nvmet-auth: complete a request only after freeing the dhchap pointers
commit f965b281 upstream. It may happen that the work to destroy a queue (for example nvmet_tcp_release_queue_work()) is started while an auth-send or auth-receive command is still completing. nvmet_sq_destroy() will block, waiting for all the references to the sq to be dropped, the last reference is then dropped when nvmet_req_complete() is called. When this happens, both nvmet_sq_destroy() and nvmet_execute_auth_send()/_receive() will free the dhchap pointers by calling nvmet_auth_sq_free(). Since there isn't any lock, the two threads may race against each other, causing double frees and memory corruptions, as reported by KASAN. Reproduced by stress blktests nvme/041 nvme/042 nvme/043 nvme nvme2: qid 0: authenticated with hash hmac(sha512) dhgroup ffdhe4096 ================================================================== BUG: KASAN: double-free in kfree+0xec/0x4b0 Call Trace: <TASK> kfree+0xec/0x4b0 nvmet_auth_sq_free+0xe1/0x160 [nvmet] nvmet_execute_auth_send+0x482/0x16d0 [nvmet] process_one_work+0x8e5/0x1510 Allocated by task 191846: __kasan_kmalloc+0x81/0xa0 nvmet_auth_ctrl_sesskey+0xf6/0x380 [nvmet] nvmet_auth_reply+0x119/0x990 [nvmet] Freed by task 143270: kfree+0xec/0x4b0 nvmet_auth_sq_free+0xe1/0x160 [nvmet] process_one_work+0x8e5/0x1510 Fix this bug by calling nvmet_req_complete() only after freeing the pointers, so we will prevent the race by holding the sq reference. V2: remove redundant code Fixes: db1312dd ("nvmet: implement basic In-Band Authentication") Signed-off-by:Maurizio Lombardi <mlombard@redhat.com> Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Keith Busch <kbusch@kernel.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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0ec655ad
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