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