Commit ab9d3db5 authored Apr 29, 2018 by Etienne Carriere Committed by Jens Wiklander May 07, 2018

tee: check shm references are consistent in offset/size

This change prevents userland from referencing TEE shared memory
outside the area initially allocated by its owner. Prior this change an
application could not reference or access memory it did not own but
it could reference memory not explicitly allocated by owner but still
allocated to the owner due to the memory allocation granule.

Reported-by: Alexandre Jutras <alexandre.jutras@nxp.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

parent bb765d1c

drivers/tee/tee_core.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -238,6 +238,17 @@ static int params_from_user(struct tee_context ctx, struct tee_param params,
		if (IS_ERR(shm))
		return PTR_ERR(shm);

		/*
		* Ensure offset + size does not overflow offset
		* and does not overflow the size of the referred
		* shared memory object.
		*/
		if ((ip.a + ip.b) < ip.a \|\|
		(ip.a + ip.b) > shm->size) {
		tee_shm_put(shm);
		return -EINVAL;
		}

		params[n].u.memref.shm_offs = ip.a;
		params[n].u.memref.size = ip.b;
		params[n].u.memref.shm = shm;

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