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 0506E1DF996; Wed, 6 Nov 2024 12:19:01 +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=1730895541; cv=none; b=lE5n8FqPHdBBnuL3iN7WZEnp059a9A81GDWKG8j++KZLuAUD5T5DZAb7NbNwIfmdZdGVqr4YQPtR99Ia29Kp+zMc/JSSqoWyXLZb/WrO9VeH32E6bla3WK/tbPEMHVnVsCYi41ZArRKQ7f+fBtQYHHfykLdfM1A4UyLdWdtcKrk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730895541; c=relaxed/simple; bh=9BLyk2x10dZKN26xwVcXaeribsBNqenBtzqqcjqqmBY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BXbpUMDiGKMmEUFtLWABmsk3CnO9COapTo7/N2Sn/C6O4JpmkY9EW9hiid7H7DL1W+Ra4SqQ1M6jMeXChc6tIijxfThr5BLZ90TKjy34wWVIIYc9wM2nKXjVUyJu8V+n5xBDw6zL8LA4LbDSgteV1ouBNDEUuNdTW3TUCKtlWdY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=A47OaFw0; 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="A47OaFw0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 789EEC4CED4; Wed, 6 Nov 2024 12:19:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730895540; bh=9BLyk2x10dZKN26xwVcXaeribsBNqenBtzqqcjqqmBY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=A47OaFw0y8zIrPOqOZKS9WdenNLcghmFwHsDmr4EvfVa73+Zoxz1BoMQKsbDAvPxX eAJFYSx6j4HBT3uIgDtzCn+qNkwUtREDcTWcz+oo0423mQO9D6QoMQeBrjQfQ18I18 oTfqgD51clhvcwL7wsBeAMylbWQkDLhi9urOn9e4= 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 , Sasha Levin Subject: [PATCH 4.19 216/350] ext4: update orig_path in ext4_find_extent() Date: Wed, 6 Nov 2024 13:02:24 +0100 Message-ID: <20241106120326.334480510@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106120320.865793091@linuxfoundation.org> References: <20241106120320.865793091@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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li [ Upstream commit 5b4b2dcace35f618fe361a87bae6f0d13af31bc1 ] 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: Sasha Levin --- fs/ext4/extents.c | 3 ++- fs/ext4/move_extent.c | 1 - 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index c538d09542391..63380c2910077 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -956,6 +956,8 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block, ext4_ext_show_path(inode, path); + if (orig_path) + *orig_path = path; return path; err: @@ -3311,7 +3313,6 @@ static int ext4_split_extent_at(handle_t *handle, } 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)) { diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 2c368d67a33ac..1581b48af1fed 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -37,7 +37,6 @@ get_ext_path(struct inode *inode, ext4_lblk_t lblock, *ppath = NULL; return -ENODATA; } - *ppath = path; return 0; } -- 2.43.0