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-rw-r--r--g10/key-clean.c614
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diff --git a/g10/key-clean.c b/g10/key-clean.c
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+/* 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;
+ }
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-17 12:53:58 +0000