Bug#878279: crtmpserver: security patch to disallow rtmp streaming from unknown remote ip addresses
Andrey
support at maasoftware.ru
Thu Oct 12 05:42:48 UTC 2017
Package: crtmpserver
Version: 1.0~dfsg-5.3
Severity: minor
Dear Maintainer,
I have sent this patch to yesterday. Duplicating it here.
I have found a security problem in crtmpserver in December 2015, still
exists.
The problem is any rtmp streams generators like web cams, ffmpeg, etc
can send they stream to you crtmpserver server anonymously and
playback it. It can be a problem for you due to anybody can use your
server for video streaming not for your sites nor your application.
To solve the problem I create a patch based on code found by google
for connect schema name and swf name check (names are got
not always). And I have my additions to check remote (source)
and local IP addresses of connection to allow to translate rtmp
from certain static IPs. By default remote rtmp streaming is disabled
in remote_ip.txt.
I am novice in open source commit, and just have to read 4 configs
from hard coding dir /etc/crtmpserver (local_ip.txt, remote_ip.txt,
tc_url.txt, swf_url.txt).
I have build modified source and tested it by changing remote_ip.txt
and local_ip.txt.
"dpkg-source -commit" say me while pre-building modified source:
dpkg-source: info: local changes have been recorded in a new patch:
crtmpserver-1.0/debian/patches/maa_crtmpserver_security_path.diff
But this diff does not have /etc/crtmpserver/*txt files included.
So I am attaching path5.txt generated by
diff -Naur crtmpserver-1.0~dfsg crtmpserver-1.0_mod >patch4.txt
Please fix me if can, about fixed path /etc/crtmpserver
Waiting for code to be integrated into new versions of crtmpserver.
-- System Information:
Debian Release: 9.2
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 4.9.0-4-amd64 (SMP w/5 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US:en (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages crtmpserver depends on:
ii crtmpserver-apps 1.0~dfsg-5.3
ii crtmpserver-libs 1.0~dfsg-5.3
ii libc6 2.24-11+deb9u1
ii libgcc1 1:6.3.0-18
ii liblua5.1-0 5.1.5-8.1+b2
ii libssl1.0.2 1.0.2l-2
ii libstdc++6 6.3.0-18
ii libtinyxml2.6.2v5 2.6.2-4
crtmpserver recommends no packages.
crtmpserver suggests no packages.
-- Configuration Files:
/etc/crtmpserver/local_ip.txt changed [not included]
/etc/crtmpserver/remote_ip.txt changed [not included]
-- no debconf information
-------------- next part --------------
diff -Naur crtmpserver-1.0~dfsg/applications/flvplayback/include/rtmpappprotocolhandler.h crtmpserver-1.0_mod/applications/flvplayback/include/rtmpappprotocolhandler.h
--- crtmpserver-1.0~dfsg/applications/flvplayback/include/rtmpappprotocolhandler.h 2012-03-18 13:43:18.000000000 +0400
+++ crtmpserver-1.0_mod/applications/flvplayback/include/rtmpappprotocolhandler.h 2017-10-11 21:13:27.089849662 +0300
@@ -34,6 +34,10 @@
virtual bool ProcessInvokeGeneric(BaseRTMPProtocol *pFrom,
Variant &request);
+ // to check schema and swf name
+ virtual bool ProcessInvokeConnect(BaseRTMPProtocol *pFrom,
+ Variant &request);
+ virtual bool ValidateRequest(Variant &request);
private:
bool ProcessGetAvailableFlvs(BaseRTMPProtocol *pFrom, Variant &request);
