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gpg: Allow import of PGP desktop exported secret keys. 

* g10/import.c (NODE_TRANSFER_SECKEY): New.
(import): Add attic kludge.
(transfer_secret_keys): Add arg only_marked.
(resync_sec_with_pub_keyblock): Return removed seckeys via new arg
r_removedsecs.
(import_secret_one): New arg r_secattic.  Change to take ownership of
arg keyblock.  Implement extra secret key import logic.  Factor some
code out to ...
(do_transfer): New.
(import_matching_seckeys): New.
--

The PGP desktops exported secret keys are really stupid.  And they
even a have kind of exception in rfc4880 which does not rule that
out (section 11.2):

  [...]  Implementations SHOULD include self-signatures on any user
  IDs and subkeys, as this allows for a complete public key to be
  automatically extracted from the transferable secret key.
  Implementations MAY choose to omit the self-signatures, especially
  if a transferable public key accompanies the transferable secret
  key.

Now if they would only put the public key before the secret
key. Anyway we now have a workaround for that ugliness.

GnuPG-bug-id: 4392
Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch 2019-03-18 13:07:14 +01:00
parent f799e9728b
commit 5205512fc0
No known key found for this signature in database
GPG Key ID: E3FDFF218E45B72B
3 changed files with 309 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

385
g10/import.c
View File

@ -1,6 +1,6 @@
/* import.c - import a key into our key storage.
* Copyright (C) 1998-2007, 2010-2011 Free Software Foundation, Inc.
* Copyright (C) 2014, 2016, 2017 Werner Koch
* Copyright (C) 2014, 2016, 2017, 2019 Werner Koch
*
* This file is part of GnuPG.
*
@ -75,6 +75,8 @@ struct import_stats_s
#define NODE_DELETION_MARK 4
/* A node flag used to temporary mark a node. */
#define NODE_FLAG_A 8
/* A flag used by transfer_secret_keys. */
#define NODE_TRANSFER_SECKEY 16
/* An object and a global instance to store selectors created from
@ -110,10 +112,15 @@ static gpg_error_t import_one (ctrl_t ctrl,
unsigned int options, int from_sk, int silent,
import_screener_t screener, void *screener_arg,
int origin, const char *url, int *r_valid);
static gpg_error_t import_matching_seckeys (
ctrl_t ctrl, kbnode_t seckeys,
const byte *mainfpr, size_t mainfprlen,
struct import_stats_s *stats, int batch);
static gpg_error_t import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
struct import_stats_s *stats, int batch,
unsigned int options, int for_migration,
import_screener_t screener, void *screener_arg);
import_screener_t screener, void *screener_arg,
kbnode_t *r_secattic);
static int import_revoke_cert (ctrl_t ctrl, kbnode_t node, unsigned int options,
struct import_stats_s *stats);
static int chk_self_sigs (ctrl_t ctrl, kbnode_t keyblock, u32 *keyid,
@ -566,6 +573,7 @@ import (ctrl_t ctrl, IOBUF inp, const char* fname,struct import_stats_s *stats,
kbnode_t keyblock = NULL; /* Need to initialize because gcc can't
grasp the return semantics of
read_block. */
kbnode_t secattic = NULL; /* Kludge for PGP desktop percularity */
int rc = 0;
int v3keys;
@ -586,18 +594,63 @@ import (ctrl_t ctrl, IOBUF inp, const char* fname,struct import_stats_s *stats,
{
stats->v3keys += v3keys;
if (keyblock->pkt->pkttype == PKT_PUBLIC_KEY)
rc = import_one (ctrl, keyblock,
