diff options
Diffstat (limited to 'src/or/buffers.c')
| -rw-r--r-- | src/or/buffers.c | 982 |
1 files changed, 4 insertions, 978 deletions
diff --git a/src/or/buffers.c b/src/or/buffers.c index bd84103c37..ef8676cd9d 100644 --- a/src/or/buffers.c +++ b/src/or/buffers.c @@ -16,23 +16,10 @@ * buffers: one for incoming data, and one for outcoming data. These are fed * and drained from functions in connection.c, trigged by events that are * monitored in main.c. - * - * This module has basic support for reading and writing on buf_t objects. It - * also contains specialized functions for handling particular protocols - * on a buf_t backend, including SOCKS (used in connection_edge.c), Tor cells - * (used in connection_or.c and channeltls.c), HTTP (used in directory.c), and - * line-oriented communication (used in control.c). **/ #define BUFFERS_PRIVATE #include "or.h" -#include "addressmap.h" #include "buffers.h" -#include "config.h" -#include "connection_edge.h" -#include "connection_or.h" -#include "control.h" -#include "reasons.h" -#include "ext_orport.h" #include "util.h" #include "torlog.h" #ifdef HAVE_UNISTD_H @@ -68,16 +55,6 @@ * forever. */ -static void socks_request_set_socks5_error(socks_request_t *req, - socks5_reply_status_t reason); - -static int parse_socks(const char *data, size_t datalen, socks_request_t *req, - int log_sockstype, int safe_socks, ssize_t *drain_out, - size_t *want_length_out); -static int parse_socks_client(const uint8_t *data, size_t datalen, - int state, char **reason, - ssize_t *drain_out); - /* Chunk manipulation functions */ #define CHUNK_HEADER_LEN offsetof(chunk_t, mem[0]) @@ -227,7 +204,7 @@ preferred_chunk_size(size_t target) * growing it as necessary, until buf->head has the first <b>bytes</b> bytes * of data from the buffer, or until buf->head has all the data in <b>buf</b>. */ -STATIC void +void buf_pullup(buf_t *buf, size_t bytes) { chunk_t *dest, *src; @@ -351,7 +328,7 @@ buf_new_with_data(const char *cp, size_t sz) #endif /** Remove the first <b>n</b> bytes from buf. */ -static inline void +void buf_remove_from_front(buf_t *buf, size_t n) { tor_assert(buf->datalen >= n); @@ -907,7 +884,7 @@ write_to_buf(const char *string, size_t string_len, buf_t *buf) /** Helper: copy the first <b>string_len</b> bytes from <b>buf</b> * onto <b>string</b>. */ -static inline void +void peek_from_buf(char *string, size_t string_len, const buf_t *buf) { chunk_t *chunk; @@ -950,79 +927,6 @@ fetch_from_buf(char *string, size_t string_len, buf_t *buf) return (int)buf->datalen; } -/** True iff the cell command <b>command</b> is one that implies a - * variable-length cell in Tor link protocol <b>linkproto</b>. */ -static inline int -cell_command_is_var_length(uint8_t command, int linkproto) -{ - /* If linkproto is v2 (2), CELL_VERSIONS is the only variable-length cells - * work as implemented here. If it's 1, there are no variable-length cells. - * Tor does not support other versions right now, and so can't negotiate - * them. - */ - switch (linkproto) { - case 1: - /* Link protocol version 1 has no variable-length cells. */ - return 0; - case 2: - /* In link protocol version 2, VERSIONS is the only variable-length cell */ - return command == CELL_VERSIONS; - case 0: - case 3: - default: - /* In link protocol version 3 and later, and in version "unknown", - * commands 128 and higher indicate variable-length. VERSIONS is - * grandfathered in. */ - return command == CELL_VERSIONS || command >= 128; - } -} - -/** Check <b>buf</b> for a variable-length cell according to the rules of link - * protocol version <b>linkproto</b>. If one is found, pull it off the buffer - * and assign a newly allocated var_cell_t to *<b>out</b>, and return 1. - * Return 0 if whatever is on the start of buf_t is not a variable-length - * cell. Return 1 and set *<b>out</b> to NULL if there seems to be the start - * of a variable-length cell on <b>buf</b>, but the whole thing isn't there - * yet. */ -int -fetch_var_cell_from_buf(buf_t *buf, var_cell_t **out, int linkproto) -{ - char hdr[VAR_CELL_MAX_HEADER_SIZE]; - var_cell_t *result; - uint8_t command; - uint16_t length; - const int wide_circ_ids = linkproto >= MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS; - const int circ_id_len = get_circ_id_size(wide_circ_ids); - const unsigned header_len = get_var_cell_header_size(wide_circ_ids); - check(); - *out = NULL; - if (buf->datalen < header_len) - return 0; - peek_from_buf(hdr, header_len, buf); - - command = get_uint8(hdr + circ_id_len); - if (!