From 91c88342ff81f4eb020992b034fb81db0f0c5147 Mon Sep 17 00:00:00 2001 From: Hans Dedecker Date: Tue, 17 Apr 2018 17:27:42 +0200 Subject: [PATCH 1/2] xtables-addons: rstp: use specific source in expected RTP connection Instead of passing a wildcard source to the expected RTP data connection; use the server IP address of the RTSP SETUP packet or the RTP media source from the SETUP URI contained in the SETUP packet. This guarantees RTP data is only accepted from the expected source. Signed-off-by: Alin Nastac Signed-off-by: Hans Dedecker --- .../patches/100-add-rtsp-conntrack.patch | 40 ++++++++++++++++--- 1 file changed, 34 insertions(+), 6 deletions(-) diff --git a/net/xtables-addons/patches/100-add-rtsp-conntrack.patch b/net/xtables-addons/patches/100-add-rtsp-conntrack.patch index bd49d92de..917baf41a 100644 --- a/net/xtables-addons/patches/100-add-rtsp-conntrack.patch +++ b/net/xtables-addons/patches/100-add-rtsp-conntrack.patch @@ -235,7 +235,7 @@ +#endif /* _NETFILTER_MIME_H */ --- /dev/null +++ b/extensions/rtsp/nf_conntrack_rtsp.c -@@ -0,0 +1,576 @@ +@@ -0,0 +1,604 @@ +/* + * RTSP extension for IP connection tracking + * (C) 2003 by Tom Marshall @@ -250,7 +250,10 @@ + * 2013-03-04: Il'inykh Sergey . Inango Systems Ltd + * - fixed rtcp nat mapping and other port mapping fixes + * - simple TEARDOWN request handling -+ * - codestyle fixes and other less significant bug fixes ++ * - codestyle fixes and other less significant bug fixes ++ * 2018-04-17: Alin Nastac ++ * Hans Dedecker ++ * - use IP address read from SETUP URI in expected connections + * + * based on ip_conntrack_irc.c + * @@ -543,6 +546,7 @@ + uint transoff = 0; + uint translen = 0; + uint off; ++ union nf_inet_addr srvaddr; + + if (!rtsp_parse_message(pdata, datalen, &dataoff, + &hdrsoff, &hdrslen, @@ -559,6 +563,32 @@ + if (strncmp(pdata+cmdoff, "SETUP ", 6) != 0) + continue; /* not a SETUP message */ + ++ srvaddr = ct->tuplehash[!dir].tuple.src.u3; ++ ++ /* try to get RTP media source from SETUP URI */ ++ off = cmdoff + 6; ++ while (off < datalen) { ++ if (strncmp(pdata+off, "://", 3) == 0) { ++ off += 3; ++ cmdoff = off; ++ ++ while (off < datalen) { ++ if (pdata[off] == ':' || ++ pdata[off] == '/' || ++ pdata[off] == ' ') { ++ in4_pton(pdata + cmdoff, ++ off - cmdoff, ++ (u8 *)&srvaddr.in, ++ -1, NULL); ++ break; ++ } ++ off++; ++ } ++ break; ++ } ++ off++; ++ } ++ + pr_debug("found a setup message\n"); + + off = 0; @@ -583,8 +613,7 @@ + } + + nf_ct_expect_init(rtp_exp, NF_CT_EXPECT_CLASS_DEFAULT, -+ nf_ct_l3num(ct), -+ NULL, /* &ct->tuplehash[!dir].tuple.src.u3, */ ++ nf_ct_l3num(ct), &srvaddr, + &ct->tuplehash[!dir].tuple.dst.u3, + IPPROTO_UDP, NULL, &be_loport); + @@ -601,8 +630,7 @@ + } + + nf_ct_expect_init(rtcp_exp, NF_CT_EXPECT_CLASS_DEFAULT, -+ nf_ct_l3num(ct), -+ NULL, /* &ct->tuplehash[!dir].tuple.src.u3, */ ++ nf_ct_l3num(ct), &srvaddr, + &ct->tuplehash[!dir].tuple.dst.u3, + IPPROTO_UDP, NULL, &be_hiport); + From 01692d9e13bab1a3faf011878aff6ae45c7e9faa Mon Sep 17 00:00:00 2001 From: Hans Dedecker Date: Wed, 18 Apr 2018 13:59:20 +0200 Subject: [PATCH 2/2] xtables-addons: rtsp: update source in expected RTP connection Update source IP of the expected RTP connection according to the SOURCE attribute value if present in the RTSP SETUP REPLY message. Signed-off-by: Hans Dedecker --- net/xtables-addons/Makefile | 2 +- .../patches/100-add-rtsp-conntrack.patch | 159 ++++++++++++++++-- 2 files changed, 