From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934238AbdKAV2Z (ORCPT ); Wed, 1 Nov 2017 17:28:25 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:35364 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933676AbdKAV2W (ORCPT ); Wed, 1 Nov 2017 17:28:22 -0400 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Stephan Mueller , Greg Kroah-Hartman , Willy Tarreau Subject: [PATCH 3.10 128/139] crypto: AF_ALG - remove SGL terminator indicator when chaining Date: Wed, 1 Nov 2017 22:26:53 +0100 Message-Id: <1509571624-5001-29-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1509571624-5001-1-git-send-email-w@1wt.eu> References: <1509571159-4405-1-git-send-email-w@1wt.eu> <1509571624-5001-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stephan Mueller commit 1d4ba7f963a93a2207fd103d4a36df1b5aeefea2 upstream. Fixed differently upstream as commit 2d97591ef43d ("crypto: af_alg - consolidation of duplicate code") The SGL is MAX_SGL_ENTS + 1 in size. The last SG entry is used for the chaining and is properly updated with the sg_chain invocation. During the filling-in of the initial SG entries, sg_mark_end is called for each SG entry. This is appropriate as long as no additional SGL is chained with the current SGL. However, when a new SGL is chained and the last SG entry is updated with sg_chain, the last but one entry still contains the end marker from the sg_mark_end. This end marker must be removed as otherwise a walk of the chained SGLs will cause a NULL pointer dereference at the last but one SG entry, because sg_next will return NULL. The patch only applies to all kernels up to and including 4.13. The patch 2d97591ef43d0587be22ad1b0d758d6df4999a0b added to 4.14-rc1 introduced a complete new code base which addresses this bug in a different way. Yet, that patch is too invasive for stable kernels and was therefore not marked for stable. Fixes: 8ff590903d5fc ("crypto: algif_skcipher - User-space interface for skcipher operations") Signed-off-by: Stephan Mueller Acked-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- crypto/algif_skcipher.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c index ea05c53..8e27474 100644 --- a/crypto/algif_skcipher.c +++ b/crypto/algif_skcipher.c @@ -92,8 +92,10 @@ static int skcipher_alloc_sgl(struct sock *sk) sg_init_table(sgl->sg, MAX_SGL_ENTS + 1); sgl->cur = 0; - if (sg) + if (sg) { scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg); + sg_unmark_end(sg + (MAX_SGL_ENTS - 1)); + } list_add_tail(&sgl->list, &ctx->tsgl); } -- 2.8.0.rc2.1.gbe9624a