From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 02B3FC001B2 for ; Tue, 20 Dec 2022 01:21:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7A9368E0003; Mon, 19 Dec 2022 20:21:46 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 759798E0001; Mon, 19 Dec 2022 20:21:46 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 621BE8E0003; Mon, 19 Dec 2022 20:21:46 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 53C798E0001 for ; Mon, 19 Dec 2022 20:21:46 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2F0A5160BEF for ; Tue, 20 Dec 2022 01:21:46 +0000 (UTC) X-FDA: 80260932612.23.BBC9253 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf27.hostedemail.com (Postfix) with ESMTP id 8C90040005 for ; Tue, 20 Dec 2022 01:21:44 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ucwfDcKe; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf27.hostedemail.com: domain of sashal@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sashal@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1671499304; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=0oq4Y6daJoDR1KtLhFG+37AtrK1vaEfoOamY9W4OTr0=; b=EX1Vl+1ybNJE27jGPaYVWfV/d3w3NDS4/B/cunZ0DOLgWRNC0hambJiQNySiymSFtTTcEm QGx7bnsXi7pZITzFFglpYn5gQJq2hebjxBpp75v0Yx5bLCj0mM6vaWJKQr8CrLcHSxPVLL PbvntN4FP4s1N04xKz6F0oc3h2XfaEI= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ucwfDcKe; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf27.hostedemail.com: domain of sashal@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sashal@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1671499304; a=rsa-sha256; cv=none; b=niEFYlzBdtvh9GYHppkjBnPTYuvmOiVAbn1dHZFhqxf9LCV7TMjCIrb4P9L+cxDVigLifk c4r1PaJ0/Yr4oVKlzFLpi2JG6+Qe7yRR54/sI7kCO/sw/99pK/mYPIlRoj1+pN4TogEEht R/Y78KJqU2D72XqWN3CMLTqnYMUUByU= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A8D946122E; Tue, 20 Dec 2022 01:21:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64FD3C43398; Tue, 20 Dec 2022 01:21:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1671499303; bh=lQGAP/snTMjwoSYXY3GbX8jpN2CvzI0RX4mIqUXyyHA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ucwfDcKewuZ1UWhlTzpL+hAHw+JxnNVH2HEeSCD+BWvpX3lkuqxwTyxB274VXGcJ1 kvEKpMSBuvy/UHEZgFfFsrvqiJNMkbs0EYLeDo3odVo+doIPL+MmpQ5F0K82iVpxLv 4BPugW83/Sk6qukdxZ2AUqhBPEMMo4jjdhYu423SdGCIBtl6PCW/6bjqibXVugkKvx 4BJfLAW/NgDmaFG34eTWE6v1A54vkGiH1Y0NO1F2k4ZCAc85tgwJafTGO5t6w2KAkr qBT+q0OYguKALks31fFxhBPoOm4O5qEdn0F5R/I1KNTLakaN4soR50LdjczLKwcXyl O9aSHOG3MB8Og== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Hawkins Jiawei , syzbot+a3e6acd85ded5c16a709@syzkaller.appspotmail.com, Mike Kravetz , Muchun Song , Ian Kent , Andrew Morton , Sasha Levin , muchun.song@linux.dev, linux-mm@kvack.org Subject: [PATCH AUTOSEL 6.0 07/16] hugetlbfs: fix null-ptr-deref in hugetlbfs_parse_param() Date: Mon, 19 Dec 2022 20:21:17 -0500 Message-Id: <20221220012127.1222311-7-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221220012127.1222311-1-sashal@kernel.org> References: <20221220012127.1222311-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 8C90040005 X-Stat-Signature: c15kaq6psb3z5onbpoewacmkeox9yyqi X-HE-Tag: 1671499304-241138 X-HE-Meta: U2FsdGVkX18peOw3bERutMXQqhoazpmQ60jyjMYwNqhJvML10+b82TvO4XbjYNFcygu6D2+djQdxl2Gr1i4CcGxMEhBzIsHpHHKnt6CQaWO8xkNPFpMW25vAB0ntRbhKSuah1ansVw+JM+D8sYiNA8IgsdHi3Yp4TQEtTp1RxpNpUkhz3pGgBPLRyrMmbSLtWRKIs6Y0wUlHThF+6W0kRslnPTf7IIa+aPFPxd3wWpcN+knJj53d/U1nDjJFi8UWidyW+kChvyXEcbiXVzi2SU4TiQIYPRoBmip1UM+F+26I/gRybFEHmfNncxjvAygNTwnMwp2UVW0x2iLNKLv1yclUQEIamaFrreDdH4ZMH/p681VTP246CUiZxpLROReFrxdQusG4GJItLr4J79Eke8vEn9ByMtZlJKbRiwbOoxiDYFzwJ5px6YB+WCZu/uMCuBH7RQg+mZTcw/+v5UPQfEUoUF9UZj2lPPatdVGP4y+zTvJP+UP+rjOtI5H2FJVyrd+9H5FgJQriNugC7wp4a/Vvuq55GnpfdiQs+wD9PuPX4ebP3OptpUUTwdFwEYtY9yJeFNy5iP3anatXslUwYQa5gV5FxtdhCpX2MMhbC4EYe1K4UdeJvpydAkTxCui2Ay/CT9DnOKqDT1aUeLoh3TjStFmcdP7c67FBd1fuzpwPcIBPzoK9NgCoufj9qJB1sgUNRvZJZrE9joqknHCWMMghtyTc1aRhxeRaqklmc3IUxroOx8kWQSVZZH1np0QcOCuakYtZUoQ47pg+pvG7Z2GK8s2GSYxkhWFpw2/gCY4/IJq/QD2/jUD+yoNl7fth34fqmElVlq+URcDmnpXP9KoDx8R46ggzDKHl5skH/rZRDJ8AkDHGfDknkNVKAqcoqNHKMAtVNL091UU7HMGlfWoo07FyuvHelDYDesGmRJe06/VhpOoDJaqBZIiVMSf4wty1ztvdeZgDUTXIc72 