EAP-pwd server: 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-2015-5314)
Bug: 25510821
Change-Id: I43a9e6270b4ae693fae15314c3ba1f4baef7c083
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/src/eap_server/eap_server_pwd.c b/src/eap_server/eap_server_pwd.c
index b61061b..d2c48a5 100644
--- a/src/eap_server/eap_server_pwd.c
+++ b/src/eap_server/eap_server_pwd.c
@@ -905,7 +905,7 @@
/*
* the first and all intermediate fragments have the M bit set
*/
- if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
+ if (EAP_PWD_GET_MORE_BIT(lm_exch) || data->in_frag_pos) {
if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
"attack detected! (%d+%d > %d)",
@@ -916,6 +916,8 @@
}
wpabuf_put_data(data->inbuf, pos, len);
data->in_frag_pos += len;
+ }
+ if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
wpa_printf(MSG_DEBUG, "EAP-pwd: Got a %d byte fragment",
(int) len);
return;
@@ -925,8 +927,6 @@
* buffering fragments so that's how we know it's the last)
*/
if (data->in_frag_pos) {
- wpabuf_put_data(data->inbuf, pos, len);
- data->in_frag_pos += len;
pos = wpabuf_head_u8(data->inbuf);
len = data->in_frag_pos;
wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