stats, fpr, fpr_len, options, 0, 0,
screener, screener_arg, origin, url, NULL);
{
rc = import_one (ctrl, keyblock,
stats, fpr, fpr_len, options, 0, 0,
screener, screener_arg, origin, url, NULL);
if (secattic)
{
byte tmpfpr[MAX_FINGERPRINT_LEN];
size_t tmpfprlen;
if (!rc && !(opt.dry_run || (options & IMPORT_DRY_RUN)))
{
/* Kudge for PGP desktop - see below. */
fingerprint_from_pk (keyblock->pkt->pkt.public_key,
tmpfpr, &tmpfprlen);
rc = import_matching_seckeys (ctrl, secattic,
tmpfpr, tmpfprlen,
stats, opt.batch);
}
release_kbnode (secattic);
secattic = NULL;
}
}
else if (keyblock->pkt->pkttype == PKT_SECRET_KEY)
rc = import_secret_one (ctrl, keyblock, stats,
opt.batch, options, 0,
screener, screener_arg);
{
release_kbnode (secattic);
secattic = NULL;
rc = import_secret_one (ctrl, keyblock, stats,
opt.batch, options, 0,
screener, screener_arg, &secattic);
keyblock = NULL; /* Ownership was transferred. */
if (secattic)
{
if (gpg_err_code (rc) == GPG_ERR_NO_PUBKEY)
rc = 0; /* Try import after the next pubkey. */
/* The attic is a workaround for the peculiar PGP
* Desktop method of exporting a secret key: The
* exported file is the concatenation of two armored
* keyblocks; first the private one and then the public
* one. The strange thing is that the secret one has no
* binding signatures at all and thus we have not
* imported it. The attic stores that secret keys and
* we try to import it once after the very next public
* keyblock. */
}
}
else if (keyblock->pkt->pkttype == PKT_SIGNATURE
&& IS_KEY_REV (keyblock->pkt->pkt.signature) )
rc = import_revoke_cert (ctrl, keyblock, options, stats);
{
release_kbnode (secattic);
secattic = NULL;
rc = import_revoke_cert (ctrl, keyblock, options, stats);
}
else
{
release_kbnode (secattic);
secattic = NULL;
log_info (_("skipping block of type %d\n"), keyblock->pkt->pkttype);
}
release_kbnode (keyblock);
@ -623,6 +676,7 @@ import (ctrl_t ctrl, IOBUF inp, const char* fname,struct import_stats_s *stats,
else if (rc && gpg_err_code (rc) != GPG_ERR_INV_KEYRING)
log_error (_("error reading '%s': %s\n"), fname, gpg_strerror (rc));
release_kbnode (secattic);
return rc;
}
@ -659,8 +713,11 @@ import_old_secring (ctrl_t ctrl, const char *fname)
while (!(err = read_block (inp, 0, &pending_pkt, &keyblock, &v3keys)))
{
if (keyblock->pkt->pkttype == PKT_SECRET_KEY)
err = import_secret_one (ctrl, keyblock, stats, 1, 0, 1,
NULL, NULL);
{
err = import_secret_one (ctrl, keyblock, stats, 1, 0, 1,
NULL, NULL, NULL);
keyblock = NULL; /* Ownership was transferred. */
}
release_kbnode (keyblock);
if (err)
break;
@ -2181,12 +2238,15 @@ import_one (ctrl_t ctrl,
/* Transfer all the secret keys in SEC_KEYBLOCK to the gpg-agent. The
function prints diagnostics and returns an error code. If BATCH is
true the secret keys are stored by gpg-agent in the transfer format
(i.e. no re-protection and aksing for passphrases). */
* function prints diagnostics and returns an error code. If BATCH is
* true the secret keys are stored by gpg-agent in the transfer format
* (i.e. no re-protection and aksing for passphrases). If ONLY_MARKED
* is set, only those nodes with flag NODE_TRANSFER_SECKEY are
* processed. */
gpg_error_t
transfer_secret_keys (ctrl_t ctrl, struct import_stats_s *stats,
kbnode_t sec_keyblock, int batch, int force)
