crypto: af_alg - whitelist mask and type

commit bb30b8848c85e18ca7e371d0a869e94b3e383bdf upstream.

The user space interface allows specifying the type and mask field used
to allocate the cipher. Only a subset of the possible flags are intended
for user space. Therefore, white-list the allowed flags.

In case the user space caller uses at least one non-allowed flag, EINVAL
is returned.

Change-Id: I69c26179fc417a999f8fc76ba31957c623393c12
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[bwh: Backported to 3.2: The CRYPTO_ALG_KERN_DRIVER_ONLY flag is not supported,
 so set allowed to 0]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
This commit is contained in:
Stephan Mueller 2018-01-02 08:55:25 +01:00 committed by syphyr
parent 71d8b8c96a
commit 16a4c4a6f1
1 changed files with 5 additions and 0 deletions

View File

@ -149,6 +149,7 @@ EXPORT_SYMBOL_GPL(af_alg_release_parent);
static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
{
const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
struct sockaddr_alg *sa = (void *)uaddr;
@ -156,6 +157,10 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
void *private;
int err;
/* If caller uses non-allowed flag, return error. */
if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
return -EINVAL;
if (sock->state == SS_CONNECTED)
return -EINVAL;