* [PATCH 4.9 42/63] crypto: x86/chacha20 - avoid sleeping with preemption disabled
[not found] <20190111131046.387528003@linuxfoundation.org>
@ 2019-01-11 14:14 ` Greg Kroah-Hartman
0 siblings, 0 replies; only message in thread
From: Greg Kroah-Hartman @ 2019-01-11 14:14 UTC (permalink / raw)
To: linux-kernel
Cc: Greg Kroah-Hartman, stable, linux-crypto, Martin Willi,
Eric Biggers, Ard Biesheuvel
4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Biggers <ebiggers@google.com>
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 9ae433bc79f9 ("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: c9320b6dcb89 ("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: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/crypto/chacha20_glue.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/crypto/chacha20_glue.c
+++ b/arch/x86/crypto/chacha20_glue.c
@@ -77,6 +77,7 @@ static int chacha20_simd(struct blkciphe
blkcipher_walk_init(&walk, dst, src, nbytes);
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);
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