kbnode_t sec_keyblock, int batch, int force,
int only_marked)
{
gpg_error_t err = 0;
void *kek = NULL;
@ -2227,12 +2287,16 @@ transfer_secret_keys (ctrl_t ctrl, struct import_stats_s *stats,
xfree (kek);
kek = NULL;
/* Note: We need to use walk_kbnode so that we skip nodes which are
* marked as deleted. */
main_pk = NULL;
while ((node = walk_kbnode (sec_keyblock, &ctx, 0)))
{
if (node->pkt->pkttype != PKT_SECRET_KEY
&& node->pkt->pkttype != PKT_SECRET_SUBKEY)
continue;
if (only_marked && !(node->flag & NODE_TRANSFER_SECKEY))
continue;
pk = node->pkt->pkt.public_key;
if (!main_pk)
main_pk = pk;
@ -2531,12 +2595,15 @@ sec_to_pub_keyblock (kbnode_t sec_keyblock)
/* Delete all notes in the keyblock at R_KEYBLOCK which are not in
* PUB_KEYBLOCK. Modifies the tags of both keyblock's nodes. */
static gpg_error_t
resync_sec_with_pub_keyblock (kbnode_t *r_keyblock, kbnode_t pub_keyblock)
resync_sec_with_pub_keyblock (kbnode_t *r_keyblock, kbnode_t pub_keyblock,
kbnode_t *r_removedsecs)
{
kbnode_t sec_keyblock = *r_keyblock;
kbnode_t node;
kbnode_t node, prevnode;
unsigned int *taglist;
unsigned int ntaglist, n;
kbnode_t attic = NULL;
kbnode_t *attic_head = &attic;
/* Collect all tags in an array for faster searching. */
for (ntaglist = 0, node = pub_keyblock; node; node = node->next)
@ -2548,40 +2615,188 @@ resync_sec_with_pub_keyblock (kbnode_t *r_keyblock, kbnode_t pub_keyblock)
taglist[ntaglist++] = node->tag;
/* Walks over the secret keyblock and delete all nodes which are not
* in the tag list. Those nodes have been delete in the
* pub_keyblock. Sequential search is a bit lazt and could be
* optimized by sorting and bsearch; however secret key rings are
* short and there are easier weaus to DoS gpg. */
for (node = sec_keyblock; node; node = node->next)
* in the tag list. Those nodes have been deleted in the
* pub_keyblock. Sequential search is a bit lazy and could be
* optimized by sorting and bsearch; however secret keyrings are
* short and there are easier ways to DoS the import. */
again:
for (prevnode=NULL, node=sec_keyblock; node; prevnode=node, node=node->next)
{
for (n=0; n < ntaglist; n++)
if (taglist[n] == node->tag)
break;
if (n == ntaglist)
delete_kbnode (node);
if (n == ntaglist) /* Not in public keyblock. */
{
if (node->pkt->pkttype == PKT_SECRET_KEY
|| node->pkt->pkttype == PKT_SECRET_SUBKEY)
{
if (!prevnode)
sec_keyblock = node->next;
else
prevnode->next = node->next;
node->next = NULL;
*attic_head = node;
attic_head = &node->next;
goto again; /* That's lame; I know. */
}
else
delete_kbnode (node);
}
}
xfree (taglist);
/* Commit the as deleted marked nodes and return the possibly
* modified keyblock. */
* modified keyblock and a list of removed secret key nodes. */
commit_kbnode (&sec_keyblock);
*r_keyblock = sec_keyblock;
*r_removedsecs = attic;
return 0;
}
/****************
* Ditto for secret keys. Handling is simpler than for public keys.
* We allow secret key importing only when allow is true, this is so
* that a secret key can not be imported accidentally and thereby tampering
* with the trust calculation.
/* Helper for import_secret_one. */
static gpg_error_t
do_transfer (ctrl_t ctrl, kbnode_t keyblock, PKT_public_key *pk,
struct import_stats_s *stats, int batch, int only_marked)
{
gpg_error_t err;
struct import_stats_s subkey_stats = {0};
