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- From f7d268864a2660b7239b9a8ff5ad37faeeb751ba Mon Sep 17 00:00:00 2001
- From: Jouni Malinen <jouni@codeaurora.org>
- Date: Wed, 3 Jun 2020 22:41:02 +0300
- Subject: [PATCH 2/3] WPS UPnP: Fix event message generation using a long URL
- path
- More than about 700 character URL ended up overflowing the wpabuf used
- for building the event notification and this resulted in the wpabuf
- buffer overflow checks terminating the hostapd process. Fix this by
- allocating the buffer to be large enough to contain the full URL path.
- However, since that around 700 character limit has been the practical
- limit for more than ten years, start explicitly enforcing that as the
- limit or the callback URLs since any longer ones had not worked before
- and there is no need to enable them now either.
- Upstream-Status: Backport
- CVE: CVE-2020-12695 patch #2
- Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
- Signed-off-by: Armin Kuster <akuster@mvista.com>
- ---
- src/wps/wps_upnp.c | 9 +++++++--
- src/wps/wps_upnp_event.c | 3 ++-
- 2 files changed, 9 insertions(+), 3 deletions(-)
- diff --git a/src/wps/wps_upnp.c b/src/wps/wps_upnp.c
- index 7d4b7439940e..ab685d52ecab 100644
- --- a/src/wps/wps_upnp.c
- +++ b/src/wps/wps_upnp.c
- @@ -328,9 +328,14 @@ static void subscr_addr_add_url(struct subscription *s, const char *url,
- int rerr;
- size_t host_len, path_len;
- - /* url MUST begin with http: */
- - if (url_len < 7 || os_strncasecmp(url, "http://", 7))
- + /* URL MUST begin with HTTP scheme. In addition, limit the length of
- + * the URL to 700 characters which is around the limit that was
- + * implicitly enforced for more than 10 years due to a bug in
- + * generating the event messages. */
- + if (url_len < 7 || os_strncasecmp(url, "http://", 7) || url_len > 700) {
- + wpa_printf(MSG_DEBUG, "WPS UPnP: Reject an unacceptable URL");
- goto fail;
- + }
- url += 7;
- url_len -= 7;
- diff --git a/src/wps/wps_upnp_event.c b/src/wps/wps_upnp_event.c
- index d7e6edcc6503..08a23612f338 100644
- --- a/src/wps/wps_upnp_event.c
- +++ b/src/wps/wps_upnp_event.c
- @@ -147,7 +147,8 @@ static struct wpabuf * event_build_message(struct wps_event_ *e)
- struct wpabuf *buf;
- char *b;
- - buf = wpabuf_alloc(1000 + wpabuf_len(e->data));
- + buf = wpabuf_alloc(1000 + os_strlen(e->addr->path) +
- + wpabuf_len(e->data));
- if (buf == NULL)
- return NULL;
- wpabuf_printf(buf, "NOTIFY %s HTTP/1.1\r\n", e->addr->path);
- --
- 2.20.1
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