path: root/fs
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authorRabin Vincent <rabin.vincent@axis.com>2014-12-19 13:36:08 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-08 09:58:17 -0800
commit3d53f1f7166c4bc5e936155de143676bf5fc7b0c (patch)
treea7a7b34e34ee34240ffaca273d639489be9b3427 /fs
parent3150a5ae1c08aac6aba8454cb536316a48eecc52 (diff)
crypto: af_alg - fix backlog handling
commit 7e77bdebff5cb1e9876c561f69710b9ab8fa1f7e upstream. If a request is backlogged, it's complete() handler will get called twice: once with -EINPROGRESS, and once with the final error code. af_alg's complete handler, unlike other users, does not handle the -EINPROGRESS but instead always completes the completion that recvmsg() is waiting on. This can lead to a return to user space while the request is still pending in the driver. If userspace closes the sockets before the requests are handled by the driver, this will lead to use-after-frees (and potential crashes) in the kernel due to the tfm having been freed. The crashes can be easily reproduced (for example) by reducing the max queue length in cryptod.c and running the following (from http://www.chronox.de/libkcapi.html) on AES-NI capable hardware: $ while true; do kcapi -x 1 -e -c '__ecb-aes-aesni' \ -k 00000000000000000000000000000000 \ -p 00000000000000000000000000000000 >/dev/null & done Signed-off-by: Rabin Vincent <rabin.vincent@axis.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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