gpgsm: select unexpired certificates skipping expired ones

* sm/certchain.c (check_validity_period_cm):  Make function global.
* sm/certlist.c (gpgsm_add_to_certlist): If an expired certificate is
found, continue looking for another one.

--

This enables the user to select a certificate by subject, and keep
old expired certificates in the store in case he wishes to decrypt
or verify an old file. This makes renewal of certificate smoother.

Due to a broken patch I had to massage the patch and while doing this
also fixed the indentation and moved a declaration to the begin of a
block.  - wk@gnupg.org

sm/certchain.c

@@ -1433,7 +1433,7 @@ check_validity_period (ksba_isotime_t current_time,
    model.  The extra constraint here is that notBefore and notAfter
    must exists and if the additional argument CHECK_TIME is given this
    time is used to check the validity period of SUBJECT_CERT.  */
-static gpg_error_t
+gpg_error_t
 check_validity_period_cm (ksba_isotime_t current_time,
                           ksba_isotime_t check_time,
                           ksba_cert_t subject_cert,

sm/certlist.c

@@ -337,6 +337,9 @@ gpgsm_add_to_certlist (ctrl_t ctrl, const char *name, int secret,
   KEYDB_SEARCH_DESC desc;
   KEYDB_HANDLE kh = NULL;
   ksba_cert_t cert = NULL;
+  ksba_isotime_t current_time = {0, };
+  ksba_isotime_t exp_time = {0, };
+  int current_time_loaded = 0;
 
   rc = classify_user_id (name, &desc, 0);
   if (!rc)
@@ -365,10 +368,20 @@ gpgsm_add_to_certlist (ctrl_t ctrl, const char *name, int secret,
                 }
               rc = secret? gpgsm_cert_use_sign_p (cert, 0)
                          : gpgsm_cert_use_encrypt_p (cert);
+              if (!rc)
+                {
+                  if (!current_time_loaded)
+                    {
+                      gnupg_get_isotime (current_time);
+                      current_time_loaded = 1;
+                    }
+                  rc = check_validity_period_cm (current_time, current_time,
+                                                 cert, exp_time, 0, NULL, 0);
+                }
               if (gpg_err_code (rc) == GPG_ERR_WRONG_KEY_USAGE)
                 {
                   /* There might be another certificate with the
-                     correct usage, so we try again */
+                   * correct usage, so we try again */
                   if (!wrong_usage
                       || same_subject_issuer (first_subject, first_issuer,cert))
                     {
@@ -381,7 +394,13 @@ gpgsm_add_to_certlist (ctrl_t ctrl, const char *name, int secret,
                     }
                   else
                     wrong_usage = rc;
-
+                }
+              else if (gpg_err_code (rc) == GPG_ERR_CERT_EXPIRED)
+                {
+                  ksba_cert_release (cert);
+                  cert = NULL;
+                  log_info (_("looking for another certificate\n"));
+                  goto get_next;
                 }
             }
           /* We want the error code from the first match in this case. */
@@ -416,14 +435,34 @@ gpgsm_add_to_certlist (ctrl_t ctrl, const char *name, int secret,
                      keybox).  */
                   if (!keydb_get_cert (kh, &cert2))
                     {
-                      int tmp = (same_subject_issuer (first_subject,
+                      int tmp;
+
+                      if (!current_time_loaded)
+                        {
+                          gnupg_get_isotime (current_time);
+                          current_time_loaded = 1;
+                        }
+
+                      tmp =
+                        (same_subject_issuer (first_subject,
                                              first_issuer,
                                              cert2)
                          && ((gpg_err_code (
-                                      secret? gpgsm_cert_use_sign_p (cert2,0)
+                               secret? gpgsm_cert_use_sign_p (cert2, 0)
                                      : gpgsm_cert_use_encrypt_p (cert2)
                                )
-                                     )  == GPG_ERR_WRONG_KEY_USAGE));
+                              ) == GPG_ERR_WRONG_KEY_USAGE
+                             || (gpg_err_code (
+                                  check_validity_period_cm (current_time,
+                                                            current_time,
+                                                            cert,
+                                                            exp_time,
+                                                            0, NULL, 0)
+                                  ) == GPG_ERR_CERT_EXPIRED
+                                )
+                             )
+                         );
+
                       if (tmp)
                         gpgsm_add_cert_to_certlist (ctrl, cert2,
                                                     &dup_certs, 0);

sm/gpgsm.h

@@ -441,6 +441,11 @@ int gpgsm_validate_chain (ctrl_t ctrl, ksba_cert_t cert,
                           ksba_isotime_t r_exptime,
                           int listmode, estream_t listfp,
                           unsigned int flags, unsigned int *retflags);
+gpg_error_t check_validity_period_cm (ksba_isotime_t current_time,
+                          ksba_isotime_t check_time,
+                          ksba_cert_t subject_cert,
+                          ksba_isotime_t exptime,
+                          int listmode, estream_t listfp, int depth);
 int gpgsm_basic_cert_check (ctrl_t ctrl, ksba_cert_t cert);
 
 /*-- certlist.c --*/