tee: Fix tee_shm_register() for kernel TEE drivers

Commit 056d3fed3d1f ("tee: add tee_shm_register_{user,kernel}_buf()")
refactored tee_shm_register() into corresponding user and kernel space
functions named tee_shm_register_{user,kernel}_buf(). The upstream fix
commit 573ae4f13f63 ("tee: add overflow check in register_shm_helper()")
only applied to tee_shm_register_user_buf().

But the stable kernel 4.19, 5.4, 5.10 and 5.15 don't have the above
mentioned tee_shm_register() refactoring commit. Hence a direct backport
wasn't possible and the fix has to be rather applied to
tee_ioctl_shm_register().

Somehow the fix was correctly backported to 4.19 and 5.4 stable kernels
but the backports for 5.10 and 5.15 stable kernels were broken as fix
was applied to common tee_shm_register() function which broke its kernel
space users such as trusted keys driver.

Fortunately the backport for 5.10 stable kernel was incidently fixed by:
commit 606fe84a4185 ("tee: fix memory leak in tee_shm_register()"). So
fix the backport for 5.15 stable kernel as well.

Fixes: 578c349570d2 ("tee: add overflow check in register_shm_helper()")
Cc: stable@vger.kernel.org # 5.15
Reported-by: Sahil Malhotra <sahil.malhotra@nxp.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 3fc426d..a44e5b5 100644 (file)
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -334,6 +334,9 @@ tee_ioctl_shm_register(struct tee_context *ctx,
        if (data.flags)
                return -EINVAL;
 
+       if (!access_ok((void __user *)(unsigned long)data.addr, data.length))
+               return -EFAULT;
+
        shm = tee_shm_register(ctx, data.addr, data.length,
                               TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED);
        if (IS_ERR(shm))

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index bd96ebb..6fb4400 100644 (file)
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -223,9 +223,6 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
                goto err;
        }
 
-       if (!access_ok((void __user *)addr, length))
-               return ERR_PTR(-EFAULT);
-
        mutex_lock(&teedev->mutex);
        shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
        mutex_unlock(&teedev->mutex);