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g10: Change decryption key selection for public key encryption.

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* g10/mainproc.c (struct mainproc_context): It's now pubkey_enc_list.
(do_proc_packets): Remove the first arg CTRL.  Fix call of
proc_pubkey_enc.
(release_list): Handle pubkey_enc_list.
(proc_pubkey_enc): Remove the first arg CTRL.  Simply put the packet
to pubkey_enc_list.
(print_pkenc_list): Remove the last arg FAILED.
(proc_encrypted): Only call print_pkenc_list once.
Handle DEK here.
(proc_packets, proc_signature_packets, proc_signature_packets_by_fd)
(proc_encryption_packets): Fix call of do_proc_packets.
* g10/packet.h (struct pubkey_enc_list): Define.
* g10/pubkey-enc.c (get_it): Change the second argument K.
(get_session_key): Select session key by LIST, using enum_secret_keys.
* g10/gpgv.c (get_session_key): Change the second argument K.
* g10/test-stubs.c (get_session_key): Likewise.

--

Collect all PKT_PUBKEY_ENC packets, and then, process the
PKT_ENCRYPTED* packet.

Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>
This commit is contained in:
NIIBE Yutaka 2018-08-27 13:12:31 +09:00
parent 1b309d9f61
commit ce2f717601
5 changed files with 155 additions and 179 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
g10/gpgv.c
View File

@ -490,7 +490,7 @@ read_key_from_file (ctrl_t ctrl, const char *fname, kbnode_t *r_keyblock)
* No encryption here but mainproc links to these functions.
*/
gpg_error_t
get_session_key (ctrl_t ctrl, PKT_pubkey_enc *k, DEK *dek)
get_session_key (ctrl_t ctrl, struct pubkey_enc_list *k, DEK *dek)
{
(void)ctrl;
(void)k;

