linux-stable.git/crypto/algif_hash.c, branch linux-4.4.y

crypto: af_alg - fix use-after-free in af_alg_accept() due to bh_lock_sock()

2020-07-09T07:35:08+00:00

commit 34c86f4c4a7be3b3e35aa48bd18299d4c756064d upstream.

The locking in af_alg_release_parent is broken as the BH socket
lock can only be taken if there is a code-path to handle the case
where the lock is owned by process-context.  Instead of adding
such handling, we can fix this by changing the ref counts to
atomic_t.

This patch also modifies the main refcnt to include both normal
and nokey sockets.  This way we don't have to fudge the nokey
ref count when a socket changes from nokey to normal.

Credits go to Mauricio Faria de Oliveira who diagnosed this bug
and sent a patch for it:

https://lore.kernel.org/linux-crypto/20200605161657.535043-1-mfo@canonical.com/

Reported-by: Brian Moyles 
Reported-by: Mauricio Faria de Oliveira 
Fixes: 37f96694cf73 ("crypto: af_alg - Use bh_lock_sock in...")
Cc: 
Signed-off-by: Herbert Xu 
Signed-off-by: Greg Kroah-Hartman

crypto: algif_hash - avoid zero-sized array

2017-03-30T07:35:20+00:00

commit 6207119444595d287b1e9e83a2066c17209698f3 upstream.

With this reproducer:
  struct sockaddr_alg alg = {
          .salg_family = 0x26,
          .salg_type = "hash",
          .salg_feat = 0xf,
          .salg_mask = 0x5,
          .salg_name = "digest_null",
  };
  int sock, sock2;

  sock = socket(AF_ALG, SOCK_SEQPACKET, 0);
  bind(sock, (struct sockaddr *)&alg, sizeof(alg));
  sock2 = accept(sock, NULL, NULL);
  setsockopt(sock, SOL_ALG, ALG_SET_KEY, "\x9b\xca", 2);
  accept(sock2, NULL, NULL);

==== 8< ======== 8< ======== 8< ======== 8< ====

one can immediatelly see an UBSAN warning:
UBSAN: Undefined behaviour in crypto/algif_hash.c:187:7
variable length array bound value 0 <= 0
CPU: 0 PID: 15949 Comm: syz-executor Tainted: G            E      4.4.30-0-default #1
...
Call Trace:
...
 [] ? __ubsan_handle_vla_bound_not_positive+0x13d/0x188
 [] ? __ubsan_handle_out_of_bounds+0x1bc/0x1bc
 [] ? hash_accept+0x5bd/0x7d0 [algif_hash]
 [] ? hash_accept_nokey+0x3f/0x51 [algif_hash]
 [] ? hash_accept_parent_nokey+0x4a0/0x4a0 [algif_hash]
 [] ? SyS_accept+0x2b/0x40

It is a correct warning, as hash state is propagated to accept as zero,
but creating a zero-length variable array is not allowed in C.

Fix this as proposed by Herbert -- do "?: 1" on that site. No sizeof or
similar happens in the code there, so we just allocate one byte even
though we do not use the array.

Signed-off-by: Jiri Slaby 
Cc: Herbert Xu 
Cc: "David S. Miller"  (maintainer:CRYPTO API)
Reported-by: Sasha Levin 
Signed-off-by: Herbert Xu 
Cc: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

crypto: algif_hash - wait for crypto_ahash_init() to complete

2016-02-17T20:31:04+00:00

commit fe09786178f9df713a4b2dd6b93c0a722346bf5e upstream.

hash_sendmsg/sendpage() need to wait for the completion
of crypto_ahash_init() otherwise it can cause panic.

Signed-off-by: Rui Wang 
Signed-off-by: Herbert Xu 
Signed-off-by: Greg Kroah-Hartman

crypto: algif_hash - Fix race condition in hash_check_key

2016-02-17T20:31:04+00:00

commit ad46d7e33219218605ea619e32553daf4f346b9f upstream.

We need to lock the child socket in hash_check_key as otherwise
two simultaneous calls can cause the parent socket to be freed.

Signed-off-by: Herbert Xu 
Signed-off-by: Greg Kroah-Hartman

crypto: algif_hash - Remove custom release parent function

2016-02-17T20:31:03+00:00

commit f1d84af1835846a5a2b827382c5848faf2bb0e75 upstream.

This patch removes the custom release parent function as the
generic af_alg_release_parent now works for nokey sockets too.

Signed-off-by: Herbert Xu 
Signed-off-by: Greg Kroah-Hartman

crypto: algif_hash - Require setkey before accept(2)

2016-02-17T20:31:03+00:00

commit 6de62f15b581f920ade22d758f4c338311c2f0d4 upstream.

Hash implementations that require a key may crash if you use
them without setting a key.  This patch adds the necessary checks
so that if you do attempt to use them without a key that we return
-ENOKEY instead of proceeding.

This patch also adds a compatibility path to support old applications
that do acept(2) before setkey.

Signed-off-by: Herbert Xu 
Signed-off-by: Greg Kroah-Hartman

crypto: algif_hash - Only export and import on sockets with data

2015-11-02T09:48:30+00:00

The hash_accept call fails to work on sockets that have not received
any data.  For some algorithm implementations it may cause crashes.

This patch fixes this by ensuring that we only export and import on
sockets that have received data.

Cc: stable@vger.kernel.org
Reported-by: Harsh Jain 
Signed-off-by: Herbert Xu 
Tested-by: Stephan Mueller

new helper: msg_data_left()

2015-04-11T19:53:35+00:00

convert open-coded instances

Signed-off-by: Al Viro

net: Remove iocb argument from sendmsg and recvmsg

2015-03-02T18:06:31+00:00

After TIPC doesn't depend on iocb argument in its internal
implementations of sendmsg() and recvmsg() hooks defined in proto
structure, no any user is using iocb argument in them at all now.
Then we can drop the redundant iocb argument completely from kinds of
implementations of both sendmsg() and recvmsg() in the entire
networking stack.

Cc: Christoph Hellwig 
Suggested-by: Al Viro 
Signed-off-by: Ying Xue 
Signed-off-by: David S. Miller

crypto: switch af_alg_make_sg() to iov_iter

2015-02-04T06:34:15+00:00

With that, all ->sendmsg() instances are converted to iov_iter primitives
and are agnostic wrt the kind of iov_iter they are working with.
So's the last remaining ->recvmsg() instance that wasn't kind-agnostic yet.
All ->sendmsg() and ->recvmsg() advance ->msg_iter by the amount actually
copied and none of them modifies the underlying iovec, etc.

Cc: linux-crypto@vger.kernel.org
Signed-off-by: Al Viro