1 files changed, 678 insertions, 0 deletions

diff --git a/src/lib-http/http-url.c b/src/lib-http/http-url.c
new file mode 100644
index 0000000..229a58a
--- /dev/null
+++ b/src/lib-http/http-url.c
@@ -0,0 +1,678 @@
+/* Copyright (c) 2013-2018 Dovecot authors, see the included COPYING file */
+
+#include "lib.h"
+#include "str.h"
+#include "strfuncs.h"
+#include "net.h"
+#include "uri-util.h"
+
+#include "http-url.h"
+#include "http-request.h"
+
+/*
+ * HTTP URL parser
+ */
+
+struct http_url_parser {
+	struct uri_parser parser;
+
+	enum http_url_parse_flags flags;
+
+	struct http_url *url;
+	struct http_url *base;
+
+	enum http_request_target_format req_format;
+
+ 	bool relative:1;
+	bool request_target:1;
+};
+
+static bool http_url_parse_authority_form(struct http_url_parser *url_parser);
+
+static bool
+http_url_parse_scheme(struct http_url_parser *url_parser, const char **scheme_r)
+{
+	struct uri_parser *parser = &url_parser->parser;
+
+	*scheme_r = NULL;
+	if ((url_parser->flags & HTTP_URL_PARSE_SCHEME_EXTERNAL) != 0)
+		return TRUE;
+
+	if (uri_parse_scheme(parser, scheme_r) <= 0) {
+		parser->cur = parser->begin;
+		return FALSE;
+	}
+
+	return TRUE;
+}
+
+static bool http_url_parse_unknown_scheme(struct http_url_parser *url_parser)
+{
+	struct uri_parser *parser = &url_parser->parser;
+
+	if (url_parser->request_target) {
+		/* Valid as non-HTTP scheme, but also try to parse as authority
+		 */
+		parser->cur = parser->begin;
+		if (!http_url_parse_authority_form(url_parser)) {
+			/* indicate non-http-url */
+			url_parser->url = NULL;
+			url_parser->req_format =
+				HTTP_REQUEST_TARGET_FORMAT_ABSOLUTE;
+		}
+		return TRUE;
+	}
+	parser->error = "Not an HTTP URL";
+	return FALSE;
+}
+
+static bool
+http_url_parse_userinfo(struct http_url_parser *url_parser,
+			struct uri_authority *auth,
+			const char **user_r, const char **password_r)
+{
+	struct uri_parser *parser = &url_parser->parser;
+	const char *p;
+
+	*user_r = *password_r = NULL;
+
+	if (auth->enc_userinfo == NULL)
+		return TRUE;
+
+	if ((url_parser->flags & HTTP_URL_ALLOW_USERINFO_PART) == 0) {
+		/* RFC 7230, Section 2.7.1: http URI Scheme
+
+		   A sender MUST NOT generate the userinfo subcomponent (and its
+		   "@" delimiter) when an "http" URI reference is generated
+		   within a message as a request target or header field value.
+		   Before making use of an "http" URI reference received from an
+		   untrusted source, a recipient SHOULD parse for userinfo and
+		   treat its presence as an error; it is likely being used to
+		   obscure the authority for the sake of phishing attacks.
+		 */
+		parser->error = "HTTP URL does not allow `userinfo@' part";
+		return FALSE;
+	}
+
+	p = strchr(auth->enc_userinfo, ':');
+	if (p == NULL) {
+		if (!uri_data_decode(parser, auth->enc_userinfo, NULL, user_r))
+			return FALSE;
+	} else {
+		if (!uri_data_decode(parser, auth->enc_userinfo, p, user_r))
+			return FALSE;
+		if (!uri_data_decode(parser, p + 1, NULL, password_r))
+			return FALSE;
+	}
+	return TRUE;
+}
+
+static bool http_url_parse_authority(struct http_url_parser *url_parser)
+{
+	struct uri_parser *parser = &url_parser->parser;
+	struct http_url *url = url_parser->url;
+	struct uri_authority auth;
+	const char *user = NULL, *password = NULL;
+	int ret;
+
+	if ((ret = uri_parse_host_authority(parser, &auth)) < 0)
+		return FALSE;
+	if (auth.host.name == NULL || *auth.host.name == '\0') {
+		/* RFC 7230, Section 2.7.1: http URI Scheme
+
+		   A sender MUST NOT generate an "http" URI with an empty host
+		   identifier.  A recipient that processes such a URI reference
+		   MUST reject it as invalid.
