linux-stable.git/crypto/algif_hash.c, branch linux-3.16.y

crypto: hash - prevent using keyed hashes without setting key

2018-06-16T21:21:52+00:00

commit 9fa68f620041be04720d0cbfb1bd3ddfc6310b24 upstream.

Currently, almost none of the keyed hash algorithms check whether a key
has been set before proceeding.  Some algorithms are okay with this and
will effectively just use a key of all 0's or some other bogus default.
However, others will severely break, as demonstrated using
"hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash
via a (potentially exploitable) stack buffer overflow.

A while ago, this problem was solved for AF_ALG by pairing each hash
transform with a 'has_key' bool.  However, there are still other places
in the kernel where userspace can specify an arbitrary hash algorithm by
name, and the kernel uses it as unkeyed hash without checking whether it
is really unkeyed.  Examples of this include:

    - KEYCTL_DH_COMPUTE, via the KDF extension
    - dm-verity
    - dm-crypt, via the ESSIV support
    - dm-integrity, via the "internal hash" mode with no key given
    - drbd (Distributed Replicated Block Device)

This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no
privileges to call.

Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the
->crt_flags of each hash transform that indicates whether the transform
still needs to be keyed or not.  Then, make the hash init, import, and
digest functions return -ENOKEY if the key is still needed.

The new flag also replaces the 'has_key' bool which algif_hash was
previously using, thereby simplifying the algif_hash implementation.

Reported-by: syzbot 
Signed-off-by: Eric Biggers 
Signed-off-by: Herbert Xu 
[bwh: Backported to 3.16:
 - In hash_accept_parent_nokey(), update initialisation of ds to use tfm
 - Adjust context]
Signed-off-by: Ben Hutchings

crypto: algif_hash - wait for crypto_ahash_init() to complete

2016-02-25T00:18:38+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: Luis Henriques

crypto: algif_hash - Fix race condition in hash_check_key

2016-02-24T14:40:37+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: Luis Henriques

crypto: algif_hash - Remove custom release parent function

2016-02-24T14:35:03+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: Luis Henriques

crypto: algif_hash - Require setkey before accept(2)

2016-02-24T14:28:54+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 
[bwh: Backported to 3.2:
 - Add struct kiocb * parameter to {recv,send}msg ops
 - Adjust context]
Signed-off-by: Ben Hutchings 
Signed-off-by: Luis Henriques

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

2015-12-13T17:49:02+00:00

commit 4afa5f9617927453ac04b24b584f6c718dfb4f45 upstream.

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.

Reported-by: Harsh Jain 
Signed-off-by: Herbert Xu 
Tested-by: Stephan Mueller 
Signed-off-by: Luis Henriques

net: update consumers of MSG_MORE to recognize MSG_SENDPAGE_NOTLAST

2013-11-29T21:32:54+00:00

Commit 35f9c09fe (tcp: tcp_sendpages() should call tcp_push() once)
added an internal flag MSG_SENDPAGE_NOTLAST, similar to
MSG_MORE.

algif_hash, algif_skcipher, and udp used MSG_MORE from tcp_sendpages()
and need to see the new flag as identical to MSG_MORE.

This fixes sendfile() on AF_ALG.

v3: also fix udp

Cc: Tom Herbert 
Cc: Eric Dumazet 
Cc: David S. Miller 
Cc:  # 3.4.x + 3.2.x
Reported-and-tested-by: Shawn Landden 
Original-patch: Richard Weinberger 
Signed-off-by: Shawn Landden 
Signed-off-by: David S. Miller

net: rework recvmsg handler msg_name and msg_namelen logic

2013-11-21T02:52:30+00:00

This patch now always passes msg->msg_namelen as 0. recvmsg handlers must
set msg_namelen to the proper size <= sizeof(struct sockaddr_storage)
to return msg_name to the user.

This prevents numerous uninitialized memory leaks we had in the
recvmsg handlers and makes it harder for new code to accidentally leak
uninitialized memory.

Optimize for the case recvfrom is called with NULL as address. We don't
need to copy the address at all, so set it to NULL before invoking the
recvmsg handler. We can do so, because all the recvmsg handlers must
cope with the case a plain read() is called on them. read() also sets
msg_name to NULL.

Also document these changes in include/linux/net.h as suggested by David
Miller.

Changes since RFC:

Set msg->msg_name = NULL if user specified a NULL in msg_name but had a
non-null msg_namelen in verify_iovec/verify_compat_iovec. This doesn't
affect sendto as it would bail out earlier while trying to copy-in the
address. It also more naturally reflects the logic by the callers of
verify_iovec.

With this change in place I could remove "
if (!uaddr || msg_sys->msg_namelen == 0)
	msg->msg_name = NULL
".

This change does not alter the user visible error logic as we ignore
msg_namelen as long as msg_name is NULL.

Also remove two unnecessary curly brackets in ___sys_recvmsg and change
comments to netdev style.

Cc: David Miller 
Suggested-by: Eric Dumazet 
Signed-off-by: Hannes Frederic Sowa 
Signed-off-by: David S. Miller

crypto: algif - suppress sending source address information in recvmsg

2013-04-10T06:26:06+00:00

The current code does not set the msg_namelen member to 0 and therefore
makes net/socket.c leak the local sockaddr_storage variable to userland
-- 128 bytes of kernel stack memory. Fix that.

Cc:  # 2.6.38
Signed-off-by: Mathias Krause 
Signed-off-by: Herbert Xu

crypto: algif_hash - Handle initial af_alg_make_sg error correctly

2011-06-29T23:44:06+00:00

When the first call to af_alg_make_sg fails, we may return garbage
instead of the real error.  This patch fixes it by setting the error
if "copied" is zero.

Based on a patch by Jesper Juhl.

Reported-by: Jesper Juhl 
Signed-off-by: Herbert Xu