From 7983f47ed4d055fd67c42ea5d9a1ddb8801d3ad9 Mon Sep 17 00:00:00 2001 From: simon Date: Sat, 21 Sep 2002 16:52:21 +0000 Subject: [PATCH] Cleanups to proxy code: greater robustness in receiving proxy data, better error reporting for SOCKS 5 and HTTP proxies. git-svn-id: svn://svn.tartarus.org/sgt/putty@1973 cda61777-01e9-0310-a592-d414129be87e --- misc.c | 48 +++++++++++++---- misc.h | 1 + proxy.c | 178 +++++++++++++++++++++++++++++++++++++++++++--------------------- 3 files changed, 160 insertions(+), 67 deletions(-) diff --git a/misc.c b/misc.c index 34e613ef..f91e8a71 100644 --- a/misc.c +++ b/misc.c @@ -88,6 +88,7 @@ void base64_encode_atom(unsigned char *data, int n, char *out) * - return a (pointer,length) pair giving some initial data in * the list, suitable for passing to a send or write system * call + * - retrieve a larger amount of initial data from the list * - return the current size of the buffer chain in bytes */ @@ -155,16 +156,23 @@ void bufchain_add(bufchain *ch, void *data, int len) void bufchain_consume(bufchain *ch, int len) { + struct bufchain_granule *tmp; + assert(ch->buffersize >= len); - assert(ch->head != NULL && ch->head->bufpos + len <= ch->head->buflen); - ch->head->bufpos += len; - ch->buffersize -= len; - if (ch->head->bufpos >= ch->head->buflen) { - struct bufchain_granule *tmp = ch->head; - ch->head = tmp->next; - sfree(tmp); - if (!ch->head) - ch->tail = NULL; + while (len > 0) { + int remlen = len; + assert(ch->head != NULL); + if (remlen >= ch->head->buflen - ch->head->bufpos) { + remlen = ch->head->buflen - ch->head->bufpos; + tmp = ch->head; + ch->head = tmp->next; + sfree(tmp); + if (!ch->head) + ch->tail = NULL; + } else + ch->head->bufpos += remlen; + ch->buffersize -= remlen; + len -= remlen; } } @@ -174,6 +182,28 @@ void bufchain_prefix(bufchain *ch, void **data, int *len) *data = ch->head->buf + ch->head->bufpos; } +void bufchain_fetch(bufchain *ch, void *data, int len) +{ + struct bufchain_granule *tmp; + char *data_c = (char *)data; + + tmp = ch->head; + + assert(ch->buffersize >= len); + while (len > 0) { + int remlen = len; + + assert(tmp != NULL); + if (remlen >= tmp->buflen - tmp->bufpos) + remlen = tmp->buflen - tmp->bufpos; + memcpy(data_c, tmp->buf + tmp->bufpos, remlen); + + tmp = tmp->next; + len -= remlen; + data_c += remlen; + } +} + /* ---------------------------------------------------------------------- * My own versions of malloc, realloc and free. Because I want * malloc and realloc to bomb out and exit the program if they run diff --git a/misc.h b/misc.h index 3a908899..a59317e0 100644 --- a/misc.h +++ b/misc.h @@ -27,6 +27,7 @@ int bufchain_size(bufchain *ch); void bufchain_add(bufchain *ch, void *data, int len); void bufchain_prefix(bufchain *ch, void **data, int *len); void bufchain_consume(bufchain *ch, int len); +void bufchain_fetch(bufchain *ch, void *data, int len); /* * Debugging functions. diff --git a/proxy.c b/proxy.c index 408552a4..7b42622b 100644 --- a/proxy.c +++ b/proxy.c @@ -7,6 +7,8 @@ #include +#include + #define DEFINE_PLUG_METHOD_MACROS #include "putty.h" #include "network.h" @@ -329,7 +331,7 @@ Socket new_connection(SockAddr addr, char *hostname, } else if (cfg.proxy_type == PROXY_TELNET) { ret->negotiate = proxy_telnet_negotiate; } else { - ret->error = "Network error: Unknown proxy method"; + ret->error = "Proxy error: Unknown proxy method"; return (Socket) ret; } @@ -484,7 +486,7 @@ int proxy_http_negotiate (Proxy_Socket p, int change) * we'll need to parse, process, and respond to appropriately. */ - void *data; + char *data, *datap; int len; int eol; @@ -493,27 +495,45 @@ int proxy_http_negotiate (Proxy_Socket p, int change) int min_ver, maj_ver, status; /* get the status line */ - bufchain_prefix(&p->pending_input_data, &data, &len); + len = bufchain_size(&p->pending_input_data); + assert(len > 0); /* or we wouldn't be here */ + data = smalloc(len); + bufchain_fetch(&p->pending_input_data, data, len); + eol = get_line_end(data, len); - if (eol < 0) return 1; + if (eol < 0) { + sfree(data); + return 1; + } - sscanf((char *)data, "HTTP/%i.%i %i", &maj_ver, &min_ver, &status); + status = -1; + /* We can't rely on whether the %n incremented the sscanf return */ + if (sscanf((char *)data, "HTTP/%i.