198
g10/mainproc.c
View File

@ -46,16 +46,6 @@
#define MAX_NESTING_DEPTH 32
/* An object to build a list of keyid related info. */
struct kidlist_item
{
struct kidlist_item *next;
u32 kid[2];
int pubkey_algo;
int reason;
};
/*
* Object to hold the processing context.
*/
@ -95,7 +85,7 @@ struct mainproc_context
iobuf_t iobuf; /* Used to get the filename etc. */
int trustletter; /* Temporary usage in list_node. */
ulong symkeys; /* Number of symmetrically encrypted session keys. */
struct kidlist_item *pkenc_list; /* List of encryption packets. */
struct pubkey_enc_list *pkenc_list; /* List of encryption packets. */
struct {
unsigned int sig_seen:1; /* Set to true if a signature packet
has been seen. */
@ -112,7 +102,7 @@ static int literals_seen;
/*** Local prototypes. ***/
static int do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a);
static int do_proc_packets (CTX c, iobuf_t a);
static void list_node (CTX c, kbnode_t node);
static void proc_tree (CTX c, kbnode_t node);
@ -135,7 +125,10 @@ release_list( CTX c )
release_kbnode (c->list);
while (c->pkenc_list)
{
struct kidlist_item *tmp = c->pkenc_list->next;
struct pubkey_enc_list *tmp = c->pkenc_list->next;
mpi_release (c->pkenc_list->data[0]);
mpi_release (c->pkenc_list->data[1]);
xfree (c->pkenc_list);
c->pkenc_list = tmp;
}
@ -458,10 +451,9 @@ proc_symkey_enc (CTX c, PACKET *pkt)
static void
proc_pubkey_enc (ctrl_t ctrl, CTX c, PACKET *pkt)
proc_pubkey_enc (CTX c, PACKET *pkt)
{
PKT_pubkey_enc *enc;
int result = 0;
/* Check whether the secret key is available and store in this case. */
c->last_was_session_key = 1;
@ -472,7 +464,7 @@ proc_pubkey_enc (ctrl_t ctrl, CTX c, PACKET *pkt)
if (opt.verbose)
log_info (_("public key is %s\n"), keystr (enc->keyid));
if (is_status_enabled())
if (is_status_enabled ())
{
char buf[50];
snprintf (buf, sizeof buf, "%08lX%08lX %d 0",
@ -480,68 +472,21 @@ proc_pubkey_enc (ctrl_t ctrl, CTX c, PACKET *pkt)
write_status_text (STATUS_ENC_TO, buf);
}
if (!opt.list_only && opt.override_session_key)
if (!opt.list_only && !opt.override_session_key)
{
/* It does not make much sense to store the session key in
* secure memory because it has already been passed on the
* command line and the GCHQ knows about it. */
c->dek = xmalloc_clear (sizeof *c->dek);
result = get_override_session_key (c->dek, opt.override_session_key);
if (result)
{
xfree (c->dek);
c->dek = NULL;
}
}
else if (enc->pubkey_algo == PUBKEY_ALGO_ELGAMAL_E
|| enc->pubkey_algo == PUBKEY_ALGO_ECDH
|| enc->pubkey_algo == PUBKEY_ALGO_RSA
|| enc->pubkey_algo == PUBKEY_ALGO_RSA_E
|| enc->pubkey_algo == PUBKEY_ALGO_ELGAMAL)
{
/* Note that we also allow type 20 Elgamal keys for decryption.
There are still a couple of those keys in active use as a
subkey. */
struct pubkey_enc_list *x = xmalloc (sizeof *x);
/* FIXME: Store this all in a list and process it later so that
we can prioritize what key to use. This gives a better user
experience if wildcard keyids are used. */
if (!c->dek && ((!enc->keyid[0] && !enc->keyid[1])
|| opt.try_all_secrets
|| have_secret_key_with_kid (enc->keyid)))
{
if(opt.list_only)
result = GPG_ERR_MISSING_ACTION; /* fixme: Use better error code. */
else
{
c->dek = xmalloc_secure_clear (sizeof *c->dek);
if ((result = get_session_key (ctrl, enc, c->dek)))
{
/* Error: Delete the DEK. */
xfree (c->dek);
c->dek = NULL;
}
}
}
else
