diff options
Diffstat (limited to 'g10/sig-check.c')
| -rw-r--r-- | g10/sig-check.c | 134 |
1 files changed, 71 insertions, 63 deletions
diff --git a/g10/sig-check.c b/g10/sig-check.c index 60e988e60..a4ef142df 100644 --- a/g10/sig-check.c +++ b/g10/sig-check.c @@ -738,38 +738,38 @@ check_key_signature (ctrl_t ctrl, kbnode_t root, kbnode_t node, /* Returns whether SIGNER generated the signature SIG over the packet - PACKET, which is a key, subkey or uid, and comes from the key block - KB. (KB is PACKET's corresponding keyblock; we don't assume that - SIG has been added to the keyblock.) - - If SIGNER is set, then checks whether SIGNER generated the - signature. Otherwise, uses SIG->KEYID to find the alleged signer. - This parameter can be used to effectively override the alleged - signer that is stored in SIG. - - KB may be NULL if SIGNER is set. - - Unlike check_key_signature, this function ignores any cached - results! That is, it does not consider SIG->FLAGS.CHECKED and - SIG->FLAGS.VALID nor does it set them. - - This doesn't check the signature's semantic mean. Concretely, it - doesn't check whether a non-self signed revocation signature was - created by a designated revoker. In fact, it doesn't return an - error for a binding generated by a completely different key! - - Returns 0 if the signature is valid. Returns GPG_ERR_SIG_CLASS if - this signature can't be over PACKET. Returns GPG_ERR_NOT_FOUND if - the key that generated the signature (according to SIG) could not - be found. Returns GPG_ERR_BAD_SIGNATURE if the signature is bad. - Other errors codes may be returned if something else goes wrong. - - IF IS_SELFSIG is not NULL, sets *IS_SELFSIG to 1 if this is a - self-signature (by the key's primary key) or 0 if not. - - If RET_PK is not NULL, returns a copy of the public key that - generated the signature (i.e., the signer) on success. This must - be released by the caller using release_public_key_parts (). */ + * PACKET, which is a key, subkey or uid, and comes from the key block + * KB. (KB is PACKET's corresponding keyblock; we don't assume that + * SIG has been added to the keyblock.) + * + * If SIGNER is set, then checks whether SIGNER generated the + * signature. Otherwise, uses SIG->KEYID to find the alleged signer. + * This parameter can be used to effectively override the alleged + * signer that is stored in SIG. + * + * KB may be NULL if SIGNER is set. + * + * Unlike check_key_signature, this function ignores any cached + * results! That is, it does not consider SIG->FLAGS.CHECKED and + * SIG->FLAGS.VALID nor does it set them. + * + * This doesn't check the signature's semantic mean. Concretely, it + * doesn't check whether a non-self signed revocation signature was + * created by a designated revoker. In fact, it doesn't return an + * error for a binding generated by a completely different key! + * + * Returns 0 if the signature is valid. Returns GPG_ERR_SIG_CLASS if + * this signature can't be over PACKET. Returns GPG_ERR_NOT_FOUND if + * the key that generated the signature (according to SIG) could not + * be found. Returns GPG_ERR_BAD_SIGNATURE if the signature is bad. + * Other errors codes may be returned if something else goes wrong. + * + * IF IS_SELFSIG is not NULL, sets *IS_SELFSIG to 1 if this is a + * self-signature (by the key's primary key) or 0 if not. + * + * If RET_PK is not NULL, returns a copy of the public key that + * generated the signature (i.e., the signer) on success. This must + * be released by the caller using release_public_key_parts (). */ gpg_error_t check_signature_over_key_or_uid (ctrl_t ctrl, PKT_public_key *signer, PKT_signature *sig, KBNODE kb, PACKET *packet, @@ -796,8 +796,8 @@ check_signature_over_key_or_uid (ctrl_t ctrl, PKT_public_key *signer, /* Primary key revocation. */ || sig->sig_class == 0x20) { + /* Key revocations can only be over primary keys. */ if (packet->pkttype != PKT_PUBLIC_KEY) - /* Key revocations can only be over primary keys. */ return gpg_error (GPG_ERR_SIG_CLASS); } else if (/* Subkey binding. */ @@ -840,19 +840,19 @@ check_signature_over_key_or_uid (ctrl_t ctrl, PKT_public_key *signer, /* Get the signer. If possible, avoid a look up. */ if (sig->keyid[0] == pripk->keyid[0] && sig->keyid[1] == pripk->keyid[1]) - /* Issued by the primary key. */ { + /* Issued by the primary key. */ signer = pripk; if (is_selfsig) *is_selfsig = 1; } else { + /* See if one of the subkeys was the signer (although this + is extremely unlikely). */ kbnode_t ctx = NULL; kbnode_t n; - /* See if one of the subkeys was the signer (although this - is extremely unlikely). */ while ((n = walk_kbnode (kb, &ctx, 0))) { PKT_public_key *subk; @@ -863,16 +863,16 @@ check_signature_over_key_or_uid (ctrl_t ctrl, PKT_public_key *signer, subk = n->pkt->pkt.public_key; if (sig->keyid[0] == subk->keyid[0] && sig->keyid[1] == subk->keyid[1]) - /* Issued by a subkey. */ { + /* Issued by a subkey. */ signer = subk; break; } } if (! signer) - /* Signer by some other key. */ { + /* Signer by some other key. */ if (is_selfsig) *is_selfsig = 0; if (ret_pk) @@ -893,14 +893,14 @@ check_signature_over_key_or_uid (ctrl_t ctrl, PKT_public_key *signer, xfree (signer); signer = NULL; signer_alloced = 0; - goto out; + goto leave; } } } } /* We checked above that we supported this algo, so an error here is - a bug. */ + * a bug. */ if (gcry_md_open (&md, sig->digest_algo, 0)) BUG (); @@ -916,7 +916,7 @@ check_signature_over_key_or_uid (ctrl_t ctrl, PKT_public_key *signer, rc = check_signature_end_simple (signer, sig, md); } else if (/* Primary key binding (made by a subkey). */ - sig->sig_class == 0x19) + sig->sig_class == 0x19) { log_assert (packet->pkttype == PKT_PUBLIC_KEY); hash_public_key (md, packet->pkt.public_key); @@ -947,27 +947,31 @@ check_signature_over_key_or_uid (ctrl_t ctrl, PKT_public_key *signer, rc = check_signature_end_simple (signer, sig, md); } else - /* We should never get here. (The first if above should have - already caught this error.) */ - BUG (); + { + /* We should never get here. (The first if above should have + * already caught this error.) */ + BUG (); + } gcry_md_close (md); - out: + leave: if (! rc && ret_pk && (signer_alloced == -1 || ret_pk != signer)) copy_public_key (ret_pk, signer); + if (signer_alloced == 1) - /* We looked up SIGNER; it is not a pointer into KB. */ { + /* We looked up SIGNER; it is not a pointer into KB. */ release_public_key_parts (signer); + /* Free if we also allocated the memory. */ if (signer_alloced == 2) - /* We also allocated the memory. */ xfree (signer); } return rc; } + /* Check that a signature over a key (e.g., a key revocation, key * binding, user id certification, etc.) is valid. If the function * detects a self-signature, it uses the public key from the specified @@ -1027,9 +1031,9 @@ check_key_signature2 (ctrl_t ctrl, algo = sig->digest_algo; /* Check whether we have cached the result of a previous signature - check. Note that we may no longer have the pubkey or hash - needed to verify a sig, but can still use the cached value. A - cache refresh detects and clears these cases. */ + * check. Note that we may no longer have the pubkey or hash + * needed to verify a sig, but can still use the cached value. A + * cache refresh detects and clears these cases. */ if ( !opt.no_sig_cache ) { cache_stats.total++; @@ -1045,7 +1049,7 @@ check_key_signature2 (ctrl_t ctrl, *is_selfsig = 1; } /* BUG: This is wrong for non-self-sigs... needs to be the - actual pk. */ + * actual pk. */ rc = check_signature_metadata_validity (pk, sig, r_expired, NULL); if (rc) return rc; @@ -1094,13 +1098,15 @@ check_key_signature2 (ctrl_t ctrl, rc = check_signature_metadata_validity (pk, sig, r_expired, NULL); if (! rc) - /* 0x28 must be a self-sig, but 0x18 needn't be. */ - rc = check_signature_over_key_or_uid (ctrl, - sig->sig_class == 0x18 - ? NULL : pk, - sig, root, snode->pkt, - is_selfsig, ret_pk); - } + { + /* 0x28 must be a self-sig, but 0x18 needn't be. */ + rc = check_signature_over_key_or_uid (ctrl, + sig->sig_class == 0x18 + ? NULL : pk, + sig, root, snode->pkt, + is_selfsig, ret_pk); + } + } else { if (opt.verbose) @@ -1137,11 +1143,13 @@ check_key_signature2 (ctrl_t ctrl, { rc = check_signature_metadata_validity (pk, sig, r_expired, NULL); if (! rc) - /* If this is a self-sig, ignore check_pk. */ - rc = check_signature_over_key_or_uid - (ctrl, - keyid_cmp (pk_keyid (pk), sig->keyid) == 0 ? pk : check_pk, - sig, root, unode->pkt, NULL, ret_pk); + { + /* If this is a self-sig, ignore check_pk. */ + rc = check_signature_over_key_or_uid + (ctrl, + keyid_cmp (pk_keyid (pk), sig->keyid) == 0 ? pk : check_pk, + sig, root, unode->pkt, NULL, ret_pk); + } } else { |