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gpg: Verify multiple detached signatures with different hash algos. 

* g10/mainproc.c (proc_tree): Loose check.  Enable all algos.

Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch 2016-10-27 19:51:56 +02:00
parent ece9ade4b4
commit 8fced66be3
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
1 changed files with 23 additions and 5 deletions
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28
g10/mainproc.c
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@ -2359,11 +2359,16 @@ proc_tree (CTX c, kbnode_t node)
for (; n1; (n1 = find_next_kbnode(n1, PKT_SIGNATURE)))
{
/* We can't currently handle multiple signatures of
different classes or digests (we'd pretty much have
to run a different hash context for each), but if
they are all the same, make an exception. */
* different classes (we'd pretty much have to run a
* different hash context for each), but if they are all
* the same and it is detached signature, we make an
* exception. Note that the old code also disallowed
* multiple signatures if the digest algorithms are
* different. We softened this restriction only for
* detached signatures, to be on the safe side. */
if (n1->pkt->pkt.signature->sig_class != class
|| n1->pkt->pkt.signature->digest_algo != hash)
|| (c->any.data
&& n1->pkt->pkt.signature->digest_algo != hash))
{
multiple_ok = 0;
log_info (_("WARNING: multiple signatures detected. "
@ -2385,6 +2390,17 @@ proc_tree (CTX c, kbnode_t node)
if (rc)
goto detached_hash_err;
if (multiple_ok)
{
/* If we have and want to handle multiple signatures we
* need to enable all hash algorithms for the context. */
for (n1 = node; (n1 = find_next_kbnode (n1, PKT_SIGNATURE)); )
if (!openpgp_md_test_algo (n1->pkt->pkt.signature->digest_algo))
gcry_md_enable (c->mfx.md,
map_md_openpgp_to_gcry
(n1->pkt->pkt.signature->digest_algo));
}
if (RFC2440 || RFC4880)
; /* Strict RFC mode. */
else if (sig->digest_algo == DIGEST_ALGO_SHA1
@ -2392,7 +2408,9 @@ proc_tree (CTX c, kbnode_t node)
&& sig->sig_class == 0x01)
{
/* Enable a workaround for a pgp5 bug when the detached
* signature has been created in textmode. */
* signature has been created in textmode. Note that we
* do not implement this for multiple signatures with
* different hash algorithms. */
rc = gcry_md_open (&c->mfx.md2, sig->digest_algo, 0);
if (rc)
goto detached_hash_err;