[PATCH v2 14/28] mbedtls/external: support decoding multiple signer's cert
Ilias Apalodimas
ilias.apalodimas at linaro.org
Wed May 8 16:34:21 CEST 2024
Hi Raymond
On Tue, 7 May 2024 at 20:57, Raymond Mao <raymond.mao at linaro.org> wrote:
>
> Support decoding multiple signer's cert in the signed data within
> a PKCS7 message.
For all similar external mbedTLS patches, try to explain which belong
to mbedTLS must be sent upstream and which ones we need to carry
internally. I don't expect us to have to carry anything in U-Boot
Thanks
/Ilias
>
> Signed-off-by: Raymond Mao <raymond.mao at linaro.org>
> ---
> Changes in v2
> - 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
>
More information about the U-Boot
mailing list