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authorEric Biggers <ebiggers@google.com>2019-01-07 15:15:59 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-13 10:05:32 +0100
commit557f16c7fe26a2d16013c2821c5ce5a90a7da97e (patch)
tree49a1f16236426c2bb49f0e7e814018777ede8eb3 /arch/x86/crypto/chacha20_glue.c
parent69c1fd103bbb9afe3a6b345a3e026a627257d76b (diff)
crypto: x86/chacha20 - avoid sleeping with preemption disabled
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>
Diffstat (limited to 'arch/x86/crypto/chacha20_glue.c')
-rw-r--r--arch/x86/crypto/chacha20_glue.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/crypto/chacha20_glue.c b/arch/x86/crypto/chacha20_glue.c
index 8baaff5af0b5..75b9d43069f1 100644
--- a/arch/x86/crypto/chacha20_glue.c
+++ b/arch/x86/crypto/chacha20_glue.c
@@ -77,6 +77,7 @@ static int chacha20_simd(struct blkcipher_desc *desc, struct scatterlist *dst,
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);