PKCS7 Parser - RFC 2315

include/mbedtls/asn1.h

@@ -39,8 +39,9 @@
 
 /**
  * \name ASN1 Error codes
- * These error codes are OR'ed to X509 error codes for
+ * These error codes are combined with other error codes for
  * higher error granularity.
+ * e.g. X.509 and PKCS #7 error codes
  * ASN1 is a standard to specify data structures.
  * \{
  */

include/mbedtls/check_config.h

@@ -1062,6 +1062,14 @@
 #error "MBEDTLS_SSL_TRUNCATED_HMAC was removed in Mbed TLS 3.0. See https://github.com/Mbed-TLS/mbedtls/issues/4341"
 #endif
 
+#if defined(MBEDTLS_PKCS7_C) && ( ( !defined(MBEDTLS_ASN1_PARSE_C) ) || \
+    ( !defined(MBEDTLS_OID_C) ) || ( !defined(MBEDTLS_PK_PARSE_C) ) || \
+    ( !defined(MBEDTLS_X509_CRT_PARSE_C) ) ||\
+    ( !defined(MBEDTLS_X509_CRL_PARSE_C) ) || ( !defined(MBEDTLS_BIGNUM_C) ) || \
+    ( !defined(MBEDTLS_MD_C) ) )
+#error  "MBEDTLS_PKCS7_C is defined, but not all prerequisites"
+#endif
+
 /*
  * Avoid warning from -pedantic. This is a convenient place for this
  * workaround since this is included by every single file before the

include/mbedtls/error.h

@@ -96,6 +96,7 @@
  * ECP       4   10 (Started from top)
  * MD        5   5
  * HKDF      5   1 (Started from top)
+ * PKCS7     5   12 (Started from 0x5300)
  * SSL       5   2 (Started from 0x5F00)
  * CIPHER    6   8 (Started from 0x6080)
  * SSL       6   22 (Started from top, plus 0x6000)

include/mbedtls/mbedtls_config.h

@@ -2780,6 +2780,22 @@
  */
 #define MBEDTLS_PKCS5_C
 
+/**
+ * \def MBEDTLS_PKCS7_C
+ *
+ * Enable PKCS7 core for using PKCS7 formatted signatures.
+ * RFC Link - https://tools.ietf.org/html/rfc2315
+ *
+ * Module:  library/pkcs7.c
+ *
+ * Requires: MBEDTLS_ASN1_PARSE_C, MBEDTLS_OID_C, MBEDTLS_PK_PARSE_C,
+ *           MBEDTLS_X509_CRT_PARSE_C MBEDTLS_X509_CRL_PARSE_C,
+ *           MBEDTLS_BIGNUM_C, MBEDTLS_MD_C
+ *
+ * This module is required for the PKCS7 parsing modules.
+ */
+#define MBEDTLS_PKCS7_C
+
 /**
  * \def MBEDTLS_PKCS12_C
  *

include/mbedtls/oid.h

@@ -220,6 +220,7 @@
 #define MBEDTLS_OID_PKCS                MBEDTLS_OID_RSA_COMPANY "\x01" /**< pkcs OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) 1 } */
 #define MBEDTLS_OID_PKCS1               MBEDTLS_OID_PKCS "\x01" /**< pkcs-1 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 1 } */
 #define MBEDTLS_OID_PKCS5               MBEDTLS_OID_PKCS "\x05" /**< pkcs-5 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 5 } */
+#define MBEDTLS_OID_PKCS7               MBEDTLS_OID_PKCS "\x07" /**< pkcs-7 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 7 } */
 #define MBEDTLS_OID_PKCS9               MBEDTLS_OID_PKCS "\x09" /**< pkcs-9 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 9 } */
 #define MBEDTLS_OID_PKCS12              MBEDTLS_OID_PKCS "\x0c" /**< pkcs-12 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 12 } */
 
@@ -300,6 +301,16 @@
 #define MBEDTLS_OID_PKCS5_PBE_SHA1_DES_CBC      MBEDTLS_OID_PKCS5 "\x0a" /**< pbeWithSHA1AndDES-CBC OBJECT IDENTIFIER ::= {pkcs-5 10} */
 #define MBEDTLS_OID_PKCS5_PBE_SHA1_RC2_CBC      MBEDTLS_OID_PKCS5 "\x0b" /**< pbeWithSHA1AndRC2-CBC OBJECT IDENTIFIER ::= {pkcs-5 11} */
 