err = transfer_secret_keys (ctrl, &subkey_stats, keyblock,
batch, 0, only_marked);
if (gpg_err_code (err) == GPG_ERR_NOT_PROCESSED)
{
/* TRANSLATORS: For a smartcard, each private key on host has a
* reference (stub) to a smartcard and actual private key data
* is stored on the card. A single smartcard can have up to
* three private key data. Importing private key stub is always
* skipped in 2.1, and it returns GPG_ERR_NOT_PROCESSED.
* Instead, user should be suggested to run 'gpg --card-status',
* then, references to a card will be automatically created
* again. */
log_info (_("To migrate '%s', with each smartcard, "
"run: %s\n"), "secring.gpg", "gpg --card-status");
err = 0;
}
if (!err)
{
int status = 16;
if (!opt.quiet)
log_info (_("key %s: secret key imported\n"), keystr_from_pk (pk));
if (subkey_stats.secret_imported)
{
status |= 1;
stats->secret_imported += 1;
}
if (subkey_stats.secret_dups)
stats->secret_dups += 1;
if (is_status_enabled ())
print_import_ok (pk, status);
}
return err;
}
/* If the secret keys (main or subkey) in SECKEYS have a corresponding
* public key in the public key described by (FPR,FPRLEN) import these
* parts.
*/
static gpg_error_t
import_matching_seckeys (ctrl_t ctrl, kbnode_t seckeys,
const byte *mainfpr, size_t mainfprlen,
struct import_stats_s *stats, int batch)
{
gpg_error_t err;
kbnode_t pub_keyblock = NULL;
kbnode_t node;
struct { byte fpr[MAX_FINGERPRINT_LEN]; size_t fprlen; } *fprlist = NULL;
size_t n, nfprlist;
byte fpr[MAX_FINGERPRINT_LEN];
size_t fprlen;
PKT_public_key *pk;
/* Get the entire public key block from our keystore and put all its
* fingerprints into an array. */
err = get_pubkey_byfprint (ctrl, NULL, &pub_keyblock, mainfpr, mainfprlen);
if (err)
goto leave;
log_assert (pub_keyblock && pub_keyblock->pkt->pkttype == PKT_PUBLIC_KEY);
pk = pub_keyblock->pkt->pkt.public_key;
for (nfprlist = 0, node = pub_keyblock; node; node = node->next)
if (node->pkt->pkttype == PKT_PUBLIC_KEY
|| node->pkt->pkttype == PKT_PUBLIC_SUBKEY)
nfprlist++;
log_assert (nfprlist);
fprlist = xtrycalloc (nfprlist, sizeof *fprlist);
if (!fprlist)
{
err = gpg_error_from_syserror ();
goto leave;
}
for (n = 0, node = pub_keyblock; node; node = node->next)
if (node->pkt->pkttype == PKT_PUBLIC_KEY
|| node->pkt->pkttype == PKT_PUBLIC_SUBKEY)
{
fingerprint_from_pk (node->pkt->pkt.public_key,
fprlist[n].fpr, &fprlist[n].fprlen);
n++;
}
log_assert (n == nfprlist);
/* for (n=0; n < nfprlist; n++) */
/* log_printhex (fprlist[n].fpr, fprlist[n].fprlen, "pubkey %zu:", n); */
/* Mark all secret keys which have a matching public key part in
* PUB_KEYBLOCK. */
for (node = seckeys; node; node = node->next)
{
if (node->pkt->pkttype != PKT_SECRET_KEY
&& node->pkt->pkttype != PKT_SECRET_SUBKEY)
continue; /* Should not happen. */
fingerprint_from_pk (node->pkt->pkt.public_key, fpr, &fprlen);
node->flag &= ~NODE_TRANSFER_SECKEY;
for (n=0; n < nfprlist; n++)
if (fprlist[n].fprlen == fprlen && !memcmp (fprlist[n].fpr,fpr,fprlen))
{
node->flag |= NODE_TRANSFER_SECKEY;
/* log_debug ("found matching seckey\n"); */
break;
}
}
/* Transfer all marked keys. */
err = do_transfer (ctrl, seckeys, pk, stats, batch, 1);
leave:
xfree (fprlist);
release_kbnode (pub_keyblock);
return err;
}
/* Import function for a single secret keyblock. Handling is simpler
