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Dynamically allocate the slot values

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Instead of relying on a static MAX_SLOTS array, allocated it based on the
number of slots we have on the device. The previous checks for MAX_SLOTS were
incomplete, causing out-of-bound reads.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Peter Hutterer 2014-02-27 11:34:47 +10:00
parent 2e06aed955
commit 89e7998fee
2 changed files with 32 additions and 11 deletions
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2
libevdev/libevdev-int.h
View file

@ -95,7 +95,7 @@ struct libevdev {
unsigned long led_values[NLONGS(LED_CNT)]; unsigned long led_values[NLONGS(LED_CNT)];
unsigned long sw_values[NLONGS(SW_CNT)]; unsigned long sw_values[NLONGS(SW_CNT)];
struct input_absinfo abs_info[ABS_CNT]; struct input_absinfo abs_info[ABS_CNT];
int mt_slot_vals[MAX_SLOTS][ABS_MT_CNT]; int *mt_slot_vals; /* [num_slots * ABS_MT_CNT] */
int num_slots; /**< valid slots in mt_slot_vals */ int num_slots; /**< valid slots in mt_slot_vals */
int current_slot; int current_slot;
int rep_values[REP_CNT]; int rep_values[REP_CNT];

41
libevdev/libevdev.c
View file

@ -38,6 +38,21 @@
static int sync_mt_state(struct libevdev *dev, int create_events); static int sync_mt_state(struct libevdev *dev, int create_events);
static inline int*
slot_value(const struct libevdev *dev, int slot, int axis)
{
if (unlikely(slot > dev->num_slots)) {
log_bug("Slot %d exceeds number of slots (%d)\n", slot, dev->num_slots);
slot = 0;
}
if (unlikely(axis < ABS_MT_MIN || axis > ABS_MT_MAX)) {
log_bug("MT axis %d is outside the valid range [%d,%d]\n",
axis, ABS_MT_MIN, ABS_MT_MAX);
axis = ABS_MT_MIN;
}
return &dev->mt_slot_vals[slot * ABS_MT_CNT + axis - ABS_MT_MIN];
}
static int static int
init_event_queue(struct libevdev *dev) init_event_queue(struct libevdev *dev)
{ {
@ -136,6 +151,7 @@ libevdev_reset(struct libevdev *dev)
free(dev->name); free(dev->name);
free(dev->phys); free(dev->phys);
free(dev->uniq); free(dev->uniq);
free(dev->mt_slot_vals);
memset(dev, 0, sizeof(*dev)); memset(dev, 0, sizeof(*dev));
dev->fd = -1; dev->fd = -1;
dev->initialized = false; dev->initialized = false;
@ -187,6 +203,7 @@ libevdev_free(struct libevdev *dev)
free(dev->name); free(dev->name);
free(dev->phys); free(dev->phys);
free(dev->uniq); free(dev->uniq);
free(dev->mt_slot_vals);
queue_free(dev); queue_free(dev);
free(dev); free(dev);
} }
@ -369,6 +386,11 @@ libevdev_set_fd(struct libevdev* dev, int fd)
if (i == ABS_MT_SLOT && if (i == ABS_MT_SLOT &&
!libevdev_has_event_code(dev, EV_ABS, ABS_MT_SLOT - 1)) { !libevdev_has_event_code(dev, EV_ABS, ABS_MT_SLOT - 1)) {
dev->num_slots = abs_info.maximum + 1; dev->num_slots = abs_info.maximum + 1;
dev->mt_slot_vals = calloc(dev->num_slots * ABS_MT_CNT, sizeof(int));
if (!dev->mt_slot_vals) {
rc = -ENOMEM;
goto out;
}
dev->current_slot = abs_info.value; dev->current_slot = abs_info.value;
} }
@ -579,14 +601,14 @@ sync_mt_state(struct libevdev *dev, int create_events)
if (!libevdev_has_event_code(dev, EV_ABS, j)) if (!libevdev_has_event_code(dev, EV_ABS, j))
continue; continue;
if (dev->mt_slot_vals[i][jdx] == mt_state[jdx].val[i]) if (*slot_value(dev, i, j) == mt_state[jdx].val[i])
