[PATCH backport for 5.4/5.10/5.15] tee: optee: Fix incorrect page free bug

[PATCH backport for 5.4/5.10/5.15] tee: optee: Fix incorrect page free bug

[Sumit Garg]

commit 18549bf4b21c739a9def39f27dcac53e27286ab5 upstream.

Pointer to the allocated pages (struct page *page) has already
progressed towards the end of allocation. It is incorrect to perform
__free_pages(page, order) using this pointer as we would free any
arbitrary pages. Fix this by stop modifying the page pointer.

Fixes: ec185dd3ab25 ("optee: Fix memory leak when failing to register shm pages")
Cc: stable@vger.kernel.org
Reported-by: Patrik Lantz <patrik.lantz@axis.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
[SG: Backport for stable kernels]
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/tee/optee/shm_pool.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/tee/optee/shm_pool.c b/drivers/tee/optee/shm_pool.c
index d167039af519..1aa843f2ecc7 100644
--- a/drivers/tee/optee/shm_pool.c
+++ b/drivers/tee/optee/shm_pool.c
@@ -41,10 +41,8 @@ static int pool_op_alloc(struct tee_shm_pool_mgr *poolm,
 			goto err;
 		}
 
-		for (i = 0; i < nr_pages; i++) {
-			pages[i] = page;
-			page++;
-		}
+		for (i = 0; i < nr_pages; i++)
+			pages[i] = page + i;
 
 		shm->flags |= TEE_SHM_REGISTER;
 		rc = optee_shm_register(shm->ctx, shm, pages, nr_pages,
-- 
2.25.1

Re: [PATCH backport for 5.4/5.10/5.15] tee: optee: Fix incorrect page free bug

[Greg KH]

On Mon, Dec 27, 2021 at 05:44:32PM +0530, Sumit Garg wrote:
> commit 18549bf4b21c739a9def39f27dcac53e27286ab5 upstream.
> 
> Pointer to the allocated pages (struct page *page) has already
> progressed towards the end of allocation. It is incorrect to perform
> __free_pages(page, order) using this pointer as we would free any
> arbitrary pages. Fix this by stop modifying the page pointer.
> 
> Fixes: ec185dd3ab25 ("optee: Fix memory leak when failing to register shm pages")
> Cc: stable@vger.kernel.org
> Reported-by: Patrik Lantz <patrik.lantz@axis.com>
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
> [SG: Backport for stable kernels]
> Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
> ---
>  drivers/tee/optee/shm_pool.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)

Now queued up, thanks.

greg k-h