From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1BA1E3FD955; Tue, 13 Oct 2026 12:16:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893811; cv=none; b=V82BNKfMM8sWM1svvJ0QQMrYPgJmx+2nkN0qeBioS3Ab5TWXWNXwaLzmymgxiT5uk9iC9GmbH09l6EJpUGOiIvlKyNJ5U4Xsflx/NlYQxv0diTXo8yJy7LW0FyNvaolSC1Z7u3fiMwwc/igHKXLtvGcEX7kEycZlVVYBJcZh+yo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791893811; c=relaxed/simple; bh=EWBBhvKcqkjOHjW1u7o70xKbxEqyg5g+xnnW6tAbzdw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=hR9tE+W9egzEsNn2N0hZ3BjL4JRXiNKUBsI43qS+gBJkRGiShxOkDoxhb1ur5qAVp2udjHs4sXyGQBcWTtp5Q5Jfeom1xw0b7tM9JaVF3mtR2oKZBU6tPsq6xdXgpmC9GUhmpAlLmDAW6XTXOPKfgzZE05SAEeHGZvWEJMjL8AE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=K/VAHdx2; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="K/VAHdx2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6B33F1F000FF; Tue, 13 Oct 2026 12:16:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791893810; bh=sVBmOE7IPgJsNVRTr6i1KunnRVCLhDz2BckRs9cGsao=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K/VAHdx29AC+tahUYLPj7hzNJHyScVD1+3cxJZMNSszxeFF8ds6/XpEmpGx63eF76 wTsaUyCaJgyVRO8x3lbSH22gBxuobl42a/4+ExzdZCkZr6cXcynCh1AXDY82kXVuOl chSuiHEv0fpV8lR808zsBtgRzMZiqRuwr/M1zt48= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, David Lee , Qu Wenruo , David Sterba , Sasha Levin Subject: [PATCH 6.18 343/621] btrfs: lzo: reject inline extents without valid headers Date: Tue, 13 Oct 2026 13:35:38 +0200 Message-ID: <20261013112928.993053092@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261013112920.855194808@linuxfoundation.org> References: <20261013112920.855194808@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Lee [ Upstream commit 0fa78ef637deb5dbe341582f88553a4bce496de0 ] [BUG] For a crafted btrfs image, the following KASAN can be triggered when reading an inline lzo compressed file extent: BUG: KASAN: slab-out-of-bounds in lzo_decompress+0x57d/0x700 Read of size 4 at addr ffff888006f2e644 by task btrfs_lzo_inlin/77 Call Trace: dump_stack_lvl+0x5b/0x70 print_report+0xd1/0x610 kasan_report+0xe0/0x110 __asan_report_load_n_noabort+0x13/0x20 lzo_decompress+0x57d/0x700 btrfs_decompress+0x140/0x1c0 uncompress_inline+0x147/0x1b0 btrfs_get_extent+0xb23/0x10a0 btrfs_do_readpage.constprop.0+0x538/0x1ac0 btrfs_readahead+0x32f/0x5f0 read_pages+0x16f/0x850 page_cache_ra_unbounded+0x296/0x490 do_page_cache_ra+0xd9/0x130 page_cache_sync_ra+0x3ee/0x6f0 filemap_get_pages+0x306/0x15c0 filemap_read+0x329/0xd00 btrfs_file_read_iter+0x1f8/0x2b0 vfs_read+0x4ef/0x720 ksys_read+0xf8/0x1d0 __x64_sys_read+0x71/0xb0 x64_sys_call+0x1ab0/0x1b70 do_syscall_64+0x61/0x470 entry_SYSCALL_64_after_hwframe+0x4b/0x53 [CAUSE] For an inline lzo compressed file extent, there should always be one lzo header, recording the total length of the compressed data, followed by one segment header, recording the compressed lzo payload. But if a crafted inline lzo compressed file extent contains only an lzo header, without the segment header or payload, lzo_decompress() will still try to read the segment header, causing a read beyond the item boundary. Furthermore if the inline lzo compressed file extent is the first item of the leaf, it will be at the extent buffer boundary. The above out-of-boundary read will go beyond the extent buffer boundary, triggering the above KASAN report. [FIX] Validate the total length of the inlined lzo compressed file extent, to make sure there is at least one LZO header and one segment header, and a non-zero payload. Fixes: a6fa6fae40ec ("btrfs: Add lzo compression support") Assisted-by: Codex:gpt-5.5 Signed-off-by: David Lee [ Rework the commit message to remove slop ] Signed-off-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/lzo.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index 4758f66da449c..6b1cf1e67be72 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -458,7 +458,8 @@ int lzo_decompress(struct list_head *ws, const u8 *data_in, size_t max_segment_len = workspace_buf_length(fs_info); int ret = 0; - if (unlikely(srclen < LZO_LEN || srclen > max_segment_len + LZO_LEN * 2)) + if (unlikely(srclen <= LZO_LEN * 2 || + srclen > max_segment_len + LZO_LEN * 2)) return -EUCLEAN; in_len = read_compress_length(data_in); -- 2.53.0