From 0909a1a76546284f27fb1b17a6f545a04537cc36 Mon Sep 17 00:00:00 2001

From: Peter Hutterer <peter.hutterer@who-t.net>

Date: Tue, 10 Jul 2018 11:17:50 +1000

Subject: [PATCH xf86-input-libinput] draglock: fix memory overwrite during

 draglock parsing

Passing in the size of the array but using it as "number of elements" inside

the function. Rename a bunch of arguments to avoid this.

https://bugs.freedesktop.org/show_bug.cgi?id=107166

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

---

 src/draglock.c     | 14 +++++++-------

 src/draglock.h     |  6 +++---

 src/xf86libinput.c |  2 +-

 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/draglock.c b/src/draglock.c

index b0bcac3..e0a91d0 100644

--- a/src/draglock.c

+++ b/src/draglock.c

@@ -116,7 +116,7 @@ draglock_get_meta(const struct draglock *dl)

 }

 size_t

-draglock_get_pairs(const struct draglock *dl, int *array, size_t sz)

+draglock_get_pairs(const struct draglock *dl, int *array, size_t nelem)

 {

 	unsigned int i;

 	size_t last = 0;

@@ -131,8 +131,8 @@ draglock_get_pairs(const struct draglock *dl, int *array, size_t sz)

 	}

 	/* size N array with a[0] == 0, the rest ordered by button number */

-	memset(array, 0, sz * sizeof(array[0]));

-	for (i = 0; i < sz && i < ARRAY_SIZE(dl->lock_pair); i++) {

+	memset(array, 0, nelem * sizeof(array[0]));

+	for (i = 0; i < nelem && i < ARRAY_SIZE(dl->lock_pair); i++) {

 		array[i] = dl->lock_pair[i];

 		if (array[i] != 0 && i > last)

 			last = i;

@@ -153,20 +153,20 @@ draglock_set_meta(struct draglock *dl, int meta_button)

 }

 int

-draglock_set_pairs(struct draglock *dl, const int *array, size_t sz)

+draglock_set_pairs(struct draglock *dl, const int *array, size_t nelem)

 {

 	unsigned int i;

-	if (sz == 0 || array[0] != 0)

+	if (nelem == 0 || array[0] != 0)

 		return 1;

-	for (i = 0; i < sz; i++) {

+	for (i = 0; i < nelem; i++) {

 		if (array[i] < 0 || array[i] >= DRAGLOCK_MAX_BUTTONS)

 			return 1;

 	}

 	dl->mode = DRAGLOCK_DISABLED;

-	for (i = 0; i < sz; i++) {

+	for (i = 0; i < nelem; i++) {

 		dl->lock_pair[i] = array[i];

 		if (dl->lock_pair[i])

 			dl->mode = DRAGLOCK_PAIRS;

diff --git a/src/draglock.h b/src/draglock.h

index acc1314..900d538 100644

--- a/src/draglock.h

+++ b/src/draglock.h

@@ -107,13 +107,13 @@ draglock_get_meta(const struct draglock *dl);

  * @note Button numbers start at 1, array[0] is always 0.

  *

  * @param[in|out] array Caller-allocated array to hold the button mappings.

- * @param[in] sz Maximum number of elements in array

+ * @param[in] nelem Maximum number of elements in array

  *

  * @return The number of valid elements in array or 0 if the current mode is

  * not DRAGLOCK_PAIRS

  */

 size_t

-draglock_get_pairs(const struct draglock *dl, int *array, size_t sz);

+draglock_get_pairs(const struct draglock *dl, int *array, size_t nelem);

 /**

  * Set the drag lock config to the DRAGLOCK_META mode, with the given

@@ -140,7 +140,7 @@ draglock_set_meta(struct draglock *dl, int meta_button);

  * @return 0 on successor nonzero otherwise

  */

 int

-draglock_set_pairs(struct draglock *dl, const int *array, size_t sz);

+draglock_set_pairs(struct draglock *dl, const int *array, size_t nelem);

 /**

  * Process the given button event through the drag lock state machine.

diff --git a/src/xf86libinput.c b/src/xf86libinput.c

index 2e950cd..34f1102 100644

--- a/src/xf86libinput.c

+++ b/src/xf86libinput.c

@@ -5326,7 +5326,7 @@ LibinputInitDragLockProperty(DeviceIntPtr dev,

 		break;

 	case DRAGLOCK_PAIRS:

 		sz = draglock_get_pairs(&driver_data->draglock,

-					dl_values, sizeof(dl_values));

+					dl_values, ARRAY_SIZE(dl_values));

 		break;

 	default:

 		xf86IDrvMsg(dev->public.devicePrivate,

-- 

2.17.1