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From: Christoph Hellwig <hch@lst.de>
To: linux-ext4@vger.kernel.org, viro@zeniv.linux.org.uk
Cc: jack@suse.cz, tytso@mit.edu, adilger@dilger.ca,
	riteshh@linux.ibm.com, amir73il@gmail.com,
	linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org,
	syzbot+77fa5bdb65cc39711820@syzkaller.appspotmail.com
Subject: [PATCH 1/8] ext4: fix EXT4_MAX_LOGICAL_BLOCK macro
Date: Mon, 27 Apr 2020 11:58:51 +0200	[thread overview]
Message-ID: <20200427095858.1440608-2-hch@lst.de> (raw)
In-Reply-To: <20200427095858.1440608-1-hch@lst.de>

From: Ritesh Harjani <riteshh@linux.ibm.com>

ext4 supports max number of logical blocks in a file to be 0xffffffff.
(This is since ext4_extent's ee_block is __le32).
This means that EXT4_MAX_LOGICAL_BLOCK should be 0xfffffffe (starting
from 0 logical offset). This patch fixes this.

The issue was seen when ext4 moved to iomap_fiemap API and when
overlayfs was mounted on top of ext4. Since overlayfs was missing
filemap_check_ranges(), so it could pass a arbitrary huge length which
lead to overflow of map.m_len logic.

This patch fixes that.

Fixes: d3b6f23f7167 ("ext4: move ext4_fiemap to use iomap framework")
Reported-by: syzbot+77fa5bdb65cc39711820@syzkaller.appspotmail.com
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/ext4/ext4.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 91eb4381cae5b..ad2dbf6e49245 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -722,7 +722,7 @@ enum {
 #define EXT4_MAX_BLOCK_FILE_PHYS	0xFFFFFFFF
 
 /* Max logical block we can support */
-#define EXT4_MAX_LOGICAL_BLOCK		0xFFFFFFFF
+#define EXT4_MAX_LOGICAL_BLOCK		0xFFFFFFFE
 
 /*
  * Structure of an inode on the disk
-- 
2.26.1


  reply	other threads:[~2020-04-27  9:59 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-27  9:58 fix fiemap for ext4 bitmap files (+ cleanups) Christoph Hellwig
2020-04-27  9:58 ` Christoph Hellwig [this message]
2020-04-27  9:58 ` [PATCH 2/8] ext4: fix fiemap size checks for bitmap files Christoph Hellwig
2020-04-27  9:58 ` [PATCH 3/8] ext4: split _ext4_fiemap Christoph Hellwig
2020-04-27  9:58 ` [PATCH 4/8] ext4: remove the call to fiemap_check_flags in ext4_fiemap Christoph Hellwig
2020-04-27  9:58 ` [PATCH 5/8] fs: mark __generic_block_fiemap static Christoph Hellwig
2020-04-27  9:58 ` [PATCH 6/8] fs: move the fiemap definitions out of fs.h Christoph Hellwig
2020-04-27  9:58 ` [PATCH 7/8] iomap: fix the iomap_fiemap prototype Christoph Hellwig
2020-04-27  9:58 ` [PATCH 8/8] fs: move fiemap range validation into the file systems instances Christoph Hellwig

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