+/*
+ * PKCS#7 OIDs
+ */
+#define MBEDTLS_OID_PKCS7_DATA                        MBEDTLS_OID_PKCS7 "\x01" /**< Content type is Data OBJECT IDENTIFIER ::= {pkcs-7 1} */
+#define MBEDTLS_OID_PKCS7_SIGNED_DATA                 MBEDTLS_OID_PKCS7 "\x02" /**< Content type is Signed Data OBJECT IDENTIFIER ::= {pkcs-7 2} */
+#define MBEDTLS_OID_PKCS7_ENVELOPED_DATA              MBEDTLS_OID_PKCS7 "\x03" /**< Content type is Enveloped Data OBJECT IDENTIFIER ::= {pkcs-7 3} */
+#define MBEDTLS_OID_PKCS7_SIGNED_AND_ENVELOPED_DATA   MBEDTLS_OID_PKCS7 "\x04" /**< Content type is Signed and Enveloped Data OBJECT IDENTIFIER ::= {pkcs-7 4} */
+#define MBEDTLS_OID_PKCS7_DIGESTED_DATA               MBEDTLS_OID_PKCS7 "\x05" /**< Content type is Digested Data OBJECT IDENTIFIER ::= {pkcs-7 5} */
+#define MBEDTLS_OID_PKCS7_ENCRYPTED_DATA              MBEDTLS_OID_PKCS7 "\x06" /**< Content type is Encrypted Data OBJECT IDENTIFIER ::= {pkcs-7 6} */
+
 /*
  * PKCS#8 OIDs
  */

