From 8057821706784608b828e769ccefbced95591e50 Mon Sep 17 00:00:00 2001 From: Jouni Malinen 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 --- 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