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dirmngr: Allow redirection from https to http for CRLs

* dirmngr/ks-engine.h (KS_HTTP_FETCH_NOCACHE): New flag.
(KS_HTTP_FETCH_TRUST_CFG): Ditto.
(KS_HTTP_FETCH_NO_CRL): Ditto.
(KS_HTTP_FETCH_ALLOW_DOWNGRADE): Ditto.
* dirmngr/ks-engine-http.c (ks_http_fetch): Replace args send_no_cache
and extra_http_trust_flags by a new flags arg.  Allow redirectiong
from https to http it KS_HTTP_FETCH_ALLOW_DOWNGRADE is set.
* dirmngr/loadswdb.c (fetch_file): Call with KS_HTTP_FETCH_NOCACHE.
* dirmngr/ks-action.c (ks_action_get): Ditto.
(ks_action_fetch): Ditto.
* dirmngr/crlfetch.c (crl_fetch): Call with the appropriate flags.
--

Signed-off-by: Werner Koch <wk@gnupg.org>
dkg/fix-T3995
Werner Koch 4 years ago
parent
commit
1de4462974
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
  1. 13
      dirmngr/crlfetch.c
  2. 5
      dirmngr/ks-action.c
  3. 31
      dirmngr/ks-engine-http.c
  4. 10
      dirmngr/ks-engine.h
  5. 2
      dirmngr/loadswdb.c

13
dirmngr/crlfetch.c

@ -175,11 +175,14 @@ crl_fetch (ctrl_t ctrl, const char *url, ksba_reader_t *reader)
else
{
/* Note that we also allow root certificates loaded from
* "/etc/gnupg/trusted-certs/". We also do not consult
* the CRL for the TLS connection - that may lwad to a
* loop. */
err = ks_http_fetch (ctrl, url, 0,
(HTTP_FLAG_TRUST_CFG | HTTP_FLAG_NO_CRL),
* "/etc/gnupg/trusted-certs/". We also do not consult the
* CRL for the TLS connection - that may lead to a loop.
* Due to cacert.org redirecting their https URL to http we
* also allow such a downgrade. */
err = ks_http_fetch (ctrl, url,
(KS_HTTP_FETCH_TRUST_CFG
| KS_HTTP_FETCH_NO_CRL
| KS_HTTP_FETCH_ALLOW_DOWNGRADE ),
&httpfp);
}

5
dirmngr/ks-action.c

@ -257,7 +257,8 @@ ks_action_get (ctrl_t ctrl, uri_item_t keyservers,
if (is_hkp_s)
err = ks_hkp_get (ctrl, uri->parsed_uri, sl->d, &infp);
else if (is_http_s)
err = ks_http_fetch (ctrl, uri->parsed_uri->original, 1, 0,
err = ks_http_fetch (ctrl, uri->parsed_uri->original,
KS_HTTP_FETCH_NOCACHE,
&infp);
else
BUG ();
@ -315,7 +316,7 @@ ks_action_fetch (ctrl_t ctrl, const char *url, estream_t outfp)
if (parsed_uri->is_http)
{
err = ks_http_fetch (ctrl, url, 1, 0, &infp);
err = ks_http_fetch (ctrl, url, KS_HTTP_FETCH_NOCACHE, &infp);
if (!err)
{
err = copy_stream (infp, outfp);

