| Message ID | 20190107231559.13357-1-ebiggers@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | [4.9,4.4] crypto: x86/chacha20 - avoid sleeping with preemption disabled | expand |
On Tue, 8 Jan 2019 at 00:16, Eric Biggers <ebiggers@kernel.org> wrote: > > From: Eric Biggers <ebiggers@google.com> > > Hi Greg, please consider applying this to 4.9-stable and 4.4-stable. > It's a minimal fix for a bug that was fixed incidentally by a large > refactoring in v4.11. > > >8------------------------------------------------------8< > > 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> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > arch/x86/crypto/chacha20_glue.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/crypto/chacha20_glue.c b/arch/x86/crypto/chacha20_glue.c > index f910d1d449f00..0a5fedf43bdc8 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); > > -- > 2.20.1.97.g81188d93c3-goog >
On Mon, Jan 07, 2019 at 03:15:59PM -0800, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > Hi Greg, please consider applying this to 4.9-stable and 4.4-stable. > It's a minimal fix for a bug that was fixed incidentally by a large > refactoring in v4.11. > > >8------------------------------------------------------8< > > 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> > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> > Signed-off-by: Eric Biggers <ebiggers@google.com> > --- > arch/x86/crypto/chacha20_glue.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/x86/crypto/chacha20_glue.c b/arch/x86/crypto/chacha20_glue.c > index f910d1d449f00..0a5fedf43bdc8 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); > > -- > 2.20.1.97.g81188d93c3-goog > Now queued up, thanks. greg k-h
diff --git a/arch/x86/crypto/chacha20_glue.c b/arch/x86/crypto/chacha20_glue.c index f910d1d449f00..0a5fedf43bdc8 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);