continue; continue;
if (create_events) { if (create_events) {
ev = queue_push(dev); ev = queue_push(dev);
init_event(dev, ev, EV_ABS, j, mt_state[jdx].val[i]); init_event(dev, ev, EV_ABS, j, mt_state[jdx].val[i]);
} }
dev->mt_slot_vals[i][jdx] = mt_state[jdx].val[i]; *slot_value(dev, i, j) = mt_state[jdx].val[i];
} }
} }
@ -667,14 +689,14 @@ update_mt_state(struct libevdev *dev, const struct input_event *e)
/* sync abs_info with the current slot values */ /* sync abs_info with the current slot values */
for (i = ABS_MT_SLOT + 1; i <= ABS_MT_MAX; i++) { for (i = ABS_MT_SLOT + 1; i <= ABS_MT_MAX; i++) {
if (libevdev_has_event_code(dev, EV_ABS, i)) if (libevdev_has_event_code(dev, EV_ABS, i))
dev->abs_info[i].value = dev->mt_slot_vals[dev->current_slot][i - ABS_MT_MIN]; dev->abs_info[i].value = *slot_value(dev, dev->current_slot, i);
} }
return 0; return 0;
} else if (dev->current_slot == -1) } else if (dev->current_slot == -1)
return 1; return 1;
dev->mt_slot_vals[dev->current_slot][e->code - ABS_MT_MIN] = e->value; *slot_value(dev, dev->current_slot, e->code) = e->value;
return 0; return 0;
} }
@ -1070,13 +1092,13 @@ libevdev_get_slot_value(const struct libevdev *dev, unsigned int slot, unsigned
if (!libevdev_has_event_type(dev, EV_ABS) || !libevdev_has_event_code(dev, EV_ABS, code)) if (!libevdev_has_event_type(dev, EV_ABS) || !libevdev_has_event_code(dev, EV_ABS, code))
return 0; return 0;
if (dev->num_slots < 0 || slot >= (unsigned int)dev->num_slots || slot >= MAX_SLOTS) if (dev->num_slots < 0 || slot >= (unsigned int)dev->num_slots)
return 0; return 0;
if (code > ABS_MT_MAX || code < ABS_MT_MIN) if (code > ABS_MT_MAX || code < ABS_MT_MIN)
return 0; return 0;
return dev->mt_slot_vals[slot][code - ABS_MT_MIN]; return *slot_value(dev, slot, code);
} }
LIBEVDEV_EXPORT int LIBEVDEV_EXPORT int
@ -1085,7 +1107,7 @@ libevdev_set_slot_value(struct libevdev *dev, unsigned int slot, unsigned int co
if (!libevdev_has_event_type(dev, EV_ABS) || !libevdev_has_event_code(dev, EV_ABS, code)) if (!libevdev_has_event_type(dev, EV_ABS) || !libevdev_has_event_code(dev, EV_ABS, code))
return -1; return -1;
if (dev->num_slots == -1 || slot >= (unsigned int)dev->num_slots || slot >= MAX_SLOTS) if (dev->num_slots == -1 || slot >= (unsigned int)dev->num_slots)
return -1; return -1;
if (code > ABS_MT_MAX || code < ABS_MT_MIN) if (code > ABS_MT_MAX || code < ABS_MT_MIN)
@ -1097,8 +1119,7 @@ libevdev_set_slot_value(struct libevdev *dev, unsigned int slot, unsigned int co
dev->current_slot = value; dev->current_slot = value;
} }
dev->mt_slot_vals[slot][code - ABS_MT_MIN] = value; *slot_value(dev, slot, code) = value;
return 0; return 0;
} }
@ -1109,7 +1130,7 @@ libevdev_fetch_slot_value(const struct libevdev *dev, unsigned int slot, unsigne
if (libevdev_has_event_type(dev, EV_ABS) && if (libevdev_has_event_type(dev, EV_ABS) &&
libevdev_has_event_code(dev, EV_ABS, code) && libevdev_has_event_code(dev, EV_ABS, code) &&
dev->num_slots >= 0 && dev->num_slots >= 0 &&
slot < (unsigned int)dev->num_slots && slot < MAX_SLOTS) { slot < (unsigned int)dev->num_slots) {
*value = libevdev_get_slot_value(dev, slot, code); *value = libevdev_get_slot_value(dev, slot, code);
return 1; return 1;
} else } else