linux-stable.git/fs/fuse, branch v4.19.166

fuse: fix page dereference after free

2020-11-05T10:08:34+00:00

commit d78092e4937de9ce55edcb4ee4c5e3c707be0190 upstream.

After unlock_request() pages from the ap->pages[] array may be put (e.g. by
aborting the connection) and the pages can be freed.

Prevent use after free by grabbing a reference to the page before calling
unlock_request().

The original patch was created by Pradeep P V K.

Reported-by: Pradeep P V K 
Cc: 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: don't check refcount after stealing page

2020-10-01T11:14:44+00:00

[ Upstream commit 32f98877c57bee6bc27f443a96f49678a2cd6a50 ]

page_count() is unstable.  Unless there has been an RCU grace period
between when the page was removed from the page cache and now, a
speculative reference may exist from the page cache.

Reported-by: Matthew Wilcox 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Sasha Levin

fuse: fix weird page warning

2020-07-29T08:16:46+00:00

commit a5005c3cda6eeb6b95645e6cc32f58dafeffc976 upstream.

When PageWaiters was added, updating this check was missed.

Reported-by: Nikolaus Rath 
Reported-by: Hugh Dickins 
Fixes: 62906027091f ("mm: add PageWaiters indicating tasks are waiting for a page bit")
Signed-off-by: Miklos Szeredi 
Signed-off-by: André Almeida 
Signed-off-by: Sasha Levin

fuse: Fix parameter for FS_IOC_{GET,SET}FLAGS

2020-07-22T07:32:10+00:00

commit 31070f6ccec09f3bd4f1e28cd1e592fa4f3ba0b6 upstream.

The ioctl encoding for this parameter is a long but the documentation says
it should be an int and the kernel drivers expect it to be an int.  If the
fuse driver treats this as a long it might end up scribbling over the stack
of a userspace process that only allocated enough space for an int.

This was previously discussed in [1] and a patch for fuse was proposed in
[2].  From what I can tell the patch in [2] was nacked in favor of adding
new, "fixed" ioctls and using those from userspace.  However there is still
no "fixed" version of these ioctls and the fact is that it's sometimes
infeasible to change all userspace to use the new one.

Handling the ioctls specially in the fuse driver seems like the most
pragmatic way for fuse servers to support them without causing crashes in
userspace applications that call them.

[1]: https://lore.kernel.org/linux-fsdevel/20131126200559.GH20559@hall.aurel32.net/T/
[2]: https://sourceforge.net/p/fuse/mailman/message/31771759/

Signed-off-by: Chirantan Ekbote 
Fixes: 59efec7b9039 ("fuse: implement ioctl support")
Cc: 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: verify attributes

2019-12-13T07:52:36+00:00

commit eb59bd17d2fa6e5e84fba61a5ebdea984222e6d5 upstream.

If a filesystem returns negative inode sizes, future reads on the file were
causing the cpu to spin on truncate_pagecache.

Create a helper to validate the attributes.  This now does two things:

 - check the file mode
 - check if the file size fits in i_size without overflowing

Reported-by: Arijit Banerjee 
Fixes: d8a5ba45457e ("[PATCH] FUSE - core")
Cc:  # v2.6.14
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: verify nlink

2019-12-13T07:52:35+00:00

commit c634da718db9b2fac201df2ae1b1b095344ce5eb upstream.

When adding a new hard link, make sure that i_nlink doesn't overflow.

Fixes: ac45d61357e8 ("fuse: fix nlink after unlink")
Cc:  # v3.4
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: use READ_ONCE on congestion_threshold and max_background

2019-11-20T17:47:53+00:00

[ Upstream commit 2a23f2b8adbe4bd584f936f7ac17a99750eed9d7 ]

Since they are of unsigned int type, it's allowed to read them
unlocked during reporting to userspace. Let's underline this fact
with READ_ONCE() macroses.

Signed-off-by: Kirill Tkhai 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Sasha Levin

fuse: truncate pending writes on O_TRUNC

2019-11-06T12:06:13+00:00

commit e4648309b85a78f8c787457832269a8712a8673e upstream.

Make sure cached writes are not reordered around open(..., O_TRUNC), with
the obvious wrong results.

Fixes: 4d99ff8f12eb ("fuse: Turn writeback cache on")
Cc:  # v3.15+
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: flush dirty data/metadata before non-truncate setattr

2019-11-06T12:06:13+00:00

commit b24e7598db62386a95a3c8b9c75630c5d56fe077 upstream.

If writeback cache is enabled, then writes might get reordered with
chmod/chown/utimes.  The problem with this is that performing the write in
the fuse daemon might itself change some of these attributes.  In such case
the following sequence of operations will result in file ending up with the
wrong mode, for example:

  int fd = open ("suid", O_WRONLY|O_CREAT|O_EXCL);
  write (fd, "1", 1);
  fchown (fd, 0, 0);
  fchmod (fd, 04755);
  close (fd);

This patch fixes this by flushing pending writes before performing
chown/chmod/utimes.

Reported-by: Giuseppe Scrivano 
Tested-by: Giuseppe Scrivano 
Fixes: 4d99ff8f12eb ("fuse: Turn writeback cache on")
Cc:  # v3.15+
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman

fuse: fix memleak in cuse_channel_open

2019-10-11T16:21:20+00:00

[ Upstream commit 9ad09b1976c562061636ff1e01bfc3a57aebe56b ]

If cuse_send_init fails, need to fuse_conn_put cc->fc.

cuse_channel_open->fuse_conn_init->refcount_set(&fc->count, 1)
                 ->fuse_dev_alloc->fuse_conn_get
                 ->fuse_dev_free->fuse_conn_put

Fixes: cc080e9e9be1 ("fuse: introduce per-instance fuse_dev structure")
Reported-by: Hulk Robot 
Signed-off-by: zhengbin 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Sasha Levin