%i %n", + &maj_ver, &min_ver, &status) < 2 || status == -1) { + plug_closing(p->plug, "Proxy error: HTTP response was absent", + PROXY_ERROR_GENERAL, 0); + sfree(data); + return 1; + } /* remove the status line from the input buffer. */ bufchain_consume(&p->pending_input_data, eol); - - /* TODO: we need to support Proxy-Auth headers */ - - if (status < 200 || status > 299) { + if (data[status] != '2') { /* error */ - /* TODO: return a more specific error message, - * TODO: based on the status code. - */ - plug_closing(p->plug, "Network error: Error while communicating with proxy", - PROXY_ERROR_GENERAL, 0); + char buf[1024]; + data[eol] = '\0'; + while (eol > status && + (data[eol-1] == '\r' || data[eol-1] == '\n')) + data[--eol] = '\0'; + sprintf(buf, "Proxy error: %.900s", + data+status); + plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); + sfree(data); return 1; } + sfree(data); + p->state = 2; } @@ -523,16 +543,22 @@ int proxy_http_negotiate (Proxy_Socket p, int change) * header of length 2, (ie. just "\r\n") */ - bufchain_prefix(&p->pending_input_data, &data, &len); - eol = get_line_end(data, len); + len = bufchain_size(&p->pending_input_data); + assert(len > 0); /* or we wouldn't be here */ + data = smalloc(len); + datap = data; + bufchain_fetch(&p->pending_input_data, data, len); + + eol = get_line_end(datap, len); + if (eol < 0) { + sfree(data); + return 1; + } while (eol > 2) { - /* TODO: Proxy-Auth stuff. in some cases, we will - * TODO: need to extract information from headers. - */ bufchain_consume(&p->pending_input_data, eol); - bufchain_prefix(&p->pending_input_data, &data, &len); - eol = get_line_end(data, len); + datap += eol; + eol = get_line_end(datap, len); } if (eol == 2) { @@ -541,14 +567,16 @@ int proxy_http_negotiate (Proxy_Socket p, int change) proxy_activate(p); /* proxy activate will have dealt with * whatever is left of the buffer */ + sfree(data); return 1; } + sfree(data); return 1; } } - plug_closing(p->plug, "Network error: Unexpected proxy error", + plug_closing(p->plug, "Proxy error: unexpected proxy error", PROXY_ERROR_UNEXPECTED, 0); return 1; } @@ -576,8 +604,8 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change) char * command; if (sk_addrtype(p->remote_addr) != AF_INET) { - plug_closing(p->plug, "Network error: SOCKS version 4 does not support IPv6", - PROXY_ERROR_GENERAL, 0); + plug_closing(p->plug, "Proxy error: SOCKS version 4 does" + " not support IPv6", PROXY_ERROR_GENERAL, 0); return 1; } @@ -650,14 +678,16 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change) * dest. address (4 bytes) */ - char *data; - int len; + char data[8]; + if (bufchain_size(&p->pending_input_data) < 8) + return 1; /* not got anything yet */ + /* get the response */ - bufchain_prefix(&p->pending_input_data, &data, &len); + bufchain_fetch(&p->pending_input_data, data, 8); if (data[0] != 0) { - plug_closing(p->plug, "Network error: SOCKS proxy responded with " + plug_closing(p->plug, "Proxy error: SOCKS proxy responded with " "unexpected reply code version", PROXY_ERROR_GENERAL, 0); return 1; @@ -667,23 +697,23 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change) switch (data[1]) { case 92: - plug_closing(p->plug, "Network error: SOCKS server wanted IDENTD on client", + plug_closing(p->plug, "Proxy error: SOCKS server wanted IDENTD on client", PROXY_ERROR_GENERAL, 0); break; case 93: - plug_closing(p->plug, "Network error: Username and IDENTD on client don't agree", + plug_closing(p->plug, "Proxy error: Username and IDENTD on client don't agree", PROXY_ERROR_GENERAL, 0); break; case 91: default: - plug_closing(p->plug, "Network error: Error while communicating with proxy", + plug_closing(p->plug, "Proxy error: Error while communicating with proxy", PROXY_ERROR_GENERAL, 0); break; } return 1; } - bufchain_consume(&p->pending_input_data, 2); + bufchain_consume(&p->pending_input_data, 8); /* we're done */ proxy_activate(p); @@ -693,7 +723,7 @@ int proxy_socks4_negotiate (Proxy_Socket p, int change) } } - plug_closing(p->plug, "Network error: Unexpected proxy error", + plug_closing(p->plug, "Proxy error: unexpected proxy error", PROXY_ERROR_UNEXPECTED, 0); return 1; } @@ -770,9 +800,6 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change) * we'll