d6bba3ece9
commit 31ad74b20227ce6b40910ff78b1c604e42975cf1 upstream.
At present, the object->file has the NULL pointer dereference problem in
ondemand-mode. The root cause is that the allocated fd and object->file
lifetime are inconsistent, and the user-space invocation to anon_fd uses
object->file. Following is the process that triggers the issue:
[write fd] [umount]
cachefiles_ondemand_fd_write_iter
fscache_cookie_state_machine
cachefiles_withdraw_cookie
if (!file) return -ENOBUFS
cachefiles_clean_up_object
cachefiles_unmark_inode_in_use
fput(object->file)
object->file = NULL
// file NULL pointer dereference!
__cachefiles_write(..., file, ...)
Fix this issue by add an additional reference count to the object->file
before write/llseek, and decrement after it finished.
Fixes:
|
||
|---|---|---|
| .. | ||
| cache.c | ||
| daemon.c | ||
| error_inject.c | ||
| interface.c | ||
| internal.h | ||
| io.c | ||
| Kconfig | ||
| key.c | ||
| main.c | ||
| Makefile | ||
| namei.c | ||
| ondemand.c | ||
| security.c | ||
| volume.c | ||
| xattr.c | ||