Hi Greg,
On Mon, 22 Aug 2022 at 18:42, Jens Wiklander <jens.wiklander@xxxxxxxxxx> 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]
> Signed-off-by: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> ---
> drivers/tee/tee_core.c | 3 +++
> 1 file changed, 3 insertions(+)
>
The v5.15 backport [1] for this fix has broken the kernel consumers
for tee_shm_register(), the trusted keys driver is one of them
reported here [2]. We need to fix that up with the following change
[3]. Would you like to revert the backport and apply the correct one
or should I prepare a fix patch for the following [3]?
[1] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.15.y&id=c12f0e6126ad223806a365084e86370511654bf1
[2] https://github.com/OP-TEE/optee_os/issues/5624
[3]
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 3fc426dad2df..d5c4fcd8733d 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -334,6 +334,9 @@ tee_ioctl_shm_register(struct tee_context *ctx,
if (data.flags)
return -EINVAL;
+ if (!access_ok((void __user *)data.addr, data.length))
+ return ERR_PTR(-EFAULT);
+
shm = tee_shm_register(ctx, data.addr, data.length,
TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED);
if (IS_ERR(shm))
diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index bd96ebb82c8e..6fb4400333fb 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -223,9 +223,6 @@ 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);
-
mutex_lock(&teedev->mutex);
shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL);
mutex_unlock(&teedev->mutex);
-Sumit
> 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;
> +
> shm = tee_shm_register(ctx, data.addr, data.length,
> TEE_SHM_DMA_BUF | TEE_SHM_USER_MAPPED);
> if (IS_ERR(shm))
> --
> 2.31.1
>
