[PATCH for 5.10.y] tee: fix memory leak in tee_shm_register()

[Jens Wiklander <jens.wiklander@linaro.org>]

Moves the access_ok() check for valid memory range from user space from
the function tee_shm_register() to tee_ioctl_shm_register(). With this
we error out early before anything is done that must be undone on error.

Fixes: 578c349570d2 ("tee: add overflow check in register_shm_helper()")
Cc: stable@vger.kernel.org # 5.10
Reported-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
Hi,

This patch targets the 5.10.y release to take care of a recently introduced
issue there.

Thanks,
Jens

 drivers/tee/tee_core.c | 3 +++
 drivers/tee/tee_shm.c  | 3 ---
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index e07f997cf8dd..9cc4a7b63b0d 100644
--- 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 6e662fb131d5..499fccba3d74 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -222,9 +222,6 @@ 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);
-- 
2.31.1