Add ability to drop overly large packets

[onak.git] / cleankey.c

diff --git a/cleankey.c b/cleankey.c
index 7d0bfe4b8cb16315926399f395f58b2142061aad..fe24c3b6a31a7502de8554ce12bf692b3d18dbb5 100644 (file)
--- a/cleankey.c
+++ b/cleankey.c
@@ -13,8 +13,7 @@
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
- * this program; if not, write to the Free Software Foundation, Inc., 51
- * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 #include <stdbool.h>
@@ -22,11 +21,12 @@
 #include <stdlib.h>
 
 #include "cleankey.h"
+#include "keyid.h"
 #include "keystructs.h"
 #include "log.h"
 #include "mem.h"
 #include "merge.h"
-#include "onak-conf.h"
+#include "openpgp.h"
 #include "sigcheck.h"
 
 /**
@@ -73,6 +73,53 @@ int dedupuids(struct openpgp_publickey *key)
        return merged;
 }
 
+/**
+ *     dedupsubkeys - Merge duplicate subkeys on a key.
+ *     @key: The key to de-dup subkeys on.
+ *
+ *     This function attempts to merge duplicate subkeys on a key. It returns
+ *     0 if the key is unchanged, otherwise the number of dups merged.
+ */
+int dedupsubkeys(struct openpgp_publickey *key)
+{
+       struct openpgp_signedpacket_list *cursubkey = NULL;
+       struct openpgp_signedpacket_list *dup = NULL;
+       struct openpgp_signedpacket_list *tmp = NULL;
+       int                               merged = 0;
+       uint64_t                          subkeyid;
+
+       log_assert(key != NULL);
+       cursubkey = key->subkeys;
+       while (cursubkey != NULL) {
+               dup = find_signed_packet(cursubkey->next, cursubkey->packet);
+               while (dup != NULL) {
+                       get_packetid(cursubkey->packet, &subkeyid);
+                       logthing(LOGTHING_INFO,
+                               "Found duplicate subkey: 0x%016" PRIX64,
+                               subkeyid);
+                       merged++;
+                       merge_packet_sigs(cursubkey, dup);
+                       /*
+                        * Remove the duplicate uid.
+                        */
+                       tmp = cursubkey;
+                       while (tmp != NULL && tmp->next != dup) {
+                               tmp = tmp->next;
+                       }
+                       log_assert(tmp != NULL);
+                       tmp->next = dup->next;
+                       dup->next = NULL;
+                       free_signedpacket_list(dup);
+
+                       dup = find_signed_packet(cursubkey->next,
+                               cursubkey->packet);
+               }
+               cursubkey = cursubkey->next;
+       }
+
+       return merged;
+}
+
 /**
  *     check_sighashes - Check that sig hashes are correct.
  *     @key - the check to check the sig hashes of.
@@ -132,27 +179,86 @@ int clean_key_sighashes(struct openpgp_publickey *key)
        return removed;
 }
 
+#define UAT_LIMIT      0xFFFF
+#define UID_LIMIT      1024
+#define PACKET_LIMIT   8383            /* Fits in 2 byte packet length */
+int clean_large_packets(struct openpgp_publickey *key)
+{
+       struct openpgp_signedpacket_list **curuid = NULL;
+       struct openpgp_signedpacket_list *tmp = NULL;
+       bool                              drop;
+       int                               dropped = 0;
+
+       log_assert(key != NULL);
+       curuid = &key->uids;
+       while (*curuid != NULL) {
+               drop = false;
+               switch ((*curuid)->packet->tag) {
+               case OPENPGP_PACKET_UID:
+                       if ((*curuid)->packet->length > UID_LIMIT)
+                               drop = true;
+                       break;
+               case OPENPGP_PACKET_UAT:
+                       if ((*curuid)->packet->length > UAT_LIMIT)
+                               drop = true;
+                       break;
+               default:
+                       if ((*curuid)->packet->length > PACKET_LIMIT)
+                               drop = true;
+                       break;
+               }
+
+               if (drop) {
+                       logthing(LOGTHING_INFO,
+                                       "Dropping large (%d) packet, type %d",
+                                       (*curuid)->packet->length,
+                                       (*curuid)->packet->tag);
+                       /* Remove the entire large signed packet list */
+                       tmp = *curuid;
+                       *curuid = (*curuid)->next;
+                       tmp->next = NULL;
+                       free_signedpacket_list(tmp);
+                       dropped++;
+               } else {
+                       curuid = &(*curuid)->next;
+               }
+       }
+
+       return dropped;
+}
+
 /**
  *     cleankeys - Apply all available cleaning options on a list of keys.
- *     @keys: The list of keys to clean.
+ *     @policies: The cleaning policies to apply.
  *
- *     Applies all the cleaning options we can (eg duplicate key ids) to a
- *     list of keys. Returns 0 if no changes were made, otherwise the number
- *     of keys cleaned.
+ *     Applies the requested cleaning policies to a list of keys. These are
+ *     specified from the ONAK_CLEAN_* set of flags, or ONAK_CLEAN_ALL to
+ *     apply all available cleaning options. Returns 0 if no changes were
+ *     made, otherwise the number of keys cleaned. Note that some options
+ *     may result in keys being removed entirely from the list.
  */
-int cleankeys(struct openpgp_publickey *keys)
+int cleankeys(struct openpgp_publickey **keys, uint64_t policies)
 {
-       int changed = 0, count;
+       struct openpgp_publickey *curkey;
+       int changed = 0, count = 0;
 
-       while (keys != NULL) {
-               count = dedupuids(keys);
-               if (config.check_sighash) {
-                       count += clean_key_sighashes(keys);
+       if (keys == NULL)
+               return 0;
+
+       curkey = *keys;
+       while (curkey != NULL) {
+               if (policies & ONAK_CLEAN_LARGE_PACKETS) {
+                       count += clean_large_packets(curkey);
+               }
+               count += dedupuids(curkey);
+               count += dedupsubkeys(curkey);
+               if (policies & ONAK_CLEAN_CHECK_SIGHASH) {
+                       count += clean_key_sighashes(curkey);
                }
                if (count > 0) {
                        changed++;
                }
-               keys = keys->next;
+               curkey = curkey->next;
        }
 
        return changed;