include/mbedtls/pkcs7.h

@@ -0,0 +1,241 @@
+/**
+ * \file pkcs7.h
+ *
+ * \brief PKCS7 generic defines and structures
+ *  https://tools.ietf.org/html/rfc2315
+ */
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+/**
+ * Note: For the time being, this implementation of the PKCS7 cryptographic
+ * message syntax is a partial implementation of RFC 2315.
+ * Differences include:
+ *  - The RFC specifies 6 different content types. The only type currently
+ *    supported in Mbed TLS is the signed data content type.
+ *  - The only supported PKCS7 Signed Data syntax version is version 1
+ *  - The RFC specifies support for BER. This implementation is limited to
+ *    DER only.
+ *  - The RFC specifies that multiple digest algorithms can be specified
+ *    in the Signed Data type. Only one digest algorithm is supported in Mbed TLS.
+ *  - The RFC specifies the Signed Data type can contain multiple X509 or PKCS6
+ *    certificates. In Mbed TLS, this list can only contain 0 or 1 certificates
+ *    and they must be in X509 format.
+ *  - The RFC specifies the Signed Data type can contain
+ *    certificate-revocation lists (crls). This implementation has no support
+ *    for crls so it is assumed to be an empty list.
+ *  - The RFC allows for SignerInfo structure to optionally contain
+ *    unauthenticatedAttributes and authenticatedAttributes. In Mbed TLS it is
+ *    assumed these fields are empty.
+ */
+
+#ifndef MBEDTLS_PKCS7_H
+#define MBEDTLS_PKCS7_H
+
+#include "mbedtls/private_access.h"
+
+#include "mbedtls/build_info.h"
+
+#include "mbedtls/asn1.h"
+#include "mbedtls/x509.h"
+#include "mbedtls/x509_crt.h"
+
+/**
+ * \name PKCS7 Module Error codes
+ * \{
+ */
+#define MBEDTLS_ERR_PKCS7_INVALID_FORMAT                   -0x5300  /**< The format is invalid, e.g. different type expected. */
+#define MBEDTLS_ERR_PKCS7_FEATURE_UNAVAILABLE              -0x5380  /**< Unavailable feature, e.g. anything other than signed data. */
+#define MBEDTLS_ERR_PKCS7_INVALID_VERSION                  -0x5400  /**< The PKCS7 version element is invalid or cannot be parsed. */
+#define MBEDTLS_ERR_PKCS7_INVALID_CONTENT_INFO             -0x5480  /**< The PKCS7 content info invalid or cannot be parsed. */
+#define MBEDTLS_ERR_PKCS7_INVALID_ALG                      -0x5500  /**< The algorithm tag or value is invalid or cannot be parsed. */
+#define MBEDTLS_ERR_PKCS7_INVALID_CERT                     -0x5580  /**< The certificate tag or value is invalid or cannot be parsed. */
+#define MBEDTLS_ERR_PKCS7_INVALID_SIGNATURE                -0x5600  /**< Error parsing the signature */
+#define MBEDTLS_ERR_PKCS7_INVALID_SIGNER_INFO              -0x5680  /**< Error parsing the signer's info */
+#define MBEDTLS_ERR_PKCS7_BAD_INPUT_DATA                   -0x5700  /**< Input invalid. */
+#define MBEDTLS_ERR_PKCS7_ALLOC_FAILED                     -0x5780  /**< Allocation of memory failed. */
+#define MBEDTLS_ERR_PKCS7_VERIFY_FAIL                      -0x5800  /**< Verification Failed */
+#define MBEDTLS_ERR_PKCS7_CERT_DATE_INVALID                -0x5880  /**< The PKCS7 date issued/expired dates are invalid */
+/* \} name */
+
+/**
+ * \name PKCS7 Supported Version
+ * \{
+ */
+#define MBEDTLS_PKCS7_SUPPORTED_VERSION                           0x01
+/* \} name */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Type-length-value structure that allows for ASN1 using DER.
+ */
+typedef mbedtls_asn1_buf mbedtls_pkcs7_buf;
+
+/**
+ * Container for ASN1 named information objects.
+ * It allows for Relative Distinguished Names (e.g. cn=localhost,ou=code,etc.).
+ */
+typedef mbedtls_asn1_named_data mbedtls_pkcs7_name;
+
+/**
+ * Container for a sequence of ASN.1 items
+ */
+typedef mbedtls_asn1_sequence mbedtls_pkcs7_sequence;
+
+/**
+ * PKCS7 types
+ */
+typedef enum {
+    MBEDTLS_PKCS7_NONE=0,
+    MBEDTLS_PKCS7_DATA,
+    MBEDTLS_PKCS7_SIGNED_DATA,
+    MBEDTLS_PKCS7_ENVELOPED_DATA,
+    MBEDTLS_PKCS7_SIGNED_AND_ENVELOPED_DATA,
+    MBEDTLS_PKCS7_DIGESTED_DATA,
+    MBEDTLS_PKCS7_ENCRYPTED_DATA,
+}
+mbedtls_pkcs7_type;
+
+/**
+ * Structure holding PKCS7 signer info
+ */
+typedef struct mbedtls_pkcs7_signer_info
+{
+    int MBEDTLS_PRIVATE(version);
+    mbedtls_x509_buf MBEDTLS_PRIVATE(serial);
+    mbedtls_x509_name MBEDTLS_PRIVATE(issuer);
+    mbedtls_x509_buf MBEDTLS_PRIVATE(issuer_raw);
