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| author | Eric Biggers <ebiggers@google.com> | 2017-10-09 22:46:18 +0300 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2017-10-12 19:16:40 +0300 |
| commit | d60b5b7854c3d135b869f74fb93eaf63cbb1991a (patch) | |
| tree | be7b147d0cb48d18f7069e053c4271dead139f94 /fs/crypto/keyinfo.c | |
| parent | 192cabd6a296cbc57b3d8c05c4c89d87fc102506 (diff) | |
| download | linux-d60b5b7854c3d135b869f74fb93eaf63cbb1991a.tar.xz | |
fscrypt: fix dereference of NULL user_key_payload
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>
Cc: <stable@vger.kernel.org> [v4.1+]
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'fs/crypto/keyinfo.c')
| -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 018c588c7ac3..8e704d12a1cf 100644 --- a/fs/crypto/keyinfo.c +++ b/fs/crypto/keyinfo.c @@ -109,6 +109,11 @@ static int validate_user_key(struct fscrypt_info *crypt_info, goto out; } ukp = user_key_payload_locked(keyring_key); + if (!ukp) { + /* key was revoked before we acquired its semaphore */ + res = -EKEYREVOKED; + goto out; + } if (ukp-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; |