    }
+
+    return 0;
+}
+
+int mbedtls_pkcs7_parse_der(mbedtls_pkcs7 *pkcs7, const unsigned char *buf,
+                            const size_t buflen)
+{
+    unsigned char *p;
+    unsigned char *end;
+    size_t len = 0;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+    if (pkcs7 == NULL) {
+        return MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA;
+    }
+
+    /* make an internal copy of the buffer for parsing */
+    pkcs7->raw.p = p = mbedtls_calloc(1, buflen);
+    if (pkcs7->raw.p == NULL) {
+        ret = MBEDTLS_ERR_PKCS7_ALLOC_FAILED;
+        goto out;
+    }
+    memcpy(p, buf, buflen);
+    pkcs7->raw.len = buflen;
+    end = p + buflen;
+
+    ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED
+                               | MBEDTLS_ASN1_SEQUENCE);
+    if (ret != 0) {
+        ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_FORMAT, ret);
+        goto out;
+    }
+
+    if ((size_t) (end - p) != len) {
+        ret = MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_FORMAT,
+                                MBEDTLS_ERR_ASN1_LENGTH_MISMATCH);
+        goto out;
+    }
+
+    if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OID)) != 0) {
+        if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
+            goto out;
+        }
+        p = pkcs7->raw.p;
+        len = buflen;
+        goto try_data;
+    }
+
+    if (MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS7_SIGNED_DATA, p, len)) {
+        /* OID is not MBEDTLS_OID_PKCS7_SIGNED_DATA, which is the only supported feature */
+        if (!MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS7_DATA, p, len)
+            || !MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS7_ENCRYPTED_DATA, p, len)
+            || !MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS7_ENVELOPED_DATA, p, len)
+            || !MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS7_SIGNED_AND_ENVELOPED_DATA, p, len)
+            || !MBEDTLS_OID_CMP_RAW(MBEDTLS_OID_PKCS7_DIGESTED_DATA, p, len)) {
+            /* OID is valid according to the spec, but unsupported */
+            ret =  MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE;
+        } else {
+            /* OID is invalid according to the spec */
+            ret = MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA;
+        }
+        goto out;
+    }
+
+    p += len;
+
+    ret = pkcs7_get_next_content_len(&p, end, &len);
+    if (ret != 0) {
+        goto out;
+    }
+
+    /* ensure no extra/missing data */
+    if (p + len != end) {
+        ret = MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA;
+        goto out;
+    }
+
+try_data:
+    ret = pkcs7_get_signed_data(p, len, &pkcs7->signed_data);
+    if (ret != 0) {
+        goto out;
+    }
+
+    ret = MBEDTLS_PKCS7_SIGNED_DATA;
+
+out:
+    if (ret < 0) {
+        mbedtls_pkcs7_free(pkcs7);
+    }
+
+    return ret;
+}
+
+static int mbedtls_pkcs7_data_or_hash_verify(mbedtls_pkcs7 *pkcs7,
+                                             const mbedtls_x509_crt *cert,
+                                             const unsigned char *data,
+                                             size_t datalen,
+                                             const int is_data_hash)
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    unsigned char *hash;
+    mbedtls_pk_context pk_cxt = cert->pk;
+    const mbedtls_md_info_t *md_info;
+    mbedtls_md_type_t md_alg;
+    mbedtls_pkcs7_signer_info *signer;
+
+    if (pkcs7->signed_data.no_of_signers == 0) {
+        return MBEDTLS_ERR_PKCS7_INVALID_CERT;
+    }
+
+    if (mbedtls_x509_time_is_past(&cert->valid_to) ||
+        mbedtls_x509_time_is_future(&cert->valid_from)) {
+        return MBEDTLS_ERR_PKCS7_CERT_DATE_INVALID;
+    }
+
+    ret = mbedtls_oid_get_md_alg(&pkcs7->signed_data.digest_alg_identifiers, &md_alg);
+    if (ret != 0) {
+        return ret;
+    }
+
+    md_info = mbedtls_md_info_from_type(md_alg);
+    if (md_info == NULL) {
+        return MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
+    }
+
+    hash = mbedtls_calloc(mbedtls_md_get_size(md_info), 1);
+    if (hash == NULL) {
+        return MBEDTLS_ERR_PKCS7_ALLOC_FAILED;
+    }
+
+    /* BEGIN must free hash before jumping out */
+    if (is_data_hash) {
+        if (datalen != mbedtls_md_get_size(md_info)) {
+            ret = MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
+        } else {
+            memcpy(hash, data, datalen);
+        }
+    } else {
+        ret = mbedtls_md(md_info, data, datalen, hash);
+    }
+    if (ret != 0) {
+        mbedtls_free(hash);
+        return MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
+    }
+
+    /* assume failure */
+    ret = MBEDTLS_ERR_PKCS7_VERIFY_FAIL;
+
+    /*
+     * Potential TODOs
+     * Currently we iterate over all signers and return success if any of them
+     * verify.
+     *
+     * However, we could make this better by checking against the certificate's
+     * identification and SignerIdentifier fields first. That would also allow
+     * us to distinguish between 'no signature for key' and 'signature for key
+     * failed to validate'.
+     */
+    for (signer = &pkcs7->signed_data.signers; signer; signer = signer->next) {
+        ret = mbedtls_pk_verify(&pk_cxt, md_alg, hash,
+                                mbedtls_md_get_size(md_info),
+                                signer->sig.p, signer->sig.len);
+
+        if (ret == 0) {
+            break;
+        }
+    }
+
+    mbedtls_free(hash);
+    /* END must free hash before jumping out */
+    return ret;
+}
+
+int mbedtls_pkcs7_signed_data_verify(mbedtls_pkcs7 *pkcs7,
+                                     const mbedtls_x509_crt *cert,
+                                     const unsigned char *data,
+                                     size_t datalen)
+{
+    if (data == NULL) {
+        return MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA;
+    }
+    return mbedtls_pkcs7_data_or_hash_verify(pkcs7, cert, data, datalen, 0);
+}
+
+int mbedtls_pkcs7_signed_hash_verify(mbedtls_pkcs7 *pkcs7,
+                                     const mbedtls_x509_crt *cert,
+                                     const unsigned char *hash,
+                                     size_t hashlen)
+{
+    if (hash == NULL) {
+        return MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA;
+    }
+    return mbedtls_pkcs7_data_or_hash_verify(pkcs7, cert, hash, hashlen, 1);
+}
+
+/*
+ * Unallocate all pkcs7 data
+ */
+void mbedtls_pkcs7_free(mbedtls_pkcs7 *pkcs7)
+{
+    mbedtls_pkcs7_signer_info *signer_cur;
+    mbedtls_pkcs7_signer_info *signer_prev;
+
+    if (pkcs7 == NULL || pkcs7->raw.p == NULL) {
+        return;
+    }
+
+    mbedtls_free(pkcs7->raw.p);
+
+    mbedtls_x509_crt_free(&pkcs7->signed_data.certs);
+    mbedtls_x509_crl_free(&pkcs7->signed_data.crl);
+
+    signer_cur = pkcs7->signed_data.signers.next;
+    pkcs7_free_signer_info(&pkcs7->signed_data.signers);
+    while (signer_cur != NULL) {
+        signer_prev = signer_cur;
+        signer_cur = signer_prev->next;
+        pkcs7_free_signer_info(signer_prev);
+        mbedtls_free(signer_prev);
+    }
+
+    pkcs7->raw.p = NULL;
+}
+
+#endif