Commit 192cabd6 authored by Eric Biggers's avatar Eric Biggers Committed by David Howells
Browse files

lib/digsig: fix dereference of NULL user_key_payload

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: 051dbb91

 ("crypto: digital signature verification support")
Reviewed-by: default avatarJames Morris <>
Cc: <>    [v3.3+]
Cc: Dmitry Kasatkin <>
Signed-off-by: default avatarEric Biggers <>
Signed-off-by: default avatarDavid Howells <>
parent d124b2c5
......@@ -87,6 +87,12 @@ static int digsig_verify_rsa(struct key *key,
ukp = user_key_payload_locked(key);
if (!ukp) {
/* key was revoked before we acquired its semaphore */
goto err1;
if (ukp->datalen < sizeof(*pkh))
goto err1;
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