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dirmngr: Implement CNAME and SRV record lookup via libdns.
* dirmngr/dns-stuff.c (dns_free): New macro. (libdns): Move var to the top. (libdns_error_to_gpg_error): Map error codes to the new gpg-error codes. (resolve_name_libdns): Restructure code. (getsrv_libdns): New. (get_dns_cname_libdns): New. Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch
parent
4a030f682e
commit
4c13e4e3de
@ -49,6 +49,12 @@
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/* William Ahern's DNS library, included as a source copy. */
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#include "dns.h"
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/* dns.c has a dns_p_free but it is not exported. We use our own
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* wrapper here so that we do not accidentally use xfree which would
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* be wrong for dns.c allocated data. */
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#define dns_free(a) free ((a))
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#ifdef WITHOUT_NPTH /* Give the Makefile a chance to build without Pth. */
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# undef USE_NPTH
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#endif
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@ -105,6 +111,16 @@ static char tor_nameserver[40+20];
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/* A string to hold the credentials presented to Tor. */
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static char tor_credentials[50];
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/* Libdns gobal data. */
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struct
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{
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struct dns_resolv_conf *resolv_conf;
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struct dns_hosts *hosts;
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struct dns_hints *hints;
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struct sockaddr_storage socks_host;
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} libdns;
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/* Calling this function with YES set to True forces the use of the
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* standard resolver even if dirmngr has been built with support for
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@ -216,34 +232,42 @@ map_eai_to_gpg_error (int ec)
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return err;
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}
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struct
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{
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struct dns_resolv_conf *resolv_conf;
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struct dns_hosts *hosts;
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struct dns_hints *hints;
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struct sockaddr_storage socks_host;
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} libdns;
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static gpg_error_t
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libdns_error_to_gpg_error (int error)
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libdns_error_to_gpg_error (int serr)
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{
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gpg_err_code_t ec;
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switch (error)
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switch (serr)
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{
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case 0:
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return 0;
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case 0: ec = 0; break;
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case DNS_ENOBUFS: ec = GPG_ERR_BUFFER_TOO_SHORT; break;
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case DNS_EILLEGAL: ec = GPG_ERR_INV_OBJ; break;
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case DNS_EORDER: ec = GPG_ERR_INV_ORDER; break;
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case DNS_ESECTION: ec = GPG_ERR_DNS_SECTION; break;
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case DNS_EUNKNOWN: ec = GPG_ERR_DNS_UNKNOWN; break;
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case DNS_EADDRESS: ec = GPG_ERR_DNS_ADDRESS; break;
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case DNS_ENOQUERY: ec = GPG_ERR_DNS_NO_QUERY; break;
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case DNS_ENOANSWER:ec = GPG_ERR_DNS_NO_ANSWER; break;
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case DNS_EFETCHED: ec = GPG_ERR_ALREADY_FETCHED; break;
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case DNS_ESERVICE: ec = GPG_ERR_NOT_SUPPORTED; break;
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case DNS_ENONAME: ec = GPG_ERR_NO_NAME; break;
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case DNS_EFAIL: ec = GPG_ERR_SERVER_FAILED; break;
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case DNS_ECONNFIN: ec = GPG_ERR_DNS_CLOSED; break;
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case DNS_EVERIFY: ec = GPG_ERR_DNS_VERIFY; break;
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default:
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/* XXX */
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fprintf (stderr, "libdns: %s\n", dns_strerror (error));
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ec = GPG_ERR_GENERAL;
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if (serr >= 0)
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ec = gpg_err_code_from_errno (serr);
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else
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ec = GPG_ERR_DNS_UNKNOWN;
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break;
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}
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return gpg_error (ec);
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}
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static gpg_error_t
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libdns_init (void)
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{
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@ -288,25 +312,25 @@ resolve_name_libdns (const char *name, unsigned short port,
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int want_family, int want_socktype,
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dns_addrinfo_t *r_dai, char **r_canonname)
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{
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gpg_error_t err = 0;
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gpg_error_t err;
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dns_addrinfo_t daihead = NULL;
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dns_addrinfo_t dai;
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struct dns_resolver *res;
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struct dns_resolver *res = NULL;
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struct dns_addrinfo *ai = NULL;
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struct addrinfo hints;
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struct addrinfo *ent;
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char portstr_[21];
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char *portstr = portstr_;
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int ret;
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err = libdns_init ();
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if (err)
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return err;
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char *portstr = NULL;
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int derr;
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*r_dai = NULL;
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if (r_canonname)
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*r_canonname = NULL;
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err = libdns_init ();
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if (err)
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goto leave;
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memset (&hints, 0, sizeof hints);
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hints.ai_family = want_family;
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hints.ai_socktype = want_socktype;
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@ -315,24 +339,52 @@ resolve_name_libdns (const char *name, unsigned short port,
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hints.ai_flags |= AI_CANONNAME;
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if (port)
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snprintf (portstr_, sizeof portstr_, "%hu", port);
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else
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portstr = NULL;
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{
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snprintf (portstr_, sizeof portstr_, "%hu", port);
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portstr = portstr_;
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}
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res = dns_res_open (libdns.resolv_conf, libdns.hosts, libdns.hints, NULL,
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dns_opts (/*.socks_host=&libdns.socks_host*/), &ret);
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if (! res)
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return libdns_error_to_gpg_error (ret);
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dns_opts (/*.socks_host=&libdns.socks_host*/), &derr);
