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 373BF2265C3; Fri, 4 Oct 2024 18:30:17 +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=1728066618; cv=none; b=j/WjQECkuXLGom5w24n2r0MzAnTV+iD6Q40f5LyDP3oMlqpj1gHScMKU1CvUdmd2T6IKPH1JredaKv4iwRCkVtUSjnMIfFzcAdMBMuEXmnhL53b8MFXK3nIB4aNpb4kYwalt4VQhu0WiJLsbKo+PKbhSiOGX3nt/Fk/gdt5wNl8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728066618; c=relaxed/simple; bh=PcqW5FXVNwLlY82L71+Pj3mHhn+vHvOKyuN6BHkNvkI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iQG8tsQAlYyw/uQITwWozXiBEUUYi/p0o7W4CB68eyaEingrzdicQ5R+1+UgToNWLe3L3ue5JMJDeDUfi09GI66HF2nNU3gFUFvpDhmhU8CUON4CyRZ5taESlmAyp7cNDf68GJ1cx+kRcmx5G4Ibe4+HUnQLoJPk6tqbt3EhyYc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=V6Ia/A4C; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="V6Ia/A4C" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5C9BC4CECC; Fri, 4 Oct 2024 18:30:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728066617; bh=PcqW5FXVNwLlY82L71+Pj3mHhn+vHvOKyuN6BHkNvkI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V6Ia/A4CLbjpilL6gEftn8vXeWxx+r7lOJ11mVa/mFtfTh1QSf365GYenHXNLZ1tl dtSwmu8hOWrFd5qOAahwujj5LBxjm1eb1k1C0ean0iR5kF3k8PXn9Q+iNJLHsDqpYg 1hjPD2HNeBIrB/mYJ1N5s/fUrkZQfZuLf/CDQJhHRYqnApP3S9hHaE6hDCxUdD096M iPt1aI2M32+4k1GMKXFpgHNEFf1XhzWuOdTWdfqMjDEyhdjhXoOwry7J4pn+mkQ0MX ADjdk1XAgCZ464FKmS7pgy/gH3dn0KZmIAFj8V7C8CgstASAJQOr12S6rNiXr8aAwX TAwb9j2pwthUg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Baokun Li , Jan Kara , Ojaswin Mujoo , Theodore Ts'o , Sasha Levin , adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 06/26] ext4: avoid use-after-free in ext4_ext_show_leaf() Date: Fri, 4 Oct 2024 14:29:32 -0400 Message-ID: <20241004183005.3675332-6-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241004183005.3675332-1-sashal@kernel.org> References: <20241004183005.3675332-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.10.226 Content-Transfer-Encoding: 8bit From: Baokun Li [ Upstream commit 4e2524ba2ca5f54bdbb9e5153bea00421ef653f5 ] In ext4_find_extent(), path may be freed by error or be reallocated, so using a previously saved *ppath may have been freed and thus may trigger use-after-free, as follows: ext4_split_extent path = *ppath; ext4_split_extent_at(ppath) path = ext4_find_extent(ppath) ext4_split_extent_at(ppath) // ext4_find_extent fails to free path // but zeroout succeeds ext4_ext_show_leaf(inode, path) eh = path[depth].p_hdr // path use-after-free !!! Similar to ext4_split_extent_at(), we use *ppath directly as an input to ext4_ext_show_leaf(). Fix a spelling error by the way. Same problem in ext4_ext_handle_unwritten_extents(). Since 'path' is only used in ext4_ext_show_leaf(), remove 'path' and use *ppath directly. This issue is triggered only when EXT_DEBUG is defined and therefore does not affect functionality. Signed-off-by: Baokun Li Reviewed-by: Jan Kara Reviewed-by: Ojaswin Mujoo Tested-by: Ojaswin Mujoo Link: https://patch.msgid.link/20240822023545.1994557-5-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/extents.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index f5fa9d542d648..b92464c8f63b4 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3283,7 +3283,7 @@ static int ext4_split_extent_at(handle_t *handle, } /* - * ext4_split_extents() splits an extent and mark extent which is covered + * ext4_split_extent() splits an extent and mark extent which is covered * by @map as split_flags indicates * * It may result in splitting the extent into multiple extents (up to three) @@ -3360,7 +3360,7 @@ static int ext4_split_extent(handle_t *handle, goto out; } - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); out: return err ? err : allocated; } @@ -3825,14 +3825,13 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode, struct ext4_ext_path **ppath, int flags, unsigned int allocated, ext4_fsblk_t newblock) { - struct ext4_ext_path __maybe_unused *path = *ppath; int ret = 0; int err = 0; ext_debug(inode, "logical block %llu, max_blocks %u, flags 0x%x, allocated %u\n", (unsigned long long)map->m_lblk, map->m_len, flags, allocated); - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); /* * When writing into unwritten space, we should not fail to @@ -3929,7 +3928,7 @@ ext4_ext_handle_unwritten_extents(handle_t *handle, struct inode *inode, if (allocated > map->m_len) allocated = map->m_len; map->m_len = allocated; - ext4_ext_show_leaf(inode, path); + ext4_ext_show_leaf(inode, *ppath); out2: return err ? err : allocated; } -- 2.43.0