bool ProcessInsertMetadata(BaseRTMPProtocol *pFrom, Variant &request);
diff -Naur crtmpserver-1.0~dfsg/applications/flvplayback/src/rtmpappprotocolhandler.cpp crtmpserver-1.0_mod/applications/flvplayback/src/rtmpappprotocolhandler.cpp
--- crtmpserver-1.0~dfsg/applications/flvplayback/src/rtmpappprotocolhandler.cpp 2012-03-18 13:43:18.000000000 +0400
+++ crtmpserver-1.0_mod/applications/flvplayback/src/rtmpappprotocolhandler.cpp 2017-10-11 23:45:36.529694557 +0300
@@ -19,6 +19,7 @@
#ifdef HAS_PROTOCOL_RTMP
+#include "common.h"
#include "rtmpappprotocolhandler.h"
#include "protocols/rtmp/basertmpprotocol.h"
#include "protocols/rtmp/messagefactories/messagefactories.h"
@@ -27,6 +28,95 @@
#include "streaming/streamstypes.h"
using namespace app_flvplayback;
+
+//===
+// Moiseenko Andrey's security checks for local and remote IPs
+static unsigned GetMaskByNum(int Num)
+{
+ if (!Num)
+ {
+ return 0;
+ }
+ return ~ ((1 << (32 - Num)) - 1);
+}
+static bool CheckIp(string ip, const char * fn)
+{
+ const char * pip = ip.c_str();
+ unsigned xx[4] = { 0, 0, 0, 0 };
+ sscanf(pip, "%d.%d.%d.%d", &xx[0], &xx[1], &xx[2], &xx[3]);
+ unsigned Ip = (((((xx[0] << 8) | xx[1]) << 8) | xx[2]) << 8) | xx[3];
+ fprintf(stderr, "%d.%d.%d.%d %08x\n", xx[0], xx[1], xx[2], xx[3], Ip);
+ FILE * f = fopen(fn, "rb");
+ if (f)
+ {
+ char Buffer[256];
+ while(fgets(Buffer, (int)sizeof(Buffer) - 1, f))
+ {
+ int l = strlen(Buffer);
+ while(l > 0 && (Buffer[l - 1] == '\r' || Buffer[l - 1] == '\n'))
+ {
+ Buffer[--l] = 0;
+ }
+ if (Buffer[0] == ';' || Buffer[0] == '#' || Buffer[0] == 0)
+ {
+ continue;
+ }
+ pip = Buffer;
+ unsigned cmp_ip = 0, x;
+ for (int i = 0; i < 4; i++)
+ {
+ x = 0;
+ sscanf(pip, "%d", &x);
+ fprintf(stderr, "%d.\n", x);
+ cmp_ip = (cmp_ip << 8) | x;
+ while(*pip >= '0' && *pip <= '9') pip++;
+ if (*pip == '.' || *pip == '/') pip++;
+ }
+ x = 32;
+ sscanf(pip, "%d", &x);
+ fprintf(stderr, "/%d\n", x);
+ x = GetMaskByNum((int)x);
+ fprintf(stderr, "%08x&%08x (%08x) == %08x&%08x (%08x) ?\n", cmp_ip, x, (cmp_ip & x), Ip, x, (Ip & x));
+ if ((cmp_ip & x) == (Ip & x))
+ {
+ fclose(f);
+ return true;
+ }
+ }
+ fclose(f);
+ }
+ return false;
+}
+static bool CheckUrl(string url, const char * fn)
+{
+ const char * purl = url.c_str();
+ FILE * f = fopen(fn, "rb");
+ if (f)
+ {
+ char Buffer[512];
+ while(fgets(Buffer, (int)sizeof(Buffer) - 1, f))
+ {
+ int l = strlen(Buffer);
+ while(l > 0 && (Buffer[l - 1] == '\r' || Buffer[l - 1] == '\n'))
+ {
+ Buffer[--l] = 0;
+ }
+ if (Buffer[0] == ';' || Buffer[0] == '#' || Buffer[0] == 0)
+ {
+ continue;
+ }
+ if (!strcmp(purl, Buffer) || !strcmp(Buffer, "*"))
+ {
+ fclose(f);
+ return true;
+ }
+ }
+ fclose(f);
+ }
+ return false;
+}
+//===
+
RTMPAppProtocolHandler::RTMPAppProtocolHandler(Variant &configuration)
: BaseRTMPAppProtocolHandler(configuration) {
@@ -48,6 +138,199 @@
}
}
+// adding functions for filter validations
+bool RTMPAppProtocolHandler::ProcessInvokeConnect(BaseRTMPProtocol *pFrom, Variant &request) {
+
+ // check white remote ip
+ if (pFrom->GetType() == PT_INBOUND_RTMP)
+ {
+ //INFO("// pFrom->GetType() == PT_INBOUND_RTMP");
+ IOHandler *pIOHandler = pFrom->GetIOHandler();
+ /*if (pIOHandler)
+ {