+		 */
+		parser->error = "HTTP URL does not allow empty host identifier";
+		return FALSE;
+	}
+	if (ret > 0) {
+		if (!http_url_parse_userinfo(url_parser, &auth,
+					     &user, &password))
+			return FALSE;
+	}
+	if (url != NULL) {
+		uri_host_copy(parser->pool, &url->host, &auth.host);
+		url->port = auth.port;
+		url->user = p_strdup(parser->pool, user);
+		url->password = p_strdup(parser->pool, password);
+	}
+	return TRUE;
+}
+
+static bool http_url_parse_authority_form(struct http_url_parser *url_parser)
+{
+	struct uri_parser *parser = &url_parser->parser;
+
+	if (!http_url_parse_authority(url_parser))
+		return FALSE;
+	if (parser->cur != parser->end)
+		return FALSE;
+	url_parser->req_format = HTTP_REQUEST_TARGET_FORMAT_AUTHORITY;
+	return TRUE;
+}
+
+static int
+http_url_parse_path(struct http_url_parser *url_parser)
+{
+	struct uri_parser *parser = &url_parser->parser;
+	struct http_url *url = url_parser->url, *base = url_parser->base;
+	const char *const *path;
+	int path_relative;
+	string_t *fullpath = NULL;
+	int ret;
+
+	/* path-abempty / path-absolute / path-noscheme / path-empty */
+	if ((ret = uri_parse_path(parser, &path_relative, &path)) < 0)
+		return -1;
+
+	/* Resolve path */
+	if (ret == 0) {
+		if (url_parser->relative && url != NULL)
+			url->path = p_strdup(parser->pool, base->path);
+		return 0;
+	}
+
+	if (url != NULL)
+		fullpath = t_str_new(256);
+
+	if (url_parser->relative && path_relative > 0 && base->path != NULL) {
+		const char *pbegin = base->path;
+		const char *pend = base->path + strlen(base->path);
+		const char *p = pend - 1;
+
+		i_assert(*pbegin == '/');
+
+		/* Discard trailing segments of base path based on how many
+		   effective leading '..' segments were found in the relative
+		   path.
+		 */
+		while (path_relative > 0 && p > pbegin) {
+			while (p > pbegin && *p != '/') p--;
+			if (p >= pbegin) {
+				pend = p;
+				path_relative--;
+			}
+			if (p > pbegin) p--;
+		}
+
+		if (url != NULL && pend > pbegin)
+			str_append_data(fullpath, pbegin, pend - pbegin);
+	}
+
+	/* Append relative path */
+	while (*path != NULL) {
+		const char *part;
+
+		if (!uri_data_decode(parser, *path, NULL, &part))
+			return -1;
+
+		if (url != NULL) {
+			str_append_c(fullpath, '/');
+			str_append(fullpath, part);
+		}
+		path++;
+	}
+
+	if (url != NULL)
+		url->path = p_strdup(parser->pool, str_c(fullpath));
+	return 1;
+}
+
+static bool
+http_url_parse_query(struct http_url_parser *url_parser, bool have_path)
+{
+	struct uri_parser *parser = &url_parser->parser;
+	struct http_url *url = url_parser->url, *base = url_parser->base;
+	const char *query;
+	int ret;
+
+	if ((ret = uri_parse_query(parser, &query)) < 0)
+		return FALSE;
+	if (url == NULL)
+		return TRUE;
+
+	if (ret > 0)
+		url->enc_query = p_strdup(parser->pool, query);
+	else if (url_parser->relative && !have_path)
+		url->enc_query = p_strdup(parser->pool, base->enc_query);
+	return TRUE;
+}
+
+static bool
+http_url_parse_fragment(struct http_url_parser *url_parser, bool have_path)
+{
+	struct uri_parser *parser = &url_parser->parser;
+	struct http_url *url = url_parser->url, *base = url_parser->base;
+	const char *fragment;
+	int ret;
+
+	if ((ret = uri_parse_fragment(parser, &fragment)) < 0)
+		return FALSE;
+	if (ret > 0 &&
+	    (url_parser->flags & HTTP_URL_ALLOW_FRAGMENT_PART) == 0) {
+		parser->error =
+			"URL fragment not allowed for HTTP URL in this context";
+		return FALSE;
+	}
+	if (url == NULL)
+		return TRUE;
+
+	if (ret > 0)
+		url->enc_fragment =  p_strdup(parser->pool, fragment);
+	else if (url_parser->relative && !have_path)
