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0fc75c5940
Even with CACHEFILES_DEAD set, we can still read the requests, so in the
following concurrency the request may be used after it has been freed:
mount | daemon_thread1 | daemon_thread2
------------------------------------------------------------
cachefiles_ondemand_init_object
cachefiles_ondemand_send_req
REQ_A = kzalloc(sizeof(*req) + data_len)
wait_for_completion(&REQ_A->done)
cachefiles_daemon_read
cachefiles_ondemand_daemon_read
// close dev fd
cachefiles_flush_reqs
complete(&REQ_A->done)
kfree(REQ_A)
xa_lock(&cache->reqs);
cachefiles_ondemand_select_req
req->msg.opcode != CACHEFILES_OP_READ
// req use-after-free !!!
xa_unlock(&cache->reqs);
xa_destroy(&cache->reqs)
Hence remove requests from cache->reqs when flushing them to avoid
accessing freed requests.
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 | ||