On Thu, Nov 02, 2023 at 08:21:35PM +0100, Philipp Stanner wrote:
> The functions (v)memdup_user() are utilized to copy userspace arrays.
> This is done without overflow checks.
>
> Use the new wrappers memdup_array_user() and vmemdup_array_user() to
> copy the arrays more safely.
> @@ -644,7 +644,7 @@ int con_set_unimap(struct vc_data *vc, ushort ct, struct unipair __user *list)
> if (!ct)
> return 0;
> - unilist = vmemdup_user(list, array_size(sizeof(*unilist), ct));
> + unilist = vmemdup_array_user(list, ct, sizeof(*unilist));
> if (IS_ERR(unilist))
> return PTR_ERR(unilist);
a 16bit value times sizeof(something).
> diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
> index 1fe6107b539b..802ceb0a5e4c 100644
> --- a/drivers/tty/vt/keyboard.c
> +++ b/drivers/tty/vt/keyboard.c
> @@ -1773,8 +1773,8 @@ int vt_do_diacrit(unsigned int cmd, void __user *udp, int perm)
... and here we have
if (ct >= MAX_DIACR)
return -EINVAL;
directly upstream, so it's even better - a value below 256 times sizeof(something)
> if (ct) {
>
> - dia = memdup_user(a->kbdiacr,
> - sizeof(struct kbdiacr) * ct);
> + dia = memdup_array_user(a->kbdiacr,
> + ct, sizeof(struct kbdiacr));
> if (IS_ERR(dia))
> return PTR_ERR(dia);
>
> @@ -1811,8 +1811,8 @@ int vt_do_diacrit(unsigned int cmd, void __user *udp, int perm)
> return -EINVAL;
Ditto.
> if (ct) {
> - buf = memdup_user(a->kbdiacruc,
> - ct * sizeof(struct kbdiacruc));
> + buf = memdup_array_user(a->kbdiacruc,
> + ct, sizeof(struct kbdiacruc));