145 insertions(+), 16 deletions(-) diff --git a/net/xtables-addons/Makefile b/net/xtables-addons/Makefile index b8d8abe49..5c78ff891 100644 --- a/net/xtables-addons/Makefile +++ b/net/xtables-addons/Makefile @@ -10,7 +10,7 @@ include $(INCLUDE_DIR)/kernel.mk PKG_NAME:=xtables-addons PKG_VERSION:=2.14 -PKG_RELEASE:=3 +PKG_RELEASE:=4 PKG_HASH:=d215a9a8b8e66aae04b982fa2e1228e8a71e7dfe42320df99e34e5000cbdf152 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz diff --git a/net/xtables-addons/patches/100-add-rtsp-conntrack.patch b/net/xtables-addons/patches/100-add-rtsp-conntrack.patch index 917baf41a..7ac2cc563 100644 --- a/net/xtables-addons/patches/100-add-rtsp-conntrack.patch +++ b/net/xtables-addons/patches/100-add-rtsp-conntrack.patch @@ -235,7 +235,7 @@ +#endif /* _NETFILTER_MIME_H */ --- /dev/null +++ b/extensions/rtsp/nf_conntrack_rtsp.c -@@ -0,0 +1,604 @@ +@@ -0,0 +1,732 @@ +/* + * RTSP extension for IP connection tracking + * (C) 2003 by Tom Marshall @@ -254,6 +254,9 @@ + * 2018-04-17: Alin Nastac + * Hans Dedecker + * - use IP address read from SETUP URI in expected connections ++ * 2018-04-18: Hans Dedecker ++ * - update RTP expected connection source IP based on SOURCE ++ * in the SETUP reply message + * + * based on ip_conntrack_irc.c + * @@ -402,13 +405,14 @@ +} + +/* -+ * Find lo/hi client ports (if any) in transport header ++ * Find lo/hi client ports and/or source (if any) in transport header + * In: + * ptcp, tcplen = packet + * tranoff, tranlen = buffer to search + * + * Out: + * pport_lo, pport_hi = lo/hi ports (host endian) ++ * srvaddr + * + * Returns nonzero if any client ports found + * @@ -485,6 +489,17 @@ + } + rc = 1; + } ++ } else if (strncmp(ptran+off, "source=", 7) == 0) { ++ uint srcaddrlen; ++ ++ off += 7; ++ srcaddrlen = nextfieldoff - off - 1; ++ ++ if (in4_pton(ptran + off, srcaddrlen, ++ (u8 *)&prtspexp->srvaddr.in, ++ -1, NULL)) ++ pr_debug("source found : %pI4\n", ++ &prtspexp->srvaddr.ip); + } + + /* @@ -687,11 +702,120 @@ + + +static inline int -+help_in(struct sk_buff *skb, size_t pktlen, -+ struct nf_conn* ct, enum ip_conntrack_info ctinfo) -+{ -+ return NF_ACCEPT; -+} ++help_in(struct sk_buff *skb, unsigned char *rb_ptr, unsigned int datalen, ++#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0) ++ struct nf_conn *ct, enum ip_conntrack_info ctinfo, ++ unsigned int protoff) ++#else ++ struct nf_conn *ct, enum ip_conntrack_info ctinfo) ++#endif ++ { ++ struct ip_ct_rtsp_expect expinfo; ++ union nf_inet_addr srvaddr; ++ int dir = CTINFO2DIR(ctinfo); /* = IP_CT_DIR_ORIGINAL */ ++ int len; ++ char* pdata = rb_ptr; ++ uint dataoff = 0; ++ int ret = NF_ACCEPT; ++ u_int8_t family; ++ struct nf_conntrack_expect *exp_ct = NULL; ++ struct nf_conntrack_tuple t; ++ struct net *net = nf_ct_net(ct); ++ ++ memset(&expinfo, 0, sizeof(expinfo)); ++ ++ while (dataoff < datalen) { ++ uint cmdoff = dataoff; ++ uint hdrsoff = 0; ++ uint hdrslen = 0; ++ uint cseqoff = 0; ++ uint cseqlen = 0; ++ uint transoff = 0; ++ uint translen = 0; ++ ++ if (!rtsp_parse_message(pdata, datalen, &dataoff, ++ &hdrsoff, &hdrslen, ++ &cseqoff, &cseqlen, ++ &transoff, &translen)) ++ break; /* not a valid message */ ++ ++ if (strncmp(pdata+cmdoff, "RTSP/", 5) == 0 && translen) { ++ union nf_inet_addr zeroaddr; ++ ++ memset(&zeroaddr, 0, sizeof(zeroaddr)); ++ ++ if (!rtsp_parse_transport(pdata+transoff, translen, &expinfo)) ++ continue; ++ ++ srvaddr = expinfo.srvaddr; ++ ++ if (nf_inet_addr_cmp(&srvaddr, &ct->tuplehash[dir].tuple.src.u3) || ++ nf_inet_addr_cmp(&srvaddr, &zeroaddr)) ++ continue; ++ } else ++ continue; /* not valid RTSP reply */ ++ ++ if (expinfo.loport == 0) { ++ pr_debug("no udp transports found\n"); ++ continue; /* no udp transports found */ ++ } ++ ++ family = nf_ct_l3num(ct); ++ if (family == AF_INET) ++ len = 4; ++ else ++ len = 16; ++ ++ /* replace rtp expect src addr */ ++ t.src.l3num = family; ++ t.dst.protonum = IPPROTO_UDP; ++ ++ memcpy(&t.src.u3, &ct->tuplehash[dir].tuple.src.u3, len); ++ if (sizeof(t.src.u3) > len) ++ /* address needs to be cleared for nf_ct_tuple_equal */ ++ memset((void *)&t.src.u3 + len, 0, sizeof(t.src.u3) - len); ++ ++ t.src.u.all = 0; ++ ++ memcpy(&t.dst.u3, &ct->tuplehash[dir].tuple.dst.u3, len); ++ if (sizeof(t.dst.u3) > len) ++ /* address needs to be cleared for nf_ct_tuple_equal */ ++ memset((void *)&t.dst.u3 + len, 0, sizeof(t.dst.u3) - len); ++ ++ t.dst.u.all = htons(expinfo.loport); ++ ++ /* get the rtp expect and replace the srcaddr with RTP server addr */ ++ exp_ct = nf_ct_expect_find_get(net, nf_ct_zone(ct), &t); ++ if (exp_ct) { ++ memcpy(&exp_ct->tuple.src.u3, &srvaddr, len); ++ if (sizeof(exp_ct->tuple.src.u3) > len) ++ /* address needs to be cleared for nf_ct_tuple_equal */ ++ memset((void *)&exp_ct->tuple.src.u3 + len, 0, ++ sizeof(exp_ct->tuple.src.u3) - len); ++ } else ++ goto out; ++ ++ /* replace rtcp expect src addr */ ++ if (expinfo.pbtype == pb_range) { ++ t.dst.u.all = htons(expinfo.hiport); ++ ++ /* get the rtcp expect and replace the srcaddr with RTP server addr */ ++ exp_ct = nf_ct_expect_find_get(net, nf_ct_zone(ct), &t); ++ if (exp_ct) { ++ memcpy(&exp_ct->tuple.src.u3, &srvaddr, len); ++ if (sizeof(exp_ct->tuple.src.u3) > len) ++ /* address needs to be cleared for nf_ct_tuple_equal */ ++ memset((void *)&exp_ct->tuple.src.u3 + len, 0, ++ sizeof(exp_ct->tuple.src.u3) - len); ++ } else ++ goto out; ++ } ++ ++ goto out; ++ } ++out: ++ return ret; ++ } + +static int help(struct sk_buff *skb, unsigned int protoff, + struct nf_conn *ct, enum ip_conntrack_info ctinfo) @@ -748,7 +872,11 @@ + case IP_CT_DIR_REPLY: + pr_debug("IP_CT_DIR_REPLY\n"); + /* inbound packet: server->client */ -+ ret = NF_ACCEPT; ++#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0) ++ ret = help_in(skb, rb_ptr, datalen, ct, ctinfo, protoff); ++#else ++ ret = help_in(skb, rb_ptr, datalen, ct, ctinfo); ++#endif + break; + } + @@ -842,7 +970,7 @@ +module_exit(fini); --- /dev/null +++ b/extensions/rtsp/nf_conntrack_rtsp.h -@@ -0,0 +1,72 @@ +@@ -0,0 +1,73 @@ +/* + * RTSP extension for IP connection tracking. + * (C) 2003 by Tom Marshall @@ -889,13 +1017,14 @@ + */ +struct ip_ct_rtsp_expect +{ -+ u_int32_t len; /* length of header block */ -+ portblock_t pbtype; /* Type of port block that was requested */ -+ u_int16_t loport; /* Port that was requested, low or first */ -+ u_int16_t hiport; /* Port that was requested, high or second */ ++ u_int32_t len; /* length of header block */ ++ portblock_t pbtype; /* Type of port block that was requested */ ++ u_int16_t loport; /* Port that was requested, low or first */ ++ u_int16_t hiport; /* Port that was requested, high or second */ ++ union nf_inet_addr srvaddr; /* src address in SETUP reply */ +#if 0 -+ uint method; /* RTSP method */ -+ uint cseq; /* CSeq from request */ ++ uint method; /* RTSP method */ ++ uint cseq; /* CSeq from request */ +#endif +}; +