]> the.earth.li Git - onak.git/blobdiff - cleankey.c
Add ability to drop overly large packets
[onak.git] / cleankey.c
index 4d1ec1c890424f347281f52655bbe31c248ce50c..fe24c3b6a31a7502de8554ce12bf692b3d18dbb5 100644 (file)
@@ -1,9 +1,19 @@
 /*
  * cleankey.c - Routines to look for common key problems and clean them up.
  *
- * Jonathan McDowell <noodles@earth.li>
+ * Copyright 2004,2012 Jonathan McDowell <noodles@earth.li>
  *
- * Copyright 2004 Project Purple
+ * This program is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
 #include <stdbool.h>
 #include <stdlib.h>
 
 #include "cleankey.h"
+#include "keyid.h"
 #include "keystructs.h"
+#include "log.h"
 #include "mem.h"
 #include "merge.h"
-#include "log.h"
+#include "openpgp.h"
+#include "sigcheck.h"
 
 /**
  *     dedupuids - Merge duplicate uids on a key.
@@ -60,23 +73,192 @@ 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.
+ *
+ *     Given an OpenPGP key confirm that all of the sigs on it have the
+ *     appropriate 2 octet hash beginning, as stored as part of the sig.
+ *     This is a simple way to remove junk sigs and, for example, catches
+ *     subkey sig corruption as produced by old pksd implementations.
+ *     Any sig that has an incorrect hash is removed from the key. If the
+ *     hash cannot be checked (eg we don't support that hash type) we err
+ *     on the side of caution and keep it.
+ */
+int clean_sighashes(struct openpgp_publickey *key,
+               struct openpgp_packet *sigdata,
+               struct openpgp_packet_list **sigs)
+{
+       struct openpgp_packet_list *tmpsig;
+       int removed = 0;
+
+       while (*sigs != NULL) {
+               if (check_packet_sighash(key, sigdata, (*sigs)->packet) == 0) {
+                       tmpsig = *sigs;
+                       *sigs = (*sigs)->next;
+                       tmpsig->next = NULL;
+                       free_packet_list(tmpsig);
+                       removed++;
+               } else {
+                       sigs = &(*sigs)->next;
+               }
+       }
+
+       return removed;
+}
+
+int clean_list_sighashes(struct openpgp_publickey *key,
+                       struct openpgp_signedpacket_list *siglist)
+{
+       int removed = 0;
+
+       while (siglist != NULL) {
+               removed += clean_sighashes(key, siglist->packet,
+                       &siglist->sigs);
+               siglist = siglist->next;
+       }
+
+       return removed;
+}
+
+int clean_key_sighashes(struct openpgp_publickey *key)
+{
+       int removed;
+
+       removed = clean_sighashes(key, NULL, &key->sigs);
+       removed += clean_list_sighashes(key, key->uids);
+       removed += clean_list_sighashes(key, key->subkeys);
+
+       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;
+       struct openpgp_publickey *curkey;
+       int changed = 0, count = 0;
+
+       if (keys == NULL)
+               return 0;
 
-       while (keys != NULL) {
-               if (dedupuids(keys) > 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;