On Fri, Dec 19, 2014 at 01:36:08PM +0100, Rabin Vincent wrote: > 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@xxxxxxxx> Patch applied to crypto. Thanks! -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
