From: Rakesh Pandit Date: Wed, 12 Jul 2017 21:34:07 +0000 (-0700) Subject: bfs: fix sanity checks for empty files X-Git-Tag: MMI-PSA29.97-13-9~5165^2~74 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5f9f48f5b385457426b4b8f3f4a604019a8e7350;p=GitHub%2FMotorolaMobilityLLC%2Fkernel-slsi.git bfs: fix sanity checks for empty files Mount fails if file system image has empty files because of sanity check while reading superblock. For empty files disk offset to end of file (i_eoffset) is cpu_to_le32(-1). Sanity check comparison, which compares disk offset with file system size isn't valid for this value and hence is ignored with this patch. Steps to reproduce: $ dd if=/dev/zero of=bfs-image count=204800 $ mkfs.bfs bfs-image $ mkdir bfs-mount-point $ sudo mount -t bfs -o loop bfs-image bfs-mount-point/ $ cd bfs-mount-point/ $ sudo touch a $ cd .. $ sudo umount bfs-mount-point/ $ sudo mount -t bfs -o loop bfs-image bfs-mount-point/ mount: /dev/loop0: can't read superblock $ dmesg [25526.689580] BFS-fs: bfs_fill_super(): Inode 0x00000003 corrupted Tigran said: "If you had created the filesystem with the proper mkfs under SCO UnixWare 7 you (probably) wouldn't encounter this issue. But since commercial Unix-es are now part of history and the only proper way is the Linux mkfs.bfs utility, your patch is fine" Link: http://lkml.kernel.org/r/20170505201625.GA3097@hercules.tuxera.com Signed-off-by: Rakesh Pandit Acked-by: Tigran Aivazian Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/bfs/inode.c b/fs/bfs/inode.c index 25e312cb6071..9a69392f1fb3 100644 --- a/fs/bfs/inode.c +++ b/fs/bfs/inode.c @@ -419,7 +419,7 @@ static int bfs_fill_super(struct super_block *s, void *data, int silent) if (i_sblock > info->si_blocks || i_eblock > info->si_blocks || i_sblock > i_eblock || - i_eoff > s_size || + (i_eoff != le32_to_cpu(-1) && i_eoff > s_size) || i_sblock * BFS_BSIZE > i_eoff) { printf("Inode 0x%08x corrupted\n", i);