+ INFO("// pIOHandler != NULL, ->GetType() = %d (%d?, %d?)", (int)pIOHandler->GetType(), (int)IOHT_TCP_CARRIER, (int)IOHT_UDP_CARRIER);
+ }
+ else
+ {
+ INFO("// pIOHandler == NULL");
+ }*/
+ if (pIOHandler && (pIOHandler->GetType() == IOHT_TCP_CARRIER || pIOHandler->GetType() == IOHT_UDP_CARRIER))
+ {
+ int fd = pIOHandler->GetInboundFd();
+
+ struct sockaddr_in s;
+ socklen_t len;
+ memset(&s, 0, sizeof(s));
+ len = sizeof(s);
+ if (getpeername(fd, (struct sockaddr *)&s, &len))
+ {
+ //Error("getpeername()");
+ }
+ else
+ {
+ unsigned long RemoteIp = (unsigned long)(s.sin_addr.s_addr);
+ int RemotePort = ntohs(s.sin_port);
+ unsigned char * pucIp = (unsigned char *)&RemoteIp;
+ string strIp = format("%hhu.%hhu.%hhu.%hhu",
+ (uint8_t) pucIp[0],
+ (uint8_t) pucIp[1],
+ (uint8_t) pucIp[2],
+ (uint8_t) pucIp[3]);
+ RemoteIp = ntohl(RemoteIp);
+ //if (RemoteIp == 0xc2b11453 /*194.177.20.83*/)
+ //if (strIp == "194.177.20.83")
+ // Moiseenko Andrey's security checks for remote IPs
+ if (CheckIp(strIp, "/etc/crtmpserver/remote_ip.txt"))
+ {
+ INFO("// PT_INBOUND_RTMP is from white ip: remote IP:Port=%s:%d", STR(strIp), RemotePort);
+ return BaseRTMPAppProtocolHandler::ProcessInvokeConnect(pFrom, request);
+ }
+ else
+ {
+ INFO("// PT_INBOUND_RTMP is from not white remote IP:Port=%s:%d, check next...", STR(strIp), RemotePort);
+ }
+ }
+ }
+ }
+
+ //1. Get the request params
+ if (M_INVOKE_PARAMS(request).MapSize() < 1) {
+ FATAL("Invalid request");
+ return false;
+ }
+ Variant connectParameters = M_INVOKE_PARAM(request, 0);
+
+ if (_authMethod != "") {
+ //we have adobe auth enabled
+ string flashVer = connectParameters[RM_INVOKE_PARAMS_CONNECT_FLASHVER];
+ if (!_configuration[CONF_APPLICATION_AUTH][CONF_APPLICATION_AUTH_ENCODER_AGENTS].HasKey(flashVer)) {
+ //this connection will not be authenticated, so we will try to validate the URI's
+ if (!ValidateRequest(request)) {
+ FATAL("Invalid connect request");
+ return false;
+ }
+ }
+ } else {
+ //we don't have adobe auth enabled at all. We will try to validate the URI's
+ if (!ValidateRequest(request)) {
+ FATAL("Invalid connect request");
+ return false;
+ }
+ }
+
+ return BaseRTMPAppProtocolHandler::ProcessInvokeConnect(pFrom, request);
+}
+
+bool RTMPAppProtocolHandler::ValidateRequest(Variant &request) {
+ //TODO: Validate the various URI's inside the request here
+ //0. Dump the request on console, just to see its structure
+ FINEST("Initial request:\n%s", STR(request.ToString()));
+
+ //1. Get the connect params from the connect invoke
+ Variant connectParams = M_INVOKE_PARAM(request, 0);
+
+ //2. This should be a key-value map
+ if (connectParams != V_MAP) {
+ FATAL("Incorrect invoke params:\n%s", STR(request.ToString()));
+ return false;
+ }
+
+ //3. Let's extract few values. Make sure we extract them using non-case-sensitive keys
+ Variant tcUrl = connectParams.GetValue(RM_INVOKE_PARAMS_CONNECT_TCURL, false);
+
+ //If you are sure about case-sensitive settings, you can extract it directly like this
+ Variant swfUrl = connectParams[RM_INVOKE_PARAMS_CONNECT_SWFURL];
+ //Variant tcUrl = connectParams[RM_INVOKE_PARAMS_CONNECT_TCURL];
+ Variant pageUrl = connectParams[RM_INVOKE_PARAMS_CONNECT_PAGEURL];
+
+
+ //4. Do some validation on them.
