4.14-stable review patch. If anyone has any objections, please let me know.
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From: Etienne Carriere etienne.carriere@linaro.org
[ Upstream commit ab9d3db5b320a052452b9cd035599ee3c84bbee9 ]
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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tee/tee_core.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
--- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -181,6 +181,17 @@ static int params_from_user(struct tee_c 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;