From patchwork Sun Nov 3 19:38:45 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Kanner X-Patchwork-Id: 13860563 Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 77D831CAB8 for ; Sun, 3 Nov 2024 19:38:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.46 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730662733; cv=none; b=eVP6po+Ofwg84wJ/3mSyYCfDBzstfOI2bOyxY68etvY7G9h+vyJ+9LDEcN2r9xk3EY6v4SJax7+LETEDF54k14wl/bGS5B/3SMTQzM/ifyUSh6M0dITk5N9ZUixXyzjfivZuMxYBBG1nRHe0Yzx2zFPPoLermlry27NTAc2o7QA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730662733; c=relaxed/simple; bh=sM9GzluozgQPIg5Vs5SoQTDViRP22kkDSOQI1XA113Y=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=pChAouJkA/+E6K9fzrkvASYDNRxM6in5PyWcif0K9FdJy+3gIUzZNkqdLwCT/s9K8gLmlUh4khNlXSSfGgovLqQyiDuY7Inmh4sxCdVXvYv2wXzcsZOYJc4h9bU9jbxm/AbmmR/SEhCMOMNgTq5TgOanyXIX9HNSdc1WGWDBddo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=aA4LRSQd; arc=none smtp.client-ip=209.85.128.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="aA4LRSQd" Received: by mail-wm1-f46.google.com with SMTP id 5b1f17b1804b1-4315df7b43fso29000025e9.0 for ; Sun, 03 Nov 2024 11:38:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1730662730; x=1731267530; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=0la0sxqzxsLHUVj5b4t1hec1mDb/IwBoSRs+TYmwypw=; b=aA4LRSQdtTNSXGaCwzEf9V3DHiS4S5BlEiTzXF6QKNR5T8CRB9NmSpkdtqy6GhY+jL sc2MKeQHyHbwZcAfQv7759zu47bdUsiaCEFeqwKYs3aUejSeiqwyw95FQg9nrJ47qvmc mYWTTgH9/ims5WZo/Ve0cXluUQiazeP+iu0pvPuytsaOp0rTeb5o15JDVwzeyxng7Gup tQHmkWfsolKcLsU2mF6FUN4J0OhBXfZ/shQn1LLFDGxKoTcWhCa0/he5uhYrf5cdoAZP hEKV6RHsZ4NhlDnc0SdkOi/rgmmRNw0qqTynQUsi9fGtVckLzX9og/a5/s8LxP+cIJ9k p59g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1730662730; x=1731267530; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=0la0sxqzxsLHUVj5b4t1hec1mDb/IwBoSRs+TYmwypw=; b=sWIzOC7Cd0pkaH+/KvC9PgdG55LXKmO3g58yKy16S5nPR5R8XWzrjDN7OK3nN2lq+Q jlor38Jk6mNOCMt541bWZ6G2/HlCelaBRhZa67/ZWDnUnEXEGmtfz42NAQJNWhl8zCAG lZOppX0Zcjff2WJkKFs252/31pgtQ1tuE2uNFdJxr8ndfQtibKGKvgzMACNksiDyduHg 7uH+4JrmuamlRH+uszxYEFUkoWph6+7nxqcOujL7bMGV3ch6RpUcyWy26qEyLyDVdqz+ eK3N+MAfYD4ZbVHdNvdmzHEClMhACotA/RoaCJQ4GrKu0RkHuo83MuHVH1Eg7rpvKzLc QshA== X-Gm-Message-State: AOJu0YxzHebT4+eo3SIByDxAbymQADfdmZJkBN3ZtJU0so3zstmHvr3d 2qB2+reisWvNp2+7YF0UIvYBOZER9vOEYhmlTGbjbMREqsF6oCz7 X-Google-Smtp-Source: AGHT+IHQpQ5MNy8oH8DdhfDZP6iuVsNji2bUgccCrZZ5BsDM/DcexIYeciCpQFEqimnM/5PEZj0WaQ== X-Received: by 2002:a05:600c:5118:b0:42c:b995:2100 with SMTP id 5b1f17b1804b1-4319ac75a0amr229764275e9.6.1730662729505; Sun, 03 Nov 2024 11:38:49 -0800 (PST) Received: from dev7.kernelcare.com ([2a01:4f8:201:23::2]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4327d5c65absm129759615e9.16.2024.11.03.11.38.