diff options
Diffstat (limited to 'dirmngr/http.c')
| -rw-r--r-- | dirmngr/http.c | 171 |
1 files changed, 169 insertions, 2 deletions
diff --git a/dirmngr/http.c b/dirmngr/http.c index 6846107d0..d37faa87f 100644 --- a/dirmngr/http.c +++ b/dirmngr/http.c @@ -1347,6 +1347,8 @@ do_parse_uri (parsed_uri_t uri, int only_local_part, uri->v6lit = 0; uri->onion = 0; uri->explicit_port = 0; + uri->off_host = 0; + uri->off_path = 0; /* A quick validity check. */ if (strspn (p, VALID_URI_CHARS) != n) @@ -1390,7 +1392,19 @@ do_parse_uri (parsed_uri_t uri, int only_local_part, { p += 2; if ((p2 = strchr (p, '/'))) - *p2++ = 0; + { + if (p2 - uri->buffer > 10000) + return GPG_ERR_BAD_URI; + uri->off_path = p2 - uri->buffer; + *p2++ = 0; + } + else + { + n = (p - uri->buffer) + strlen (p); + if (n > 10000) + return GPG_ERR_BAD_URI; + uri->off_path = n; + } /* Check for username/password encoding */ if ((p3 = strchr (p, '@'))) @@ -1409,11 +1423,19 @@ do_parse_uri (parsed_uri_t uri, int only_local_part, *p3++ = '\0'; /* worst case, uri->host should have length 0, points to \0 */ uri->host = p + 1; + if (p - uri->buffer > 10000) + return GPG_ERR_BAD_URI; + uri->off_host = (p + 1) - uri->buffer; uri->v6lit = 1; p = p3; } else - uri->host = p; + { + uri->host = p; + if (p - uri->buffer > 10000) + return GPG_ERR_BAD_URI; + uri->off_host = p - uri->buffer; + } if ((p3 = strchr (p, ':'))) { @@ -3490,3 +3512,148 @@ uri_query_lookup (parsed_uri_t uri, const char *key) return NULL; } + + +/* Return true if both URI point to the same host. */ +static int +same_host_p (parsed_uri_t a, parsed_uri_t b) +{ + return a->host && b->host && !ascii_strcasecmp (a->host, b->host); +} + + +/* Prepare a new URL for a HTTP redirect. INFO has flags controlling + * the operaion, STATUS_CODE is used for diagnostics, LOCATION is the + * value of the "Location" header, and R_URL reveives the new URL on + * success or NULL or error. Note that INFO->ORIG_URL is + * required. */ +gpg_error_t +http_prepare_redirect (http_redir_info_t *info, unsigned int status_code, + const char *location, char **r_url) +{ + gpg_error_t err; + parsed_uri_t locuri; + parsed_uri_t origuri; + char *newurl; + char *p; + + *r_url = NULL; + + if (!info || !info->orig_url) + return gpg_error (GPG_ERR_INV_ARG); + + if (!info->silent) + log_info (_("URL '%s' redirected to '%s' (%u)\n"), + info->orig_url, location? location:"[none]", status_code); + + if (!info->redirects_left) + { + if (!info->silent) + log_error (_("too many redirections\n")); + return gpg_error (GPG_ERR_NO_DATA); + } + info->redirects_left--; + + if (!location || !*location) + return gpg_error (GPG_ERR_NO_DATA); + + err = http_parse_uri (&locuri, location, 0); + if (err) + return err; + + /* Make sure that an onion address only redirects to another + * onion address, or that a https address only redirects to a + * https address. */ + if (info->orig_onion && !locuri->onion) + { + http_release_parsed_uri (locuri); + return gpg_error (GPG_ERR_FORBIDDEN); + } + if (!info->allow_downgrade && info->orig_https && !locuri->use_tls) + { + http_release_parsed_uri (locuri); + return gpg_error (GPG_ERR_FORBIDDEN); + } + + if (info->trust_location) + { + /* We trust the Location - return it verbatim. */ + http_release_parsed_uri (locuri); + newurl = xtrystrdup (location); + if (!newurl) + { + err = gpg_error_from_syserror (); + http_release_parsed_uri (locuri); + return err; + } + } + else if ((err = http_parse_uri (&origuri, info->orig_url, 0))) + { + http_release_parsed_uri (locuri); + return err; + } + else if (same_host_p (origuri, locuri)) + { + /* The host is the same and thus we can take the location + * verbatim. */ + http_release_parsed_uri (origuri); + http_release_parsed_uri (locuri); + newurl = xtrystrdup (location); + if (!newurl) + { + err = gpg_error_from_syserror (); + http_release_parsed_uri (locuri); + return err; + } + } + else + { + /* We take only the host and port from the URL given in the + * Location. This limits the effects of redirection attacks by + * rogue hosts returning an URL to servers in the client's own + * network. We don't even include the userinfo because they + * should be considered similar to the path and query parts. + */ + if (!(locuri->off_path - locuri->off_host)) + { + http_release_parsed_uri (origuri); + http_release_parsed_uri (locuri); + return gpg_error (GPG_ERR_BAD_URI); + } + if (!(origuri->off_path - origuri->off_host)) + { + http_release_parsed_uri (origuri); + http_release_parsed_uri (locuri); + return gpg_error (GPG_ERR_BAD_URI); + } + + newurl = xtrymalloc (strlen (origuri->original) + + (locuri->off_path - locuri->off_host) + 1); + if (!newurl) + { + err = gpg_error_from_syserror (); + http_release_parsed_uri (origuri); + http_release_parsed_uri (locuri); + return err; + } + /* Build new URL from + * uriguri: scheme userinfo ---- ---- path rest + * locuri: ------ -------- host port ---- ---- + */ + p = newurl; + memcpy (p, origuri->original, origuri->off_host); + p += origuri->off_host; + memcpy (p, locuri->original + locuri->off_host, + (locuri->off_path - locuri->off_host)); + p += locuri->off_path - locuri->off_host; + strcpy (p, origuri->original + origuri->off_path); + + http_release_parsed_uri (origuri); + http_release_parsed_uri (locuri); + if (!info->silent) + log_info (_("redirection changed to '%s'\n"), newurl); + } + + *r_url = newurl; + return 0; +} |