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atheros: Avoid undefined behavior in pointer arithmetic

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Reorder terms in a way that no invalid pointers are generated with
pos+len operations. end-pos is always defined (with a valid pos pointer)
while pos+len could end up pointing beyond the end pointer which would
be undefined behavior.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2015-10-18 19:07:13 +03:00
parent 40762fcede
commit d034f498ce
1 changed files with 8 additions and 8 deletions
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16
src/drivers/driver_atheros.c
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@ -1246,7 +1246,7 @@ atheros_wireless_event_wireless_custom(struct atheros_driver_data *drv,
* Format: "Manage.prob_req <frame len>" | zero padding | frame * Format: "Manage.prob_req <frame len>" | zero padding | frame
*/ */
int len = atoi(custom + 16); int len = atoi(custom + 16);
if (len < 0 || custom + MGMT_FRAM_TAG_SIZE + len > end) { if (len < 0 || MGMT_FRAM_TAG_SIZE + len > end - custom) {
wpa_printf(MSG_DEBUG, "Invalid Manage.prob_req event " wpa_printf(MSG_DEBUG, "Invalid Manage.prob_req event "
"length %d", len); "length %d", len);
return; return;
@ -1259,7 +1259,7 @@ atheros_wireless_event_wireless_custom(struct atheros_driver_data *drv,
/* Format: "Manage.assoc_req <frame len>" | zero padding | /* Format: "Manage.assoc_req <frame len>" | zero padding |
* frame */ * frame */
int len = atoi(custom + 17); int len = atoi(custom + 17);
if (len < 0 || custom + MGMT_FRAM_TAG_SIZE + len > end) { if (len < 0 || MGMT_FRAM_TAG_SIZE + len > end - custom) {
wpa_printf(MSG_DEBUG, wpa_printf(MSG_DEBUG,
"Invalid Manage.assoc_req event length %d", "Invalid Manage.assoc_req event length %d",
len); len);
@ -1271,7 +1271,7 @@ atheros_wireless_event_wireless_custom(struct atheros_driver_data *drv,
/* Format: "Manage.auth <frame len>" | zero padding | frame */ /* Format: "Manage.auth <frame len>" | zero padding | frame */
int len = atoi(custom + 12); int len = atoi(custom + 12);
if (len < 0 || if (len < 0 ||
custom + MGMT_FRAM_TAG_SIZE + len > end) { MGMT_FRAM_TAG_SIZE + len > end - custom) {
wpa_printf(MSG_DEBUG, wpa_printf(MSG_DEBUG,
"Invalid Manage.auth event length %d", len); "Invalid Manage.auth event length %d", len);
return; return;
@ -1284,7 +1284,7 @@ atheros_wireless_event_wireless_custom(struct atheros_driver_data *drv,
/* Format: "Manage.assoc_req <frame len>" | zero padding | frame /* Format: "Manage.assoc_req <frame len>" | zero padding | frame
*/ */
int len = atoi(custom + 14); int len = atoi(custom + 14);
if (len < 0 || custom + MGMT_FRAM_TAG_SIZE + len > end) { if (len < 0 || MGMT_FRAM_TAG_SIZE + len > end - custom) {
wpa_printf(MSG_DEBUG, wpa_printf(MSG_DEBUG,
"Invalid Manage.action event length %d", "Invalid Manage.action event length %d",
len); len);
@ -1384,7 +1384,7 @@ atheros_wireless_event_atheros_custom(struct atheros_driver_data *drv,
static void static void
atheros_wireless_event_wireless(struct atheros_driver_data *drv, atheros_wireless_event_wireless(struct atheros_driver_data *drv,
char *data, int len) char *data, unsigned int len)
{ {
struct iw_event iwe_buf, *iwe = &iwe_buf; struct iw_event iwe_buf, *iwe = &iwe_buf;
char *pos, *end, *custom, *buf; char *pos, *end, *custom, *buf;
@ -1392,13 +1392,13 @@ atheros_wireless_event_wireless(struct atheros_driver_data *drv,
pos = data; pos = data;
end = data + len; end = data + len;
while (pos + IW_EV_LCP_LEN <= end) { while ((size_t) (end - pos) >= IW_EV_LCP_LEN) {
/* Event data may be unaligned, so make a local, aligned copy /* Event data may be unaligned, so make a local, aligned copy
* before processing. */ * before processing. */
memcpy(&iwe_buf, pos, IW_EV_LCP_LEN); memcpy(&iwe_buf, pos, IW_EV_LCP_LEN);
wpa_printf(MSG_MSGDUMP, "Wireless event: cmd=0x%x len=%d", wpa_printf(MSG_MSGDUMP, "Wireless event: cmd=0x%x len=%d",
iwe->cmd, iwe->len); iwe->cmd, iwe->len);
if (iwe->len <= IW_EV_LCP_LEN) if (iwe->len <= IW_EV_LCP_LEN || iwe->len > end - pos)
return; return;
custom = pos + IW_EV_POINT_LEN; custom = pos + IW_EV_POINT_LEN;
@ -1430,7 +1430,7 @@ atheros_wireless_event_wireless(struct atheros_driver_data *drv,
* just like IWEVCUSTOM. * just like IWEVCUSTOM.
*/ */
case IWEVCUSTOM: case IWEVCUSTOM:
if (custom + iwe->u.data.length > end) if (iwe->u.data.length > end - custom)
return; return;
buf = malloc(iwe->u.data.length + 1); buf = malloc(iwe->u.data.length + 1);
if (buf == NULL) if (buf == NULL)