| Upstream-Status: Backport |
| |
| Signed-off-by: Fan Xin <fan.xin@jp.fujitsu.com> |
| |
| From 5acd23f4581da58683f3cf5e36cb71bbe4070bd7 Mon Sep 17 00:00:00 2001 |
| From: Jouni Malinen <j@w1.fi> |
| Date: Tue, 28 Apr 2015 17:08:33 +0300 |
| Subject: [PATCH] WPS: Fix HTTP chunked transfer encoding parser |
| |
| strtoul() return value may end up overflowing the int h->chunk_size and |
| resulting in a negative value to be stored as the chunk_size. This could |
| result in the following memcpy operation using a very large length |
| argument which would result in a buffer overflow and segmentation fault. |
| |
| This could have been used to cause a denial service by any device that |
| has been authorized for network access (either wireless or wired). This |
| would affect both the WPS UPnP functionality in a WPS AP (hostapd with |
| upnp_iface parameter set in the configuration) and WPS ER |
| (wpa_supplicant with WPS_ER_START control interface command used). |
| |
| Validate the parsed chunk length value to avoid this. In addition to |
| rejecting negative values, we can also reject chunk size that would be |
| larger than the maximum configured body length. |
| |
| Thanks to Kostya Kortchinsky of Google security team for discovering and |
| reporting this issue. |
| |
| Signed-off-by: Jouni Malinen <j@w1.fi> |
| --- |
| src/wps/httpread.c | 7 +++++++ |
| 1 file changed, 7 insertions(+) |
| |
| diff --git a/src/wps/httpread.c b/src/wps/httpread.c |
| index 2f08f37..d2855e3 100644 |
| --- a/src/wps/httpread.c |
| +++ b/src/wps/httpread.c |
| @@ -533,6 +533,13 @@ static void httpread_read_handler(int sd, void *eloop_ctx, void *sock_ctx) |
| if (!isxdigit(*cbp)) |
| goto bad; |
| h->chunk_size = strtoul(cbp, NULL, 16); |
| + if (h->chunk_size < 0 || |
| + h->chunk_size > h->max_bytes) { |
| + wpa_printf(MSG_DEBUG, |
| + "httpread: Invalid chunk size %d", |
| + h->chunk_size); |
| + goto bad; |
| + } |
| /* throw away chunk header |
| * so we have only real data |
| */ |
| -- |
| 1.9.1 |
| |