From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:47640 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388214AbfAKO2s (ORCPT ); Fri, 11 Jan 2019 09:28:48 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, linux-crypto@vger.kernel.org, Martin Willi , Eric Biggers , Ard Biesheuvel Subject: [PATCH 4.9 42/63] crypto: x86/chacha20 - avoid sleeping with preemption disabled Date: Fri, 11 Jan 2019 15:14:45 +0100 Message-Id: <20190111131052.654348898@linuxfoundation.org> In-Reply-To: <20190111131046.387528003@linuxfoundation.org> References: <20190111131046.387528003@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-crypto-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers 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 Signed-off-by: Eric Biggers Acked-by: Ard Biesheuvel Signed-off-by: Greg Kroah-Hartman --- 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);