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Implemented PKA trust model

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This commit is contained in:
Werner Koch 2005-07-28 18:59:36 +00:00
parent a1cdf3c75f
commit 986a137c58
19 changed files with 576 additions and 62 deletions
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20
g10/ChangeLog
View file

@ -1,3 +1,23 @@
2005-07-28 Werner Koch <wk@g10code.com>
* Makefile.am (other_libs): Add SRVLIBS.
* parse-packet.c (can_handle_critical_notation): We know about
pka-address@gnupg.org.
* packet.h (PKT_signature): New fields PKA_INFO and PKA_TRIED.
(pka_info_t): New.
* free-packet.c (cp_pka_info): New.
(free_seckey_enc, copy_signature): Support new fields.
* mainproc.c (get_pka_address, pka_uri_from_sig): New.
(check_sig_and_print): Try to get the keyserver from the PKA
record.
* pkclist.c (check_signatures_trust): Adjust the trust based on
the PKA.
* gpgv.c (parse_keyserver_uri): New stub.
* keygen.c (has_invalid_email_chars): Moved to ..
* misc.c (has_invalid_email_chars): .. here and made global.
2005-07-27 Werner Koch <wk@g10code.com>
* export.c (do_export_stream): Make two strings translatable.

2
g10/Makefile.am
View file

@ -28,7 +28,7 @@ if ! HAVE_DOSISH_SYSTEM
AM_CFLAGS = -DGNUPG_LIBEXECDIR="\"$(libexecdir)/@PACKAGE@\""
endif
needed_libs = ../cipher/libcipher.a ../mpi/libmpi.a ../util/libutil.a
other_libs = $(LIBICONV) $(LIBINTL) $(CAPLIBS)
other_libs = $(LIBICONV) $(SRVLIBS) $(LIBINTL) $(CAPLIBS)
bin_PROGRAMS = gpg gpgv

29
g10/free-packet.c
View file

@ -1,6 +1,6 @@
/* free-packet.c - cleanup stuff for packets
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
* Free Software Foundation, Inc.
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
* 2005 Free Software Foundation, Inc.
*
* This file is part of GnuPG.
*
@ -62,10 +62,17 @@ free_seckey_enc( PKT_signature *sig )
mpi_free(sig->data[0]);
for(i=0; i < n; i++ )
mpi_free( sig->data[i] );
xfree(sig->revkey);
xfree(sig->hashed);
xfree(sig->unhashed);
if (sig->pka_info)
{
xfree (sig->pka_info->uri);
xfree (sig->pka_info);
}
xfree(sig);
}
@ -195,6 +202,21 @@ copy_public_parts_to_secret_key( PKT_public_key *pk, PKT_secret_key *sk )
sk->keyid[1] = pk->keyid[1];
}
static pka_info_t *
cp_pka_info (const pka_info_t *s)
{
pka_info_t *d = xmalloc (sizeof *s + strlen (s->email));
d->valid = s->valid;
d->checked = s->checked;
d->uri = s->uri? xstrdup (s->uri):NULL;
memcpy (d->fpr, s->fpr, sizeof s->fpr);
strcpy (d->email, s->email);
return d;
}
PKT_signature *
copy_signature( PKT_signature *d, PKT_signature *s )
{
@ -210,6 +232,7 @@ copy_signature( PKT_signature *d, PKT_signature *s )
for(i=0; i < n; i++ )
d->data[i] = mpi_copy( s->data[i] );
}
d->pka_info = s->pka_info? cp_pka_info (s->pka_info) : NULL;
d->hashed = cp_subpktarea (s->hashed);
d->unhashed = cp_subpktarea (s->unhashed);
if(s->numrevkeys)

7
g10/gpgv.c
View file

@ -333,6 +333,13 @@ passphrase_to_dek( u32 *keyid, int pubkey_algo,
}
struct keyserver_spec *parse_preferred_keyserver(PKT_signature *sig) {return NULL;}
struct keyserver_spec *parse_keyserver_uri(const char *uri,int require_scheme,
const char *configname,
unsigned int configlineno)
{
return NULL;
}
void free_keyserver_spec(struct keyserver_spec *keyserver) {}
/* Stubs to avoid linking to photoid.c */

