Adding upstream version 2.2.27.upstream/2.2.27upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 614 insertions, 0 deletions

diff --git a/g10/key-clean.c b/g10/key-clean.c
new file mode 100644
index 0000000..f66a0db
--- /dev/null
+++ b/g10/key-clean.c
@@ -0,0 +1,614 @@
+/* key-clean.c - Functions to clean a keyblock
+ * Copyright (C) 1998-2008, 2010-2011 Free Software Foundation, Inc.
+ * Copyright (C) 2014, 2016-2018  Werner Koch
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG 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; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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/>.
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "gpg.h"
+#include "keydb.h"
+#include "../common/util.h"
+#include "../common/host2net.h"
+#include "../common/i18n.h"
+#include "options.h"
+#include "packet.h"
+#include "main.h"
+#include "key-clean.h"
+
+
+/*
+ * Mark the signature of the given UID which are used to certify it.
+ * To do this, we first revmove all signatures which are not valid and
+ * from the remain ones we look for the latest one.  If this is not a
+ * certification revocation signature we mark the signature by setting
+ * node flag bit 8.  Revocations are marked with flag 11, and sigs
+ * from unavailable keys are marked with flag 12.  Note that flag bits
+ * 9 and 10 are used for internal purposes.
+ */
+void
+mark_usable_uid_certs (ctrl_t ctrl, kbnode_t keyblock, kbnode_t uidnode,
+                       u32 *main_kid, struct key_item *klist,
+                       u32 curtime, u32 *next_expire)
+{
+  kbnode_t node;
+  PKT_signature *sig;
+
+  /* First check all signatures.  */
+  for (node=uidnode->next; node; node = node->next)
+    {
+      int rc;
+
+      node->flag &= ~(1<<8 | 1<<9 | 1<<10 | 1<<11 | 1<<12);
+      if (node->pkt->pkttype == PKT_USER_ID
+          || node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+          || node->pkt->pkttype == PKT_SECRET_SUBKEY)
+        break; /* ready */
+      if (node->pkt->pkttype != PKT_SIGNATURE)
+        continue;
+      sig = node->pkt->pkt.signature;
+      if (main_kid
+	  && sig->keyid[0] == main_kid[0] && sig->keyid[1] == main_kid[1])
+        continue; /* ignore self-signatures if we pass in a main_kid */
+      if (!IS_UID_SIG(sig) && !IS_UID_REV(sig))
+        continue; /* we only look at these signature classes */
+      if(sig->sig_class>=0x11 && sig->sig_class<=0x13 &&
+	 sig->sig_class-0x10<opt.min_cert_level)
+	continue; /* treat anything under our min_cert_level as an
+		     invalid signature */
+      if (klist && !is_in_klist (klist, sig))
+        continue;  /* no need to check it then */
+      if ((rc=check_key_signature (ctrl, keyblock, node, NULL)))
+	{
+	  /* we ignore anything that won't verify, but tag the
+	     no_pubkey case */
+	  if (gpg_err_code (rc) == GPG_ERR_NO_PUBKEY)
+            node->flag |= 1<<12;
+          continue;
+        }
+      node->flag |= 1<<9;
+    }
+  /* Reset the remaining flags. */
+  for (; node; node = node->next)
+    node->flag &= ~(1<<8 | 1<<9 | 1<<10 | 1<<11 | 1<<12);
+
+  /* kbnode flag usage: bit 9 is here set for signatures to consider,
+   * bit 10 will be set by the loop to keep track of keyIDs already
+   * processed, bit 8 will be set for the usable signatures, and bit
+   * 11 will be set for usable revocations. */
+
+  /* For each cert figure out the latest valid one.  */
+  for (node=uidnode->next; node; node = node->next)
