On Mon, Aug 22, 2022 at 3:32 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Mon, Aug 22, 2022 at 03:12:27PM +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 # 5.4
> > Cc: stable@xxxxxxxxxxxxxxx # 5.10
> > 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 5.4 and 5.10 + update commit message]
>
> You already sent me a 5.4 version here:
> https://lore.kernel.org/r/20220822092621.3691771-1-jens.wiklander@xxxxxxxxxx
>
> And I applied that.
>
> And for 5.10, it's already in the tree as commit 578c349570d2 ("tee: add
> overflow check in register_shm_helper()") and was in the 5.10.137
> release.
>
> > Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > ---
> > drivers/tee/tee_core.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
> > index a7ccd4d2bd10..2db144d2d26f 100644
> > --- a/drivers/tee/tee_core.c
> > +++ b/drivers/tee/tee_core.c
> > @@ -182,6 +182,9 @@ 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;
>
> What I took in 5.10.137 was:
>
> + if (!access_ok((void __user *)addr, length))
> + return ERR_PTR(-EFAULT);
>
> Should I fix it up to look like what you sent here instead?
Yes, please.
>
> confused,
I'm sorry for the confusion.
Thanks,
Jens
>
> greg k-h