* than for public keys. We allow secret key importing only when
* allow is true, this is so that a secret key can not be imported
* accidentally and thereby tampering with the trust calculation.
*
* Ownership of KEYBLOCK is transferred to this function!
*
* If R_SECATTIC is not null the last special sec_keyblock is stored
* there.
*/
static gpg_error_t
import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
struct import_stats_s *stats, int batch,
unsigned int options, int for_migration,
import_screener_t screener, void *screener_arg)
import_screener_t screener, void *screener_arg,
kbnode_t *r_secattic)
{
PKT_public_key *pk;
struct seckey_info *ski;
@ -2590,6 +2805,9 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
gpg_error_t err = 0;
int nr_prev;
kbnode_t pub_keyblock;
kbnode_t attic = NULL;
byte fpr[MAX_FINGERPRINT_LEN];
size_t fprlen;
char pkstrbuf[PUBKEY_STRING_SIZE];
/* Get the key and print some info about it */
@ -2599,6 +2817,7 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
pk = node->pkt->pkt.public_key;
fingerprint_from_pk (pk, fpr, &fprlen);
keyid_from_pk (pk, keyid);
uidnode = find_next_kbnode (keyblock, PKT_USER_ID);
@ -2606,6 +2825,7 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
{
log_error (_("secret key %s: %s\n"), keystr_from_pk (pk),
_("rejected by import screener"));
release_kbnode (keyblock);
return 0;
}
@ -2625,6 +2845,7 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
{
if (!for_migration)
log_error (_("importing secret keys not allowed\n"));
release_kbnode (keyblock);
return 0;
}
@ -2632,6 +2853,7 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
{
if (!for_migration)
log_error( _("key %s: no user ID\n"), keystr_from_pk (pk));
release_kbnode (keyblock);
return 0;
}
@ -2640,6 +2862,7 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
{
/* Actually an internal error. */
log_error ("key %s: secret key info missing\n", keystr_from_pk (pk));
release_kbnode (keyblock);
return 0;
}
@ -2650,6 +2873,7 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
if (!for_migration)
log_error (_("key %s: secret key with invalid cipher %d"
" - skipped\n"), keystr_from_pk (pk), ski->algo);
release_kbnode (keyblock);
return 0;
}
@ -2660,6 +2884,7 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
to put a secret key into the keyring and the user might later
be tricked into signing stuff with that key. */
log_error (_("importing secret keys not allowed\n"));
release_kbnode (keyblock);
return 0;
}
#endif
@ -2691,16 +2916,43 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
* the public keyblock. Otherwise we would import just the
* secret key without having the public key. That would be
* surprising and clutters out private-keys-v1.d. */
err = resync_sec_with_pub_keyblock (&keyblock, pub_keyblock);
err = resync_sec_with_pub_keyblock (&keyblock, pub_keyblock, &attic);
if (err)
goto leave;
if (!valid)
{
err = gpg_error (GPG_ERR_NO_SECKEY);
/* If the block was not valid the primary key is left in the
* original keyblock because we require that for the first
* node. Move it to ATTIC. */
if (keyblock && keyblock->pkt->pkttype == PKT_SECRET_KEY)
{
node = keyblock;
keyblock = node->next;
node->next = NULL;
if (attic)
{
node->next = attic;
attic = node;
}
else
attic = node;
}
/* Try to import the secret key iff we have a public key. */