+    {
+      KBNODE n, signode;
+      u32 kid[2];
+      u32 sigdate;
+
+      if (node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+          || node->pkt->pkttype == PKT_SECRET_SUBKEY)
+        break;
+      if ( !(node->flag & (1<<9)) )
+        continue; /* not a node to look at */
+      if ( (node->flag & (1<<10)) )
+        continue; /* signature with a keyID already processed */
+      node->flag |= (1<<10); /* mark this node as processed */
+      sig = node->pkt->pkt.signature;
+      signode = node;
+      sigdate = sig->timestamp;
+      kid[0] = sig->keyid[0]; kid[1] = sig->keyid[1];
+
+      /* Now find the latest and greatest signature */
+      for (n=uidnode->next; n; n = n->next)
+        {
+          if (n->pkt->pkttype == PKT_PUBLIC_SUBKEY
+              || n->pkt->pkttype == PKT_SECRET_SUBKEY)
+            break;
+          if ( !(n->flag & (1<<9)) )
+            continue;
+          if ( (n->flag & (1<<10)) )
+            continue; /* shortcut already processed signatures */
+          sig = n->pkt->pkt.signature;
+          if (kid[0] != sig->keyid[0] || kid[1] != sig->keyid[1])
+            continue;
+          n->flag |= (1<<10); /* mark this node as processed */
+
+	  /* If signode is nonrevocable and unexpired and n isn't,
+             then take signode (skip).  It doesn't matter which is
+             older: if signode was older then we don't want to take n
+             as signode is nonrevocable.  If n was older then we're
+             automatically fine. */
+
+	  if(((IS_UID_SIG(signode->pkt->pkt.signature) &&
+	       !signode->pkt->pkt.signature->flags.revocable &&
+	       (signode->pkt->pkt.signature->expiredate==0 ||
+		signode->pkt->pkt.signature->expiredate>curtime))) &&
+	     (!(IS_UID_SIG(n->pkt->pkt.signature) &&
+		!n->pkt->pkt.signature->flags.revocable &&
+		(n->pkt->pkt.signature->expiredate==0 ||
+		 n->pkt->pkt.signature->expiredate>curtime))))
+	    continue;
+
+	  /* If n is nonrevocable and unexpired and signode isn't,
+             then take n.  Again, it doesn't matter which is older: if
+             n was older then we don't want to take signode as n is
+             nonrevocable.  If signode was older then we're
+             automatically fine. */
+
+	  if((!(IS_UID_SIG(signode->pkt->pkt.signature) &&
+		!signode->pkt->pkt.signature->flags.revocable &&
+		(signode->pkt->pkt.signature->expiredate==0 ||
+		 signode->pkt->pkt.signature->expiredate>curtime))) &&
+	     ((IS_UID_SIG(n->pkt->pkt.signature) &&
+	       !n->pkt->pkt.signature->flags.revocable &&
+	       (n->pkt->pkt.signature->expiredate==0 ||
+		n->pkt->pkt.signature->expiredate>curtime))))
+            {
+              signode = n;
+              sigdate = sig->timestamp;
+	      continue;
+            }
+
+	  /* At this point, if it's newer, it goes in as the only
+             remaining possibilities are signode and n are both either
+             revocable or expired or both nonrevocable and unexpired.
+             If the timestamps are equal take the later ordered
+             packet, presuming that the key packets are hopefully in
+             their original order. */
+
+          if (sig->timestamp >= sigdate)
+            {
+              signode = n;
+              sigdate = sig->timestamp;
+            }
+        }
+
+      sig = signode->pkt->pkt.signature;
+      if (IS_UID_SIG (sig))
+        { /* this seems to be a usable one which is not revoked.
