diff options
| -rw-r--r-- | src/lib/tls/tortls_nss.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/src/lib/tls/tortls_nss.c b/src/lib/tls/tortls_nss.c index f1ef3ef277..1436442e1c 100644 --- a/src/lib/tls/tortls_nss.c +++ b/src/lib/tls/tortls_nss.c @@ -742,14 +742,23 @@ tor_tls_cert_matches_key,(const tor_tls_t *tls, const unsigned int peer_info_orig_len = peer_info->subjectPublicKey.len; const unsigned int cert_info_orig_len = cert_info->subjectPublicKey.len; - peer_info->subjectPublicKey.len = (peer_info_orig_len >> 3); - cert_info->subjectPublicKey.len = (cert_info_orig_len >> 3); + /* We convert the length from bits to bytes, but instead of using NSS's + * `DER_ConvertBitString()` macro on both of peer_info->subjectPublicKey and + * cert_info->subjectPublicKey, we have to do the conversion explicitly since + * both of the two subjectPublicKey fields are allowed to point to the same + * memory address. Otherwise, the bits to bytes conversion would potentially + * be applied twice, which would lead to us comparing too few of the bytes + * when we call SECITEM_ItemsAreEqual(), which would be catastrophic. + */ + peer_info->subjectPublicKey.len = ((peer_info_orig_len + 7) >> 3); + cert_info->subjectPublicKey.len = ((cert_info_orig_len + 7) >> 3); rv = SECOID_CompareAlgorithmID(&peer_info->algorithm, &cert_info->algorithm) == 0 && SECITEM_ItemsAreEqual(&peer_info->subjectPublicKey, &cert_info->subjectPublicKey); + /* Convert from bytes back to bits. */ peer_info->subjectPublicKey.len = peer_info_orig_len; cert_info->subjectPublicKey.len = cert_info_orig_len; |