+		url->enc_fragment = p_strdup(parser->pool, base->enc_fragment);
+	return TRUE;
+}
+
+static bool http_url_do_parse(struct http_url_parser *url_parser)
+{
+	struct uri_parser *parser = &url_parser->parser;
+	struct http_url *url = url_parser->url, *base = url_parser->base;
+	bool relative = TRUE, have_scheme = FALSE, have_authority = FALSE,
+		have_path = FALSE;
+	const char *scheme;
+	int ret;
+
+	/* RFC 7230, Appendix B:
+
+	   http-URI       = "http://" authority path-abempty [ "?" query ]
+	                    [ "#" fragment ]
+	   https-URI      = "https://" authority path-abempty [ "?" query ]
+	                    [ "#" fragment ]
+	   partial-URI    = relative-part [ "?" query ]
+
+	   request-target = origin-form / absolute-form / authority-form /
+	                    asterisk-form
+
+	   origin-form    = absolute-path [ "?" query ]
+	   absolute-form  = absolute-URI
+	   authority-form = authority
+	   asterisk-form  = "*"
+	                  ; Not parsed here
+
+	   absolute-path  = 1*( "/" segment )
+
+	   RFC 3986, Appendix A: (implemented in uri-util.h)
+
+	   absolute-URI   = scheme ":" hier-part [ "?" query ]
+
+	   hier-part      = "//" authority path-abempty
+	                  / path-absolute
+	                  / path-rootless
+	                  / path-empty
+
+	   relative-part  = "//" authority path-abempty
+	                  / path-absolute
+	                  / path-noscheme
+	                  / path-empty
+
+	   authority     = [ userinfo "@" ] host [ ":" port ]
+
+	   path-abempty   = *( "/" segment )
+	   path-absolute  = "/" [ segment-nz *( "/" segment ) ]
+	   path-noscheme  = segment-nz-nc *( "/" segment )
+	   path-rootless  = segment-nz *( "/" segment )
+	   path-empty     = 0<pchar>
+
+	   segment        = *pchar
+	   segment-nz     = 1*pchar
+	   segment-nz-nc  = 1*( unreserved / pct-encoded / sub-delims / "@" )
+                    ; non-zero-length segment without any colon ":"
+
+	   query          = *( pchar / "/" / "?" )
+	   fragment       = *( pchar / "/" / "?" )
+	 */
+
+	/* "http:" / "https:" */
+	if (http_url_parse_scheme(url_parser, &scheme)) {
+		if (scheme == NULL) {
+			/* Scheme externally parsed */
+		} else if (strcasecmp(scheme, "https") == 0) {
+			if (url != NULL)
+				url->have_ssl = TRUE;
+		} else if (strcasecmp(scheme, "http") != 0) {
+			return http_url_parse_unknown_scheme(url_parser);
+		}
+
+		relative = FALSE;
+		have_scheme = TRUE;
+	}
+
+	/* "//" authority   ; or
+	 * ["//"] authority ; when parsing a request target
+	 */
+	if (parser->cur < parser->end && parser->cur[0] == '/') {
+		if ((have_scheme || !url_parser->request_target) &&
+		    (parser->cur + 1) < parser->end && parser->cur[1] == '/') {
+			parser->cur += 2;
+			relative = FALSE;
+			have_authority = TRUE;
+		} else {
+			/* start of absolute-path */
+		}
+	} else if (url_parser->request_target && !have_scheme) {
+		if (!http_url_parse_authority_form(url_parser)) {
+			/* not non-HTTP scheme and invalid as authority-form */
+			parser->error = "Request target is invalid";
+			return FALSE;
+		}
+		return TRUE;
+	}
+
+	if (have_scheme && !have_authority) {
+		parser->error = "Absolute HTTP URL requires `//' after `http:'";
+ 		return FALSE;
+	}
+
+	if (have_authority) {
+		if (!http_url_parse_authority(url_parser))
+			return FALSE;
+	}
+
+	/* Relative URLs are only valid when we have a base URL */
+	if (relative) {
+		if (base == NULL) {
+			parser->error = "Relative HTTP URL not allowed";
+			return FALSE;
+		} else if (!have_authority && url != NULL) {
+			uri_host_copy(parser->pool, &url->host, &base->host);
+			url->port = base->port;
