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@xxxxxxxxxxxxxxx # 4.19
> Reported-by: Nimish Mishra <neelam.nimish@xxxxxxxxx>
> Reported-by: Anirban Chakraborty <ch.anirban00727@xxxxxxxxx>
> Reported-by: Debdeep Mukhopadhyay <debdeep.mukhopadhyay@xxxxxxxxx>
> Suggested-by: Jerome Forissier <jerome.forissier@xxxxxxxxxx>
> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> [JW: backport to stable-4.19 + update commit message]
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> ---
> 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
