From: bodea Date: Wed, 3 Nov 2004 13:22:39 +0000 (+0000) Subject: cleanup packet length handling X-Git-Tag: release_2_0_3~2 X-Git-Url: http://git.sameswireless.fr/l2tpns.git/commitdiff_plain/6b74bac40e76b26c2c6968705b3c9929ceb89454?hp=27e17ad461cfd47b29b6d8c1ec2183302d226988 cleanup packet length handling --- diff --git a/ppp.c b/ppp.c index cf34bc0..6908e90 100644 --- a/ppp.c +++ b/ppp.c @@ -1,6 +1,6 @@ // L2TPNS PPP Stuff -char const *cvs_id_ppp = "$Id: ppp.c,v 1.17 2004/10/29 04:01:53 bodea Exp $"; +char const *cvs_id_ppp = "$Id: ppp.c,v 1.18 2004/11/03 13:22:39 bodea Exp $"; #include #include @@ -26,11 +26,11 @@ extern struct configt *config; void sendccp(tunnelidt t, sessionidt s); // Process PAP messages -void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l) +void processpap(tunnelidt t, sessionidt s, u8 *p, u16 l) { char user[129]; char pass[129]; - + u16 hl; CSTAT(call_processpap); @@ -41,18 +41,22 @@ void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l) STAT(tunnel_rx_errors); return ; } - if (*p != 1) + + if ((hl = ntohs(*(u16 *) (p + 2))) > l) { - log(1, 0, s, t, "Unexpected PAP code %d\n", *p); + log(1, 0, s, t, "Length mismatch PAP %u/%u\n", hl, l); STAT(tunnel_rx_errors); return ; } - if (ntohs(*(u16 *) (p + 2)) > l) + l = hl; + + if (*p != 1) { - log(1, 0, s, t, "Length mismatch PAP %d/%d\n", ntohs(*(u16 *) (p + 2)), l); + log(1, 0, s, t, "Unexpected PAP code %d\n", *p); STAT(tunnel_rx_errors); return ; } + { u8 *b = p; b += 4; @@ -123,11 +127,10 @@ void processpap(tunnelidt t, sessionidt s, u8 * p, u16 l) } // Process CHAP messages -void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l) +void processchap(tunnelidt t, sessionidt s, u8 *p, u16 l) { u16 r; - u16 len; - + u16 hl; CSTAT(call_processchap); @@ -142,6 +145,22 @@ void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l) STAT(tunnel_rx_errors); return; } + + if (l < 4) + { + log(1, 0, s, t, "Short CHAP %u bytes\n", l); + STAT(tunnel_rx_errors); + return ; + } + + if ((hl = ntohs(*(u16 *) (p + 2))) > l) + { + log(1, 0, s, t, "Length mismatch CHAP %u/%u\n", hl, l); + STAT(tunnel_rx_errors); + return ; + } + l = hl; + if (*p != 2) { log(1, 0, s, t, "Unexpected CHAP response code %d\n", *p); @@ -154,22 +173,19 @@ void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l) STAT(tunnel_rx_errors); return ; } - len = ntohs(*(u16 *) (p + 2)); - if (len > l) - { - log(1, 0, s, t, "Bad CHAP length %d\n", len); - STAT(tunnel_rx_errors); - return ; - } - if (p[4] != 16) + + if (l < 5 || p[4] != 16) { - log(1, 0, s, t, "Bad CHAP response length %d\n", p[4]); + log(1, 0, s, t, "Bad CHAP response length %d\n", l < 5 ? -1 : p[4]); STAT(tunnel_rx_errors); return ; } - if (len - 21 >= sizeof(session[s].user)) + + l -= 5; + p += 5; + if (l < 16 || l - 16 >= sizeof(session[s].user)) { - log(1, 0, s, t, "CHAP user too long %d\n", len - 21); + log(1, 0, s, t, "CHAP user too long %d\n", l - 16); STAT(tunnel_rx_errors); return ; } @@ -178,10 +194,10 @@ void processchap(tunnelidt t, sessionidt s, u8 * p, u16 l) { struct param_pre_auth packet = { &tunnel[t], &session[s], NULL, NULL, PPPCHAP, 1 }; - packet.username = calloc(len-20, 1); + packet.username = calloc(l - 16 + 1, 1); packet.password = calloc(16, 1); - memcpy(packet.username, p + 21, len - 21); - memcpy(packet.password, p + 5, 16); + memcpy(packet.username, p + 16, l - 16); + memcpy(packet.password, p, 16); run_plugins(PLUGIN_PRE_AUTH, &packet); if (!packet.continue_auth) @@ -222,7 +238,7 @@ char *ppp_lcp_types[] = { void dumplcp(u8 *p, int l) { - signed int x = l - 4; + int x = l - 4; u8 *o = (p + 4); log_hex(5, "PPP LCP Packet", p, l); @@ -305,12 +321,12 @@ void dumplcp(u8 *p, int l) } // Process LCP messages -void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l) +void processlcp(tunnelidt t, sessionidt s, u8 *p, u16 l) { u8 b[MAXCONTROL]; u8 *q = NULL; - u32 magicno = 0; - + u32 magicno = 0; + u16 hl; CSTAT(call_processlcp); @@ -321,6 +337,15 @@ void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l) STAT(tunnel_rx_errors); return ; } + + if ((hl = ntohs(*(u16 *) (p + 2))) > l) + { + log(1, 0, s, t, "Length mismatch LCP %u/%u\n", hl, l); + STAT(tunnel_rx_errors); + return ; + } + l = hl; + if (*p == ConfigAck) { log(3, session[s].ip, s, t, "LCP: Discarding ConfigAck\n"); @@ -328,12 +353,11 @@ void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l) } else if (*p == ConfigReq) { - l = ntohs(*(u16 *)(p + 2)); - signed int x = l - 4; + int x = l - 4; u8 *o = (p + 4); log(3, session[s].ip, s, t, "LCP: ConfigReq (%d bytes)...\n", l); - dumplcp(p, l); + if (config->debug > 3) dumplcp(p, l); while (x > 2) { @@ -436,7 +460,7 @@ void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l) else if (*p == ConfigNak) { log(1, session[s].ip, s, t, "Remote end sent a ConfigNak. Ignoring\n"); - dumplcp(p, l); + if (config->debug > 3) dumplcp(p, l); return ; } else if (*p == TerminateReq) @@ -497,8 +521,9 @@ void processlcp(tunnelidt t, sessionidt s, u8 * p, u16 l) } // Process IPCP messages -void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l) +void processipcp(tunnelidt t, sessionidt s, u8 *p, u16 l) { + u16 hl; CSTAT(call_processipcp); @@ -509,6 +534,15 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l) STAT(tunnel_rx_errors); return ; } + + if ((hl = ntohs(*(u16 *) (p + 2))) > l) + { + log(1, 0, s, t, "Length mismatch IPCP %u/%u\n", hl, l); + STAT(tunnel_rx_errors); + return ; + } + l = hl; + if (*p == ConfigAck) { // happy with our IPCP @@ -532,12 +566,7 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l) return ; } log(4, session[s].ip, s, t, "IPCP ConfigReq received\n"); - if (ntohs(*(u16 *) (p + 2)) > l) - { - log(1, 0, s, t, "Length mismatch IPCP %d/%d\n", ntohs(*(u16 *) (p + 2)), l); - STAT(tunnel_rx_errors); - return ; - } + if (!session[s].ip) { log(3, 0, s, t, "Waiting on radius reply\n"); @@ -549,7 +578,6 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l) u8 *i, *q; - l = ntohs(*(u16 *) (p + 2)); // We must use length from IPCP len field q = p + 4; i = p + l; while (q < i && q[1]) @@ -634,7 +662,7 @@ void processipcp(tunnelidt t, sessionidt s, u8 * p, u16 l) // // This MUST be called with at least 4 byte behind 'p'. // (i.e. this routine writes to p[-4]). -void processipin(tunnelidt t, sessionidt s, u8 * p, u16 l) +void processipin(tunnelidt t, sessionidt s, u8 *p, u16 l) { ipt ip; @@ -723,7 +751,7 @@ void send_ipin(sessionidt s, u8 *buf, int len) // Process LCP messages -void processccp(tunnelidt t, sessionidt s, u8 * p, u16 l) +void processccp(tunnelidt t, sessionidt s, u8 *p, u16 l) { CSTAT(call_processccp); @@ -813,7 +841,7 @@ void sendchap(tunnelidt t, sessionidt s) // fill in a L2TP message with a PPP frame, // copies existing PPP message and changes magic number if seen // returns start of PPP frame -u8 *makeppp(u8 * b, int size, u8 * p, int l, tunnelidt t, sessionidt s, u16 mtype) +u8 *makeppp(u8 *b, int size, u8 *p, int l, tunnelidt t, sessionidt s, u16 mtype) { if (size < 12) return NULL; // Need more space than this!! @@ -845,7 +873,7 @@ u8 *makeppp(u8 * b, int size, u8 * p, int l, tunnelidt t, sessionidt s, u16 mtyp } // find a PPP option, returns point to option, or 0 if not found -u8 *findppp(u8 * b, u8 mtype) +u8 *findppp(u8 *b, u8 mtype) { u16 l = ntohs(*(u16 *) (b + 2)); if (l < 4)