diff options
| author | Eric Biggers <ebiggers@google.com> | 2017-10-09 12:43:20 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-01-01 20:51:52 +0000 |
| commit | 89fd0e583cfaf225075fd6a5c392940f7a71fa73 (patch) | |
| tree | d589df99b84a43f55b22424416e89fd88c751a25 /lib | |
| parent | 48a69df6da32de78c3b398f62dc7429989528b36 (diff) | |
lib/digsig: fix dereference of NULL user_key_payload
commit 192cabd6a296cbc57b3d8c05c4c89d87fc102506 upstream.
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: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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payload.data; + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + err = -EKEYREVOKED; + goto err1; + } + if (ukp-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; |