linux/fs/afs
David Howells a45ea48e2b afs: Fix characters allowed into cell names
The afs filesystem needs to prohibit certain characters from cell names,
such as '/', as these are used to form filenames in procfs, leading to
the following warning being generated:

	WARNING: CPU: 0 PID: 3489 at fs/proc/generic.c:178

Fix afs_alloc_cell() to disallow nonprintable characters, '/', '@' and
names that begin with a dot.

Remove the check for "@cell" as that is then redundant.

This can be tested by running:

	echo add foo/.bar 1.2.3.4 >/proc/fs/afs/cells

Note that we will also need to deal with:

 - Names ending in ".invalid" shouldn't be passed to the DNS.

 - Names that contain non-valid domainname chars shouldn't be passed to
   the DNS.

 - DNS replies that say "your-dns-needs-immediate-attention.<gTLD>" and
   replies containing A records that say 127.0.53.53 should be
   considered invalid.
   [https://www.icann.org/en/system/files/files/name-collision-mitigation-01aug14-en.pdf]

but these need to be dealt with by the kafs-client DNS program rather
than the kernel.

Reported-by: syzbot+b904ba7c947a37b4b291@syzkaller.appspotmail.com
Cc: stable@kernel.org
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-26 08:54:04 -08:00
..
addr_list.c
afs.h
afs_cm.h
afs_fs.h
afs_vl.h
cache.c
callback.c
cell.c
cmservice.c
dir.c
dir_edit.c
dir_silly.c
dynroot.c
file.c
flock.c
fs_probe.c
fsclient.c
inode.c
internal.h
Kconfig
main.c
Makefile
misc.c
mntpt.c
proc.c
protocol_uae.h
protocol_yfs.h
rotate.c
rxrpc.c
security.c
server.c
server_list.c
super.c
vl_list.c
vl_probe.c
vl_rotate.c
vlclient.c
volume.c
write.c
xattr.c
xdr_fs.h
yfsclient.c