+			url->have_ssl = base->have_ssl;
+			url->user = p_strdup_empty(parser->pool, base->user);
+			url->password = p_strdup_empty(parser->pool,
+						       base->password);
+		}
+
+		url_parser->relative = TRUE;
+	}
+
+	/* path-abempty / path-absolute / path-noscheme / path-empty */
+	ret = http_url_parse_path(url_parser);
+	if (ret < 0)
+		return FALSE;
+	have_path = (ret > 0);
+
+	/* [ "?" query ] */
+	if (!http_url_parse_query(url_parser, have_path))
+		return FALSE;
+
+	/* [ "#" fragment ] */
+	if (!http_url_parse_fragment(url_parser, have_path))
+		return FALSE;
+
+	/* must be at end of URL now */
+	i_assert(parser->cur == parser->end);
+
+	if (have_scheme)
+		url_parser->req_format = HTTP_REQUEST_TARGET_FORMAT_ABSOLUTE;
+	return TRUE;
+}
+
+/* Public API */
+
+int http_url_parse(const char *url, struct http_url *base,
+		   enum http_url_parse_flags flags, pool_t pool,
+		   struct http_url **url_r, const char **error_r)
+{
+	struct http_url_parser url_parser;
+
+	/* base != NULL indicates whether relative URLs are allowed. However,
+	   certain flags may also dictate whether relative URLs are
+	   allowed/required. */
+	i_assert((flags & HTTP_URL_PARSE_SCHEME_EXTERNAL) == 0 || base == NULL);
+
+	i_zero(&url_parser);
+	uri_parser_init(&url_parser.parser, pool, url);
+	url_parser.parser.allow_pct_nul = (flags & HTTP_URL_ALLOW_PCT_NUL) != 0;
+
+	url_parser.url = p_new(pool, struct http_url, 1);
+	url_parser.base = base;
+	url_parser.flags = flags;
+
+	if (!http_url_do_parse(&url_parser)) {
+		*error_r = url_parser.parser.error;
+		return -1;
+	}
+	*url_r = url_parser.url;
+	return 0;
+}
+
+int http_url_request_target_parse(const char *request_target,
+				  const char *host_header,
+				  const struct http_url *default_base,
+				  pool_t pool,
+				  struct http_request_target *target,
+				  const char **error_r)
+{
+	struct http_url_parser url_parser;
+	struct uri_authority auth;
+	struct http_url base;
+
+	i_zero(&base);
+	if (host_header != NULL && *host_header != '\0') {
+		struct uri_parser *parser;
+		
+		i_zero(&url_parser);
+		parser = &url_parser.parser;
+		uri_parser_init(parser, pool, host_header);
+
+		if (uri_parse_host_authority(parser, &auth) <= 0) {
+			*error_r = t_strdup_printf("Invalid Host header: %s",
+						   parser->error);
+			return -1;
+		}
+
+		if (parser->cur != parser->end || auth.enc_userinfo != NULL) {
+			*error_r = "Invalid Host header: "
+				   "Contains invalid character";
+			return -1;
+		}
+
+		base.host = auth.host;
+		base.port = auth.port;
+	} else if (default_base == NULL) {
+		*error_r = "Empty Host header";
+		return -1;
+	} else {
+		i_assert(default_base != NULL);
+		base = *default_base;
+	}
+
+	if (request_target[0] == '*' && request_target[1] == '\0') {
+		struct http_url *url = p_new(pool, struct http_url, 1);
+
+		uri_host_copy(pool, &url->host, &base.host);
+		url->port = base.port;
+		target->url = url;
+		target->format = HTTP_REQUEST_TARGET_FORMAT_ASTERISK;
+		return 0;
+	}
+
+	i_zero(&url_parser);
+	uri_parser_init(&url_parser.parser, pool, request_target);
+
+	url_parser.url = p_new(pool, struct http_url, 1);
+	url_parser.request_target = TRUE;
+	url_parser.req_format = HTTP_REQUEST_TARGET_FORMAT_ORIGIN;
+	url_parser.base = &base;
+	url_parser.flags = 0;
+
+	if (!http_url_do_parse(&url_parser)) {
+		*error_r = url_parser.parser.error;
+		return -1;
+	}
+
+	target->url = url_parser.url;
+	target->format = url_parser.req_format;
+	return 0;
+}
+
+/*
+ * HTTP URL manipulation
+ */
+
+void http_url_init_authority_from(struct http_url *dest,
+				  const struct http_url *src)
+{
+	i_zero(dest);
