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 3114B8825 for ; Fri, 10 Mar 2023 15:01:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4EC5C433A8; Fri, 10 Mar 2023 15:01:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678460488; bh=+Di6mEXN9G2ImwIWJqyFDIz3cVF3s9l5AUN86uS81yQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xkiowP1zaaXMxGLKCgl/iNMkMat6Qi1dFdF1XxcEj9rhjs4rS7w03JU69L06tcaUa RzjstO2RkVPAD8aVeS5aH1jA7aPnuI4TfBhB/4neuVBj/1MDi6RqxV5OqvqG3WuVdi JJUMZrAPiQB5Vvu0cY83cyMXmp2s0yJAk7q97i9M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Biggers , Chao Yu , Jaegeuk Kim Subject: [PATCH 5.10 344/529] f2fs: fix information leak in f2fs_move_inline_dirents() Date: Fri, 10 Mar 2023 14:38:07 +0100 Message-Id: <20230310133820.958388854@linuxfoundation.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230310133804.978589368@linuxfoundation.org> References: <20230310133804.978589368@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Eric Biggers commit 9a5571cff4ffcfc24847df9fd545cc5799ac0ee5 upstream. When converting an inline directory to a regular one, f2fs is leaking uninitialized memory to disk because it doesn't initialize the entire directory block. Fix this by zero-initializing the block. This bug was introduced by commit 4ec17d688d74 ("f2fs: avoid unneeded initializing when converting inline dentry"), which didn't consider the security implications of leaking uninitialized memory to disk. This was found by running xfstest generic/435 on a KMSAN-enabled kernel. Fixes: 4ec17d688d74 ("f2fs: avoid unneeded initializing when converting inline dentry") Cc: # v4.3+ Signed-off-by: Eric Biggers Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman --- fs/f2fs/inline.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) --- a/fs/f2fs/inline.c +++ b/fs/f2fs/inline.c @@ -420,18 +420,17 @@ static int f2fs_move_inline_dirents(stru dentry_blk = page_address(page); + /* + * Start by zeroing the full block, to ensure that all unused space is + * zeroed and no uninitialized memory is leaked to disk. + */ + memset(dentry_blk, 0, F2FS_BLKSIZE); + make_dentry_ptr_inline(dir, &src, inline_dentry); make_dentry_ptr_block(dir, &dst, dentry_blk); /* copy data from inline dentry block to new dentry block */ memcpy(dst.bitmap, src.bitmap, src.nr_bitmap); - memset(dst.bitmap + src.nr_bitmap, 0, dst.nr_bitmap - src.nr_bitmap); - /* - * we do not need to zero out remainder part of dentry and filename - * field, since we have used bitmap for marking the usage status of - * them, besides, we can also ignore copying/zeroing reserved space - * of dentry block, because them haven't been used so far. - */ memcpy(dst.dentry, src.dentry, SIZE_OF_DIR_ENTRY * src.max); memcpy(dst.filename, src.filename, src.max * F2FS_SLOT_LEN);