From patchwork Sun Oct 23 16:39:45 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hawkins Jiawei X-Patchwork-Id: 13016334 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C59B2ECAAA1 for ; Sun, 23 Oct 2022 16:41:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230337AbiJWQln (ORCPT ); Sun, 23 Oct 2022 12:41:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45106 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230355AbiJWQlm (ORCPT ); Sun, 23 Oct 2022 12:41:42 -0400 Received: from mail-pg1-x52f.google.com (mail-pg1-x52f.google.com [IPv6:2607:f8b0:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3CB665667; Sun, 23 Oct 2022 09:41:41 -0700 (PDT) Received: by mail-pg1-x52f.google.com with SMTP id q71so6804037pgq.8; Sun, 23 Oct 2022 09:41:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Y2bDAIefZxbRVSM/SaH1NL1oBBLTDGxU2sWjuEVySo0=; b=Al/bcK0raH1SRXE3/4nftiI+qFU0z7u3k5IRgL6icE1yDmPYX2WINBttZZWg6W9gdw qHV+4EGaMiArBjM6MvF2wwY6mN2LVba5NOMZj/QrP/5+Bryf2WTfQlW+08VUjSMr5MG/ 13kG3W3i7TdUKHtJrSytliHcOPp9cuLRBFRAuhlht3va1ku6Xf1g7XQFZMHBzKnqsAMH Ae21n34Q7N6EUO2YWsClQUHKZZwnQnTl2NdNcEAbjYYplZ6LBpjtKQj1EwcNKC750YTE uI7vtK/s1V8cusDsD9AUW+bkBmYF9/UMTyhRCRsXOxv79AISblKjdYeq2okdLegW+Jpw MZ8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Y2bDAIefZxbRVSM/SaH1NL1oBBLTDGxU2sWjuEVySo0=; b=rxm/W7eI9a0komlZLMZWCKPXIs/fD8BKPFgqGSUU0vcG/NAta5SUHft2TQlSoq/os8 AtD0T+C5m+JxcaIXFDGnFgdf4xm2Y+RZSxyqGyOhgUxVH6B9vnB9p+BZm9HOnTF7Am+C aDijTa3+TxsHf6urxkHIt4AB/HTv1OVR3993BfJcP6CvRkmASiIkgqQQB1imri+/3zCj n7gPTwfI8l0AOGZu/iWjz9P/vetGn6tNc9Viqr5jj3RgH6rz0EL7lza5gzi3ddPW09ba GK35aLFVoKjzObqrleU6QKU/s3Ibe7R2ZiDzzOoI8GrHMiiHgkCAZiTbCpLTVoZXx9dl cHjQ== X-Gm-Message-State: ACrzQf0I3brjG7BhCcw15Y7QxNdUXqE5/1urXm8Uy5E3KiyoK2J3d2pX jYzMYtgMaLA9li44uSueZMA= X-Google-Smtp-Source: AMsMyM7irLWDlav1VeIiY5mui3ckyNhI3n2zU5dxXGRJ0JYZXVfYymRXmX9OmNkmEthf8F8HB6u5Zw== X-Received: by 2002:a05:6a00:27a1:b0:566:8937:27c2 with SMTP id bd33-20020a056a0027a100b00566893727c2mr29010630pfb.24.1666543301375; Sun, 23 Oct 2022 09:41:41 -0700 (PDT) Received: from localhost ([223.104.41.250]) by smtp.gmail.com with ESMTPSA id f7-20020a170902684700b0017a04542a45sm5618366pln.159.2022.10.23.09.41.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 23 Oct 2022 09:41:41 -0700 (PDT) From: Hawkins Jiawei To: yin31149@gmail.com, Trond Myklebust , Anna Schumaker Cc: 18801353760@163.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org Subject: [PATCH -next 2/5] nfs: fix possible null-ptr-deref when parsing param Date: Mon, 24 Oct 2022 00:39:45 +0800 Message-Id: <20221023163945.39920-3-yin31149@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221023163945.39920-1-yin31149@gmail.com> References: <20221023163945.39920-1-yin31149@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org 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, nfs_fs_context_parse_param() will dereferences the param->string, without checking whether it is a null pointer, which may trigger a null-ptr-deref bug. This patch solves it by adding sanity check on param->string in nfs_fs_context_parse_param(). Signed-off-by: Hawkins Jiawei Reviewed-by: Jeff Layton --- fs/nfs/fs_context.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/nfs/fs_context.c b/fs/nfs/fs_context.c index 4da701fd1424..0c330bc13ef2 100644 --- a/fs/nfs/fs_context.c +++ b/fs/nfs/fs_context.c @@ -684,6 +684,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc, return ret; break; case Opt_vers: + if (!param->string) + goto out_invalid_value; trace_nfs_mount_assign(param->key, param->string); ret = nfs_parse_version_string(fc, param->string); if (ret < 0) @@ -696,6 +698,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc, break; case Opt_proto: + if (!param->string) + goto out_invalid_value; trace_nfs_mount_assign(param->key, param->string); protofamily = AF_INET; switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) { @@ -732,6 +736,8 @@ static int nfs_fs_context_parse_param(struct fs_context *fc, break; case Opt_mountproto: + if (!param->string) + goto out_invalid_value; trace_nfs_mount_assign(param->key, param->string); mountfamily = AF_INET; switch (lookup_constant(nfs_xprt_protocol_tokens, param->string, -1)) {