linux.git/fs/proc/fd.c, branch v4.0

fs: Convert show_fdinfo functions to void

2014-11-05T19:13:23+00:00

seq_printf functions shouldn't really check the return value.
Checking seq_has_overflowed() occasionally is used instead.

Update vfs documentation.

Link: http://lkml.kernel.org/p/e37e6e7b76acbdcc3bb4ab2a57c8f8ca1ae11b9a.1412031505.git.joe@perches.com

Cc: David S. Miller 
Cc: Al Viro 
Signed-off-by: Joe Perches 
[ did a few clean ups ]
Signed-off-by: Steven Rostedt

vfs: Remove d_drop calls from d_revalidate implementations

2014-10-09T06:38:58+00:00

Now that d_invalidate always succeeds it is not longer necessary or
desirable to hard code d_drop calls into filesystem specific
d_revalidate implementations.

Remove the unnecessary d_drop calls and rely on d_invalidate
to drop the dentries.  Using d_invalidate ensures that paths
to mount points will not be dropped.

Reviewed-by: Miklos Szeredi 
Signed-off-by: "Eric W. Biederman" 
Signed-off-by: Al Viro

proc: add and remove /proc entry create checks

2014-08-08T22:57:22+00:00

* remove proc_create(NULL, ...) check, let it oops

* warn about proc_create("", ...) and proc_create("very very long name", ...)
  proc code keeps length as u8, no 256+ name length possible

* warn about proc_create("123", ...)
  /proc/$PID and /proc/misc namespaces are separate things,
  but dumb module might create funky a-la $PID entry.

* remove post mortem strchr('/') check
  Triggering it implies either strchr() is buggy or memory corruption.
  It should be VFS check anyway.

In reality, none of these checks will ever trigger,
it is preparation for the next patch.

Based on patch from Al Viro.

Signed-off-by: Alexey Dobriyan 
Cc: Al Viro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: show mnt_id in /proc/pid/fdinfo

2014-04-07T23:36:04+00:00

Currently we don't have a way how to determing from which mount point
file has been opened.  This information is required for proper dumping
and restoring file descriptos due to presence of mount namespaces.  It's
possible, that two file descriptors are opened using the same paths, but
one fd references mount point from one namespace while the other fd --
from other namespace.

$ ls -l /proc/1/fd/1
lrwx------ 1 root root 64 Mar 19 23:54 /proc/1/fd/1 -> /dev/null

$ cat /proc/1/fdinfo/1
pos:	0
flags:	0100002
mnt_id:	16

$ cat /proc/1/mountinfo | grep ^16
16 32 0:4 / /dev rw,nosuid shared:2 - devtmpfs devtmpfs rw,size=1013356k,nr_inodes=253339,mode=755

Signed-off-by: Andrey Vagin 
Acked-by: Pavel Emelyanov 
Acked-by: Cyrill Gorcunov 
Cc: Rob Landley 
Cc: Al Viro 
Cc: Oleg Nesterov 
Cc: "Eric W. Biederman" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: make proc_fd_permission() thread-friendly

2013-09-11T22:59:03+00:00

proc_fd_permission() says "process can still access /proc/self/fd after it
has executed a setuid()", but the "task_pid() = proc_pid() check only
helps if the task is group leader, /proc/self points to
/proc/.

Change this check to use task_tgid() so that the whole thread group can
access its /proc/self/fd or /proc//fd.

Notes:
	- CLONE_THREAD does not require CLONE_FILES so task->files
	  can differ, but I don't think this can lead to any security
	  problem. And this matches same_thread_group() in
	  __ptrace_may_access().

	- /proc/self should probably point to /proc/, but
	  it is too late to change the rules. Perhaps it makes sense
	  to add /proc/thread though.

Test-case:

	void *tfunc(void *arg)
	{
		assert(opendir("/proc/self/fd"));
		return NULL;
	}

	int main(void)
	{
		pthread_t t;
		pthread_create(&t, NULL, tfunc, NULL);
		pthread_join(t, NULL);
		return 0;
	}

fails if, say, this executable is not readable and suid_dumpable = 0.

Signed-off-by: Oleg Nesterov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

proc: kill the extra proc_readfd_common()->dir_emit_dots()

2013-08-24T16:10:22+00:00

proc_readfd_common() does dir_emit_dots() twice in a row,
we need to do this only once.

Signed-off-by: Oleg Nesterov 
Signed-off-by: Al Viro

proc_fill_cache(): just make instantiate_t return int

2013-06-29T08:57:18+00:00

all instances always return ERR_PTR(-E...) or NULL, anyway

Signed-off-by: Al Viro

[readdir] convert procfs

2013-06-29T08:56:32+00:00

Signed-off-by: Al Viro

procfs: add ability to plug in auxiliary fdinfo providers

2012-12-18T01:15:27+00:00

This patch brings ability to print out auxiliary data associated with
file in procfs interface /proc/pid/fdinfo/fd.

In particular further patches make eventfd, evenpoll, signalfd and
fsnotify to print additional information complete enough to restore
these objects after checkpoint.

To simplify the code we add show_fdinfo callback inside struct
file_operations (as Al and Pavel are proposing).

Signed-off-by: Cyrill Gorcunov 
Acked-by: Pavel Emelyanov 
Cc: Oleg Nesterov 
Cc: Andrey Vagin 
Cc: Al Viro 
Cc: Alexey Dobriyan 
Cc: James Bottomley 
Cc: "Aneesh Kumar K.V" 
Cc: Alexey Dobriyan 
Cc: Matthew Helsley 
Cc: "J. Bruce Fields" 
Cc: "Aneesh Kumar K.V" 
Cc: Tvrtko Ursulin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

don't leak O_CLOEXEC into ->f_flags

2012-09-27T01:10:01+00:00

Signed-off-by: Al Viro