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0a79004083
The following concurrency may cause a read request to fail to be completed
and result in a hung:
t1 | t2
---------------------------------------------------------
cachefiles_ondemand_copen
req = xa_erase(&cache->reqs, id)
// Anon fd is maliciously closed.
cachefiles_ondemand_fd_release
xa_lock(&cache->reqs)
cachefiles_ondemand_set_object_close(object)
xa_unlock(&cache->reqs)
cachefiles_ondemand_set_object_open
// No one will ever close it again.
cachefiles_ondemand_daemon_read
cachefiles_ondemand_select_req
// Get a read req but its fd is already closed.
// The daemon can't issue a cread ioctl with an closed fd, then hung.
So add spin_lock for cachefiles_ondemand_info to protect ondemand_id and
state, thus we can avoid the above problem in cachefiles_ondemand_copen()
by using ondemand_id to determine if fd has been closed.
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 | ||