The patch titled
Subject: fat: don't allow to mount if the FAT length == 0
has been added to the -mm tree. Its filename is
fat-dont-allow-to-mount-if-the-fat-length-==-0.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/fat-dont-allow-to-mount-if-the-fat-length-%3D%3D-0.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/fat-dont-allow-to-mount-if-the-fat-length-%3D%3D-0.patch
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------------------------------------------------------
From: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
Subject: fat: don't allow to mount if the FAT length == 0
If FAT length == 0, the image doesn't have any data. And it can be the
cause of overlapping the root dir and FAT entries.
Also Windows treats it as invalid format.
Link: http://lkml.kernel.org/r/87r1wz8mrd.fsf@xxxxxxxxxxxxxxxxxx
Reported-by: syzbot+6f1624f937d9d6911e2d@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/fat/inode.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/fat/inode.c~fat-dont-allow-to-mount-if-the-fat-length-==-0
+++ a/fs/fat/inode.c
@@ -1520,6 +1520,12 @@ static int fat_read_bpb(struct super_blo
goto out;
}
+ if (bpb->fat_fat_length == 0 && bpb->fat32_length == 0) {
+ if (!silent)
+ fat_msg(sb, KERN_ERR, "bogus number of FAT sectors");
+ goto out;
+ }
+
error = 0;
out:
_
Patches currently in -mm which might be from hirofumi@xxxxxxxxxxxxxxxxxx are
fat-dont-allow-to-mount-if-the-fat-length-==-0.patch