(cell_command_is_var_length(command, linkproto))) - return 0; - - length = ntohs(get_uint16(hdr + circ_id_len + 1)); - if (buf->datalen < (size_t)(header_len+length)) - return 1; - result = var_cell_new(length); - result->command = command; - if (wide_circ_ids) - result->circ_id = ntohl(get_uint32(hdr)); - else - result->circ_id = ntohs(get_uint16(hdr)); - - buf_remove_from_front(buf, header_len); - peek_from_buf((char*) result->payload, length, buf); - buf_remove_from_front(buf, length); - check(); - - *out = result; - return 1; -} - /** Move up to *<b>buf_flushlen</b> bytes from <b>buf_in</b> to * <b>buf_out</b>, and modify *<b>buf_flushlen</b> appropriately. * Return the number of bytes actually copied. @@ -1150,7 +1054,7 @@ buf_matches_at_pos(const buf_pos_t *pos, const char *s, size_t n) /** Return the first position in <b>buf</b> at which the <b>n</b>-character * string <b>s</b> occurs, or -1 if it does not occur. */ -STATIC int +int buf_find_string_offset(const buf_t *buf, const char *s, size_t n) { buf_pos_t pos; @@ -1167,868 +1071,6 @@ buf_find_string_offset(const buf_t *buf, const char *s, size_t n) return -1; } -/** - * Scan the HTTP headers in the <b>headerlen</b>-byte memory range at - * <b>headers</b>, looking for a "Content-Length" header. Try to set - * *<b>result_out</b> to the numeric value of that header if possible. - * Return -1 if the header was malformed, 0 if it was missing, and 1 if - * it was present and well-formed. - */ -STATIC int -buf_http_find_content_length(const char *headers, size_t headerlen, - size_t *result_out) -{ - const char *p, *newline; - char *len_str, *eos=NULL; - size_t remaining, result; - int ok; - *result_out = 0; /* The caller shouldn't look at this unless the - * return value is 1, but let's prevent confusion */ - -#define CONTENT_LENGTH "\r\nContent-Length: " - p = (char*) tor_memstr(headers, headerlen, CONTENT_LENGTH); - if (p == NULL) - return 0; - - tor_assert(p >= headers && p < headers+headerlen); - remaining = (headers+headerlen)-p; - p += strlen(CONTENT_LENGTH); - remaining -= strlen(CONTENT_LENGTH); - - newline = memchr(p, '\n', remaining); - if (newline == NULL) - return -1; - - len_str = tor_memdup_nulterm(p, newline-p); - /* We limit the size to INT_MAX because other parts of the buffer.c - * code don't like buffers to be any bigger than that. */ - result = (size_t) tor_parse_uint64(len_str, 10, 0, INT_MAX, &ok, &eos); - if (eos && !tor_strisspace(eos)) { - ok = 0; - } else { - *result_out = result; - } - tor_free(len_str); - - return ok ? 1 : -1; -} - -/** There is a (possibly incomplete) http statement on <b>buf</b>, of the - * form "\%s\\r\\n\\r\\n\%s", headers, body. (body may contain NULs.) - * If a) the headers include a Content-Length field and all bytes in - * the body are present, or b) there's no Content-Length field and - * all headers are present, then: - * - * - strdup headers into <b>*headers_out</b>, and NUL-terminate it. - * - memdup body into <b>*body_out</b>, and NUL-terminate it. - * - Then remove them from <b>buf</b>, and return 1. - * - * - If headers or body is NULL, discard that part of the buf. - * - If a headers or body doesn't fit in the arg, return -1. - * (We ensure that the headers or body don't exceed max len, - * _even if_ we're planning to discard them.) - * - If force_complete is true, then succeed even if not all of the - * content has arrived. - * - * Else, change nothing and return 0. - */ -int -fetch_from_buf_http(buf_t *buf, - char **headers_out, size_t max_headerlen, - char **body_out, size_t *body_used, size_t max_bodylen, - int force_complete) -{ - char *headers; - size_t headerlen, bodylen, contentlen=0; - int crlf_offset; - int r; - - check(); - if (!buf->head) - return 0; - - crlf_offset = buf_find_string_offset(buf, "\r\n\r\n", 4); - if (crlf_offset > (int)max_headerlen || - (crlf_offset < 0 && buf->datalen > max_headerlen)) { - log_debug(LD_HTTP,"headers too long."); - return -1; - } else if (crlf_offset < 0) { - log_debug(LD_HTTP,"headers not all here yet."); - return 0; - } - /* Okay, we have a full header. Make sure it all appears in the first - * chunk. */ - if ((int)buf->head->datalen < crlf_offset + 4) - buf_pullup(buf, crlf_offset+4); - headerlen = crlf_offset + 4; - - headers = buf->head->data; - bodylen = buf->datalen - headerlen; - log_debug(LD_HTTP,"headerlen %d, bodylen %d.", (int)headerlen, (int)bodylen); - - if (max_headerlen <= headerlen) { - log_warn(LD_HTTP,"headerlen %d larger than %d. Failing.", - (int)headerlen, (int)max_headerlen-1); - return -1; - } - if (max_bodylen <= bodylen) { - log_warn(LD_HTTP,"bodylen %d larger than %d. Failing.", - (int)bodylen, (int)max_bodylen-1); - return -1; - } - - r = buf_http_find_content_length(headers, headerlen, &contentlen); - if (r == -1) { - log_warn(LD_PROTOCOL, "Content-Length is bogus; maybe " - "someone is trying to crash us."); - return -1; - } else if (r == 1) { - /* if content-length is malformed, then our body length is 0. fine. */ - log_debug(LD_HTTP,"Got a contentlen of %d.",(int)contentlen); - if (bodylen < contentlen) { - if (!force_complete) { - log_debug(LD_HTTP,"body not all here yet."); - return 0; /* not all there yet */ - } - } - if (bodylen > contentlen) { - bodylen = contentlen; - log_debug(LD_HTTP,"bodylen reduced to %d.",(int)bodylen); - } - } else { - tor_assert(r == 0); - /* Leave bodylen alone */ - } - - /* all happy. copy into the appropriate places, and return 1 */ - if (headers_out) { - *headers_out = tor_malloc(headerlen+1); - fetch_from_buf(*headers_out, headerlen, buf); - (*headers_out)[headerlen] = 0; /* NUL terminate it */ - } - if (body_out) { - tor_assert(body_used); - *body_used = bodylen; - *body_out = tor_malloc(bodylen+1); - fetch_from_buf(*body_out, bodylen, buf); - (*body_out)[bodylen] = 0; /* NUL terminate it */ - } - check(); - return 1; -} - -/** - * Wait this many seconds before warning the user about using SOCKS unsafely - * again. */ -#define SOCKS_WARN_INTERVAL 5 - -/** Warn that the user application has made an unsafe socks request using - * protocol <b>socks_protocol</b> on port <b>port</b>. Don't warn more than - * once per SOCKS_WARN_INTERVAL, unless <b>safe_socks</b> is set. */ -static void -log_unsafe_socks_warning(int socks_protocol, const char *address, - uint16_t port, int safe_socks) -{ - static ratelim_t socks_ratelim = RATELIM_INIT(SOCKS_WARN_INTERVAL); - - if (safe_socks) { - log_fn_ratelim(&socks_ratelim, LOG_WARN, LD_APP, - "Your application (using socks%d to port %d) is giving " - "Tor only an IP address. Applications that do DNS resolves " - "themselves may leak information. Consider using Socks4A " - "(e.g. via privoxy or socat) instead. For more information, " - "please see https://wiki.torproject.org/TheOnionRouter/" - "TorFAQ#SOCKSAndDNS.%s", - socks_protocol, - (int)port, - safe_socks ? " Rejecting." : ""); - } - control_event_client_status(LOG_WARN, - "DANGEROUS_SOCKS PROTOCOL=SOCKS%d ADDRESS=%s:%d", - socks_protocol, address, (int)port); -} - -/** Do not attempt to parse socks messages longer than this. This value is - * actually significantly higher than the longest possible socks message. */ -#define MAX_SOCKS_MESSAGE_LEN 512 - -/** Return a new socks_request_t. */ -socks_request_t * -socks_request_new(void) -{ - return tor_malloc_zero(sizeof(socks_request_t)); -} - -/** Free all storage held in the socks_request_t <b>req</b>. */ -void -socks_request_free(socks_request_t *req) -{ - if (!req) - return; - if (req->username) { - memwipe(req->username, 0x10, req->usernamelen); - tor_free(req->username); - } - if (req->password) { - memwipe(req->password, 0x04, req->passwordlen); - tor_free(req->password); - } - memwipe(req, 0xCC, sizeof(socks_request_t)); - tor_free(req); -} - -/** There is a (possibly incomplete) socks handshake on <b>buf</b>, of one - * of the forms - * - socks4: "socksheader username\\0" - * - socks4a: "socksheader username\\0 destaddr\\0" - * - socks5 phase one: "version #methods methods" - * - socks5 phase two: "version command 0 addresstype..." - * If it's a complete and valid handshake, and destaddr fits in - * MAX_SOCKS_ADDR_LEN bytes, then pull the handshake off the buf, - * assign to <b>req</b>, and return 1. - * - * If it's invalid or too big, return -1. - * - * Else it's not all there yet, leave buf alone and return 0. - * - * If you want to specify the socks reply, write it into <b>req->reply</b> - * and set <b>req->replylen</b>, else leave <b>req->replylen</b> alone. - * - * If <b>log_sockstype</b> is non-zero, then do a notice-level log of whether - * the connection is possibly leaking DNS requests locally or not. - * - * If <b>safe_socks</b> is true, then reject unsafe socks protocols. - * - * If returning 0 or -1, <b>req->address</b> and <b>req->port</b> are - * undefined. - */ -int -fetch_from_buf_socks(buf_t *buf, socks_request_t *req, - int log_sockstype, int safe_socks) -{ - int res; - ssize_t n_drain; - size_t want_length = 128; - - if (buf->datalen < 2) /* version and another byte */ - return 0; - - do { - n_drain = 0; - buf_pullup(buf, want_length); - tor_assert(buf->head && buf->head->datalen >= 2); - want_length = 0; - - res = parse_socks(buf->head->data, buf->head->datalen, req, log_sockstype, - safe_socks, &n_drain, &want_length); - - if (n_drain < 0) - buf_clear(buf); - else if (n_drain > 0) - buf_remove_from_front(buf, n_drain); - - } while (res == 0 && buf->head && want_length < buf->datalen && - buf->datalen >= 2); - - return res; -} - -/** The size of the header of an Extended ORPort message: 2 bytes for - * COMMAND, 2 bytes for BODYLEN */ -#define EXT_OR_CMD_HEADER_SIZE 4 - -/** Read <b>buf</b>, which should contain an Extended ORPort message - * from a transport proxy. If well-formed, create and populate - * <b>out</b> with the Extended ORport message. Return 0 if the - * buffer was incomplete, 1 if it was well-formed and -1 if we - * encountered an error while parsing it. */ -int -fetch_ext_or_command_from_buf(buf_t *buf, ext_or_cmd_t **out) -{ - char hdr[EXT_OR_CMD_HEADER_SIZE]; - uint16_t len; - - check(); - if (buf->datalen < EXT_OR_CMD_HEADER_SIZE) - return 0; - peek_from_buf(hdr, sizeof(hdr), buf); - len = ntohs(get_uint16(hdr+2)); - if (buf->datalen < (unsigned)len + EXT_OR_CMD_HEADER_SIZE) - return 0; - *out = ext_or_cmd_new(len); - (*out)->cmd = ntohs(get_uint16(hdr)); - (*out)->len = len; - buf_remove_from_front(buf, EXT_OR_CMD_HEADER_SIZE); - fetch_from_buf((*out)->body, len, buf); - return 1; -} - -/** Create a SOCKS5 reply message with <b>reason</b> in its REP field and - * have Tor send it as error response to <b>req</b>. - */ -static void -socks_request_set_socks5_error(socks_request_t *req, - socks5_reply_status_t reason) -{ - req->replylen = 10; - memset(req->reply,0,10); - - req->reply[0] = 0x05; // VER field. - req->reply[1] = reason; // REP field. - req->reply[3] = 0x01; // ATYP field. -} - -static const char SOCKS_PROXY_IS_NOT_AN_HTTP_PROXY_MSG[] = - "HTTP/1.0 501 Tor is not an HTTP Proxy\r\n" - "Content-Type: text/html; charset=iso-8859-1\r\n\r\n" - "<html>\n" - "<head>\n" - "<title>Tor is not an HTTP Proxy</title>\n" - "</head>\n" - "<body>\n" - "<h1>Tor is not an HTTP Proxy</h1>\n" - "<p>\n" - "It appears you have configured your web browser to use Tor as " - "an HTTP proxy.\n\n" - "This is not correct: Tor is a SOCKS proxy, not an HTTP proxy.\n" - "Please configure your client accordingly.\n" - "</p>\n" - "<p>\n" - "See <a href=\"https://www.torproject.org/documentation.html\">" - "https://www.torproject.org/documentation.html</a> for more " - "information.\n" - "<!-- Plus this comment, to make the body response more than 512 bytes, so " - " IE will be willing to display it. Comment comment comment comment " - " comment comment comment comment comment comment comment comment.