diff options
| -rw-r--r-- | crypto/asymmetric_keys/x509_cert_parser.c | 55 |
1 files changed, 47 insertions, 8 deletions
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c index 7fabc4c..facbf26 100644 --- a/crypto/asymmetric_keys/x509_cert_parser.c +++ b/crypto/asymmetric_keys/x509_cert_parser.c @@ -373,6 +373,9 @@ int rsa_extract_mpi(void *context, size_t hdrlen, return 0; } +/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */ +#define SEQ_TAG_KEYID (ASN1_CONT << 6) + /* * Process certificate extensions that are used to qualify the certificate. */ @@ -407,21 +410,57 @@ int x509_process_extension(void *context, size_t hdrlen, } if (ctx->last_oid == OID_authorityKeyIdentifier) { + size_t key_len; + /* Get hold of the CA key fingerprint */ if (vlen < 5) return -EBADMSG; - if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5)) || - v[1] != vlen - 2 || - v[2] != (ASN1_CONT << 6) || - v[3] != vlen - 4) + + /* Authority Key Identifier must be a Constructed SEQUENCE */ + if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5))) return -EBADMSG; - v += 4; - vlen -= 4; - f = kmalloc(vlen * 2 + 1, GFP_KERNEL); + /* Authority Key Identifier is not indefinite length */ + if (unlikely(vlen == ASN1_INDEFINITE_LENGTH)) + return -EBADMSG; + + if (vlen < ASN1_INDEFINITE_LENGTH) { + /* Short Form length */ + if (v[1] != vlen - 2 || + v[2] != SEQ_TAG_KEYID || + v[3] > vlen - 4) + return -EBADMSG; + + key_len = v[3]; + v += 4; + } else { + /* Long Form length */ + size_t seq_len = 0; + size_t sub = v[1] - ASN1_INDEFINITE_LENGTH; + + if (sub > 2) + return -EBADMSG; + + /* calculate the length from subsequent octets */ + v += 2; + for (i = 0; i < sub; i++) { + seq_len <<= 8; + seq_len |= v[i]; + } + + if (seq_len != vlen - 2 - sub || + v[sub] != SEQ_TAG_KEYID || + v[sub + 1] > vlen - 4 - sub) + return -EBADMSG; + + key_len = v[sub + 1]; + v += (sub + 2); + } + + f = kmalloc(key_len * 2 + 1, GFP_KERNEL); if (!f) return -ENOMEM; - for (i = 0; i < vlen; i++) + for (i = 0; i < key_len; i++) sprintf(f + i * 2, "%02x", v[i]); pr_debug("authority %s\n", f); ctx->cert->authority = f; |