31
dirmngr/ks-engine-http.c

@ -67,11 +67,12 @@ ks_http_help (ctrl_t ctrl, parsed_uri_t uri)
* data via https or http.
*/
gpg_error_t
ks_http_fetch (ctrl_t ctrl, const char *url, int send_no_cache,
unsigned int extra_http_trust_flags, estream_t *r_fp)
ks_http_fetch (ctrl_t ctrl, const char *url, unsigned int flags,
estream_t *r_fp)
{
gpg_error_t err;
http_session_t session = NULL;
unsigned int session_flags;
http_t http = NULL;
int redirects_left = MAX_REDIRECTS;
estream_t fp = NULL;
@ -85,14 +86,16 @@ ks_http_fetch (ctrl_t ctrl, const char *url, int send_no_cache,
is_onion = uri->onion;
is_https = uri->use_tls;
once_more:
/* By default we only use the system provided certificates with this
* fetch command. However, EXTRA_HTTP_FLAGS can be used to add more
* flags. */
err = http_session_new (&session, NULL,
((ctrl->http_no_crl? HTTP_FLAG_NO_CRL : 0)
| HTTP_FLAG_TRUST_SYS
| extra_http_trust_flags),
* fetch command. */
session_flags = HTTP_FLAG_TRUST_SYS;
if ((flags & KS_HTTP_FETCH_NO_CRL) || ctrl->http_no_crl)
session_flags |= HTTP_FLAG_NO_CRL;
if ((flags & KS_HTTP_FETCH_TRUST_CFG))
session_flags |= HTTP_FLAG_TRUST_CFG;
once_more:
err = http_session_new (&session, NULL, session_flags,
gnupg_http_tls_verify_cb, ctrl);
if (err)
goto leave;
@ -120,7 +123,7 @@ ks_http_fetch (ctrl_t ctrl, const char *url, int send_no_cache,
/* Avoid caches to get the most recent copy of the key. We set
* both the Pragma and Cache-Control versions of the header, so
* we're good with both HTTP 1.0 and 1.1. */
if (send_no_cache)
if ((flags & KS_HTTP_FETCH_NOCACHE))
es_fputs ("Pragma: no-cache\r\n"
"Cache-Control: no-cache\r\n", fp);
http_start_data (http);
@ -172,7 +175,13 @@ ks_http_fetch (ctrl_t ctrl, const char *url, int send_no_cache,
if (err)
goto leave;
if ((is_onion && ! uri->onion) || (is_https && ! uri->use_tls))
if (is_onion && !uri->onion)
{
err = gpg_error (GPG_ERR_FORBIDDEN);
goto leave;
}
if (!(flags & KS_HTTP_FETCH_ALLOW_DOWNGRADE)
&& is_https && !uri->use_tls)
{
err = gpg_error (GPG_ERR_FORBIDDEN);
goto leave;

10
dirmngr/ks-engine.h

@ -41,9 +41,15 @@ gpg_error_t ks_hkp_put (ctrl_t ctrl, parsed_uri_t uri,
const void *data, size_t datalen);
/*-- ks-engine-http.c --*/
/* Flags for the ks_http_fetch. */
#define KS_HTTP_FETCH_NOCACHE 1 /* Request no caching. */
#define KS_HTTP_FETCH_TRUST_CFG 2 /* Requests HTTP_FLAG_TRUST_CFG. */
#define KS_HTTP_FETCH_NO_CRL 4 /* Requests HTTP_FLAG_NO_CRL. */
#define KS_HTTP_FETCH_ALLOW_DOWNGRADE 8 /* Allow redirect https -> http. */
gpg_error_t ks_http_help (ctrl_t ctrl, parsed_uri_t uri);
gpg_error_t ks_http_fetch (ctrl_t ctrl, const char *url, int send_no_cache,
unsigned int extra_http_trust_flags,
gpg_error_t ks_http_fetch (ctrl_t ctrl, const char *url, unsigned int flags,
estream_t *r_fp);

2
dirmngr/loadswdb.c

@ -126,7 +126,7 @@ fetch_file (ctrl_t ctrl, const char *url, estream_t *r_fp)
size_t nread, nwritten;
char buffer[1024];
if ((err = ks_http_fetch (ctrl, url, 1, 0, &httpfp)))
if ((err = ks_http_fetch (ctrl, url, KS_HTTP_FETCH_NOCACHE, &httpfp)))
goto leave;
/* We now read the data from the web server into a memory buffer.

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