Jens Wiklander 3d556a28bb tee: handle lookup of shm with reference count 0 ... commit dfd0743f1d upstream. Since the tee subsystem does not keep a strong reference to its idle shared memory buffers, it races with other threads that try to destroy a shared memory through a close of its dma-buf fd or by unmapping the memory. In tee_shm_get_from_id() when a lookup in teedev->idr has been successful, it is possible that the tee_shm is in the dma-buf teardown path, but that path is blocked by the teedev mutex. Since we don't have an API to tell if the tee_shm is in the dma-buf teardown path or not we must find another way of detecting this condition. Fix this by doing the reference counting directly on the tee_shm using a new refcount_t refcount field. dma-buf is replaced by using anon_inode_getfd() instead, this separates the life-cycle of the underlying file from the tee_shm. tee_shm_put() is updated to hold the mutex when decreasing the refcount to 0 and then remove the tee_shm from teedev->idr before releasing the mutex. This means that the tee_shm can never be found unless it has a refcount larger than 0. Fixes: 967c9cca2c ("tee: generic TEE subsystem") Cc: stable@vger.kernel.org Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Lars Persson <larper@axis.com> Reviewed-by: Sumit Garg <sumit.garg@linaro.org> Reported-by: Patrik Lantz <patrik.lantz@axis.com> [JW: backported to 4.14-stable] Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-01-05 12:33:48 +01:00
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optee	tee: optee: do not check memref size on return from Secure World	2021-05-22 10:57:16 +02:00
Kconfig	…
Makefile	…
tee_core.c	…
tee_private.h	tee: handle lookup of shm with reference count 0	2022-01-05 12:33:48 +01:00
tee_shm.c	tee: handle lookup of shm with reference count 0	2022-01-05 12:33:48 +01:00
tee_shm_pool.c	…