Commit e651faa2 authored by Philipp Stanner's avatar Philipp Stanner Committed by Greg Kroah-Hartman
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drivers/tty/vt: use standard array-copy-functions 



tty/vt currently uses memdup_user() and vmemdup_array_user() to copy
userspace arrays.

Whereas there is no danger of overflowing, the call to vmemdup_user()
currently utilizes array_size() to calculate the array size
nevertheless. This is not useful because array_size() would return
SIZE_MAX and pass it to vmemdup_user() in case of (the impossible)
overflow.

string.h from the core-API now provides the wrappers memdup_array_user()
and vmemdup_array_user() to copy userspace arrays in a standardized
manner. Additionally, they also perform generic overflow-checks.

Use these wrappers to make it more obvious and readable that arrays are
being copied.

As we are at it, remove two unnecessary empty lines.

Suggested-by: default avatarDave Airlie <airlied@redhat.com>
Signed-off-by: default avatarPhilipp Stanner <pstanner@redhat.com>
Link: https://lore.kernel.org/r/20231103111207.74621-2-pstanner@redhat.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 727e08b1

drivers/tty/vt/consolemap.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

drivers/tty/vt/keyboard.c

+4 −6
Original line number Diff line number Diff line
@@ -1772,12 +1772,10 @@ int vt_do_diacrit(unsigned int cmd, void __user *udp, int perm) 
			return -EINVAL;



		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);



		}



		spin_lock_irqsave(&kbd_event_lock, flags);
@@ -1811,8 +1809,8 @@ int vt_do_diacrit(unsigned int cmd, void __user *udp, int perm) 
			return -EINVAL;



		if (ct) {

			buf = memdup_user(a->kbdiacruc,

					  ct * sizeof(struct kbdiacruc));

			buf = memdup_array_user(a->kbdiacruc,

						ct, sizeof(struct kbdiacruc));

			if (IS_ERR(buf))

				return PTR_ERR(buf);

		}