Commit 44679e78 authored by Eric Biggers's avatar Eric Biggers Committed by Juerg Haefliger

crypto: x86/chacha20 - avoid sleeping with preemption disabled

BugLink: https://bugs.launchpad.net/bugs/1811647

In chacha20-simd, clear the MAY_SLEEP flag in the blkcipher_desc to
prevent sleeping with preemption disabled, under kernel_fpu_begin().

This was fixed upstream incidentally by a large refactoring,
commit 9ae433bc ("crypto: chacha20 - convert generic and x86
versions to skcipher").  But syzkaller easily trips over this when
running on older kernels, as it's easily reachable via AF_ALG.
Therefore, this patch makes the minimal fix for older kernels.

Fixes: c9320b6d ("crypto: chacha20 - Add a SSSE3 SIMD variant for x86_64")
Cc: linux-crypto@vger.kernel.org
Cc: Martin Willi <martin@strongswan.org>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Acked-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJuerg Haefliger <juergh@canonical.com>
Signed-off-by: default avatarStefan Bader <stefan.bader@canonical.com>
parent 2e077a4c
...@@ -77,6 +77,7 @@ static int chacha20_simd(struct blkcipher_desc *desc, struct scatterlist *dst, ...@@ -77,6 +77,7 @@ static int chacha20_simd(struct blkcipher_desc *desc, struct scatterlist *dst,
blkcipher_walk_init(&walk, dst, src, nbytes); blkcipher_walk_init(&walk, dst, src, nbytes);
err = blkcipher_walk_virt_block(desc, &walk, CHACHA20_BLOCK_SIZE); err = blkcipher_walk_virt_block(desc, &walk, CHACHA20_BLOCK_SIZE);
desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
crypto_chacha20_init(state, crypto_blkcipher_ctx(desc->tfm), walk.iv); crypto_chacha20_init(state, crypto_blkcipher_ctx(desc->tfm), walk.iv);
......
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