+
+ if (pageUrl != V_STRING) {
+ FATAL("Incorrect " RM_INVOKE_PARAMS_CONNECT_PAGEURL ": %s", STR(request.ToString()));
+ return false;
+ //return true;
+ }
+
+ if (tcUrl != V_STRING) {
+ FATAL("Incorrect " RM_INVOKE_PARAMS_CONNECT_TCURL ":\n%s", STR(request.ToString()));
+ return false;
+ //return true;
+ }
+
+ string rawURI;
+ URI uri;
+ if (!URI::FromString(pageUrl, true, uri)) {
+ FATAL("Unable to parse the uri %s", STR(rawURI));
+ return false;
+ }
+
+ // as proto we are going to validate rtmp/rtmpe
+ // added if/elseif/else and INFO like Andriy suggested
+ INFO("Connect schema is %s", STR((string) tcUrl));
+ if (CheckUrl((string)tcUrl, "/etc/crtmpserver/tc_url.txt"))
+ {
+ }
+ else
+ {
+ FATAL("Incorrect " RM_INVOKE_PARAMS_CONNECT_TCURL ": %s", STR(request.ToString()));
+ return false;
+ }
+ /*
+ if (((string) tcUrl) != "rtmp://media.bfy.ro/livestream") {
+ INFO("Connect schema is %s", STR((string) tcUrl));
+ } else if (((string) tcUrl) != "rtmpe://media.bfy.ro/livestream") {
+ INFO("Connect schema is %s", STR((string) tcUrl));
+ }
+ else {
+ FATAL("Incorrect " RM_INVOKE_PARAMS_CONNECT_TCURL ": %s", STR(request.ToString()));
+ return false;
+ }
+ */
+ // we use our static flowplayer which is always on the same address
+ // added if/elseif/else and INFO like Andriy suggested
+ INFO("Flash player address is %s", STR((string) swfUrl));
+ if (CheckUrl((string)swfUrl, "/etc/crtmpserver/swf_url.txt"))
+ {
+ }
+ else
+ {
+ FATAL("Incorrect " RM_INVOKE_PARAMS_CONNECT_SWFURL ": %s", STR(request.ToString()));
+ return false;
+ }
+ /*
+ if (((string) swfUrl) != "http://www.a-queens.ro/flowplayer/flowplayer-3.2.5.swf") {
+ INFO("Flash player address is %s", STR((string) swfUrl));
+ } else if (((string) swfUrl) != "http://www.a-queens.ro/player.swf") {
+ INFO("Flash player address is %s", STR((string) swfUrl));
+ }
+ else {
+ FATAL("Incorrect " RM_INVOKE_PARAMS_CONNECT_SWFURL ": %s", STR(request.ToString()));
+ return false;
+ }
+ */
+
+ // ip which resolve our calling webpage(s)/website(s)
+ // added if/elseif/else and INFO like Andriy suggested
+ string _ip = uri.ip();
+ // Moiseenko Andrey's security checks for local IPs
+ if (CheckIp(_ip, "/etc/crtmpserver/local_ip.txt"))
+ //if (_ip == "194.177.20.83")
+ {
+ INFO("Stream calling webpage is %s", STR((string) pageUrl));
+ INFO("stream Calling webpage IP is %s", STR(_ip));
+ }
+ else
+ {
+ INFO("!! Stream calling webpage is %s", STR((string) pageUrl));
+ FATAL("!! stream Calling webpage IP is %s", STR(_ip));
+ //FATAL("Incorrect " RM_INVOKE_PARAMS_CONNECT_PAGEURL ": %s", STR(request.ToString()));
+ return false;
+ }
+
+ return true;
+}
+
bool RTMPAppProtocolHandler::ProcessGetAvailableFlvs(BaseRTMPProtocol *pFrom, Variant &request) {
Variant parameters;
parameters.PushToArray(Variant());
