EAP-pwd peer: Fix last fragment length validation
All but the last fragment had their length checked against the remaining
room in the reassembly buffer. This allowed a suitably constructed last
fragment frame to try to add extra data that would go beyond the buffer.
The length validation code in wpabuf_put_data() prevents an actual
buffer write overflow from occurring, but this results in process
termination. (CVE-2015-5315)
Bug: 25510821
Change-Id: Ic509a6efedc3da9ff40f2842fab5547d087f64de
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/src/eap_peer/eap_pwd.c b/src/eap_peer/eap_pwd.c
index 267d0a5..976e017 100644
--- a/src/eap_peer/eap_pwd.c
+++ b/src/eap_peer/eap_pwd.c
@@ -760,7 +760,7 @@
/*
* buffer and ACK the fragment
*/
- if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
+ if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
data->in_frag_pos += len;
if (data->in_frag_pos > wpabuf_size(data->inbuf)) {
wpa_printf(MSG_INFO, "EAP-pwd: Buffer overflow attack "
@@ -772,7 +772,8 @@
return NULL;
}
wpabuf_put_data(data->inbuf, pos, len);
-
+ }
+ if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
EAP_PWD_HDR_SIZE,
EAP_CODE_RESPONSE, eap_get_id(reqData));
@@ -786,10 +787,8 @@
* we're buffering and this is the last fragment
*/
if (data->in_frag_pos) {
- wpabuf_put_data(data->inbuf, pos, len);
wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
(int) len);
- data->in_frag_pos += len;
pos = wpabuf_head_u8(data->inbuf);
len = data->in_frag_pos;
}