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net/tls: Only attach to sockets in ESTABLISHED state

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[ Upstream commit d91c3e17f75f218022140dee18cf515292184a8f ]

Calling accept on a TCP socket with a TLS ulp attached results
in two sockets that share the same ulp context.
The ulp context is freed while a socket is destroyed, so
after one of the sockets is released, the second second will
trigger a use after free when it tries to access the ulp context
attached to it.
We restrict the TLS ulp to sockets in ESTABLISHED state
to prevent the scenario above.

Fixes: 3c4d7559159b ("tls: kernel TLS support")
Reported-by: syzbot+904e7cd6c5c741609228@syzkaller.appspotmail.com
Signed-off-by: Ilya Lesokhin <ilyal@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ilya Lesokhin 2018-01-16 15:31:52 +02:00 committed by Greg Kroah-Hartman
parent 48606bb1ee
commit a022bbe393
1 changed files with 9 additions and 0 deletions
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9
net/tls/tls_main.c
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@ -444,6 +444,15 @@ static int tls_init(struct sock *sk)
struct tls_context *ctx;
int rc = 0;
/* The TLS ulp is currently supported only for TCP sockets
* in ESTABLISHED state.
* Supporting sockets in LISTEN state will require us
* to modify the accept implementation to clone rather then
* share the ulp context.
*/
if (sk->sk_state != TCP_ESTABLISHED)
return -ENOTSUPP;
/* allocate tls context */
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx) {