diff options
| -rw-r--r-- | networking/tls.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/networking/tls.c b/networking/tls.c index 99722cf..c8d9e96 100644 --- a/networking/tls.c +++ b/networking/tls.c @@ -1082,6 +1082,8 @@ static void find_key_in_der_cert(tls_state_t *tls, uint8_t *der, int len) * We need Certificate.tbsCertificate.subjectPublicKeyInfo.publicKey */ uint8_t *end = der + len; + uint8_t tag_class, pc, tag_number; + int version_present; /* enter "Certificate" item: [der, end) will be only Cert */ der = enter_der_item(der, &end); @@ -1089,8 +1091,24 @@ static void find_key_in_der_cert(tls_state_t *tls, uint8_t *der, int len) /* enter "tbsCertificate" item: [der, end) will be only tbsCert */ der = enter_der_item(der, &end); + /* + * Skip version field only if it is present. For a v1 certificate, the + * version field won't be present since v1 is the default value for the + * version field and fields with default values should be omitted (see + * RFC 5280 sections 4.1 and 4.1.2.1). If the version field is present + * it will have a tag class of 2 (context-specific), bit 6 as 1 + * (constructed), and a tag number of 0 (see ITU-T X.690 sections 8.1.2 + * and 8.14). + */ + tag_class = der[0] >> 6; /* bits 8-7 */ + pc = (der[0] & 32) >> 5; /* bit 6 */ + tag_number = der[0] & 31; /* bits 5-1 */ + version_present = tag_class == 2 && pc == 1 && tag_number == 0; + if (version_present) { + der = skip_der_item(der, end); /* version */ + } + /* skip up to subjectPublicKeyInfo */ - der = skip_der_item(der, end); /* version */ der = skip_der_item(der, end); /* serialNumber */ der = skip_der_item(der, end); /* signatureAlgo */ der = skip_der_item(der, end); /* issuer */ |