+           * Just need to check whether there is an expiration time,
+           * We do the expired certification after finding a suitable
+           * certification, the assumption is that a signator does not
+           * want that after the expiration of his certificate the
+           * system falls back to an older certification which has a
+           * different expiration time */
+          const byte *p;
+          u32 expire;
+
+          p = parse_sig_subpkt (sig->hashed, SIGSUBPKT_SIG_EXPIRE, NULL );
+          expire = p? sig->timestamp + buf32_to_u32(p) : 0;
+
+          if (expire==0 || expire > curtime )
+            {
+              signode->flag |= (1<<8); /* yeah, found a good cert */
+              if (next_expire && expire && expire < *next_expire)
+                *next_expire = expire;
+            }
+        }
+      else
+	signode->flag |= (1<<11);
+    }
+}
+
+
+static int
+clean_sigs_from_uid (ctrl_t ctrl, kbnode_t keyblock, kbnode_t uidnode,
+                     int noisy, int self_only)
+{
+  int deleted = 0;
+  kbnode_t node;
+  u32 keyid[2];
+
+  log_assert (keyblock->pkt->pkttype == PKT_PUBLIC_KEY
+              || keyblock->pkt->pkttype == PKT_SECRET_KEY);
+
+  keyid_from_pk (keyblock->pkt->pkt.public_key, keyid);
+
+  /* Passing in a 0 for current time here means that we'll never weed
+     out an expired sig.  This is correct behavior since we want to
+     keep the most recent expired sig in a series. */
+  mark_usable_uid_certs (ctrl, keyblock, uidnode, NULL, NULL, 0, NULL);
+
+  /* What we want to do here is remove signatures that are not
+     considered as part of the trust calculations.  Thus, all invalid
+     signatures are out, as are any signatures that aren't the last of
+     a series of uid sigs or revocations It breaks down like this:
+     coming out of mark_usable_uid_certs, if a sig is unflagged, it is
+     not even a candidate.  If a sig has flag 9 or 10, that means it
+     was selected as a candidate and vetted.  If a sig has flag 8 it
+     is a usable signature.  If a sig has flag 11 it is a usable
+     revocation.  If a sig has flag 12 it was issued by an unavailable
+     key.  "Usable" here means the most recent valid
+     signature/revocation in a series from a particular signer.
+
+     Delete everything that isn't a usable uid sig (which might be
+     expired), a usable revocation, or a sig from an unavailable
+     key. */
+
+  for (node=uidnode->next;
+       node && node->pkt->pkttype==PKT_SIGNATURE;
+       node=node->next)
+    {
+      int keep;
+
+      keep = self_only? (node->pkt->pkt.signature->keyid[0] == keyid[0]
+                         && node->pkt->pkt.signature->keyid[1] == keyid[1]) : 1;
+
+      /* Keep usable uid sigs ... */
+      if ((node->flag & (1<<8)) && keep)
+	continue;
+
+      /* ... and usable revocations... */
+      if ((node->flag & (1<<11)) && keep)
+	continue;
+
+      /* ... and sigs from unavailable keys. */
+      /* disabled for now since more people seem to want sigs from
+	 unavailable keys removed altogether.  */
+      /*
+	if(node->flag & (1<<12))
+	continue;
+      */
+
+      /* Everything else we delete */
+
+      /* At this point, if 12 is set, the signing key was unavailable.
+	 If 9 or 10 is set, it's superseded.  Otherwise, it's
+	 invalid. */
+
+      if (noisy)
+	log_info ("removing signature from key %s on user ID \"%s\": %s\n",
+                  keystr (node->pkt->pkt.signature->keyid),
+                  uidnode->pkt->pkt.user_id->name,
+                  node->flag&(1<<12)? "key unavailable":
+                  node->flag&(1<<9)?  "signature superseded"
+                  /* */               :"invalid signature"  );
+
+      delete_kbnode (node);
+      deleted++;
+    }
+
+  return deleted;
+}
+
+
+/* This is substantially easier than clean_sigs_from_uid since we just
+   have to establish if the uid has a valid self-sig, is not revoked,
+   and is not expired.  Note that this does not take into account
+   whether the uid has a trust path to it - just whether the keyholder
+   themselves has certified the uid.  Returns true if the uid was
+   compacted.  To "compact" a user ID, we simply remove ALL signatures
+   except the self-sig that caused the user ID to be remove-worthy.
+   We don't actually remove the user ID packet itself since it might
+   be resurrected in a later merge.  Note that this function requires
+   that the caller has already done a merge_keys_and_selfsig().