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 03 Nov 2024 11:38:49 -0800 (PST) From: Andrew Kanner To: mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com Cc: ocfs2-devel@lists.linux.dev, linux-kernel@vger.kernel.org, Andrew Kanner , stable@vger.kernel.org, syzbot+386ce9e60fa1b18aac5b@syzkaller.appspotmail.com Subject: [PATCH v2] ocfs2: remove entry once instead of null-ptr-dereference in ocfs2_xa_remove() Date: Sun, 3 Nov 2024 20:38:45 +0100 Message-ID: <20241103193845.2940988-1-andrew.kanner@gmail.com> X-Mailer: git-send-email 2.43.5 Precedence: bulk X-Mailing-List: ocfs2-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Syzkaller is able to provoke null-ptr-dereference in ocfs2_xa_remove(): [ 57.319872] (a.out,1161,7):ocfs2_xa_remove:2028 ERROR: status = -12 [ 57.320420] (a.out,1161,7):ocfs2_xa_cleanup_value_truncate:1999 ERROR: Partial truncate while removing xattr overlay.upper. Leaking 1 clusters and removing the entry [ 57.321727] BUG: kernel NULL pointer dereference, address: 0000000000000004 [...] [ 57.325727] RIP: 0010:ocfs2_xa_block_wipe_namevalue+0x2a/0xc0 [...] [ 57.331328] Call Trace: [ 57.331477] [...] [ 57.333511] ? do_user_addr_fault+0x3e5/0x740 [ 57.333778] ? exc_page_fault+0x70/0x170 [ 57.334016] ? asm_exc_page_fault+0x2b/0x30 [ 57.334263] ? __pfx_ocfs2_xa_block_wipe_namevalue+0x10/0x10 [ 57.334596] ? ocfs2_xa_block_wipe_namevalue+0x2a/0xc0 [ 57.334913] ocfs2_xa_remove_entry+0x23/0xc0 [ 57.335164] ocfs2_xa_set+0x704/0xcf0 [ 57.335381] ? _raw_spin_unlock+0x1a/0x40 [ 57.335620] ? ocfs2_inode_cache_unlock+0x16/0x20 [ 57.335915] ? trace_preempt_on+0x1e/0x70 [ 57.336153] ? start_this_handle+0x16c/0x500 [ 57.336410] ? preempt_count_sub+0x50/0x80 [ 57.336656] ? _raw_read_unlock+0x20/0x40 [ 57.336906] ? start_this_handle+0x16c/0x500 [ 57.337162] ocfs2_xattr_block_set+0xa6/0x1e0 [ 57.337424] __ocfs2_xattr_set_handle+0x1fd/0x5d0 [ 57.337706] ? ocfs2_start_trans+0x13d/0x290 [ 57.337971] ocfs2_xattr_set+0xb13/0xfb0 [ 57.338207] ? dput+0x46/0x1c0 [ 57.338393] ocfs2_xattr_trusted_set+0x28/0x30 [ 57.338665] ? ocfs2_xattr_trusted_set+0x28/0x30 [ 57.338948] __vfs_removexattr+0x92/0xc0 [ 57.339182] __vfs_removexattr_locked+0xd5/0x190 [ 57.339456] ? preempt_count_sub+0x50/0x80 [ 57.339705] vfs_removexattr+0x5f/0x100 [...] Reproducer uses faultinject facility to fail ocfs2_xa_remove() -> ocfs2_xa_value_truncate() with -ENOMEM. In this case the comment mentions that we can return 0 if ocfs2_xa_cleanup_value_truncate() is going to wipe the entry anyway. But the following 'rc' check is wrong and execution flow do 'ocfs2_xa_remove_entry(loc);' twice: * 1st: in ocfs2_xa_cleanup_value_truncate(); * 2nd: returning back to ocfs2_xa_remove() instead of going to 'out'. Fix this by skipping the 2nd removal of the same entry and making syzkaller repro happy. Cc: stable@vger.kernel.org Fixes: 399ff3a748cf ("ocfs2: Handle errors while setting external xattr values.") Reported-by: syzbot+386ce9e60fa1b18aac5b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/671e13ab.050a0220.2b8c0f.01d0.GAE@google.com/T/ Tested-by: syzbot+386ce9e60fa1b18aac5b@syzkaller.appspotmail.com Signed-off-by: Andrew Kanner Reviewed-by: Joseph Qi --- Notes (akanner): v2: remove rc check completely, suggested by Joseph Qi v1: https://lore.kernel.org/all/20241029224304.2169092-2-andrew.kanner@gmail.com/T/ fs/ocfs2/xattr.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index dd0a05365e79..73a6f6fd8a8e 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -2036,8 +2036,7 @@ static int ocfs2_xa_remove(struct ocfs2_xa_loc *loc, rc = 0; ocfs2_xa_cleanup_value_truncate(loc, "removing", orig_clusters); - if (rc) - goto out; + goto out; } }