-->\n" - "</p>\n" - "</body>\n" - "</html>\n"; - -/** Implementation helper to implement fetch_from_*_socks. Instead of looking - * at a buffer's contents, we look at the <b>datalen</b> bytes of data in - * <b>data</b>. Instead of removing data from the buffer, we set - * <b>drain_out</b> to the amount of data that should be removed (or -1 if the - * buffer should be cleared). Instead of pulling more data into the first - * chunk of the buffer, we set *<b>want_length_out</b> to the number of bytes - * we'd like to see in the input buffer, if they're available. */ -static int -parse_socks(const char *data, size_t datalen, socks_request_t *req, - int log_sockstype, int safe_socks, ssize_t *drain_out, - size_t *want_length_out) -{ - unsigned int len; - char tmpbuf[TOR_ADDR_BUF_LEN+1]; - tor_addr_t destaddr; - uint32_t destip; - uint8_t socksver; - char *next, *startaddr; - unsigned char usernamelen, passlen; - struct in_addr in; - - if (datalen < 2) { - /* We always need at least 2 bytes. */ - *want_length_out = 2; - return 0; - } - - if (req->socks_version == 5 && !req->got_auth) { - /* See if we have received authentication. Strictly speaking, we should - also check whether we actually negotiated username/password - authentication. But some broken clients will send us authentication - even if we negotiated SOCKS_NO_AUTH. */ - if (*data == 1) { /* username/pass version 1 */ - /* Format is: authversion [1 byte] == 1 - usernamelen [1 byte] - username [usernamelen bytes] - passlen [1 byte] - password [passlen bytes] */ - usernamelen = (unsigned char)*(data + 1); - if (datalen < 2u + usernamelen + 1u) { - *want_length_out = 2u + usernamelen + 1u; - return 0; - } - passlen = (unsigned char)*(data + 2u + usernamelen); - if (datalen < 2u + usernamelen + 1u + passlen) { - *want_length_out = 2u + usernamelen + 1u + passlen; - return 0; - } - req->replylen = 2; /* 2 bytes of response */ - req->reply[0] = 1; /* authversion == 1 */ - req->reply[1] = 0; /* authentication successful */ - log_debug(LD_APP, - "socks5: Accepted username/password without checking."); - if (usernamelen) { - req->username = tor_memdup(data+2u, usernamelen); - req->usernamelen = usernamelen; - } - if (passlen) { - req->password = tor_memdup(data+3u+usernamelen, passlen); - req->passwordlen = passlen; - } - *drain_out = 2u + usernamelen + 1u + passlen; - req->got_auth = 1; - *want_length_out = 7; /* Minimal socks5 command. */ - return 0; - } else if (req->auth_type == SOCKS_USER_PASS) { - /* unknown version byte */ - log_warn(LD_APP, "Socks5 username/password version %d not recognized; " - "rejecting.", (int)*data); - return -1; - } - } - - socksver = *data; - - switch (socksver) { /* which version of socks? */ - case 5: /* socks5 */ - - if (req->socks_version != 5) { /* we need to negotiate a method */ - unsigned char nummethods = (unsigned char)*(data+1); - int have_user_pass, have_no_auth; - int r=0; - tor_assert(!req->socks_version); - if (datalen < 2u+nummethods) { - *want_length_out = 2u+nummethods; - return 0; - } - if (!nummethods) - return -1; - req->replylen = 2; /* 2 bytes of response */ - req->reply[0] = 5; /* socks5 reply */ - have_user_pass = (memchr(data+2, SOCKS_USER_PASS, nummethods) !=NULL); - have_no_auth = (memchr(data+2, SOCKS_NO_AUTH, nummethods) !=NULL); - if (have_user_pass && !(have_no_auth && req->socks_prefer_no_auth)) { - req->auth_type = SOCKS_USER_PASS; - req->reply[1] = SOCKS_USER_PASS; /* tell client to use "user/pass" - auth method */ - req->socks_version = 5; /* remember we've already negotiated auth */ - log_debug(LD_APP,"socks5: accepted method 2 (username/password)"); - r=0; - } else if (have_no_auth) { - req->reply[1] = SOCKS_NO_AUTH; /* tell client to use "none" auth - method */ - req->socks_version = 5; /* remember we've already negotiated auth */ - log_debug(LD_APP,"socks5: accepted method 0 (no authentication)"); - r=0; - } else { - log_warn(LD_APP, - "socks5: offered methods don't include 'no auth' or " - "username/password. Rejecting."); - req->reply[1] = '\xFF'; /* reject all methods */ - r=-1; - } - /* Remove packet from buf. Some SOCKS clients will have sent extra - * junk at this point; let's hope it's an authentication message. */ - *drain_out = 2u + nummethods; - - return r; - } - if (req->auth_type != SOCKS_NO_AUTH && !req->got_auth) { - log_warn(LD_APP, - "socks5: negotiated