On Mon, Aug 22, 2022 at 05:02:53PM +0200, Jens Wiklander wrote:

commit 573ae4f13f630d6660008f1974c0a8a29c30e18a upstream.

With special lengths supplied by user space, tee_shm_register() has an integer overflow when calculating the number of pages covered by a supplied user space memory region.

This may cause pin_user_pages_fast() to do a NULL pointer dereference.

Fix this by adding an an explicit call to access_ok() in tee_ioctl_shm_register() to catch an invalid user space address early.

Fixes: 033ddf12bcf5 ("tee: add register user memory") Cc: stable@vger.kernel.org # 4.19 Reported-by: Nimish Mishra neelam.nimish@gmail.com Reported-by: Anirban Chakraborty ch.anirban00727@gmail.com Reported-by: Debdeep Mukhopadhyay debdeep.mukhopadhyay@gmail.com Suggested-by: Jerome Forissier jerome.forissier@linaro.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org [JW: backport to stable-4.19 + update commit message] Signed-off-by: Jens Wiklander jens.wiklander@linaro.org

---

drivers/tee/tee_core.c | 4 ++++ 1 file changed, 4 insertions(+)

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c index d42fc2ae8592..e568cb4b2ffc 100644 --- a/drivers/tee/tee_core.c +++ b/drivers/tee/tee_core.c @@ -175,6 +175,10 @@ tee_ioctl_shm_register(struct tee_context *ctx, if (data.flags) return -EINVAL;

• if (!access_ok(VERIFY_WRITE, (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))

-- 2.31.1

Now queued up, thanks.

greg k-h