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Interworking: Avoid undefined behavior in pointer arithmetic 

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 01:37:38 +03:00
parent 3991cb7b3c
commit 67fea55ca2
1 changed files with 37 additions and 28 deletions
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65
wpa_supplicant/interworking.c
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@ -362,13 +362,13 @@ static const u8 * nai_realm_parse_eap(struct nai_realm_eap *e, const u8 *pos,
u8 elen, auth_count, a;
const u8 *e_end;
if (pos + 3 > end) {
if (end - pos < 3) {
wpa_printf(MSG_DEBUG, "No room for EAP Method fixed fields");
return NULL;
}
elen = *pos++;
if (pos + elen > end || elen < 2) {
if (elen > end - pos || elen < 2) {
wpa_printf(MSG_DEBUG, "No room for EAP Method subfield");
return NULL;
}
@ -381,14 +381,19 @@ static const u8 * nai_realm_parse_eap(struct nai_realm_eap *e, const u8 *pos,
for (a = 0; a < auth_count; a++) {
u8 id, len;
if (pos + 2 > end || pos + 2 + pos[1] > end) {
wpa_printf(MSG_DEBUG, "No room for Authentication "
"Parameter subfield");
if (end - pos < 2) {
wpa_printf(MSG_DEBUG,
"No room for Authentication Parameter subfield header");
return NULL;
}
id = *pos++;
len = *pos++;
if (len > end - pos) {
wpa_printf(MSG_DEBUG,
"No room for Authentication Parameter subfield");
return NULL;
}
switch (id) {
case NAI_REALM_EAP_AUTH_NON_EAP_INNER_AUTH:
@ -463,7 +468,7 @@ static const u8 * nai_realm_parse_realm(struct nai_realm *r, const u8 *pos,
len = WPA_GET_LE16(pos); /* NAI Realm Data field Length */
pos += 2;
if (pos + len > end || len < 3) {
if (len > end - pos || len < 3) {
wpa_printf(MSG_DEBUG, "No room for NAI Realm Data "
"(len=%u; left=%u)",
len, (unsigned int) (end - pos));
@ -473,7 +478,7 @@ static const u8 * nai_realm_parse_realm(struct nai_realm *r, const u8 *pos,
r->encoding = *pos++;
realm_len = *pos++;
if (pos + realm_len > f_end) {
if (realm_len > f_end - pos) {
wpa_printf(MSG_DEBUG, "No room for NAI Realm "
"(len=%u; left=%u)",
realm_len, (unsigned int) (f_end - pos));
@ -485,13 +490,13 @@ static const u8 * nai_realm_parse_realm(struct nai_realm *r, const u8 *pos,
return NULL;
pos += realm_len;
if (pos + 1 > f_end) {
if (f_end - pos < 1) {
wpa_printf(MSG_DEBUG, "No room for EAP Method Count");
return NULL;
}
r->eap_count = *pos++;
wpa_printf(MSG_DEBUG, "EAP Count: %u", r->eap_count);
if (pos + r->eap_count * 3 > f_end) {
if (r->eap_count * 3 > f_end - pos) {
wpa_printf(MSG_DEBUG, "No room for EAP Methods");
return NULL;
}
@ -746,7 +751,7 @@ static int plmn_id_match(struct wpabuf *anqp, const char *imsi, int mnc_len)
return 0;
pos = wpabuf_head_u8(anqp);
end = pos + wpabuf_len(anqp);
if (pos + 2 > end)
if (end - pos < 2)
return 0;
if (*pos != 0) {
wpa_printf(MSG_DEBUG, "Unsupported GUD version 0x%x", *pos);
@ -754,7 +759,7 @@ static int plmn_id_match(struct wpabuf *anqp, const char *imsi, int mnc_len)
