xemu/hw/9pfs
Greg Kurz fff39a7ad0 9pfs: forbid illegal path names
Empty path components don't make sense for most commands and may cause
undefined behavior, depending on the backend.

Also, the walk request described in the 9P spec [1] clearly shows that
the client is supposed to send individual path components: the official
linux client never sends portions of path containing the / character for
example.

Moreover, the 9P spec [2] also states that a system can decide to restrict
the set of supported characters used in path components, with an explicit
mention "to remove slashes from name components".

This patch introduces a new name_is_illegal() helper that checks the
names sent by the client are not empty and don't contain unwanted chars.
Since 9pfs is only supported on linux hosts, only the / character is
checked at the moment. When support for other hosts (AKA. win32) is added,
other chars may need to be blacklisted as well.

If a client sends an illegal path component, the request will fail and
ENOENT is returned to the client.

[1] http://man.cat-v.org/plan_9/5/walk
[2] http://man.cat-v.org/plan_9/5/intro

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-08-30 19:21:39 +01:00
..
9p-handle.c 9p: switch back to readdir() 2016-06-06 11:52:34 +02:00
9p-local.c 9p: switch back to readdir() 2016-06-06 11:52:34 +02:00
9p-posix-acl.c 9pfs: Clean up includes 2016-01-29 15:07:23 +00:00
9p-proxy.c 9p: switch back to readdir() 2016-06-06 11:52:34 +02:00
9p-proxy.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
9p-synth.c 9p: synth: drop v9fs_ prefix 2016-07-01 14:38:54 +02:00
9p-synth.h Clean up header guards that don't match their file name 2016-07-12 16:19:16 +02:00
9p-xattr-user.c 9pfs: Clean up includes 2016-01-29 15:07:23 +00:00
9p-xattr.c 9pfs: Clean up includes 2016-01-29 15:07:23 +00:00
9p-xattr.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
9p.c 9pfs: forbid illegal path names 2016-08-30 19:21:39 +01:00
9p.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
codir.c 9p: switch back to readdir() 2016-06-06 11:52:34 +02:00
cofile.c 9p/fsdev: remove obsolete references to virtio 2016-06-06 11:52:34 +02:00
cofs.c 9p/fsdev: remove obsolete references to virtio 2016-06-06 11:52:34 +02:00
coth.c coroutine: move entry argument to qemu_coroutine_create 2016-07-13 13:26:02 +02:00
coth.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00
coxattr.c 9p/fsdev: remove obsolete references to virtio 2016-06-06 11:52:34 +02:00
Makefile.objs 9pfs: rename virtio-9p.c to 9p.c 2016-01-08 15:32:13 +05:30
trace-events trace-events: fix first line comment in trace-events 2016-08-12 10:36:01 +01:00
virtio-9p-device.c 9pfs: Wrap in vmstate 2016-07-21 20:44:20 +03:00
virtio-9p.h Clean up ill-advised or unusual header guards 2016-07-12 16:20:46 +02:00