if (attic && !(opt.dry_run || (options & IMPORT_DRY_RUN)))
err = import_matching_seckeys (ctrl, attic, fpr, fprlen,
stats, batch);
else
err = gpg_error (GPG_ERR_NO_SECKEY);
goto leave;
}
/* log_debug ("attic is:\n"); */
/* dump_kbnode (attic); */
/* Proceed with the valid parts of PUBKEYBLOCK. */
/* At least we cancel the secret key import when the public key
import was skipped due to MERGE_ONLY option and a new
key. */
@ -2709,62 +2961,37 @@ import_secret_one (ctrl_t ctrl, kbnode_t keyblock,
{
/* Read the keyblock again to get the effects of a merge for
* the public key. */
/* Fixme: we should do this based on the fingerprint or
even better let import_one return the merged
keyblock. */
node = get_pubkeyblock (ctrl, keyid);
if (!node)
log_error ("key %s: failed to re-lookup public key\n",
keystr_from_pk (pk));
err = get_pubkey_byfprint (ctrl, NULL, &node, fpr, fprlen);
if (err || !node)
log_error ("key %s: failed to re-lookup public key: %s\n",
keystr_from_pk (pk), gpg_strerror (err));
else
{
/* transfer_secret_keys collects subkey stats. */
struct import_stats_s subkey_stats = {0};
err = transfer_secret_keys (ctrl, &subkey_stats, keyblock,
batch, 0);
if (gpg_err_code (err) == GPG_ERR_NOT_PROCESSED)
{
/* TRANSLATORS: For smartcard, each private key on
host has a reference (stub) to a smartcard and
actual private key data is stored on the card. A
single smartcard can have up to three private key
data. Importing private key stub is always
skipped in 2.1, and it returns
GPG_ERR_NOT_PROCESSED. Instead, user should be
suggested to run 'gpg --card-status', then,
references to a card will be automatically
created again. */
log_info (_("To migrate '%s', with each smartcard, "
"run: %s\n"), "secring.gpg", "gpg --card-status");
err = 0;
}
err = do_transfer (ctrl, keyblock, pk, stats, batch, 0);
if (!err)
{
int status = 16;
if (!opt.quiet)
log_info (_("key %s: secret key imported\n"),
keystr_from_pk (pk));
if (subkey_stats.secret_imported)
{
status |= 1;
stats->secret_imported += 1;
}
if (subkey_stats.secret_dups)
stats->secret_dups += 1;
if (is_status_enabled ())
print_import_ok (pk, status);
check_prefs (ctrl, node);
}
check_prefs (ctrl, node);
release_kbnode (node);
if (!err && attic)
{
/* Try to import invalid subkeys. This can be the
* case if the primary secret key was imported due
* to --allow-non-selfsigned-uid. */
err = import_matching_seckeys (ctrl, attic, fpr, fprlen,
stats, batch);
}
}
}
}
leave:
release_kbnode (keyblock);
release_kbnode (pub_keyblock);
if (r_secattic)
*r_secattic = attic;
else
release_kbnode (attic);
return err;
}

2
g10/keyedit.c
View File

@ -1894,7 +1894,7 @@ keyedit_menu (ctrl_t ctrl, const char *username, strlist_t locusr,
node = new_kbnode (pkt);
/* Transfer it to gpg-agent which handles secret keys. */
err = transfer_secret_keys (ctrl, NULL, node, 1, 1);
err = transfer_secret_keys (ctrl, NULL, node, 1, 1, 0);
/* Treat the pkt as a public key. */
pkt->pkttype = PKT_PUBLIC_KEY;

3
g10/main.h
View File

@ -394,7 +394,8 @@ struct impex_filter_parm_s
const char *impex_filter_getval (void *cookie, const char *propname);
gpg_error_t transfer_secret_keys (ctrl_t ctrl, struct import_stats_s *stats,
kbnode_t sec_keyblock, int batch, int force);
kbnode_t sec_keyblock, int batch, int force,
int only_marked);
int collapse_uids( KBNODE *keyblock );