libupnp: add upstream security fix for CVE-2016-6255

If there's no registered handler for a POST request, the default behaviour
is to write it to the filesystem. Several million deployed devices appear
to have this behaviour, making it possible to (at least) store arbitrary
data on them. Add a configure option that enables this behaviour, and change
the default to just drop POSTs that aren't directly handled.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

2 files changed, 75 insertions, 0 deletions

diff --git a/package/libupnp/0001-Don-t-allow-unhandled-POSTs-to-write-to-the-filesyst.patch b/package/libupnp/0001-Don-t-allow-unhandled-POSTs-to-write-to-the-filesyst.patch
new file mode 100644
index 000000000..4bf14732c
--- /dev/null
+++ b/package/libupnp/0001-Don-t-allow-unhandled-POSTs-to-write-to-the-filesyst.patch
@@ -0,0 +1,73 @@
+From c91a8a3903367e1163765b73eb4d43be7d7927fa Mon Sep 17 00:00:00 2001
+From: Matthew Garrett <mjg59@srcf.ucam.org>
+Date: Tue, 23 Feb 2016 13:53:20 -0800
+Subject: [PATCH] Don't allow unhandled POSTs to write to the filesystem by
+ default
+
+Fixes CVE-2016-6255: write files via POST
+
+If there's no registered handler for a POST request, the default behaviour
+is to write it to the filesystem. Several million deployed devices appear
+to have this behaviour, making it possible to (at least) store arbitrary
+data on them. Add a configure option that enables this behaviour, and change
+the default to just drop POSTs that aren't directly handled.
+
+Signed-off-by: Marcelo Roberto Jimenez <mroberto@users.sourceforge.net>
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ configure.ac                         | 4 ++++
+ upnp/inc/upnpconfig.h.in             | 5 +++++
+ upnp/src/genlib/net/http/webserver.c | 4 ++++
+ 3 files changed, 13 insertions(+)
+
+diff --git a/configure.ac b/configure.ac
+index dd88734..ea2bc09 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -482,6 +482,10 @@ if test "x$enable_scriptsupport" = xyes ; then
+         AC_DEFINE(IXML_HAVE_SCRIPTSUPPORT, 1, [see upnpconfig.h])
+ fi
+ 
++RT_BOOL_ARG_ENABLE([postwrite], [no], [write to the filesystem on otherwise unhandled POST requests])
++if test "x$enable_postwrite" = xyes ; then
++        AC_DEFINE(UPNP_ENABLE_POST_WRITE, 1, [see upnpconfig.h])
++fi
+ 
+ RT_BOOL_ARG_ENABLE([samples], [yes], [compilation of upnp/sample/ code])
+ 
+diff --git a/upnp/inc/upnpconfig.h.in b/upnp/inc/upnpconfig.h.in
+index 46ddc6e..5df8c5a 100644
+--- a/upnp/inc/upnpconfig.h.in
++++ b/upnp/inc/upnpconfig.h.in
+@@ -135,5 +135,10 @@
+  *  (i.e. configure --enable-open_ssl) */
+ #undef UPNP_ENABLE_OPEN_SSL
+ 
++/** Defined to 1 if the library has been compiled to support filesystem writes on POST
++ *  (i.e. configure --enable-postwrite) */
++#undef UPNP_ENABLE_POST_WRITE
++
++
+ #endif /* UPNP_CONFIG_H */
+ 
+diff --git a/upnp/src/genlib/net/http/webserver.c b/upnp/src/genlib/net/http/webserver.c
+index 8991c16..8b2ecf2 100644
+--- a/upnp/src/genlib/net/http/webserver.c
++++ b/upnp/src/genlib/net/http/webserver.c
+@@ -1369,9 +1369,13 @@ static int http_RecvPostMessage(
+ 		if (Fp == NULL)
+ 			return HTTP_INTERNAL_SERVER_ERROR;
+ 	} else {
++#ifdef UPNP_ENABLE_POST_WRITE
+ 		Fp = fopen(filename, "wb");
+ 		if (Fp == NULL)
+ 			return HTTP_UNAUTHORIZED;
++#else
++		return HTTP_NOT_FOUND;
++#endif
+ 	}
+ 	parser->position = POS_ENTITY;
+ 	do {
+-- 
+2.10.2
+
diff --git a/package/libupnp/libupnp.mk b/package/libupnp/libupnp.mk
index e12f41050..2a4e078f9 100644
--- a/package/libupnp/libupnp.mk
+++ b/package/libupnp/libupnp.mk
@@ -11,5 +11,7 @@ LIBUPNP_CONF_ENV = ac_cv_lib_compat_ftime=no
 LIBUPNP_INSTALL_STAGING = YES
 LIBUPNP_LICENSE = BSD-3c
 LIBUPNP_LICENSE_FILES = LICENSE
+# configure.ac patched by 0001-Don-t-allow-unhandled-POSTs-to-write-to-the-filesyst.patch
+LIBUPNP_AUTORECONF = YES
 
 $(eval $(autotools-package))