Support decoding multiple signer's cert in the signed data within a PKCS7 message.
The PR for this patch is at: https://github.com/Mbed-TLS/mbedtls/pull/9001 For enabling EFI loader PKCS7 features with MbedTLS build, we need this patch on top of MbedTLS v3.6.0 before it is merged into the next MbedTLS LTS release. Signed-off-by: Raymond Mao <raymond....@linaro.org> --- Changes in v2 - None. Changes in v3 - Update commit message. Changes in v4 - None. Changes in v5 - None. lib/mbedtls/external/mbedtls/library/pkcs7.c | 75 ++++++++++++-------- 1 file changed, 47 insertions(+), 28 deletions(-) diff --git a/lib/mbedtls/external/mbedtls/library/pkcs7.c b/lib/mbedtls/external/mbedtls/library/pkcs7.c index da73fb341d6..01105227d7a 100644 --- a/lib/mbedtls/external/mbedtls/library/pkcs7.c +++ b/lib/mbedtls/external/mbedtls/library/pkcs7.c @@ -61,6 +61,36 @@ static int pkcs7_get_next_content_len(unsigned char **p, unsigned char *end, return ret; } +/** + * Get and decode one cert from a sequence. + * Return 0 for success, + * Return negative error code for failure. + **/ +static int pkcs7_get_one_cert(unsigned char **p, unsigned char *end, + mbedtls_x509_crt *certs) +{ + int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; + size_t len = 0; + unsigned char *start = *p; + unsigned char *end_cert; + + 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_CERT, ret); + } + + end_cert = *p + len; + + if ((ret = mbedtls_x509_crt_parse_der(certs, start, end_cert - start)) < 0) { + return MBEDTLS_ERR_PKCS7_INVALID_CERT; + } + + *p = end_cert; + + return 0; +} + /** * version Version * Version ::= INTEGER @@ -178,11 +208,12 @@ 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; + size_t len = 0; + unsigned char *end_set; + int num_of_certs = 0; - ret = mbedtls_asn1_get_tag(p, end, &len1, MBEDTLS_ASN1_CONSTRUCTED + /* Get the set of certs */ + ret = mbedtls_asn1_get_tag(p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_CONTEXT_SPECIFIC); if (ret == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) { return 0; @@ -190,38 +221,26 @@ static int pkcs7_get_certificates(unsigned char **p, unsigned char *end, if (ret != 0) { return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_FORMAT, ret); } - start = *p; - end_set = *p + len1; + end_set = *p + len; - ret = mbedtls_asn1_get_tag(p, end_set, &len2, MBEDTLS_ASN1_CONSTRUCTED - | MBEDTLS_ASN1_SEQUENCE); + ret = pkcs7_get_one_cert(p, end_set, certs); if (ret != 0) { - return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PKCS7_INVALID_CERT, ret); + return ret; } - end_cert = *p + len2; + num_of_certs++; - /* - * 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; + while (*p != end_set) { + ret = pkcs7_get_one_cert(p, end_set, certs); + if (ret != 0) { + return ret; + } + num_of_certs++; } - *p = end_cert; + *p = end_set; - /* - * Since in this version we strictly support single certificate, and reaching - * here implies we have parsed successfully, we return 1. - */ - return 1; + return num_of_certs; } /** -- 2.25.1