hklh2um9 f2bd7ervBFHbN2JXzNMVZ6huVJQebE4ubN2kAcHS16Vo65YU3gF6IGsT8M6/4I8p/4Pczp738mjJyY+o/4mcMjwITc8ewSvAcDUcaz2VWCmOXc0Wo9+QoK7whwsZtZ55LhWBQbfwkjGtwSqbEmgPeshO743HXUafztwLy8Fa8ku+V881t8YPcrPPbpDZt0+7PWADa0LaJ5euYqK4jJ2sGvhEKHQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Hawkins Jiawei [ Upstream commit 26215b7ee923b9251f7bb12c4e5f09dc465d35f2 ] Syzkaller reports a null-ptr-deref bug as follows: ====================================================== KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:hugetlbfs_parse_param+0x1dd/0x8e0 fs/hugetlbfs/inode.c:1380 [...] Call Trace: vfs_parse_fs_param fs/fs_context.c:148 [inline] vfs_parse_fs_param+0x1f9/0x3c0 fs/fs_context.c:129 vfs_parse_fs_string+0xdb/0x170 fs/fs_context.c:191 generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:231 do_new_mount fs/namespace.c:3036 [inline] path_mount+0x12de/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] ====================================================== According to commit "vfs: parse: deal with zero length string value", kernel will set the param->string to null pointer in vfs_parse_fs_string() if fs string has zero length. Yet the problem is that, hugetlbfs_parse_param() will dereference the param->string, without checking whether it is a null pointer. To be more specific, if hugetlbfs_parse_param() parses an illegal mount parameter, such as "size=,", kernel will constructs struct fs_parameter with null pointer in vfs_parse_fs_string(), then passes this struct fs_parameter to hugetlbfs_parse_param(), which triggers the above null-ptr-deref bug. This patch solves it by adding sanity check on param->string in hugetlbfs_parse_param(). Link: https://lkml.kernel.org/r/20221020231609.4810-1-yin31149@gmail.com Reported-by: syzbot+a3e6acd85ded5c16a709@syzkaller.appspotmail.com Tested-by: syzbot+a3e6acd85ded5c16a709@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/0000000000005ad00405eb7148c6@google.com/ Signed-off-by: Hawkins Jiawei Reviewed-by: Mike Kravetz Cc: Hawkins Jiawei Cc: Muchun Song Cc: Ian Kent Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- fs/hugetlbfs/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index fbcfa6bfee80..26169d75f6cf 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -1256,7 +1256,7 @@ static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *par case Opt_size: /* memparse() will accept a K/M/G without a digit */ - if (!isdigit(param->string[0])) + if (!param->string || !isdigit(param->string[0])) goto bad_val; ctx->max_size_opt = memparse(param->string, &rest); ctx->max_val_type = SIZE_STD; @@ -1266,7 +1266,7 @@ static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *par case Opt_nr_inodes: /* memparse() will accept a K/M/G without a digit */ - if (!isdigit(param->string[0])) + if (!param->string || !isdigit(param->string[0])) goto bad_val; ctx->nr_inodes = memparse(param->string, &rest); return 0; @@ -1282,7 +1282,7 @@ static int hugetlbfs_parse_param(struct fs_context *fc, struct fs_parameter *par case Opt_min_size: /* memparse() will accept a K/M/G without a digit */ - if (!isdigit(param->string[0])) + if (!param->string || !isdigit(param->string[0])) goto bad_val; ctx->min_size_opt = memparse(param->string, &rest); ctx->min_val_type = SIZE_STD; -- 2.35.1