| From bef802ece03f9ae9d52a21f0cf4f1bc2c5a1f8aa Mon Sep 17 00:00:00 2001 |
| From: Jouni Malinen <j@w1.fi> |
| Date: Sun, 1 Nov 2015 18:24:16 +0200 |
| Subject: [PATCH] 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) |
| |
| Signed-off-by: Jouni Malinen <j@w1.fi> |
| --- |
| src/eap_server/eap_server_pwd.c | 6 +++--- |
| 1 file changed, 3 insertions(+), 3 deletions(-) |
| |
| diff --git a/src/eap_server/eap_server_pwd.c b/src/eap_server/eap_server_pwd.c |
| index cb83ff7..9f787ab 100644 |
| --- a/src/eap_server/eap_server_pwd.c |
| +++ b/src/eap_server/eap_server_pwd.c |
| @@ -970,7 +970,7 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv, |
| /* |
| * 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)", |
| @@ -981,6 +981,8 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv, |
| } |
| 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; |
| @@ -990,8 +992,6 @@ static void eap_pwd_process(struct eap_sm *sm, void *priv, |
| * 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", |
| -- |
| 1.9.1 |
| |