+	dest->host = src->host;
+	dest->port = src->port;
+	dest->have_ssl = src->have_ssl;
+}
+
+void http_url_copy_authority(pool_t pool, struct http_url *dest,
+			     const struct http_url *src)
+{
+	i_zero(dest);
+	uri_host_copy(pool, &dest->host, &src->host);
+	dest->port = src->port;
+	dest->have_ssl = src->have_ssl;
+}
+
+struct http_url *
+http_url_clone_authority(pool_t pool, const struct http_url *src)
+{
+	struct http_url *new_url;
+
+	new_url = p_new(pool, struct http_url, 1);
+	http_url_copy_authority(pool, new_url, src);
+
+	return new_url;
+}
+
+void http_url_copy(pool_t pool, struct http_url *dest,
+		   const struct http_url *src)
+{
+	http_url_copy_authority(pool, dest, src);
+	dest->path = p_strdup(pool, src->path);
+	dest->enc_query = p_strdup(pool, src->enc_query);
+	dest->enc_fragment = p_strdup(pool, src->enc_fragment);
+}
+
+void http_url_copy_with_userinfo(pool_t pool, struct http_url *dest,
+				 const struct http_url *src)
+{
+	http_url_copy(pool, dest, src);
+	dest->user = p_strdup(pool, src->user);
+	dest->password = p_strdup(pool, src->password);
+}
+
+struct http_url *http_url_clone(pool_t pool, const struct http_url *src)
+{
+	struct http_url *new_url;
+
+	new_url = p_new(pool, struct http_url, 1);
+	http_url_copy(pool, new_url, src);
+
+	return new_url;
+}
+
+struct http_url *
+http_url_clone_with_userinfo(pool_t pool, const struct http_url *src)
+{
+	struct http_url *new_url;
+
+	new_url = p_new(pool, struct http_url, 1);
+	http_url_copy_with_userinfo(pool, new_url, src);
+
+	return new_url;
+}
+
+/*
+ * HTTP URL construction
+ */
+
+static void
+http_url_add_scheme(string_t *urlstr, const struct http_url *url)
+{
+	/* scheme */
+	if (!url->have_ssl)
+		uri_append_scheme(urlstr, "http");
+	else
+		uri_append_scheme(urlstr, "https");
+	str_append(urlstr, "//");
+}
+
+static void
+http_url_add_authority(string_t *urlstr, const struct http_url *url)
+{
+	/* host */
+	uri_append_host(urlstr, &url->host);
+	/* port */
+	uri_append_port(urlstr, url->port);
+}
+
+static void
+http_url_add_target(string_t *urlstr, const struct http_url *url)
+{
+	if (url->path == NULL || *url->path == '\0') {
+		/* Older syntax of RFC 2616 requires this slash at all times for
+		   an absolute URL. */
+		str_append_c(urlstr, '/');
+	} else {
+		uri_append_path_data(urlstr, "", url->path);
+	}
+
+	/* query (pre-encoded) */
+	if (url->enc_query != NULL) {
+		str_append_c(urlstr, '?');
+		str_append(urlstr, url->enc_query);
+	}
+}
+
+const char *http_url_create(const struct http_url *url)
+{
+	string_t *urlstr = t_str_new(512);
+
+	http_url_add_scheme(urlstr, url);
+	http_url_add_authority(urlstr, url);
+	http_url_add_target(urlstr, url);
+
+	/* fragment */
+	if (url->enc_fragment != NULL) {
+		str_append_c(urlstr, '#');
+		str_append(urlstr, url->enc_fragment);
+	}
+
+	return str_c(urlstr);
+}
+
+const char *http_url_create_host(const struct http_url *url)
+{
+	string_t *urlstr = t_str_new(512);
+
+	http_url_add_scheme(urlstr, url);
+	http_url_add_authority(urlstr, url);
+
+	return str_c(urlstr);
+}
+
+const char *http_url_create_authority(const struct http_url *url)
+{
+	string_t *urlstr = t_str_new(256);
+
+	http_url_add_authority(urlstr, url);
+
+	return str_c(urlstr);
+}
+
+const char *http_url_create_target(const struct http_url *url)
+{
+	string_t *urlstr = t_str_new(256);
+
+	http_url_add_target(urlstr, url);
+
+	return str_c(urlstr);
+}
+
+void http_url_escape_path(string_t *out, const char *data)
+{
+	uri_append_query_data(out, "&;?=+", data);
+}
+
+void http_url_escape_param(string_t *out, const char *data)
+{
+	uri_append_query_data(out, "&;/?=+", data);
+}