result = GPG_ERR_NO_SECKEY;
}
else
result = GPG_ERR_PUBKEY_ALGO;
if (1)
{
/* Store it for later display. */
struct kidlist_item *x = xmalloc (sizeof *x);
x->kid[0] = enc->keyid[0];
x->kid[1] = enc->keyid[1];
x->keyid[0] = enc->keyid[0];
x->keyid[1] = enc->keyid[1];
x->pubkey_algo = enc->pubkey_algo;
x->reason = result;
x->data[0] = x->data[1] = NULL;
if (enc->data[0])
{
x->data[0] = mpi_copy (enc->data[0]);
x->data[1] = mpi_copy (enc->data[1]);
}
x->next = c->pkenc_list;
c->pkenc_list = x;
if (!result && opt.verbose > 1)
log_info (_("public key encrypted data: good DEK\n"));
}
free_packet(pkt, NULL);
@ -553,60 +498,34 @@ proc_pubkey_enc (ctrl_t ctrl, CTX c, PACKET *pkt)
* not decrypt.
*/
static void
print_pkenc_list (ctrl_t ctrl, struct kidlist_item *list, int failed)
print_pkenc_list (ctrl_t ctrl, struct pubkey_enc_list *list)
{
for (; list; list = list->next)
{
PKT_public_key *pk;
const char *algstr;
if (failed && !list->reason)
continue;
if (!failed && list->reason)
continue;
algstr = openpgp_pk_algo_name (list->pubkey_algo);
pk = xmalloc_clear (sizeof *pk);
if (!algstr)
algstr = "[?]";
pk->pubkey_algo = list->pubkey_algo;
if (!get_pubkey (ctrl, pk, list->kid))
if (!get_pubkey (ctrl, pk, list->keyid))
{
char *p;
log_info (_("encrypted with %u-bit %s key, ID %s, created %s\n"),
nbits_from_pk (pk), algstr, keystr_from_pk(pk),
strtimestamp (pk->timestamp));
p = get_user_id_native (ctrl, list->kid);
p = get_user_id_native (ctrl, list->keyid);
log_printf (_(" \"%s\"\n"), p);
xfree (p);
}
else
log_info (_("encrypted with %s key, ID %s\n"),
algstr, keystr(list->kid));
algstr, keystr(list->keyid));
free_public_key (pk);
if (gpg_err_code (list->reason) == GPG_ERR_NO_SECKEY)
{
if (is_status_enabled())
{
char buf[20];
snprintf (buf, sizeof buf, "%08lX%08lX",
(ulong)list->kid[0], (ulong)list->kid[1]);
write_status_text (STATUS_NO_SECKEY, buf);
}
}
else if (gpg_err_code (list->reason) == GPG_ERR_MISSING_ACTION)
{
/* Not tested for secret key due to --list-only mode. */
}
else if (list->reason)
{
log_info (_("public key decryption failed: %s\n"),
gpg_strerror (list->reason));
write_status_error ("pkdecrypt_failed", list->reason);
}
}
}
@ -630,11 +549,58 @@ proc_encrypted (CTX c, PACKET *pkt)
log_info (_("encrypted with %lu passphrases\n"), c->symkeys);
else if (c->symkeys == 1)
log_info (_("encrypted with 1 passphrase\n"));
print_pkenc_list (c->ctrl, c->pkenc_list, 1 );
print_pkenc_list (c->ctrl, c->pkenc_list, 0 );
print_pkenc_list (c->ctrl, c->pkenc_list);
}
/* FIXME: Figure out the session key by looking at all pkenc packets. */
/* Figure out the session key by looking at all pkenc packets. */
if (opt.list_only || c->dek)
;
else if (opt.override_session_key)
{
c->dek = xmalloc_clear (sizeof *c->dek);
result = get_override_session_key (c->dek, opt.override_session_key);
if (result)
{
xfree (c->dek);
c->dek = NULL;
log_info (_("public key decryption failed: %s\n"),
gpg_strerror (result));
write_status_error ("pkdecrypt_failed", result);
}
}
else
{
c->dek = xmalloc_secure_clear (sizeof *c->dek);
result = get_session_key (c->ctrl, c->pkenc_list, c->dek);
if (result == GPG_ERR_NO_SECKEY)
{
if (is_status_enabled ())
{
struct pubkey_enc_list *list;
for (list = c->pkenc_list; list; list = list->next)
{
char buf[20];
snprintf (buf, sizeof buf, "%08lX%08lX",
(ulong)list->keyid[0], (ulong)list->keyid[1]);
write_status_text (STATUS_NO_SECKEY, buf);