+
+   TODO: change the import code to allow importing a uid with only a
+   revocation if the uid already exists on the keyring. */
+
+static int
+clean_uid_from_key (kbnode_t keyblock, kbnode_t uidnode, int noisy)
+{
+  kbnode_t node;
+  PKT_user_id *uid = uidnode->pkt->pkt.user_id;
+  int deleted = 0;
+
+  log_assert (keyblock->pkt->pkttype == PKT_PUBLIC_KEY
+              || keyblock->pkt->pkttype == PKT_SECRET_KEY);
+  log_assert (uidnode->pkt->pkttype==PKT_USER_ID);
+
+  /* Skip valid user IDs, compacted user IDs, and non-self-signed user
+     IDs if --allow-non-selfsigned-uid is set. */
+  if (uid->created
+      || uid->flags.compacted
+      || (!uid->flags.expired && !uid->flags.revoked && opt.allow_non_selfsigned_uid))
+    return 0;
+
+  for (node=uidnode->next;
+       node && node->pkt->pkttype == PKT_SIGNATURE;
+      node=node->next)
+    {
+      if (!node->pkt->pkt.signature->flags.chosen_selfsig)
+        {
+          delete_kbnode (node);
+          deleted = 1;
+          uidnode->pkt->pkt.user_id->flags.compacted = 1;
+        }
+    }
+
+  if (noisy)
+    {
+      const char *reason;
+      char *user = utf8_to_native (uid->name, uid->len, 0);
+
+      if (uid->flags.revoked)
+	reason = _("revoked");
+      else if (uid->flags.expired)
+	reason = _("expired");
+      else
+	reason = _("invalid");
+
+      log_info ("compacting user ID \"%s\" on key %s: %s\n",
+                user, keystr_from_pk (keyblock->pkt->pkt.public_key),
+                reason);
+
+      xfree (user);
+    }
+
+  return deleted;
+}
+
+
+/* Needs to be called after a merge_keys_and_selfsig() */
+void
+clean_one_uid (ctrl_t ctrl, kbnode_t keyblock, kbnode_t uidnode,
+               int noisy, int self_only, int *uids_cleaned, int *sigs_cleaned)
+{
+  int dummy = 0;
+
+  log_assert (keyblock->pkt->pkttype == PKT_PUBLIC_KEY
+              || keyblock->pkt->pkttype == PKT_SECRET_KEY);
+  log_assert (uidnode->pkt->pkttype==PKT_USER_ID);
+
+  if (!uids_cleaned)
+    uids_cleaned = &dummy;
+
+  if (!sigs_cleaned)
+    sigs_cleaned = &dummy;
+
+  /* Do clean_uid_from_key first since if it fires off, we don't have
+     to bother with the other.  */
+  *uids_cleaned += clean_uid_from_key (keyblock, uidnode, noisy);
+  if (!uidnode->pkt->pkt.user_id->flags.compacted)
+    *sigs_cleaned += clean_sigs_from_uid (ctrl, keyblock, uidnode,
+                                          noisy, self_only);
+}
+
+
+/* NB: This function marks the deleted nodes only and the caller is
+ * responsible to skip or remove them.  Needs to be called after a
+ * merge_keys_and_selfsig().  */
+void
+clean_all_uids (ctrl_t ctrl, kbnode_t keyblock, int noisy, int self_only,
+                int *uids_cleaned, int *sigs_cleaned)
+{
+  kbnode_t node;
+
+  for (node = keyblock->next;
+       node && !(node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+                    || node->pkt->pkttype == PKT_SECRET_SUBKEY);
+       node = node->next)
+    {
+      if (node->pkt->pkttype == PKT_USER_ID)
+        clean_one_uid (ctrl, keyblock, node, noisy, self_only,
+                       uids_cleaned, sigs_cleaned);
+    }
+
+  /* Remove bogus subkey binding signatures: The only signatures
+   * allowed are of class 0x18 and 0x28.  */
+  log_assert (!node || (node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+                        || node->pkt->pkttype == PKT_SECRET_SUBKEY));
