From 175efa81feb8405676e0136d97b10380179c92e0 Mon Sep 17 00:00:00 2001 From: Ritesh Harjani Date: Tue, 5 May 2020 17:43:14 +0200 Subject: ext4: fix EXT4_MAX_LOGICAL_BLOCK macro 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 Reviewed-by: Jan Kara Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20200505154324.3226743-2-hch@lst.de Signed-off-by: Theodore Ts'o --- fs/ext4/ext4.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/ext4/ext4.h') diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index a94e7aaea6e6..1eb07ca91fca 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -733,7 +733,7 @@ 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 -- cgit v1.2.3