authentication, but none provided"); - return -1; - } - /* we know the method; read in the request */ - log_debug(LD_APP,"socks5: checking request"); - if (datalen < 7) {/* basic info plus >=1 for addr plus 2 for port */ - *want_length_out = 7; - return 0; /* not yet */ - } - req->command = (unsigned char) *(data+1); - if (req->command != SOCKS_COMMAND_CONNECT && - req->command != SOCKS_COMMAND_RESOLVE && - req->command != SOCKS_COMMAND_RESOLVE_PTR) { - /* not a connect or resolve or a resolve_ptr? we don't support it. */ - socks_request_set_socks5_error(req,SOCKS5_COMMAND_NOT_SUPPORTED); - - log_warn(LD_APP,"socks5: command %d not recognized. Rejecting.", - req->command); - return -1; - } - switch (*(data+3)) { /* address type */ - case 1: /* IPv4 address */ - case 4: /* IPv6 address */ { - const int is_v6 = *(data+3) == 4; - const unsigned addrlen = is_v6 ? 16 : 4; - log_debug(LD_APP,"socks5: ipv4 address type"); - if (datalen < 6+addrlen) {/* ip/port there? */ - *want_length_out = 6+addrlen; - return 0; /* not yet */ - } - - if (is_v6) - tor_addr_from_ipv6_bytes(&destaddr, data+4); - else - tor_addr_from_ipv4n(&destaddr, get_uint32(data+4)); - - tor_addr_to_str(tmpbuf, &destaddr, sizeof(tmpbuf), 1); - - if (strlen(tmpbuf)+1 > MAX_SOCKS_ADDR_LEN) { - socks_request_set_socks5_error(req, SOCKS5_GENERAL_ERROR); - log_warn(LD_APP, - "socks5 IP takes %d bytes, which doesn't fit in %d. " - "Rejecting.", - (int)strlen(tmpbuf)+1,(int)MAX_SOCKS_ADDR_LEN); - return -1; - } - strlcpy(req->address,tmpbuf,sizeof(req->address)); - req->port = ntohs(get_uint16(data+4+addrlen)); - *drain_out = 6+addrlen; - if (req->command != SOCKS_COMMAND_RESOLVE_PTR && - !addressmap_have_mapping(req->address,0)) { - log_unsafe_socks_warning(5, req->address, req->port, safe_socks); - if (safe_socks) { - socks_request_set_socks5_error(req, SOCKS5_NOT_ALLOWED); - return -1; - } - } - return 1; - } - case 3: /* fqdn */ - log_debug(LD_APP,"socks5: fqdn address type"); - if (req->command == SOCKS_COMMAND_RESOLVE_PTR) { - socks_request_set_socks5_error(req, - SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED); - log_warn(LD_APP, "socks5 received RESOLVE_PTR command with " - "hostname type. Rejecting."); - return -1; - } - len = (unsigned char)*(data+4); - if (datalen < 7+len) { /* addr/port there? */ - *want_length_out = 7+len; - return 0; /* not yet */ - } - if (len+1 > MAX_SOCKS_ADDR_LEN) { - socks_request_set_socks5_error(req, SOCKS5_GENERAL_ERROR); - log_warn(LD_APP, - "socks5 hostname is %d bytes, which doesn't fit in " - "%d. Rejecting.", len+1,MAX_SOCKS_ADDR_LEN); - return -1; - } - memcpy(req->address,data+5,len); - req->address[len] = 0; - req->port = ntohs(get_uint16(data+5+len)); - *drain_out = 5+len+2; - - if (!string_is_valid_hostname(req->address)) { - socks_request_set_socks5_error(req, SOCKS5_GENERAL_ERROR); - - log_warn(LD_PROTOCOL, - "Your application (using socks5 to port %d) gave Tor " - "a malformed hostname: %s. Rejecting the connection.", - req->port, escaped_safe_str_client(req->address)); - return -1; - } - if (log_sockstype) - log_notice(LD_APP, - "Your application (using socks5 to port %d) instructed " - "Tor to take care of the DNS resolution itself if " - "necessary. This is good.", req->port); - return 1; - default: /* unsupported */ - socks_request_set_socks5_error(req, - SOCKS5_ADDRESS_TYPE_NOT_SUPPORTED); - log_warn(LD_APP,"socks5: unsupported address type %d. Rejecting.", - (int) *(data+3)); - return -1; - } - tor_assert(0); - break; - case 4: { /* socks4 */ - enum {socks4, socks4a} socks4_prot = socks4a; - const char *authstart, *authend; - /* http://ss5.sourceforge.net/socks4.protocol.txt */ - /* http://ss5.sourceforge.net/socks4A.protocol.txt */ - - req->socks_version = 4; - if (datalen < SOCKS4_NETWORK_LEN) {/* basic info available? */ - *want_length_out = SOCKS4_NETWORK_LEN; - return 0; /* not yet */ - } - // buf_pullup(buf, 1280); - req->command = (unsigned char) *(data+1); - if (req->command != SOCKS_COMMAND_CONNECT && - req->command != SOCKS_COMMAND_RESOLVE) { - /* not a connect or resolve? we don't support it. (No resolve_ptr with - * socks4.) */ - log_warn(LD_APP,"socks4: command %d not recognized. Rejecting.", - req->command); - return -1; - } - - req->port = ntohs(get_uint16(data+2)); - destip = ntohl(get_uint32(data+4)); - if ((!req->port && req->command!=SOCKS_COMMAND_RESOLVE) || !destip) { - log_warn(LD_APP,"socks4: Port or DestIP is zero. Rejecting."); - return -1; - } - if (destip >> 8) { - log_debug(LD_APP,"socks4: destip not in form 0.0.0.x."); - in.s_addr = htonl(destip); - tor_inet_ntoa(&in,tmpbuf,sizeof(tmpbuf)); - if (strlen(tmpbuf)+1 > MAX_SOCKS_ADDR_LEN) { - log_debug(LD_APP,"socks4 addr (%d bytes) too long. Rejecting.", - (int)strlen(tmpbuf)); - return -1; - } - log_debug(LD_APP, - "socks4: successfully read destip (%s)", - safe_str_client(tmpbuf)); - socks4_prot = socks4; - } - - authstart = data + SOCKS4_NETWORK_LEN; - next = memchr(authstart, 0, - datalen-SOCKS4_NETWORK_LEN); - if (!next) { - if (datalen >= 1024) { - log_debug(LD_APP, "Socks4 user name too long; rejecting."); - return -1; - } - log_debug(LD_APP,"socks4: Username not here yet."); - *want_length_out = datalen+1024; /* More than we need, but safe */ - return 0; - } - authend = next; - tor_assert(next < data+datalen); - - startaddr = NULL; - if (socks4_prot != socks4a && - !addressmap_have_mapping(tmpbuf,0)) { - log_unsafe_socks_warning(4, tmpbuf, req->port, safe_socks); - - if (safe_socks) - return -1; - } - if (socks4_prot == socks4a) { - if (next+1 == data+datalen) { - log_debug(LD_APP,"socks4: No part of destaddr here yet."); - *want_length_out = datalen + 1024; /* More than we need, but safe */ - return 0; - } - startaddr = next+1; - next = memchr(startaddr, 0, data + datalen - startaddr); - if (!next) { - if (datalen >= 1024) { - log_debug(LD_APP,"socks4: Destaddr too long."); - return -1; - } - log_debug(LD_APP,"socks4: Destaddr not all here yet."); - *want_length_out = datalen + 1024; /* More than we need, but safe */ - return 0; - } - if (MAX_SOCKS_ADDR_LEN <= next-startaddr) { - log_warn(LD_APP,"socks4: Destaddr too long. Rejecting."); - return -1; - } - // tor_assert(next < buf->cur+buf->datalen); - - if (log_sockstype) - log_notice(LD_APP, - "Your application (using socks4a to port %d) instructed " - "Tor to take care of the DNS resolution itself if " - "necessary. This is good.", req->port); - } - log_debug(LD_APP,"socks4: Everything is here. Success."); - strlcpy(req->address, startaddr ? startaddr : tmpbuf, - sizeof(req->address)); - if (!string_is_valid_hostname(req->address)) { - log_warn(LD_PROTOCOL, - "Your application (using socks4 to port %d) gave Tor " - "a malformed hostname: %s. Rejecting the connection.", - req->port, escaped_safe_str_client(req->address)); - return -1; - } - if (authend != authstart) { - req->got_auth = 1; - req->usernamelen = authend - authstart; - req->username = tor_memdup(authstart, authend - authstart); - } - /* next points to the final \0 on inbuf */ - *drain_out = next - data + 1; - return 1; - } - case 'G': /* get */ - case 'H': /* head */ - case 'P': /* put/post */ - case 'C': /* connect */ - strlcpy((char*)req->reply, SOCKS_PROXY_IS_NOT_AN_HTTP_PROXY_MSG, - MAX_SOCKS_REPLY_LEN); - req->replylen = strlen((char*)req->reply)+1; - /* fall through */ - default: /* version is not socks4 or socks5 */ - log_warn(LD_APP, - "Socks version %d not recognized. (Tor is not an http proxy.)", - *(data)); - { - /* Tell the controller the first 8 bytes. */ - char *tmp = tor_strndup(data, datalen < 8 ? datalen : 8); - control_event_client_status(LOG_WARN, - "SOCKS_UNKNOWN_PROTOCOL DATA=\"%s\"", - escaped(tmp)); - tor_free(tmp); - } - return -1; - } -} - -/** Inspect a reply from SOCKS server stored in <b>buf</b> according - * to <b>state</b>, removing the protocol data upon success. Return 0 on - * incomplete response, 1 on success and -1 on error, in which case - * <b>reason</b> is set to a descriptive message (free() when finished - * with it). - * - * As a special case, 2 is returned when user/pass is required - * during SOCKS5 handshake and user/pass is configured. - */ -int -fetch_from_buf_socks_client(buf_t *buf, int state, char **reason) -{ - ssize_t drain = 0; - int r; - if (buf->datalen < 2) - return 0; - - buf_pullup(buf, MAX_SOCKS_MESSAGE_LEN); - tor_assert(buf->head && buf->head->datalen >= 2); - - r = parse_socks_client((uint8_t*)buf->head->data, buf->head->datalen, - state, reason, &drain); - if (drain > 0) - buf_remove_from_front(buf, drain); - else if (drain < 0) - buf_clear(buf); - - return r; -} - -/** Implementation logic for fetch_from_*_socks_client. */ -static int -parse_socks_client(const uint8_t *data, size_t datalen, - int state, char **reason, - ssize_t *drain_out) -{ - unsigned int addrlen; - *drain_out = 0; - if (datalen < 2) - return 0; - - switch (state) { - case PROXY_SOCKS4_WANT_CONNECT_OK: - /* Wait for the complete response */ - if (datalen < 8) - return 0; - - if (data[1] != 0x5a) { - *reason = tor_strdup(socks4_response_code_to_string(data[1])); - return -1; - } - - /* Success */ - *drain_out = 8; - return 1; - - case PROXY_SOCKS5_WANT_AUTH_METHOD_NONE: - /* we don't have any credentials */ - if (data[1] != 0x00) { - *reason = tor_strdup("server doesn't support any of our " - "available authentication methods"); - return -1; - } - - log_info(LD_NET, "SOCKS 5 client: continuing without authentication"); - *drain_out = -1; - return 1; - - case PROXY_SOCKS5_WANT_AUTH_METHOD_RFC1929: - /* we have a username and password. return 1 if we can proceed without - * providing authentication, or 2 otherwise. */ - switch (data[1]) { - case 0x00: - log_info(LD_NET, "SOCKS 5 client: we have auth details but server " - "doesn't require authentication."); - *drain_out = -1; - return 1; - case 0x02: - log_info(LD_NET, "SOCKS 5 client: need authentication."); - *drain_out = -1; - return 2; - /* fall through */ - } - - *reason = tor_strdup("server doesn't support any of our available " - "authentication methods"); - return -1; - - case PROXY_SOCKS5_WANT_AUTH_RFC1929_OK: - /* handle server reply to rfc1929 authentication */ - if (data[1] != 0x00) { - *reason = tor_strdup("authentication failed"); - return -1; - } - - log_info(LD_NET, "SOCKS 5 client: authentication successful."); - *drain_out = -1; - return 1; - - case PROXY_SOCKS5_WANT_CONNECT_OK: - /* response is variable length. BND.ADDR, etc, isn't needed - * (don't bother with buf_pullup()), but make sure to eat all - * the data used */ - - /* wait for address type field to arrive */ - if (datalen < 4) - return 0; - - switch (data[3]) { - case 0x01: /* ip4 */ - addrlen = 4; - break; - case 0x04: /* ip6 */ - addrlen = 16; - break; - case 0x03: /* fqdn (can this happen here?) */ - if (datalen < 5) - return 0; - addrlen = 1 + data[4]; - break; - default: - *reason = tor_strdup("invalid response to connect request"); - return -1; - } - - /* wait for address and port */ - if (datalen < 6 + addrlen) - return 0; - - if (data[1] != 0x00) { - *reason = tor_strdup(socks5_response_code_to_string(data[1])); - return -1; - } - - *drain_out = 6 + addrlen; - return 1; - } - - /* shouldn't get here... */ - tor_assert(0); - - return -1; -} - -/** Return true if <b>cmd</b> looks like a HTTP (proxy) request. */ -int -peek_buf_has_http_command(const buf_t *buf) -{ - if (peek_buf_startswith(buf, "CONNECT ") || - peek_buf_startswith(buf, "DELETE ") || - peek_buf_startswith(buf, "GET ") || - peek_buf_startswith(buf, "POST ") || - peek_buf_startswith(buf, "PUT " )) - return 1; - return 0; -} - /** Return 1 iff <b>buf</b> starts with <b>cmd</b>. <b>cmd</b> must be a null * terminated string, of no more than PEEK_BUF_STARTSWITH_MAX bytes. */ int @@ -2044,22 +1086,6 @@ peek_buf_startswith(const buf_t *buf, const char *cmd) return fast_memeq(tmp, cmd, clen); } -/** Return 1 iff buf looks more like it has an (obsolete) v0 controller - * command on it than any valid v1 controller command. */ -int -peek_buf_has_control0_command(buf_t *buf) -{ - if (buf->datalen >= 4) { - char header[4]; - uint16_t cmd; - peek_from_buf(header, sizeof(header), buf); - cmd = ntohs(get_uint16(header+2)); - if (cmd <= 0x14) - return 1; /* This is definitely not a v1 control command. */ - } - return 0; -} - /** Return the index within <b>buf</b> at which <b>ch</b> first appears, * or -1 if <b>ch</b> does not appear on buf. */ static off_t |