+}
+
+
+/* Helper for clean_all_subkeys.  */
+static int
+clean_one_subkey (ctrl_t ctrl, kbnode_t subkeynode, int noisy, int clean_level)
+{
+  kbnode_t node;
+  PKT_public_key *pk = subkeynode->pkt->pkt.public_key;
+  unsigned int use = pk->pubkey_usage;
+  int do_clean = 0;
+
+  (void)ctrl;
+  (void)noisy;
+
+  log_assert (subkeynode->pkt->pkttype == PKT_PUBLIC_SUBKEY
+              || subkeynode->pkt->pkttype == PKT_SECRET_SUBKEY);
+
+  if (DBG_LOOKUP)
+    log_debug ("\tchecking subkey %08lX [%c%c%c%c%c]\n",
+               (ulong) keyid_from_pk (pk, NULL),
+               (use & PUBKEY_USAGE_ENC)? 'e':'-',
+               (use & PUBKEY_USAGE_SIG)? 's':'-',
+               (use & PUBKEY_USAGE_CERT)? 'c':'-',
+               (use & PUBKEY_USAGE_AUTH)? 'a':'-',
+               (use & PUBKEY_USAGE_UNKNOWN)? '?':'-');
+
+  if (!pk->flags.valid)
+    {
+      if (DBG_LOOKUP)
+        log_debug ("\tsubkey not valid\n");
+      if (clean_level == KEY_CLEAN_INVALID)
+        do_clean = 1;
+    }
+  if (pk->has_expired)
+    {
+      if (DBG_LOOKUP)
+        log_debug ("\tsubkey has expired\n");
+      if (clean_level == KEY_CLEAN_ALL)
+        do_clean = 1;
+      else if (clean_level == KEY_CLEAN_AUTHENCR
+               && (use & (PUBKEY_USAGE_ENC | PUBKEY_USAGE_AUTH))
+               && !(use & (PUBKEY_USAGE_SIG | PUBKEY_USAGE_CERT)))
+        do_clean = 1;
+      else if (clean_level == KEY_CLEAN_ENCR
+               && (use & PUBKEY_USAGE_ENC)
+               && !(use & (PUBKEY_USAGE_SIG | PUBKEY_USAGE_CERT
+                           | PUBKEY_USAGE_AUTH)))
+        do_clean = 1;
+    }
+  if (pk->flags.revoked)
+    {
+      if (DBG_LOOKUP)
+        log_debug ("\tsubkey has been revoked (keeping)\n");
+      /* Avoid any cleaning because revocations are important.  */
+      do_clean = 0;
+    }
+  if (!do_clean)
+    return 0;
+
+  if (DBG_LOOKUP)
+    log_debug ("\t=> removing this subkey\n");
+
+  delete_kbnode (subkeynode);
+  for (node = subkeynode->next;
+       node && !(node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+                 || node->pkt->pkttype == PKT_SECRET_SUBKEY);
+       node = node->next)
+    delete_kbnode (node);
+
+  return 1;
+}
+
+
+/* Helper for clean_all_subkeys.  Here duplicate signatures from a
+ * subkey are removed.  This should in general not happen because
+ * import takes care of that.  However, sometimes other tools are used
+ * to manage a keyring or key has been imported a long time ago.  */
+static int
+clean_one_subkey_dupsigs (ctrl_t ctrl, kbnode_t subkeynode)
+{
+  kbnode_t node;
+  PKT_public_key *pk = subkeynode->pkt->pkt.public_key;
+  int any_choosen = 0;
+  int count = 0;
+
+  (void)ctrl;
+
+  log_assert (subkeynode->pkt->pkttype == PKT_PUBLIC_SUBKEY
+              || subkeynode->pkt->pkttype == PKT_SECRET_SUBKEY);
+
+  if (DBG_LOOKUP)
+    log_debug ("\tchecking subkey %08lX for dupsigs\n",
+               (ulong) keyid_from_pk (pk, NULL));
+
+  /* First check that the choosen flag has been set.  Note that we
+   * only look at plain signatures so to keep all revocation
+   * signatures which may carry important information.  */
+  for (node = subkeynode->next;
+       node && !(node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+                 || node->pkt->pkttype == PKT_SECRET_SUBKEY);