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if (!res)
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{
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err = libdns_error_to_gpg_error (derr);
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goto leave;
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}
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ai = dns_ai_open (name, portstr, 0, &hints, res, &ret);
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if (! ai)
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goto leave;
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ai = dns_ai_open (name, portstr, 0, &hints, res, &derr);
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if (!ai)
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{
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err = libdns_error_to_gpg_error (derr);
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goto leave;
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}
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/* Loop over all records. */
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for (;;)
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{
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err = libdns_error_to_gpg_error (dns_ai_nextent (&ent, ai));
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if (gpg_err_code (err) == GPG_ERR_ENOENT)
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{
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if (daihead)
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err = 0; /* We got some results, we're good. */
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break; /* Ready. */
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}
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if (gpg_err_code (err) == GPG_ERR_EAGAIN)
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{
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if (dns_ai_elapsed (ai) > 30)
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{
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err = gpg_error (GPG_ERR_DNS_TIMEOUT);
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goto leave;
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}
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my_unprotect ();
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dns_ai_poll (ai, 1);
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my_protect ();
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continue;
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}
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if (err)
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goto leave;
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/* XXX this is blocking. */
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do {
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ret = dns_ai_nextent (&ent, ai);
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switch (ret) {
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case 0:
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if (r_canonname && ! *r_canonname && ent && ent->ai_canonname)
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{
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*r_canonname = xtrystrdup (ent->ai_canonname);
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@ -343,10 +395,10 @@ resolve_name_libdns (const char *name, unsigned short port,
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}
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}
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dai = xtrymalloc (sizeof *dai + ent->ai_addrlen - 1);
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dai = xtrymalloc (sizeof *dai + ent->ai_addrlen -1);
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if (dai == NULL)
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{
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err = ENOMEM;
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err = gpg_error_from_syserror ();
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goto leave;
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}
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@ -359,33 +411,12 @@ resolve_name_libdns (const char *name, unsigned short port,
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daihead = dai;
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xfree (ent);
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break;
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case ENOENT:
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break;
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case EAGAIN:
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if (dns_ai_elapsed (ai) > 30)
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log_assert (! "XXX: query timed-out");
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dns_ai_poll (ai, 1);
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break;
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default:
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goto leave;
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}
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} while (ret != ENOENT);
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if (ret == ENOENT && daihead != NULL)
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ret = 0; /* We got some results, we're good. */
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}
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leave:
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dns_ai_close (ai);
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dns_res_close (res);
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if (ret && ! err)
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err = libdns_error_to_gpg_error (ret);
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if (err)
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{
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if (r_canonname)
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@ -946,14 +977,123 @@ priosort(const void *a,const void *b)
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static gpg_error_t
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getsrv_libdns (const char *name, struct srventry **list, int *r_count)
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{
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return gpg_error (GPG_ERR_NOT_IMPLEMENTED);
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gpg_error_t err;
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struct dns_resolver *res = NULL;
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struct dns_packet *ans = NULL;
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struct dns_rr rr;
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struct dns_rr_i rri;
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char host[DNS_D_MAXNAME + 1];
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int derr;
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int srvcount=0;
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err = libdns_init ();
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if (err)
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goto leave;
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res = dns_res_open (libdns.resolv_conf, libdns.hosts, libdns.hints, NULL,
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dns_opts (/*.socks_host=&libdns.socks_host*/), &derr);
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if (!res)
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{
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err = libdns_error_to_gpg_error (derr);
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goto leave;
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}
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if (dns_d_anchor (host, sizeof host, name, strlen (name)) >= sizeof host)
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{
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err = gpg_error (GPG_ERR_ENAMETOOLONG);
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goto leave;
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}
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err = libdns_error_to_gpg_error
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(dns_res_submit (res, name, DNS_T_SRV, DNS_C_IN));
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if (err)
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goto leave;
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/* Loop until we found a record. */
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while ((err = libdns_error_to_gpg_error (dns_res_check (res))))
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{
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if (gpg_err_code (err) == GPG_ERR_EAGAIN)
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{
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if (dns_res_elapsed (res) > 30)
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{
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err = gpg_error (GPG_ERR_DNS_TIMEOUT);
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goto leave;
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}
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my_unprotect ();
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dns_res_poll (res, 1);
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my_protect ();
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}
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else if (err)
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goto leave;
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}
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ans = dns_res_fetch (res, &derr);
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if (!ans)
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{
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err = libdns_error_to_gpg_error (derr);
