diff options
| author | Eric Biggers <ebiggers@google.com> | 2017-10-09 12:43:20 -0700 |
|---|---|---|
| committer | Sasha Levin <alexander.levin@verizon.com> | 2017-11-05 23:54:36 -0500 |
| commit | 88857046155f875ecdc931a1ad3ac3705615fda2 (patch) | |
| tree | fe2bb05168e18d5dd0a3a34cf3c22b8657917b4a /lib | |
| parent | 0c2f1c32d2e13de35f74ae30daa693374a0f38a8 (diff) | |
lib/digsig: fix dereference of NULL user_key_payload
[ Upstream commit 192cabd6a296cbc57b3d8c05c4c89d87fc102506 ]
digsig_verify() requests a user key, then accesses its payload.
However, a revoked key has a NULL payload, and we failed to check for
this. request_key() *does* skip revoked keys, but there is still a
window where the key can be revoked before we acquire its semaphore.
Fix it by checking for a NULL payload, treating it like a key which was
already revoked at the time it was requested.
Fixes: 051dbb918c7f ("crypto: digital signature verification support")
Reviewed-by: James Morris <james.l.morris@oracle.com>
Cc: <stable@vger.kernel.org> [v3.3+]
Cc: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/digsig.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/digsig.c b/lib/digsig.c index ae05ea393fc8..4b8ef0bd315b 100644 --- a/lib/digsig.c +++ b/lib/digsig.c @@ -86,6 +86,12 @@ static int digsig_verify_rsa(struct key *key, down_read(&key->sem); ukp = key->payload.data; + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + err = -EKEYREVOKED; + goto err1; + } + if (ukp->datalen < sizeof(*pkh)) goto err1; |