}
}
}
else if (result)
{
log_info (_("public key decryption failed: %s\n"),
gpg_strerror (result));
write_status_error ("pkdecrypt_failed", result);
/* Error: Delete the DEK. */
xfree (c->dek);
c->dek = NULL;
}
}
if (c->dek && opt.verbose > 1)
log_info (_("public key encrypted data: good DEK\n"));
write_status (STATUS_BEGIN_DECRYPTION);
@ -709,7 +675,7 @@ proc_encrypted (CTX c, PACKET *pkt)
&& gnupg_cipher_is_compliant (CO_DE_VS, c->dek->algo,
GCRY_CIPHER_MODE_CFB))
{
struct kidlist_item *i;
struct pubkey_enc_list *i;
int compliant = 1;
PKT_public_key *pk = xmalloc (sizeof *pk);
@ -722,7 +688,7 @@ proc_encrypted (CTX c, PACKET *pkt)
{
memset (pk, 0, sizeof *pk);
pk->pubkey_algo = i->pubkey_algo;
if (get_pubkey (c->ctrl, pk, i->kid) != 0
if (get_pubkey (c->ctrl, pk, i->keyid) != 0
|| ! gnupg_pk_is_compliant (CO_DE_VS, pk->pubkey_algo, pk->pkey,
nbits_from_pk (pk), NULL))
compliant = 0;
@ -1367,7 +1333,7 @@ proc_packets (ctrl_t ctrl, void *anchor, iobuf_t a )
c->ctrl = ctrl;
c->anchor = anchor;
rc = do_proc_packets (ctrl, c, a);
rc = do_proc_packets (c, a);
xfree (c);
return rc;
@ -1390,7 +1356,7 @@ proc_signature_packets (ctrl_t ctrl, void *anchor, iobuf_t a,
c->signed_data.used = !!signedfiles;
c->sigfilename = sigfilename;
rc = do_proc_packets (ctrl, c, a);
rc = do_proc_packets (c, a);
/* If we have not encountered any signature we print an error
messages, send a NODATA status back and return an error code.
@ -1433,7 +1399,7 @@ proc_signature_packets_by_fd (ctrl_t ctrl,
c->signed_data.data_names = NULL;
c->signed_data.used = (signed_data_fd != -1);
rc = do_proc_packets (ctrl, c, a);
rc = do_proc_packets (c, a);
/* If we have not encountered any signature we print an error
messages, send a NODATA status back and return an error code.
@ -1466,7 +1432,7 @@ proc_encryption_packets (ctrl_t ctrl, void *anchor, iobuf_t a )
c->ctrl = ctrl;
c->anchor = anchor;
c->encrypt_only = 1;
rc = do_proc_packets (ctrl, c, a);
rc = do_proc_packets (c, a);
xfree (c);
return rc;
}
@ -1492,7 +1458,7 @@ check_nesting (CTX c)
static int
do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
do_proc_packets (CTX c, iobuf_t a)
{
PACKET *pkt;
struct parse_packet_ctx_s parsectx;
@ -1526,7 +1492,7 @@ do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
{
switch (pkt->pkttype)
{
case PKT_PUBKEY_ENC: proc_pubkey_enc (ctrl, c, pkt); break;
case PKT_PUBKEY_ENC: proc_pubkey_enc (c, pkt); break;
case PKT_SYMKEY_ENC: proc_symkey_enc (c, pkt); break;
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC:
@ -1572,7 +1538,7 @@ do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
case PKT_SIGNATURE: newpkt = add_signature (c, pkt); break;
case PKT_SYMKEY_ENC: proc_symkey_enc (c, pkt); break;
case PKT_PUBKEY_ENC: proc_pubkey_enc (ctrl, c, pkt); break;
case PKT_PUBKEY_ENC: proc_pubkey_enc (c, pkt); break;
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC:
case PKT_ENCRYPTED_AEAD: proc_encrypted (c, pkt); break;
@ -1599,7 +1565,7 @@ do_proc_packets (ctrl_t ctrl, CTX c, iobuf_t a)
break;
case PKT_USER_ID: newpkt = add_user_id (c, pkt); break;
case PKT_SIGNATURE: newpkt = add_signature (c, pkt); break;
case PKT_PUBKEY_ENC: proc_pubkey_enc (ctrl, c, pkt); break;
case PKT_PUBKEY_ENC: proc_pubkey_enc (c, pkt); break;
case PKT_SYMKEY_ENC: proc_symkey_enc (c, pkt); break;
case PKT_ENCRYPTED:
case PKT_ENCRYPTED_MDC:

