linux/fs/fuse
Miklos Szeredi 712a951025 fuse: fix page stealing
It is possible to trigger a crash by splicing anon pipe bufs to the fuse
device.

The reason for this is that anon_pipe_buf_release() will reuse buf->page if
the refcount is 1, but that page might have already been stolen and its
flags modified (e.g. PG_lru added).

This happens in the unlikely case of fuse_dev_splice_write() getting around
to calling pipe_buf_release() after a page has been stolen, added to the
page cache and removed from the page cache.

Fix by calling pipe_buf_release() right after the page was inserted into
the page cache.  In this case the page has an elevated refcount so any
release function will know that the page isn't reusable.

Reported-by: Frank Dinoff <fdinoff@google.com>
Link: https://lore.kernel.org/r/CAAmZXrsGg2xsP1CK+cbuEMumtrqdvD-NKnWzhNcvn71RV3c1yw@mail.gmail.com/
Fixes: dd3bb14f44 ("fuse: support splice() writing to fuse device")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2021-11-02 11:10:37 +01:00
..
acl.c vfs: add rcu argument to ->get_acl() callback 2021-08-18 22:08:24 +02:00
control.c fuse: name fs_context consistently 2021-08-04 13:22:58 +02:00
cuse.c cuse: simplify refcount 2021-04-14 10:40:58 +02:00
dax.c fuse: always invalidate attributes after writes 2021-10-28 09:45:32 +02:00
dev.c fuse: fix page stealing 2021-11-02 11:10:37 +01:00
dir.c fuse: only update necessary attributes 2021-10-28 09:45:33 +02:00
file.c fuse: add FOPEN_NOFLUSH 2021-10-28 10:20:31 +02:00
fuse_i.h fuse: only update necessary attributes 2021-10-28 09:45:33 +02:00
inode.c fuse: add cache_mask 2021-10-28 09:45:33 +02:00
ioctl.c fuse: use kmap_local_page() 2021-10-22 17:03:01 +02:00
Kconfig virtiofs: implement dax read/write operations 2020-09-10 11:39:23 +02:00
Makefile fuse: move ioctl to separate source file 2021-04-12 15:04:30 +02:00
readdir.c fuse: only update necessary attributes 2021-10-28 09:45:33 +02:00
virtio_fs.c virtiofs: use strscpy for copying the queue name 2021-11-02 11:08:19 +01:00
xattr.c fuse: move fuse_invalidate_attr() into fuse_update_ctime() 2021-10-22 17:03:01 +02:00