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| author | Eric Biggers <ebiggers@google.com> | 2017-10-09 22:43:20 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-27 11:17:24 +0300 |
| commit | f6a2c3d4b0ced8b34c46cf99bbd0c395e7e9bc58 (patch) | |
| tree | 7ea3b99f68c8d896180afb28ddf73dcffc03158b | |
| parent | 400f063f4dbc1210eea6aa6e18d95ea6139c3aae (diff) | |
| download | linux-f6a2c3d4b0ced8b34c46cf99bbd0c395e7e9bc58.tar.xz | |
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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payload.data; + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + err = -EKEYREVOKED; + goto err1; + } + if (ukp-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; |