+       node = node->next)
+    {
+      if (!is_deleted_kbnode (node)
+          && node->pkt->pkttype == PKT_SIGNATURE
+          && IS_SUBKEY_SIG (node->pkt->pkt.signature)
+          && node->pkt->pkt.signature->flags.chosen_selfsig)
+        {
+          any_choosen = 1;
+          break;
+        }
+    }
+
+  if (!any_choosen)
+    return 0; /* Ooops no choosen flag set - we can't decide.  */
+
+  for (node = subkeynode->next;
+       node && !(node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+                 || node->pkt->pkttype == PKT_SECRET_SUBKEY);
+       node = node->next)
+    {
+      if (!is_deleted_kbnode (node)
+          && node->pkt->pkttype == PKT_SIGNATURE
+          && IS_SUBKEY_SIG (node->pkt->pkt.signature)
+          && !node->pkt->pkt.signature->flags.chosen_selfsig)
+        {
+          delete_kbnode (node);
+          count++;
+        }
+    }
+
+  return count;
+}
+
+
+/* This function only marks the deleted nodes and the caller is
+ * responsible to skip or remove them.  Needs to be called after a
+ * merge_keys_and_selfsig.  CLEAN_LEVEL is one of the KEY_CLEAN_*
+ * values.   */
+void
+clean_all_subkeys (ctrl_t ctrl, kbnode_t keyblock, int noisy, int clean_level,
+                   int *subkeys_cleaned, int *sigs_cleaned)
+{
+  kbnode_t first_subkey, node;
+  int n;
+
+  if (DBG_LOOKUP)
+    log_debug ("clean_all_subkeys: checking key %08lX\n",
+	       (ulong) keyid_from_pk (keyblock->pkt->pkt.public_key, NULL));
+
+  for (node = keyblock->next; node; node = node->next)
+    if (!is_deleted_kbnode (node)
+        && (node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+            || node->pkt->pkttype == PKT_SECRET_SUBKEY))
+      break;
+  first_subkey = node;
+
+  /* Remove bogus subkey binding signatures: The only signatures
+   * allowed are of class 0x18 and 0x28.  */
+  for (node = first_subkey; node; node = node->next)
+    {
+      if (is_deleted_kbnode (node))
+        continue;
+      if (node->pkt->pkttype == PKT_SIGNATURE
+          && !(IS_SUBKEY_SIG (node->pkt->pkt.signature)
+                || IS_SUBKEY_REV (node->pkt->pkt.signature)))
+        {
+          delete_kbnode (node);
+          if (sigs_cleaned)
+            ++*sigs_cleaned;
+        }
+    }
+
+  /* Do the selected cleaning.  */
+  if (clean_level > KEY_CLEAN_NONE)
+    {
+      /* Clean enitre subkeys.  */
+      for (node = first_subkey; node; node = node->next)
+        {
+          if (is_deleted_kbnode (node))
+            continue;
+          if (node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+              || node->pkt->pkttype == PKT_SECRET_SUBKEY)
+            {
+              if (clean_one_subkey (ctrl, node, noisy, clean_level))
+                {
+                  if (subkeys_cleaned)
+                    ++*subkeys_cleaned;
+                }
+            }
+        }
+
+      /* Clean duplicate signatures from a subkey.  */
+      for (node = first_subkey; node; node = node->next)
+        {
+          if (is_deleted_kbnode (node))
+            continue;
+          if (node->pkt->pkttype == PKT_PUBLIC_SUBKEY
+              || node->pkt->pkttype == PKT_SECRET_SUBKEY)
+            {
+              n = clean_one_subkey_dupsigs (ctrl, node);
+              if (sigs_cleaned)
+                *sigs_cleaned += n;
+            }
+        }
+    }
+}