+    mbedtls_x509_buf MBEDTLS_PRIVATE(alg_identifier);
+    mbedtls_x509_buf MBEDTLS_PRIVATE(sig_alg_identifier);
+    mbedtls_x509_buf MBEDTLS_PRIVATE(sig);
+    struct mbedtls_pkcs7_signer_info *MBEDTLS_PRIVATE(next);
+}
+mbedtls_pkcs7_signer_info;
+
+/**
+ * Structure holding attached data as part of PKCS7 signed data format
+ */
+typedef struct mbedtls_pkcs7_data
+{
+    mbedtls_pkcs7_buf MBEDTLS_PRIVATE(oid);
+    mbedtls_pkcs7_buf MBEDTLS_PRIVATE(data);
+}
+mbedtls_pkcs7_data;
+
+/**
+ * Structure holding the signed data section
+ */
+typedef struct mbedtls_pkcs7_signed_data
+{
+    int MBEDTLS_PRIVATE(version);
+    mbedtls_pkcs7_buf MBEDTLS_PRIVATE(digest_alg_identifiers);
+    struct mbedtls_pkcs7_data MBEDTLS_PRIVATE(content);
+    int MBEDTLS_PRIVATE(no_of_certs);
+    mbedtls_x509_crt MBEDTLS_PRIVATE(certs);
+    int MBEDTLS_PRIVATE(no_of_crls);
+    mbedtls_x509_crl MBEDTLS_PRIVATE(crl);
+    int MBEDTLS_PRIVATE(no_of_signers);
+    mbedtls_pkcs7_signer_info MBEDTLS_PRIVATE(signers);
+}
+mbedtls_pkcs7_signed_data;
+
+/**
+ * Structure holding PKCS7 structure, only signed data for now
+ */
+typedef struct mbedtls_pkcs7
+{
+    mbedtls_pkcs7_buf MBEDTLS_PRIVATE(raw);
+    mbedtls_pkcs7_buf MBEDTLS_PRIVATE(content_type_oid);
+    mbedtls_pkcs7_signed_data MBEDTLS_PRIVATE(signed_data);
+}
+mbedtls_pkcs7;
+
+/**
+ * \brief          Initialize pkcs7 structure.
+ *
+ * \param pkcs7    pkcs7 structure.
+ */
+void mbedtls_pkcs7_init( mbedtls_pkcs7 *pkcs7 );
+
+/**
+ * \brief          Parse a single DER formatted pkcs7 content.
+ *
+ * \param pkcs7    The pkcs7 structure to be filled by parser for the output.
+ * \param buf      The buffer holding the DER encoded pkcs7.
+ * \param buflen   The size in Bytes of \p buf.
+ *
+ * \note           This function makes an internal copy of the PKCS7 buffer
+ *                 \p buf. In particular, \p buf may be destroyed or reused
+ *                 after this call returns.
+ *
+ * \return         The \c mbedtls_pkcs7_type of \p buf, if successful.
+ * \return         A negative error code on failure.
+ */
+int mbedtls_pkcs7_parse_der( mbedtls_pkcs7 *pkcs7, const unsigned char *buf,
+                             const size_t buflen );
+
+/**
+ * \brief          Verification of PKCS7 signature.
+ *
+ * \param pkcs7    PKCS7 structure containing signature.
+ * \param cert     Certificate containing key to verify signature.
+ * \param data     Plain data on which signature has to be verified.
+ * \param datalen  Length of the data.
+ *
+ * \note           This function internally calculates the hash on the supplied
+ *                 plain data for signature verification.
+ *
+ * \return         A negative error code on failure.
+ */
+int mbedtls_pkcs7_signed_data_verify( mbedtls_pkcs7 *pkcs7,
+                                      const mbedtls_x509_crt *cert,
+                                      const unsigned char *data,
+                                      size_t datalen );
+
+/**
+ * \brief          Verification of PKCS7 signature.
+ *
+ * \param pkcs7    PKCS7 structure containing signature.
+ * \param cert     Certificate containing key to verify signature.
+ * \param hash     Hash of the plain data on which signature has to be verified.
+ * \param hashlen  Length of the hash.
+ *
+ * \note           This function is different from mbedtls_pkcs7_signed_data_verify()
+ *                 in a way that it directly recieves the hash of the data.
+ *
+ * \return         A negative error code on failure.
+ */
+int mbedtls_pkcs7_signed_hash_verify( mbedtls_pkcs7 *pkcs7,
+                                      const mbedtls_x509_crt *cert,
+                                      const unsigned char *hash, size_t hashlen);
+
+/**
+ * \brief          Unallocate all PKCS7 data and zeroize the memory.
+ *                 It doesn't free pkcs7 itself. It should be done by the caller.
+ *
+ * \param pkcs7    PKCS7 structure to free.
+ */
+void mbedtls_pkcs7_free( mbedtls_pkcs7 *pkcs7 );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* pkcs7.h */

library/CMakeLists.txt

@@ -92,6 +92,7 @@ set(src_crypto
 )
 
 set(src_x509
+    pkcs7.c
     x509.c
     x509_create.c
     x509_crl.c

library/Makefile

@@ -168,6 +168,7 @@ OBJS_X509= \
 	   x509_csr.o \
 	   x509write_crt.o \
 	   x509write_csr.o \
+	   pkcs7.o \
 	   # This line is intentionally left blank
 
 OBJS_TLS= \