12
g10/packet.h
View File

@ -131,6 +131,16 @@ typedef struct {
} PKT_pubkey_enc;
/* An object to build a list of public-key encrypted session key. */
struct pubkey_enc_list
{
struct pubkey_enc_list *next;
u32 keyid[2];
int pubkey_algo;
gcry_mpi_t data[PUBKEY_MAX_NENC];
};
/* A one-pass signature packet as defined in RFC 4880, Section
5.4. All fields are serialized. */
typedef struct {
@ -889,7 +899,7 @@ gpg_error_t check_signature2 (ctrl_t ctrl,
/*-- pubkey-enc.c --*/
gpg_error_t get_session_key (ctrl_t ctrl, PKT_pubkey_enc *k, DEK *dek);
gpg_error_t get_session_key (ctrl_t ctrl, struct pubkey_enc_list *k, DEK *dek);
gpg_error_t get_override_session_key (DEK *dek, const char *string);
/*-- compress.c --*/

92
g10/pubkey-enc.c
View File

@ -38,7 +38,7 @@
#include "../common/compliance.h"
static gpg_error_t get_it (ctrl_t ctrl, PKT_pubkey_enc *k,
static gpg_error_t get_it (ctrl_t ctrl, struct pubkey_enc_list *k,
DEK *dek, PKT_public_key *sk, u32 *keyid);
@ -72,48 +72,21 @@ is_algo_in_prefs (kbnode_t keyblock, preftype_t type, int algo)
* which should have been allocated in secure memory by the caller.
*/
gpg_error_t
get_session_key (ctrl_t ctrl, PKT_pubkey_enc * k, DEK * dek)
get_session_key (ctrl_t ctrl, struct pubkey_enc_list *list, DEK *dek)
{
PKT_public_key *sk = NULL;
int rc;
void *enum_context = NULL;
u32 keyid[2];
int search_for_secret_keys = 1;
if (DBG_CLOCK)
log_clock ("get_session_key enter");
rc = openpgp_pk_test_algo2 (k->pubkey_algo, PUBKEY_USAGE_ENC);
if (rc)
goto leave;
while (search_for_secret_keys)
{
struct pubkey_enc_list *k;
if ((k->keyid[0] || k->keyid[1]) && !opt.try_all_secrets)
{
sk = xmalloc_clear (sizeof *sk);
sk->pubkey_algo = k->pubkey_algo; /* We want a pubkey with this algo. */
if (!(rc = get_seckey (ctrl, sk, k->keyid)))
{
/* Check compliance. */
if (! gnupg_pk_is_allowed (opt.compliance, PK_USE_DECRYPTION,
sk->pubkey_algo,
sk->pkey, nbits_from_pk (sk), NULL))
{
log_info (_("key %s is not suitable for decryption"
" in %s mode\n"),
keystr_from_pk (sk),
gnupg_compliance_option_string (opt.compliance));
rc = gpg_error (GPG_ERR_PUBKEY_ALGO);
}
else
rc = get_it (ctrl, k, dek, sk, k->keyid);
}
}
else if (opt.skip_hidden_recipients)
rc = gpg_error (GPG_ERR_NO_SECKEY);
else /* Anonymous receiver: Try all available secret keys. */
{
void *enum_context = NULL;
u32 keyid[2];
for (;;)
{
free_public_key (sk);
sk = xmalloc_clear (sizeof *sk);
rc = enum_secret_keys (ctrl, &enum_context, sk);
@ -122,14 +95,9 @@ get_session_key (ctrl_t ctrl, PKT_pubkey_enc * k, DEK * dek)
rc = GPG_ERR_NO_SECKEY;
break;
}
if (sk->pubkey_algo != k->pubkey_algo)
continue;
if (!(sk->pubkey_usage & PUBKEY_USAGE_ENC))
continue;
keyid_from_pk (sk, keyid);
if (!opt.quiet)
log_info (_("anonymous recipient; trying secret key %s ...\n"),
keystr (keyid));
/* Check compliance. */
if (! gnupg_pk_is_allowed (opt.compliance, PK_USE_DECRYPTION,
@ -143,21 +111,53 @@ get_session_key (ctrl_t ctrl, PKT_pubkey_enc * k, DEK * dek)
continue;
}
for (k = list; k; k = k->next)
{
if (!(k->pubkey_algo == PUBKEY_ALGO_ELGAMAL_E
|| k->pubkey_algo == PUBKEY_ALGO_ECDH
|| k->pubkey_algo == PUBKEY_ALGO_RSA
|| k->pubkey_algo == PUBKEY_ALGO_RSA_E
|| k->pubkey_algo == PUBKEY_ALGO_ELGAMAL))
continue;
if (openpgp_pk_test_algo2 (k->pubkey_algo, PUBKEY_USAGE_ENC))
continue;
if (sk->pubkey_algo != k->pubkey_algo)
continue;
keyid_from_pk (sk, keyid);
if (!k->keyid[0] && !k->keyid[1])
{
if (!opt.quiet)
log_info (_("anonymous recipient; trying secret key %s ...\n"),
keystr (keyid));
}
else if (opt.try_all_secrets
|| (k->keyid[0] == keyid[0] && k->keyid[1] == keyid[1]))
;
else
continue;
rc = get_it (ctrl, k, dek, sk, keyid);
if (!rc)
{
if (!opt.quiet)
if (!opt.quiet && !k->keyid[0] && !k->keyid[1])
log_info (_("okay, we are the anonymous recipient.\n"));
search_for_secret_keys = 0;
break;
}
else if (gpg_err_code (rc) == GPG_ERR_FULLY_CANCELED)
{
search_for_secret_keys = 0;
break; /* Don't try any more secret keys. */
}
enum_secret_keys (ctrl, &enum_context, NULL); /* free context */
}
leave:
}
enum_secret_keys (ctrl, &enum_context, NULL); /* free context */
free_public_key (sk);
if (DBG_CLOCK)
log_clock ("get_session_key leave");
return rc;
@ -166,7 +166,7 @@ get_session_key (ctrl_t ctrl, PKT_pubkey_enc * k, DEK * dek)
static gpg_error_t
get_it (ctrl_t ctrl,
PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
struct pubkey_enc_list *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
{
gpg_error_t err;
byte *frame = NULL;

2
g10/test-stubs.c
View File

@ -253,7 +253,7 @@ read_key_from_file (ctrl_t ctrl, const char *fname, kbnode_t *r_keyblock)
* No encryption here but mainproc links to these functions.
*/
gpg_error_t
get_session_key (ctrl_t ctrl, PKT_pubkey_enc *k, DEK *dek)
get_session_key (ctrl_t ctrl, struct pubkey_enc_list *k, DEK *dek)
{
(void)ctrl;
(void)k;