mem-cred: Support storing a delta CRL together with its base

So far every "newer" CRL (higher serial or by date) replaced an existing
"older" CRL.  This meant that delta CRLs replaced an existing base CRL
and that base CRLs weren't added if a delta CRL was already stored.  So
the base had to be re-fetched every time after a delta CRL was added.

With this change one delta CRL to the latest base may be stored.  A newer
delta CRL will replace an existing delta CRL (but not its base, older
base CRLs are removed, though).  And a newer base will replace the existing
base and optional delta CRL.

1 files changed, 30 insertions, 8 deletions

diff --git a/src/libstrongswan/credentials/sets/mem_cred.c b/src/libstrongswan/credentials/sets/mem_cred.c
index 988e709ad..0f8bff23f 100644
--- a/src/libstrongswan/credentials/sets/mem_cred.c
+++ b/src/libstrongswan/credentials/sets/mem_cred.c
@@ -1,6 +1,7 @@
 /*
- * Copyright (C) 2010-2015 Tobias Brunner
- * Hochschule fuer Technik Rapperwsil
+ * Copyright (C) 2010-2016 Tobias Brunner
+ * HSR Hochschule fuer Technik Rapperwsil
+ *
  * Copyright (C) 2010 Martin Willi
  * Copyright (C) 2010 revosec AG
  *
@@ -223,6 +224,7 @@ METHOD(mem_cred_t, add_crl, bool,
 	{
 		if (current->get_type(current) == CERT_X509_CRL)
 		{
+			chunk_t base;
 			bool found = FALSE;
 			crl_t *crl_c = (crl_t*)current;
 			chunk_t authkey = crl->get_authKeyIdentifier(crl);
@@ -246,17 +248,37 @@ METHOD(mem_cred_t, add_crl, bool,
 			}
 			if (found)
 			{
-				new = crl_is_newer(crl, crl_c);
-				if (new)
+				/* we keep at most one delta CRL for each base CRL */
+				if (crl->is_delta_crl(crl, &base))
 				{
-					this->untrusted->remove_at(this->untrusted, enumerator);
-					current->destroy(current);
+					if (!crl_c->is_delta_crl(crl_c, NULL))
+					{
+						if (chunk_equals(base, crl_c->get_serial(crl_c)))
+						{	/* keep the added delta and the existing base CRL
+							 * but check if this is the newest delta CRL for
+							 * the same base */
+							continue;
+						}
+					}
 				}
-				else
+				else if (crl_c->is_delta_crl(crl_c, &base))
+				{
+					if (chunk_equals(base, crl->get_serial(crl)))
+					{	/* keep the existing delta and the added base CRL,
+						 * but check if we don't store it already */
+						continue;
+					}
+				}
+				new = crl_is_newer(crl, crl_c);
+				if (!new)
 				{
 					cert->destroy(cert);
+					break;
 				}
-				break;
+				/* we remove the existing older CRL but there might be other
+				 * delta or base CRLs we can replace */
+				this->untrusted->remove_at(this->untrusted, enumerator);
+				current->destroy(current);
 			}
 		}
 	}