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goto leave;
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}
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/* Check the rcode. */
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switch (dns_p_rcode (ans))
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{
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case DNS_RC_NOERROR: break;
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case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
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default: err = GPG_ERR_SERVER_FAILED; break;
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}
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if (err)
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goto leave;
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memset (&rri, 0, sizeof rri);
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dns_rr_i_init (&rri, ans);
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rri.section = DNS_S_ALL & ~DNS_S_QD;
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rri.name = host;
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rri.type = DNS_T_SRV;
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while (dns_rr_grep (&rr, 1, &rri, ans, &derr))
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{
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struct dns_srv dsrv;
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struct srventry *srv;
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struct srventry *newlist;
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err = libdns_error_to_gpg_error (dns_srv_parse(&dsrv, &rr, ans));
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if (err)
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goto leave;
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newlist = xtryrealloc (*list, (srvcount+1)*sizeof(struct srventry));
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if (!newlist)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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*list = newlist;
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memset (&(*list)[srvcount], 0, sizeof(struct srventry));
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srv = &(*list)[srvcount];
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srvcount++;
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srv->priority = dsrv.priority;
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srv->weight = dsrv.weight;
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srv->port = dsrv.port;
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mem2str (srv->target, dsrv.target, sizeof srv->target);
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}
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*r_count = srvcount;
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leave:
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if (err)
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{
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xfree (*list);
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*list = NULL;
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}
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dns_free (ans);
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dns_res_close (res);
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return err;
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}
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/* Standard resolver based helper for getsrv. Note that it is
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* expected that NULL is stored at the address of LIST and 0 is stored
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* at the address of R_COUNT. */
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static int
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static gpg_error_t
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getsrv_standard (const char *name, struct srventry **list, int *r_count)
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{
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#ifdef HAVE_SYSTEM_RESOLVER
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@ -1171,11 +1311,90 @@ getsrv (const char *name, struct srventry **list)
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}
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/* libdns version of get_dns_cname. */
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gpg_error_t
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get_dns_cname_libdns (const char *name, char **r_cname)
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{
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return gpg_error (ENOTSUP);
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gpg_error_t err;
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struct dns_resolver *res = NULL;
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struct dns_packet *ans = NULL;
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struct dns_rr rr;
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struct dns_cname cname;
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int derr;
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err = libdns_init ();
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if (err)
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goto leave;
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res = dns_res_open (libdns.resolv_conf, libdns.hosts, libdns.hints, NULL,
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dns_opts (/*.socks_host=&libdns.socks_host*/), &derr);
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if (!res)
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{
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err = libdns_error_to_gpg_error (derr);
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goto leave;
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}
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err = libdns_error_to_gpg_error
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(dns_res_submit (res, name, DNS_T_CNAME, DNS_C_IN));
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if (err)
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goto leave;
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/* Loop until we found a record. */
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while ((err = libdns_error_to_gpg_error (dns_res_check (res))))
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{
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if (gpg_err_code (err) == GPG_ERR_EAGAIN)
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{
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if (dns_res_elapsed (res) > 30)
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{
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err = gpg_error (GPG_ERR_DNS_TIMEOUT);
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goto leave;
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}
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my_unprotect ();
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dns_res_poll (res, 1);
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my_protect ();
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}
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else if (err)
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goto leave;
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}
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ans = dns_res_fetch (res, &derr);
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if (!ans)
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{
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err = libdns_error_to_gpg_error (derr);
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goto leave;
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}
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/* Check the rcode. */
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switch (dns_p_rcode (ans))
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{
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case DNS_RC_NOERROR: break;
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case DNS_RC_NXDOMAIN: err = gpg_error (GPG_ERR_NO_NAME); break;
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default: err = GPG_ERR_SERVER_FAILED; break;
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}
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if (err)
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goto leave;
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/* Parse the result into CNAME. */
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err = libdns_error_to_gpg_error (dns_p_study (ans));
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if (err)
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goto leave;
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if (!dns_d_cname (&cname, sizeof cname, name, strlen (name), ans, &derr))
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{
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err = libdns_error_to_gpg_error (derr);
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goto leave;
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}
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/* Copy result. */
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*r_cname = xtrystrdup (cname.host);
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if (!*r_cname)
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err = gpg_error_from_syserror ();
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leave:
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dns_free (ans);
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dns_res_close (res);
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return err;
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}
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