From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AE89B1CEE8E; Tue, 8 Oct 2024 12:31:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728390694; cv=none; b=AJRlTJIIna3LVTlfJwvMIlRlRr1v6fRlwgfw4PusmLYbTiQYO/EosLNvwB+VJu9mPti5x2Lb40yFg/Qh2xdnhBG9zYAiwrlhmWeUE1SeCb99D95fMGrHZQvc6uAWVc8slugoP87BPXqG1T5I/ed/0Kesa3R2sHIb4aK4ilb+R8o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728390694; c=relaxed/simple; bh=pbhNuBMXOxGkqPKVl75V37LPdqXdbhuMGXMf2YAEW3M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RLEMPjoSSSzcEtaacZtRllic/WoWjmd5oJ0PcZsVzVOwzz4sW4JyPZAAy75JzvNXVYcGRccz/NnfjCmhZDLSpnobfJa7/Kp3MK/2i9lCTlhhnxYiNNjRSEYChyrPkJeUk+Zo+oGxRI9OtgDoOw0P5pJipIeOxkPZOPGj4mz/rs0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=g5LvjGhK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="g5LvjGhK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 27781C4CEC7; Tue, 8 Oct 2024 12:31:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728390694; bh=pbhNuBMXOxGkqPKVl75V37LPdqXdbhuMGXMf2YAEW3M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g5LvjGhKqGgw8lXR1dtHnAk2xL9VHi/TYFpZPzdn0lwMLuSThx42PZotxUAUXl3gx itDTk/dHkCmAItK25pJKRIVoXbhP2UzqP5pbzFm/aOfcmKqRkmYh/onnJtJq69vQa4 PA2FdKTNvZuVBsCAqolwfooxg4fzSXcE9axy8RCA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Baokun Li , Jan Kara , Theodore Tso Subject: [PATCH 6.10 334/482] ext4: update orig_path in ext4_find_extent() Date: Tue, 8 Oct 2024 14:06:37 +0200 Message-ID: <20241008115701.569140904@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241008115648.280954295@linuxfoundation.org> References: <20241008115648.280954295@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li commit 5b4b2dcace35f618fe361a87bae6f0d13af31bc1 upstream. In ext4_find_extent(), if the path is not big enough, we free it and set *orig_path to NULL. But after reallocating and successfully initializing the path, we don't update *orig_path, in which case the caller gets a valid path but a NULL ppath, and this may cause a NULL pointer dereference or a path memory leak. For example: ext4_split_extent path = *ppath = 2000 ext4_find_extent if (depth > path[0].p_maxdepth) kfree(path = 2000); *orig_path = path = NULL; path = kcalloc() = 3000 ext4_split_extent_at(*ppath = NULL) path = *ppath; ex = path[depth].p_ext; // NULL pointer dereference! ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000010 CPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847 RIP: 0010:ext4_split_extent_at+0x6d/0x560 Call Trace: ext4_split_extent.isra.0+0xcb/0x1b0 ext4_ext_convert_to_initialized+0x168/0x6c0 ext4_ext_handle_unwritten_extents+0x325/0x4d0 ext4_ext_map_blocks+0x520/0xdb0 ext4_map_blocks+0x2b0/0x690 ext4_iomap_begin+0x20e/0x2c0 [...] ================================================================== Therefore, *orig_path is updated when the extent lookup succeeds, so that the caller can safely use path or *ppath. Fixes: 10809df84a4d ("ext4: teach ext4_ext_find_extent() to realloc path if necessary") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://patch.msgid.link/20240822023545.1994557-6-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/extents.c | 3 ++- fs/ext4/move_extent.c | 1 - 2 files changed, 2 insertions(+), 2 deletions(-) --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -957,6 +957,8 @@ ext4_find_extent(struct inode *inode, ex ext4_ext_show_path(inode, path); + if (orig_path) + *orig_path = path; return path; err: @@ -3249,7 +3251,6 @@ static int ext4_split_extent_at(handle_t } depth = ext_depth(inode); ex = path[depth].p_ext; - *ppath = path; if (EXT4_EXT_MAY_ZEROOUT & split_flag) { if (split_flag & (EXT4_EXT_DATA_VALID1|EXT4_EXT_DATA_VALID2)) { --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -36,7 +36,6 @@ get_ext_path(struct inode *inode, ext4_l *ppath = NULL; return -ENODATA; } - *ppath = path; return 0; }