linux-stable.git/fs/fuse, branch v4.4.147

fuse: fix control dir setup and teardown

2018-07-03T09:21:28+00:00

commit 6becdb601bae2a043d7fb9762c4d48699528ea6e upstream.

syzbot is reporting NULL pointer dereference at fuse_ctl_remove_conn() [1].
Since fc->ctl_ndents is incremented by fuse_ctl_add_conn() when new_inode()
failed, fuse_ctl_remove_conn() reaches an inode-less dentry and tries to
clear d_inode(dentry)->i_private field.

Fix by only adding the dentry to the array after being fully set up.

When tearing down the control directory, do d_invalidate() on it to get rid
of any mounts that might have been added.

[1] https://syzkaller.appspot.com/bug?id=f396d863067238959c91c0b7cfc10b163638cac6
Reported-by: syzbot 
Fixes: bafa96541b25 ("[PATCH] fuse: add control filesystem")
Cc:  # v2.6.18
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: don't keep dead fuse_conn at fuse_fill_super().

2018-07-03T09:21:28+00:00

commit 543b8f8662fe6d21f19958b666ab0051af9db21a upstream.

syzbot is reporting use-after-free at fuse_kill_sb_blk() [1].
Since sb->s_fs_info field is not cleared after fc was released by
fuse_conn_put() when initialization failed, fuse_kill_sb_blk() finds
already released fc and tries to hold the lock. Fix this by clearing
sb->s_fs_info field after calling fuse_conn_put().

[1] https://syzkaller.appspot.com/bug?id=a07a680ed0a9290585ca424546860464dd9658db

Signed-off-by: Tetsuo Handa 
Reported-by: syzbot 
Fixes: 3b463ae0c626 ("fuse: invalidation reverse calls")
Cc: John Muir 
Cc: Csaba Henk 
Cc: Anand Avati 
Cc:  # v2.6.31
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: atomic_o_trunc should truncate pagecache

2018-07-03T09:21:28+00:00

commit df0e91d488276086bc07da2e389986cae0048c37 upstream.

Fuse has an "atomic_o_trunc" mode, where userspace filesystem uses the
O_TRUNC flag in the OPEN request to truncate the file atomically with the
open.

In this mode there's no need to send a SETATTR request to userspace after
the open, so fuse_do_setattr() checks this mode and returns.  But this
misses the important step of truncating the pagecache.

Add the missing parts of truncation to the ATTR_OPEN branch.

Reported-by: Chad Austin 
Fixes: 6ff958edbf39 ("fuse: add atomic open+truncate support")
Signed-off-by: Miklos Szeredi 
Cc: 
Signed-off-by: Greg Kroah-Hartman

fuse: fix READDIRPLUS skipping an entry

2017-11-02T08:40:49+00:00

commit c6cdd51404b7ac12dd95173ddfc548c59ecf037f upstream.

Marios Titas running a Haskell program noticed a problem with fuse's
readdirplus: when it is interrupted by a signal, it skips one directory
entry.

The reason is that fuse erronously updates ctx->pos after a failed
dir_emit().

The issue originates from the patch adding readdirplus support.

Reported-by: Jakob Unterwurzacher 
Tested-by: Marios Titas 
Signed-off-by: Miklos Szeredi 
Fixes: 0b05b18381ee ("fuse: implement NFS-like readdirplus support")
Signed-off-by: Greg Kroah-Hartman

fuse: initialize the flock flag in fuse_file on allocation

2017-08-16T20:40:28+00:00

commit 68227c03cba84a24faf8a7277d2b1a03c8959c2c upstream.

Before the patch, the flock flag could remain uninitialized for the
lifespan of the fuse_file allocation. Unless set to true in
fuse_file_flock(), it would remain in an indeterminate state until read in
an if statement in fuse_release_common(). This could consequently lead to
taking an unexpected branch in the code.

The bug was discovered by a runtime instrumentation designed to detect use
of uninitialized memory in the kernel.

Signed-off-by: Mateusz Jurczyk 
Fixes: 37fb3a30b462 ("fuse: fix flock")
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: add missing FR_FORCE

2017-03-12T05:37:28+00:00

commit 2e38bea99a80eab408adee27f873a188d57b76cb upstream.

fuse_file_put() was missing the "force" flag for the RELEASE request when
sending synchronously (fuseblk).

If this flag is not set, then a sync request may be interrupted before it
is dequeued by the userspace filesystem.  In this case the OPEN won't be
balanced with a RELEASE.

