Messages in this thread | | | From | Jens Wiklander <> | Date | Mon, 22 Aug 2022 15:03:43 +0200 | Subject | Re: [PATCH 5.10 540/545] tee: add overflow check in register_shm_helper() |
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Hi,
On Mon, Aug 22, 2022 at 1:15 PM Pavel Machek <pavel@denx.de> wrote: > > Hi! > > > From: Jens Wiklander <jens.wiklander@linaro.org> > > > > commit 573ae4f13f630d6660008f1974c0a8a29c30e18a upstream. > > > > With special lengths supplied by user space, register_shm_helper() has > > an integer overflow when calculating the number of pages covered by a > > supplied user space memory region. > > > > This causes internal_get_user_pages_fast() a helper function of > > pin_user_pages_fast() to do a NULL pointer dereference: > > Maybe this needs fixing, but this fix adds a memory leak or two. Note > the goto err, that needs to be done.
Thanks for bringing this up. I believe the best option is to take the backport I just did for 5.4, it should apply cleanly on the 5.10 stable kernel too.
Greg, can you cherry-pick the 5.4 backport patch, or would you rather have an explicit backport for this stable kernel?
Cheers, Jens
> > Best regards, > Pavel > > Signed-off-by: Pavel Machek <pavel@denx.de> > > > +++ b/drivers/tee/tee_shm.c > > @@ -222,6 +222,9 @@ struct tee_shm *tee_shm_register(struct > > 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); > > > > > diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c > index 6e662fb131d5..283fa50676a2 100644 > --- a/drivers/tee/tee_shm.c > +++ b/drivers/tee/tee_shm.c > @@ -222,8 +222,10 @@ 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); > + if (!access_ok((void __user *)addr, length)) { > + ret = ERR_PTR(-EFAULT); > + goto err; > + } > > mutex_lock(&teedev->mutex); > shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL); > > -- > DENX Software Engineering GmbH, Managing Director: Wolfgang Denk > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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