need to parse, process, and respond to appropriately. */ - char *data; - int len; - if (p->state == 1) { /* initial response: @@ -785,12 +812,16 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change) * 0x03 = CHAP * 0xff = no acceptable methods */ + char data[2]; + + if (bufchain_size(&p->pending_input_data) < 2) + return 1; /* not got anything yet */ /* get the response */ - bufchain_prefix(&p->pending_input_data, &data, &len); + bufchain_fetch(&p->pending_input_data, data, 2); if (data[0] != 5) { - plug_closing(p->plug, "Network error: Error while communicating with proxy", + plug_closing(p->plug, "Proxy error: SOCKS proxy returned unexpected version", PROXY_ERROR_GENERAL, 0); return 1; } @@ -800,8 +831,7 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change) else if (data[1] == 0x02) p->state = 5; /* username/password authentication */ else if (data[1] == 0x03) p->state = 6; /* CHAP authentication */ else { - plug_closing(p->plug, "Network error: We don't support any of the SOCKS " - "server's authentication methods", + plug_closing(p->plug, "Proxy error: SOCKS proxy did not accept our authentication", PROXY_ERROR_GENERAL, 0); return 1; } @@ -816,19 +846,25 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change) * 0 = succeeded * >0 = failed */ + char data[2]; + + if (bufchain_size(&p->pending_input_data) < 2) + return 1; /* not got anything yet */ /* get the response */ - bufchain_prefix(&p->pending_input_data, &data, &len); + bufchain_fetch(&p->pending_input_data, data, 2); if (data[0] != 1) { - plug_closing(p->plug, "Network error: Error while communicating with proxy", + plug_closing(p->plug, "Proxy error: SOCKS password " + "subnegotiation contained wrong version number", PROXY_ERROR_GENERAL, 0); return 1; } if (data[1] != 0) { - plug_closing(p->plug, "Network error: Proxy refused authentication", + plug_closing(p->plug, "Proxy error: SOCKS proxy refused" + " password authentication", PROXY_ERROR_GENERAL, 0); return 1; } @@ -904,40 +940,66 @@ int proxy_socks5_negotiate (Proxy_Socket p, int change) * server bound address (variable) * server bound port (2 bytes) [network order] */ + char data[5]; + int len; + + /* First 5 bytes of packet are enough to tell its length. */ + if (bufchain_size(&p->pending_input_data) < 5) + return 1; /* not got anything yet */ /* get the response */ - bufchain_prefix(&p->pending_input_data, &data, &len); + bufchain_fetch(&p->pending_input_data, data, 5); if (data[0] != 5) { - plug_closing(p->plug, "Network error: Error while communicating with proxy", + plug_closing(p->plug, "Proxy error: SOCKS proxy returned wrong version number", PROXY_ERROR_GENERAL, 0); return 1; } if (data[1] != 0) { + char buf[256]; + + strcpy(buf, "Proxy error: "); switch (data[1]) { - case 1: - case 2: - case 3: - case 4: - case 5: - case 6: - case 7: - case 8: - default: - plug_closing(p->plug, "Network error: Error while communicating with proxy", - PROXY_ERROR_GENERAL, 0); + case 1: strcat(buf, "General SOCKS server failure"); break; + case 2: strcat(buf, "Connection not allowed by ruleset"); break; + case 3: strcat(buf, "Network unreachable"); break; + case 4: strcat(buf, "Host unreachable"); break; + case 5: strcat(buf, "Connection refused"); break; + case 6: strcat(buf, "TTL expired"); break; + case 7: strcat(buf, "Command not supported"); break; + case 8: strcat(buf, "Address type not supported"); break; + default: sprintf(buf+strlen(buf), + "Unrecognised SOCKS error code %d", + data[1]); break; } + plug_closing(p->plug, buf, PROXY_ERROR_GENERAL, 0); return 1; } + /* + * Eat the rest of the reply packet. + */ + len = 6; /* first 4 bytes, last 2 */ + switch (data[3]) { + case 1: len += 4; break; /* IPv4 address */ + case 4: len += 16; break;/* IPv6 address */ + case 3: len += (unsigned char)data[4]; break; /* domain name */ + default: + plug_closing(p->plug, "Proxy error: SOCKS proxy returned " + "unrecognised address format", + PROXY_ERROR_GENERAL, 0); + return 1; + } + if (bufchain_size(&p->pending_input_data) < len) + return 1; /* not got whole reply yet */ + bufchain_consume(&p->pending_input_data, len); + /* we're done */ proxy_activate(p); - /* proxy activate will have dealt with - * whatever is left of the buffer */ return 1; } -- 2.11.0