}
pos++;
udhl = *pos++;
if (pos + udhl > end) {
if (udhl > end - pos) {
wpa_printf(MSG_DEBUG, "Invalid UDHL");
return 0;
}
@ -764,12 +769,12 @@ static int plmn_id_match(struct wpabuf *anqp, const char *imsi, int mnc_len)
plmn[0], plmn[1], plmn[2], plmn2[0], plmn2[1], plmn2[2],
imsi, mnc_len);
while (pos + 2 <= end) {
while (end - pos >= 2) {
u8 iei, len;
const u8 *l_end;
iei = *pos++;
len = *pos++ & 0x7f;
if (pos + len > end)
if (len > end - pos)
break;
l_end = pos + len;
@ -780,7 +785,7 @@ static int plmn_id_match(struct wpabuf *anqp, const char *imsi, int mnc_len)
pos, len);
num = *pos++;
for (i = 0; i < num; i++) {
if (pos + 3 > l_end)
if (l_end - pos < 3)
break;
if (os_memcmp(pos, plmn, 3) == 0 ||
os_memcmp(pos, plmn2, 3) == 0)
@ -1082,12 +1087,12 @@ static int roaming_consortium_element_match(const u8 *ie, const u8 *rc_id,
* OI #1, [OI #2], [OI #3]
*/
if (pos + 2 > end)
if (end - pos < 2)
return 0;
pos++; /* skip Number of ANQP OIs */
lens = *pos++;
if (pos + (lens & 0x0f) + (lens >> 4) > end)
if ((lens & 0x0f) + (lens >> 4) > end - pos)
return 0;
if ((lens & 0x0f) == rc_len && os_memcmp(pos, rc_id, rc_len) == 0)
@ -1121,7 +1126,7 @@ static int roaming_consortium_anqp_match(const struct wpabuf *anqp,
/* Set of <OI Length, OI> duples */
while (pos < end) {
len = *pos++;
if (pos + len > end)
if (len > end - pos)
break;
if (len == rc_len && os_memcmp(pos, rc_id, rc_len) == 0)
return 1;
@ -1266,7 +1271,7 @@ static int cred_over_max_bss_load(struct wpa_supplicant *wpa_s,
static int has_proto_match(const u8 *pos, const u8 *end, u8 proto)
{
while (pos + 4 <= end) {
while (end - pos >= 4) {
if (pos[0] == proto && pos[3] == 1 /* Open */)
return 1;
pos += 4;
@ -1279,7 +1284,7 @@ static int has_proto_match(const u8 *pos, const u8 *end, u8 proto)
static int has_proto_port_match(const u8 *pos, const u8 *end, u8 proto,
u16 port)
{
while (pos + 4 <= end) {
while (end - pos >= 4) {
if (pos[0] == proto && WPA_GET_LE16(&pos[1]) == port &&
pos[3] == 1 /* Open */)
return 1;
@ -2133,23 +2138,27 @@ int domain_name_list_contains(struct wpabuf *domain_names,
pos = wpabuf_head(domain_names);
end = pos + wpabuf_len(domain_names);
while (pos + 1 < end) {
if (pos + 1 + pos[0] > end)
while (end - pos > 1) {
u8 elen;
elen = *pos++;
if (elen > end - pos)
break;
wpa_hexdump_ascii(MSG_DEBUG, "Interworking: AP domain name",
pos + 1, pos[0]);
if (pos[0] == len &&
os_strncasecmp(domain, (const char *) (pos + 1), len) == 0)
pos, elen);
if (elen == len &&
os_strncasecmp(domain, (const char *) pos, len) == 0)
return 1;
if (!exact_match && pos[0] > len && pos[pos[0] - len] == '.') {
const char *ap = (const char *) (pos + 1);
int offset = pos[0] - len;
if (!exact_match && elen > len && pos[elen - len - 1] == '.') {
const char *ap = (const char *) pos;
int offset = elen - len;
if (os_strncasecmp(domain, ap + offset, len) == 0)
return 1;
}
pos += 1 + pos[0];
pos += elen;
}
return 0;