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| author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2020-06-04 16:50:56 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-06-04 19:06:25 -0700 |
| commit | b1b65750b8db67834482f758fc385bfa7560d228 (patch) | |
| tree | 7fda49892d330f38bc4d654c399429b2d79181f2 | |
| parent | ada4ab7af1a67db7eb8596709071a97afb2bf7de (diff) | |
| download | lwn-b1b65750b8db67834482f758fc385bfa7560d228.tar.gz lwn-b1b65750b8db67834482f758fc385bfa7560d228.zip | |
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.
Reported-by: syzbot+6f1624f937d9d6911e2d@syzkaller.appspotmail.com
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/87r1wz8mrd.fsf@mail.parknet.co.jp
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/fat/inode.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/fat/inode.c b/fs/fat/inode.c index e6e68b2274a5..a0cf99debb1e 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -1519,6 +1519,12 @@ static int fat_read_bpb(struct super_block *sb, struct fat_boot_sector *b, 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: |