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| author | Eric Biggers <ebiggers@google.com> | 2017-10-09 19:46:18 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-27 08:38:10 (GMT) |
| commit | b2ac5d4516fbe210a328b4b9fe65b80b3e731dee (patch) | |
| tree | 0a5adc7795ce4b0946fcc87312e39202d5002391 /fs | |
| parent | f374505b79104e8cbc6618c301f1cbb4058480bb (diff) | |
| download | linux-b2ac5d4516fbe210a328b4b9fe65b80b3e731dee.tar.xz | |
fscrypt: fix dereference of NULL user_key_payload
commit d60b5b7854c3d135b869f74fb93eaf63cbb1991a upstream.
When an fscrypt-encrypted file is opened, we request the file's master
key from the keyrings service as a logon key, then access 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: 88bd6ccdcdd6 ("ext4 crypto: add encryption key management facilities")
Reviewed-by: James Morris <james.l.morris@oracle.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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/crypto/keyinfo.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c index bb46063..a755fa1 100644 --- a/fs/crypto/keyinfo.c +++ b/fs/crypto/keyinfo.c @@ -108,6 +108,11 @@ static int validate_user_key(struct fscrypt_info *crypt_info, goto out; } ukp = user_key_payload(keyring_key); + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + res = -EKEYREVOKED; + goto out; + } if (ukp->datalen != sizeof(struct fscrypt_key)) { res = -EINVAL; goto out; |