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 9B10F1DACB0; Fri, 4 Oct 2024 18:18:51 +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=1728065931; cv=none; b=h2O32DvYOiaAm1Os8dqw2g+PiWy3m4dmLj2kgmm6OcGtliJlDejfgLNVcwybupawRgWcNHMS+qIWTRuvJmBhhDTSA0/n+QSJYR2+GzUopcuSN3oWQjcg8IRBusIqzv+DiWOpMpeJDgEKBrkjT5eGHinunN9QKNlT2uiM85BFDWo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728065931; c=relaxed/simple; bh=0dY/Rn2LCkVFNFRPdOEhLz+OBcsB+K2jKeSvCLpQWm0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jl6O7Nfqcgpp1p3XsjlFNH0GuyJ4U1n5yB+dHoBoGUDT0bZK/5I2umNt5NRULLBKb7PJn8eUZuq2XnqxU7iDKDIwFEEHaZelccOi51PMXh1dcEkyVfvgOk1gimvehd/J1t5i7rKlN48QtfQ5VO40QETpUCHCSLTnfyduGPnGvDE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Kr6lfbfN; 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="Kr6lfbfN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37AD0C4CECE; Fri, 4 Oct 2024 18:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728065931; bh=0dY/Rn2LCkVFNFRPdOEhLz+OBcsB+K2jKeSvCLpQWm0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kr6lfbfN6g7kv+9F78abtHCqoCjf29R130tQBWlUfRa8VSOl0PL0Z9UK/UbEldd96 KUFOjACjC+BgW4KgmtxVACT+r8r0VF6fO+rgkICTQj2FQq6wl6sFdqCNiol2/06cHl d/7Ivz3OGl4JyHs1/mpwsvBGR9nD6jAKjUGT/0LUM2TNvXfsJSsAtROT/tBmEYoB9U s9Fi3iBPSccqfcXFU5HSLEl3Nms9lo2HcyNa5ZK6OsVQVzBpLvrj882w7bh07Xbo39 m1CjOAYiM0BGeA4Xpq6DRJ26j2CMb21B8QqG7ygkM8SJeIDMhcTVZjxpRqyXXRAHBD AEAajx0fsSIwQ== 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 6.11 12/76] ext4: avoid use-after-free in ext4_ext_show_leaf() Date: Fri, 4 Oct 2024 14:16:29 -0400 Message-ID: <20241004181828.3669209-12-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241004181828.3669209-1-sashal@kernel.org> References: <20241004181828.3669209-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.11.2 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 e067f2dd0335c..7954430f886d8 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -3287,7 +3287,7 @@ 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) @@ -3363,7 +3363,7 @@ 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; } @@ -3828,14 +3828,13 @@ 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 @@ -3932,7 +3931,7 @@ 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