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From 8057821706784608b828e769ccefbced95591e50 Mon Sep 17 00:00:00 2001
From: Jouni Malinen <j@w1.fi>
Date: Sun, 1 Nov 2015 18:18:17 +0200
Subject: [PATCH] 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)
Signed-off-by: Jouni Malinen <j@w1.fi>
---
src/eap_peer/eap_pwd.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/src/eap_peer/eap_pwd.c b/src/eap_peer/eap_pwd.c
index 1f78544..75ceef1 100644
--- a/src/eap_peer/eap_pwd.c
+++ b/src/eap_peer/eap_pwd.c
@@ -903,7 +903,7 @@ eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
/*
* 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 "
@@ -916,7 +916,8 @@ eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
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));
@@ -930,10 +931,8 @@ eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
* 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;
}
--
1.9.1
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