Signed-off-by: Miklos Szeredi 
Fixes: 5a18ec176c93 ("fuse: fix hang of single threaded fuseblk filesystem")
Signed-off-by: Greg Kroah-Hartman

fuse: fix use after free issue in fuse_dev_do_read()

2017-02-23T16:43:09+00:00

commit 6ba4d2722d06960102c981322035239cd66f7316 upstream.

There is a potential race between fuse_dev_do_write()
and request_wait_answer() contexts as shown below:

TASK 1:
__fuse_request_send():
  |--spin_lock(&fiq->waitq.lock);
  |--queue_request();
  |--spin_unlock(&fiq->waitq.lock);
  |--request_wait_answer():
       |--if (test_bit(FR_SENT, &req->flags))
       
                                   TASK 2:
                                   fuse_dev_do_write():
                                     |--clears bit FR_SENT,
                                     |--request_end():
                                        |--sets bit FR_FINISHED
                                        |--spin_lock(&fiq->waitq.lock);
                                        |--list_del_init(&req->intr_entry);
                                        |--spin_unlock(&fiq->waitq.lock);
                                        |--fuse_put_request();
       |--queue_interrupt();
       
            |--wake_up_locked(&fiq->waitq);
       |--wait_event_freezable();
       

Now, the next fuse_dev_do_read(), see interrupts list is not empty
and then calls fuse_read_interrupt() which tries to access the request
which is already free'd and gets the below crash:

[11432.401266] Unable to handle kernel paging request at virtual address
6b6b6b6b6b6b6b6b
...
[11432.418518] Kernel BUG at ffffff80083720e0
[11432.456168] PC is at __list_del_entry+0x6c/0xc4
[11432.463573] LR is at fuse_dev_do_read+0x1ac/0x474
...
[11432.679999] [] __list_del_entry+0x6c/0xc4
[11432.687794] [] fuse_dev_do_read+0x1ac/0x474
[11432.693180] [] fuse_dev_read+0x6c/0x78
[11432.699082] [] __vfs_read+0xc0/0xe8
[11432.704459] [] vfs_read+0x90/0x108
[11432.709406] [] SyS_read+0x58/0x94

As FR_FINISHED bit is set before deleting the intr_entry with input
queue lock in request completion path, do the testing of this flag and
queueing atomically with the same lock in queue_interrupt().

Signed-off-by: Sahitya Tummala 
Signed-off-by: Miklos Szeredi 
Fixes: fd22d62ed0c3 ("fuse: no fc->lock for iqueue parts")
Signed-off-by: Greg Kroah-Hartman

fuse: clear FR_PENDING flag when moving requests out of pending queue

2017-01-26T07:23:48+00:00

commit a8a86d78d673b1c99fe9b0064739fde9e9774184 upstream.

fuse_abort_conn() moves requests from pending list to a temporary list
before canceling them. This operation races with request_wait_answer()
which also tries to remove the request after it gets a fatal signal. It
checks FR_PENDING flag to determine whether the request is still in the
pending list.

Make fuse_abort_conn() clear FR_PENDING flag so that request_wait_answer()
does not remove the request from temporary list.

This bug causes an Oops when trying to delete an already deleted list entry
in end_requests().

Fixes: ee314a870e40 ("fuse: abort: no fc->lock needed for request ending")
Signed-off-by: Tahsin Erdogan 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: fix fuse_write_end() if zero bytes were copied

2016-11-26T08:54:52+00:00

commit 59c3b76cc61d1d676f965c192cc7969aa5cb2744 upstream.

If pos is at the beginning of a page and copied is zero then page is not
zeroed but is marked uptodate.

Fix by skipping everything except unlock/put of page if zero bytes were
copied.

Reported-by: Al Viro 
Fixes: 6b12c1b37e55 ("fuse: Implement write_begin/write_end callbacks")
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: fix killing s[ug]id in setattr

2016-10-22T10:26:55+00:00

commit a09f99eddef44035ec764075a37bace8181bec38 upstream.

Fuse allowed VFS to set mode in setattr in order to clear suid/sgid on
chown and truncate, and (since writeback_cache) write.  The problem with
this is that it'll potentially restore a stale mode.

The poper fix would be to let the filesystems do the suid/sgid clearing on
the relevant operations.  Possibly some are already doing it but there's no
way we can detect this.

So fix this by refreshing and recalculating the mode.  Do this only if
ATTR_KILL_S[UG]ID is set to not destroy performance for writes.  This is
still racy but the size of the window is reduced.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman