lighttpd1.4/src/request.c

#include "first.h"

#include "request.h"
#include "base.h"
#include "burl.h"
#include "http_header.h"
#include "http_kv.h"
#include "log.h"
#include "sock_addr.h"

#include <limits.h>
#include <stdlib.h>
#include <string.h>

static int request_check_hostname(buffer *host) {
	enum { DOMAINLABEL, TOPLABEL } stage = TOPLABEL;
	size_t i;
	int label_len = 0;
	size_t host_len, hostport_len;
	char *colon;
	int is_ip = -1; /* -1 don't know yet, 0 no, 1 yes */
	int level = 0;

	/*
	 *       hostport      = host [ ":" port ]
	 *       host          = hostname | IPv4address | IPv6address
	 *       hostname      = *( domainlabel "." ) toplabel [ "." ]
	 *       domainlabel   = alphanum | alphanum *( alphanum | "-" ) alphanum
	 *       toplabel      = alpha | alpha *( alphanum | "-" ) alphanum
	 *       IPv4address   = 1*digit "." 1*digit "." 1*digit "." 1*digit
	 *       IPv6address   = "[" ... "]"
	 *       port          = *digit
	 */

	/* IPv6 adress */
	if (host->ptr[0] == '[') {
		char *c = host->ptr + 1;
		int colon_cnt = 0;

		/* check the address inside [...] */
		for (; *c && *c != ']'; c++) {
			if (*c == ':') {
				if (++colon_cnt > 7) {
					return -1;
				}
			} else if (!light_isxdigit(*c) && '.' != *c) {
				return -1;
			}
		}

		/* missing ] */
		if (!*c) {
			return -1;
		}

		/* check port */
		if (*(c+1) == ':') {
			for (c += 2; *c; c++) {
				if (!light_isdigit(*c)) {
					return -1;
				}
			}
		}
		else if ('\0' != *(c+1)) {
			/* only a port is allowed to follow [...] */
			return -1;
		}
		return 0;
	}

	hostport_len = host_len = buffer_string_length(host);

	if (NULL != (colon = memchr(host->ptr, ':', host_len))) {
		char *c = colon + 1;

		/* check portnumber */
		for (; *c; c++) {
			if (!light_isdigit(*c)) return -1;
		}

		/* remove the port from the host-len */
		host_len = colon - host->ptr;
	}

	/* Host is empty */
	if (host_len == 0) return -1;

	/* if the hostname ends in a "." strip it */
	if (host->ptr[host_len-1] == '.') {
		/* shift port info one left */
		if (NULL != colon) memmove(colon-1, colon, hostport_len - host_len);
		buffer_string_set_length(host, --hostport_len);
		if (--host_len == 0) return -1;
	}


	/* scan from the right and skip the \0 */
	for (i = host_len; i-- > 0; ) {
		const char c = host->ptr[i];

		switch (stage) {
		case TOPLABEL:
			if (c == '.') {
				/* only switch stage, if this is not the last character */
				if (i != host_len - 1) {
					if (label_len == 0) {
						return -1;
					}

					/* check the first character at right of the dot */
					if (is_ip == 0) {
						if (!light_isalnum(host->ptr[i+1])) {
							return -1;
						}
					} else if (!light_isdigit(host->ptr[i+1])) {
						is_ip = 0;
					} else if ('-' == host->ptr[i+1]) {
						return -1;
					} else {
						/* just digits */
						is_ip = 1;
					}

					stage = DOMAINLABEL;

					label_len = 0;
					level++;
				} else if (i == 0) {
					/* just a dot and nothing else is evil */
					return -1;
				}
			} else if (i == 0) {
				/* the first character of the hostname */
				if (!light_isalnum(c)) {
					return -1;
				}
				label_len++;
			} else {
				if (c != '-' && !light_isalnum(c)) {
					return -1;
				}
				if (is_ip == -1) {
					if (!light_isdigit(c)) is_ip = 0;
				}
				label_len++;
			}

			break;
		case DOMAINLABEL:
			if (is_ip == 1) {
				if (c == '.') {
					if (label_len == 0) {
						return -1;
					}

					label_len = 0;
					level++;
				} else if (!light_isdigit(c)) {
					return -1;
				} else {
					label_len++;
				}
			} else {
				if (c == '.') {
					if (label_len == 0) {
						return -1;
					}

					/* c is either - or alphanum here */
					if ('-' == host->ptr[i+1]) {
						return -1;
					}

					label_len = 0;
					level++;
				} else if (i == 0) {
					if (!light_isalnum(c)) {
						return -1;
					}
					label_len++;
				} else {
					if (c != '-' && !light_isalnum(c)) {
						return -1;
					}
					label_len++;
				}
			}

			break;
		}
	}

	/* a IP has to consist of 4 parts */
	if (is_ip == 1 && level != 3) {
		return -1;
	}

	if (label_len == 0) {
		return -1;
	}

	return 0;
}

int http_request_host_normalize(buffer *b, int scheme_port) {
    /*
     * check for and canonicalize numeric IP address and portnum (optional)
     * (IP address may be followed by ":portnum" (optional))
     * - IPv6: "[...]"
     * - IPv4: "x.x.x.x"
     * - IPv4: 12345678   (32-bit decimal number)
     * - IPv4: 012345678  (32-bit octal number)
     * - IPv4: 0x12345678 (32-bit hex number)
     *
     * allow any chars (except ':' and '\0' and stray '[' or ']')
     *   (other code may check chars more strictly or more pedantically)
     * ':'  delimits (optional) port at end of string
     * "[]" wraps IPv6 address literal
     * '\0' should have been rejected earlier were it present
     *
     * any chars includes, but is not limited to:
     * - allow '-' any where, even at beginning of word
     *     (security caution: might be confused for cmd flag if passed to shell)
     * - allow all-digit TLDs
     *     (might be mistaken for IPv4 addr by inet_aton()
     *      unless non-digits appear in subdomain)
     */

    /* Note: not using getaddrinfo() since it does not support "[]" around IPv6
     * and is not as lenient as inet_aton() and inet_addr() for IPv4 strings.
     * Not using inet_pton() (when available) on IPv4 for similar reasons. */

    const char * const p = b->ptr;
    const size_t blen = buffer_string_length(b);
    long port = 0;

    if (*p != '[') {
        char * const colon = (char *)memchr(p, ':', blen);
        if (colon) {
            if (*p == ':') return -1; /*(empty host then port, or naked IPv6)*/
            if (colon[1] != '\0') {
                char *e;
                port = strtol(colon+1, &e, 0); /*(allow decimal, octal, hex)*/
                if (0 < port && port <= USHRT_MAX && *e == '\0') {
                    /* valid port */
                } else {
                    return -1;
                }
            } /*(else ignore stray colon at string end)*/
            buffer_string_set_length(b, (size_t)(colon - p)); /*(remove port str)*/
        }

        if (light_isdigit(*p)) do {
            /* (IPv4 address literal or domain starting w/ digit (e.g. 3com))*/
            /* (check one-element cache of normalized IPv4 address string) */
            static struct { char s[INET_ADDRSTRLEN]; size_t n; } laddr;
            size_t n = colon ? (size_t)(colon - p) : blen;
            sock_addr addr;
            if (n == laddr.n && 0 == memcmp(p, laddr.s, n)) break;
            if (1 == sock_addr_inet_pton(&addr, p, AF_INET, 0)) {
                sock_addr_inet_ntop_copy_buffer(b, &addr);
                n = buffer_string_length(b);
                if (n < sizeof(laddr.s)) memcpy(laddr.s, b->ptr, (laddr.n = n));
            }
        } while (0);
    } else do { /* IPv6 addr */
      #if defined(HAVE_IPV6) && defined(HAVE_INET_PTON)

        /* (check one-element cache of normalized IPv4 address string) */
        static struct { char s[INET6_ADDRSTRLEN]; size_t n; } laddr;
        sock_addr addr;
        char *bracket = b->ptr+blen-1;
        char *percent = strchr(b->ptr+1, '%');
        size_t len;
        int rc;
        char buf[INET6_ADDRSTRLEN+16]; /*(+16 for potential %interface name)*/
        if (blen <= 2) return -1; /*(invalid "[]")*/
        if (*bracket != ']') {
            bracket = (char *)memchr(b->ptr+1, ']', blen-1);
            if (NULL == bracket || bracket[1] != ':'  || bracket - b->ptr == 1){
               return -1;
            }
            if (bracket[2] != '\0') { /*(ignore stray colon at string end)*/
                char *e;
                port = strtol(bracket+2, &e, 0); /*(allow decimal, octal, hex)*/
                if (0 < port && port <= USHRT_MAX && *e == '\0') {
                    /* valid port */
                } else {
                    return -1;
                }
            }
        }

        len = (size_t)((percent ? percent : bracket) - (b->ptr+1));
        if (laddr.n == len && 0 == memcmp(laddr.s, b->ptr+1, len)) {
            /* truncate after ']' and re-add normalized port, if needed */
            buffer_string_set_length(b, (size_t)(bracket - b->ptr + 1));
            break;
        }

        *bracket = '\0';/*(terminate IPv6 string)*/
        if (percent) *percent = '\0'; /*(remove %interface from address)*/
        rc = sock_addr_inet_pton(&addr, b->ptr+1, AF_INET6, 0);
        if (percent) *percent = '%'; /*(restore %interface)*/
        *bracket = ']'; /*(restore bracket)*/
        if (1 != rc) return -1;

        sock_addr_inet_ntop(&addr, buf, sizeof(buf));
        len = strlen(buf);
        if (percent) {
            if (percent > bracket) return -1;
            if (len + (size_t)(bracket - percent) >= sizeof(buf)) return -1;
            if (len < sizeof(laddr.s)) memcpy(laddr.s, buf, (laddr.n = len));
            memcpy(buf+len, percent, (size_t)(bracket - percent));
            len += (size_t)(bracket - percent);
        }
        buffer_string_set_length(b, 1); /* truncate after '[' */
        buffer_append_string_len(b, buf, len);
        buffer_append_string_len(b, CONST_STR_LEN("]"));

      #else

        return -1;

      #endif
    } while (0);

    if (0 != port && port != scheme_port) {
        buffer_append_string_len(b, CONST_STR_LEN(":"));
        buffer_append_int(b, (int)port);
    }

    return 0;
}

static int scheme_port (const buffer *scheme)
{
    return buffer_is_equal_string(scheme, CONST_STR_LEN("https")) ? 443 : 80;
}

int http_request_host_policy (connection *con, buffer *b, const buffer *scheme) {
    return (((con->conf.http_parseopts & HTTP_PARSEOPT_HOST_STRICT)
             && 0 != request_check_hostname(b))
            || ((con->conf.http_parseopts & HTTP_PARSEOPT_HOST_NORMALIZE)
                && 0 != http_request_host_normalize(b, scheme_port(scheme))));
}

static int http_request_split_value(array *vals, const char *current, size_t len) {
	int state = 0;
	const char *token_start = NULL, *token_end = NULL;
	/*
	 * parse
	 *
	 * val1, val2, val3, val4
	 *
	 * into a array (more or less a explode() incl. stripping of whitespaces
	 */

	for (size_t i = 0; i <= len; ++i, ++current) {
		switch (state) {
		case 0: /* find start of a token */
			switch (*current) {
			case ' ':
			case '\t': /* skip white space */
			case ',': /* skip empty token */
				break;
			case '\0': /* end of string */
				return 0;
			default:
				/* found real data, switch to state 1 to find the end of the token */
				token_start = token_end = current;
				state = 1;
				break;
			}
			break;
		case 1: /* find end of token and last non white space character */
			switch (*current) {
			case ' ':
			case '\t':
				/* space - don't update token_end */
				break;
			case ',':
			case '\0': /* end of string also marks the end of a token */
				array_insert_value(vals, token_start, token_end-token_start+1);
				state = 0;
				break;
			default:
				/* no white space, update token_end to include current character */
				token_end = current;
				break;
			}
			break;
		}
	}

	return 0;
}

static int request_uri_is_valid_char(unsigned char c) {
	if (c <= 32) return 0;
	if (c == 127) return 0;
	if (c == 255) return 0;

	return 1;
}

static void http_request_missing_CR_before_LF(server *srv, connection *con) {
	UNUSED(con);
	if (srv->srvconf.log_request_header_on_error) {
		log_error_write(srv, __FILE__, __LINE__, "s", "missing CR before LF in header -> 400");
	}
}

enum keep_alive_set {
	HTTP_CONNECTION_UNSET,
	HTTP_CONNECTION_KEEPALIVE,
	HTTP_CONNECTION_CLOSE,
};

typedef struct {
	enum keep_alive_set keep_alive_set;
	char con_length_set;
	char *reqline_host;
	int reqline_hostlen;
} parse_header_state;

static void init_parse_header_state(parse_header_state* state) {
	state->keep_alive_set = HTTP_CONNECTION_UNSET;
	state->con_length_set = 0;
	state->reqline_host = NULL;
	state->reqline_hostlen = 0;
}

/* add header to list of headers
 * certain headers are also parsed
 * might drop a header if deemed unnecessary/broken
 *
 * returns 0 on error
 */
static int parse_single_header(server *srv, connection *con, parse_header_state *state, char *k, size_t klen, char *v, size_t vlen) {
    const enum http_header_e id = http_header_hkey_get(k, klen);
    buffer **saveb = NULL;

    /* strip leading whitespace */
    for (; vlen > 0 && (v[0] == ' ' || v[0] == '\t'); ++v, --vlen) ;

    /* strip trailing whitespace */
    while (vlen > 0 && (v[vlen - 1] == ' ' || v[vlen - 1] == '\t')) --vlen;

    /* empty header-fields are not allowed by HTTP-RFC, we just ignore them */
    if (0 == vlen) return 1; /* ignore header */

    /*
     * Note: k might not be '\0'-terminated
     */

    switch (id) {
      /*case HTTP_HEADER_OTHER:*/
      default:
        break;
      case HTTP_HEADER_HOST:
        if (!(con->request.htags & HTTP_HEADER_HOST)) {
            saveb = &con->request.http_host;
            if (vlen >= 1024) { /*(expecting < 256)*/
                if (srv->srvconf.log_request_header_on_error) {
                    log_error_write(srv, __FILE__, __LINE__, "s", "uri-authority too long -> 400");
                }
                return 0; /* invalid header */
            }
        }
        else if (state->reqline_host) {
            /* ignore all Host: headers as we got Host in request line */
            return 1; /* ignore header */
        }
        else {
            if (srv->srvconf.log_request_header_on_error) {
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "duplicate Host-header -> 400");
            }
            return 0; /* invalid header */
        }
        break;
      case HTTP_HEADER_CONNECTION:
        {
            array * const vals = srv->split_vals;
            array_reset_data_strings(vals);
            http_request_split_value(vals, v, vlen); /* split on , */
            for (size_t vi = 0; vi < vals->used; ++vi) {
                data_string *dsv = (data_string *)vals->data[vi];
                if (0 == buffer_caseless_compare(CONST_BUF_LEN(dsv->value),
                                                 CONST_STR_LEN("keep-alive"))) {
                    state->keep_alive_set = HTTP_CONNECTION_KEEPALIVE;
                    break;
                }
                else if (0 == buffer_caseless_compare(CONST_BUF_LEN(dsv->value),
                                                      CONST_STR_LEN("close"))) {
                    state->keep_alive_set = HTTP_CONNECTION_CLOSE;
                    break;
                }
            }
        }
        break;
      case HTTP_HEADER_CONTENT_TYPE:
        if (con->request.htags & HTTP_HEADER_CONTENT_TYPE) {
            if (srv->srvconf.log_request_header_on_error) {
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "duplicate Content-Type-header -> 400");
            }
            return 0; /* invalid header */
        }
        break;
      case HTTP_HEADER_IF_NONE_MATCH:
        /* if dup, only the first one will survive */
        if (con->request.htags & HTTP_HEADER_IF_NONE_MATCH) {
            return 1; /* ignore header */
        }
        break;
      case HTTP_HEADER_CONTENT_LENGTH:
        if (!(con->request.htags & HTTP_HEADER_CONTENT_LENGTH)) {
            char *err;
            off_t r = strtoll(v, &err, 10);

            if (*err == '\0' && r >= 0) {
                con->request.content_length = r;
            }
            else {
                log_error_write(srv, __FILE__, __LINE__, "sss",
                                "content-length broken:", v, "-> 400");
                return 0; /* invalid header */
            }
        }
        else {
            if (srv->srvconf.log_request_header_on_error) {
                log_error_write(srv, __FILE__, __LINE__, "s",
                                "duplicate Content-Length-header -> 400");
            }
            return 0; /* invalid header */
        }
        break;
      case HTTP_HEADER_IF_MODIFIED_SINCE:
        if (con->request.htags & HTTP_HEADER_IF_MODIFIED_SINCE) {
            /* Proxies sometimes send dup headers
             * if they are the same we ignore the second
             * if not, we raise an error */
            buffer *vb =
              http_header_request_get(con, HTTP_HEADER_IF_MODIFIED_SINCE,
                                      CONST_STR_LEN("If-Modified-Since"));
            if (vb && buffer_is_equal_caseless_string(vb, v, vlen)) {
                /* ignore it if they are the same */
                return 1; /* ignore header */
            }
            else {
                if (srv->srvconf.log_request_header_on_error) {
                    log_error_write(srv, __FILE__, __LINE__, "s",
                                    "duplicate If-Modified-Since header -> 400");
                }
                return 0; /* invalid header */
            }
        }
        break;
    }

    con->request.htags |= id;
    http_header_request_append(con, id, k, klen, v, vlen);

    if (saveb) {
        *saveb = http_header_request_get(con, id, k, klen);
    }

    return 1;
}

static size_t http_request_parse_reqline(server *srv, connection *con, buffer *hdrs, parse_header_state *state) {
	char * const ptr = hdrs->ptr;
	char *uri = NULL, *proto = NULL, *method = NULL;
	int line = 0;

	int request_line_stage = 0;
	size_t i, first, ilen;
	const unsigned int http_header_strict = (con->conf.http_parseopts & HTTP_PARSEOPT_HEADER_STRICT);

	/*
	 * Request: "^(GET|POST|HEAD) ([^ ]+(\\?[^ ]+|)) (HTTP/1\\.[01])$"
	 * Option : "^([-a-zA-Z]+): (.+)$"
	 * End    : "^$"
	 */

	/* parse the first line of the request
	 *
	 * should be:
	 *
	 * <method> <uri> <protocol>\r\n
	 * */
	ilen = buffer_string_length(hdrs);
	for (i = 0, first = 0; i < ilen && line == 0; i++) {
		switch(ptr[i]) {
		case '\r':
			if (ptr[i+1] != '\n') break;
			/* fall through */
		case '\n':
			{
				http_method_t r;
				char *nuri = NULL;
				size_t j, jlen;

				buffer_copy_string_len(con->request.request_line, ptr, i);

				/* \r\n -> \0\0 */
				if (ptr[i] == '\r') {
					ptr[i] = '\0';
					++i;
				} else if (http_header_strict) { /* '\n' */
					http_request_missing_CR_before_LF(srv, con);
					return 0;
				}
				ptr[i] = '\0';

				if (request_line_stage != 2) {
					if (srv->srvconf.log_request_header_on_error) {
						log_error_write(srv, __FILE__, __LINE__, "s", "incomplete request line -> 400");
					}
					return 0;
				}

				proto = ptr + first;

				*(uri - 1) = '\0';
				*(proto - 1) = '\0';

				/* we got the first one :) */
				if (HTTP_METHOD_UNSET == (r = get_http_method_key(method))) {
					con->http_status = 501;

					if (srv->srvconf.log_request_header_on_error) {
						log_error_write(srv, __FILE__, __LINE__, "s", "unknown http-method -> 501");
					}

					return 0;
				}

				con->request.http_method = r;

				/*
				 * RFC2616 says:
				 *
				 * HTTP-Version   = "HTTP" "/" 1*DIGIT "." 1*DIGIT
				 *
				 * */
				if (0 == strncmp(proto, "HTTP/", sizeof("HTTP/") - 1)) {
					char * major = proto + sizeof("HTTP/") - 1;
					char * minor = strchr(major, '.');
					char *err = NULL;
					int major_num = 0, minor_num = 0;

					int invalid_version = 0;

					if (NULL == minor || /* no dot */
					    minor == major || /* no major */
					    *(minor + 1) == '\0' /* no minor */) {
						invalid_version = 1;
					} else {
						*minor = '\0';
						major_num = strtol(major, &err, 10);

						if (*err != '\0') invalid_version = 1;

						*minor++ = '.';
						minor_num = strtol(minor, &err, 10);

						if (*err != '\0') invalid_version = 1;
					}

					if (invalid_version) {
						if (srv->srvconf.log_request_header_on_error) {
							log_error_write(srv, __FILE__, __LINE__, "s", "unknown protocol -> 400");
						}
						return 0;
					}

					if (major_num == 1 && minor_num == 1) {
						con->request.http_version = con->conf.allow_http11 ? HTTP_VERSION_1_1 : HTTP_VERSION_1_0;
					} else if (major_num == 1 && minor_num == 0) {
						con->request.http_version = HTTP_VERSION_1_0;
					} else {
						con->http_status = 505;

						if (srv->srvconf.log_request_header_on_error) {
							log_error_write(srv, __FILE__, __LINE__, "s", "unknown HTTP version -> 505");
						}
						return 0;
					}
				} else {
					if (srv->srvconf.log_request_header_on_error) {
						log_error_write(srv, __FILE__, __LINE__, "s", "unknown protocol -> 400");