diff -Naur crtmpserver-1.0~dfsg/debian/crtmpserver.install crtmpserver-1.0_mod/debian/crtmpserver.install
--- crtmpserver-1.0~dfsg/debian/crtmpserver.install 2013-06-22 19:09:08.000000000 +0400
+++ crtmpserver-1.0_mod/debian/crtmpserver.install 2017-10-11 21:41:11.611077568 +0300
@@ -1,4 +1,8 @@
debian/crtmpserver-scripts/crtmpserver.lua etc/crtmpserver
debian/crtmpserver-scripts/log_appenders.lua etc/crtmpserver
+debian/crtmpserver-scripts/local_ip.txt etc/crtmpserver
+debian/crtmpserver-scripts/remote_ip.txt etc/crtmpserver
+debian/crtmpserver-scripts/tc_url.txt etc/crtmpserver
+debian/crtmpserver-scripts/swf_url.txt etc/crtmpserver
usr/sbin/crtmpserver
diff -Naur crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/local_ip.txt crtmpserver-1.0_mod/debian/crtmpserver-scripts/local_ip.txt
--- crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/local_ip.txt 1970-01-01 03:00:00.000000000 +0300
+++ crtmpserver-1.0_mod/debian/crtmpserver-scripts/local_ip.txt 2017-10-11 21:58:39.709222872 +0300
@@ -0,0 +1,5 @@
+; /etc/local_ip.txt: just local server's IP enabled
+; Sample:
+127.0.0.1
+0.0.0.0/0
+;10.7.52.97
diff -Naur crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/remote_ip.txt crtmpserver-1.0_mod/debian/crtmpserver-scripts/remote_ip.txt
--- crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/remote_ip.txt 1970-01-01 03:00:00.000000000 +0300
+++ crtmpserver-1.0_mod/debian/crtmpserver-scripts/remote_ip.txt 2017-10-11 21:58:55.169193293 +0300
@@ -0,0 +1,7 @@
+; /etc/remote_ip.txt: white list remote IPs for translation and connect from
+; high priority, if passed then local IPs and urls are not checked
+;
+; if not exist then urls and local ip are checking next
+; Sample:
+;185.189.1.2
+;37.78.53.97
diff -Naur crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/swf_url.txt crtmpserver-1.0_mod/debian/crtmpserver-scripts/swf_url.txt
--- crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/swf_url.txt 1970-01-01 03:00:00.000000000 +0300
+++ crtmpserver-1.0_mod/debian/crtmpserver-scripts/swf_url.txt 2017-10-11 19:51:52.000000000 +0300
@@ -0,0 +1,4 @@
+; /etc/swf_url.txt: allowed Flash player address (swf's urls) or *
+; Sample:
+;http://maasoftware.ru/ref/tarantinov/starominskaya/TarantinovFLV3.swf
+*
diff -Naur crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/tc_url.txt crtmpserver-1.0_mod/debian/crtmpserver-scripts/tc_url.txt
--- crtmpserver-1.0~dfsg/debian/crtmpserver-scripts/tc_url.txt 1970-01-01 03:00:00.000000000 +0300
+++ crtmpserver-1.0_mod/debian/crtmpserver-scripts/tc_url.txt 2017-10-11 19:51:52.000000000 +0300
@@ -0,0 +1,4 @@
+; /etc/tc_url.txt: allowed tc urls (Connect schema) or *
+; Sample:
+;rtmp://starominskaya.biz/flvplayback
+*
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