21
g10/keygen.c
View file

@ -1609,27 +1609,6 @@ ask_expiredate()
return x? make_timestamp() + x : 0;
}
static int
has_invalid_email_chars( const char *s )
{
int at_seen=0;
static char valid_chars[] = "01234567890_-."
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
for( ; *s; s++ ) {
if( *s & 0x80 )
return 1;
if( *s == '@' )
at_seen=1;
else if( !at_seen && !( !!strchr( valid_chars, *s ) || *s == '+' ) )
return 1;
else if( at_seen && !strchr( valid_chars, *s ) )
return 1;
}
return 0;
}
static char *
ask_user_id( int mode )

1
g10/main.h
View file

@ -125,6 +125,7 @@ char *argsplit(char *string);
int parse_options(char *str,unsigned int *options,
struct parse_options *opts,int noisy);
char *unescape_percent_string (const unsigned char *s);
int has_invalid_email_chars (const char *s);
char *default_homedir (void);
const char *get_libexecdir (void);

115
g10/mainproc.c
View file

@ -1296,6 +1296,86 @@ do_proc_packets( CTX c, IOBUF a )
}
/* Helper for pka_uri_from_sig to parse the to-be-verified address out
of the notation data. */
static pka_info_t *
get_pka_address (PKT_signature *sig)
{
const unsigned char *p;
size_t len, n1, n2;
int seq = 0;
pka_info_t *pka = NULL;
while ((p = enum_sig_subpkt (sig->hashed, SIGSUBPKT_NOTATION,
&len, &seq, NULL)))
{
if (len < 8)
continue; /* Notation packet is too short. */
n1 = (p[4]<<8)|p[5];
n2 = (p[6]<<8)|p[7];
if (8 + n1 + n2 != len)
continue; /* Length fields of notation packet are inconsistent. */
p += 8;
if (n1 != 21 || memcmp (p, "pka-address@gnupg.org", 21))
continue; /* Not the notation we want. */
p += n1;
if (n2 < 3)
continue; /* Impossible email address. */
if (pka)
break; /* For now we only use the first valid PKA notation. In
future we might want to keep additional PKA
notations in a linked list. */
pka = xmalloc (sizeof *pka + n2);
pka->valid = 0;
pka->checked = 0;
pka->uri = NULL;
memcpy (pka->email, p, n2);
pka->email[n2] = 0;
if (has_invalid_email_chars (pka->email))
{
/* We don't accept invalid mail addresses. */
xfree (pka);
pka = NULL;
}
}
return pka;
}
/* Return the URI from a DNS PKA record. If this record has already
be retrieved for the signature we merely return it; if not we go
out and try to get that DNS record. */
static const char *
pka_uri_from_sig (PKT_signature *sig)
{
if (!sig->flags.pka_tried)
{
assert (!sig->pka_info);
sig->flags.pka_tried = 1;
sig->pka_info = get_pka_address (sig);
if (sig->pka_info)
{
char *uri;
uri = get_pka_info (sig->pka_info->email, sig->pka_info->fpr);
if (uri)
{
sig->pka_info->valid = 1;
if (!*uri)
xfree (uri);
else
sig->pka_info->uri = uri;
}
}
}
return sig->pka_info? sig->pka_info->uri : NULL;
}
static int
check_sig_and_print( CTX c, KBNODE node )
{
@ -1419,8 +1499,34 @@ check_sig_and_print( CTX c, KBNODE node )
}
}
/* If the preferred keyserver thing above didn't work, this is a
second try. */
/* If the preferred keyserver thing above didn't work, our second
try is to use the URI from a DNS PKA record. */
if ( rc == G10ERR_NO_PUBKEY )
{
const char *uri = pka_uri_from_sig (sig);
if (uri)
{
int res;
struct keyserver_spec *spec;
spec = parse_keyserver_uri (uri, 0, NULL, 0);
if (spec)
{
glo_ctrl.in_auto_key_retrieve++;
res = keyserver_import_keyid (sig->keyid, spec);
glo_ctrl.in_auto_key_retrieve--;
free_keyserver_spec (spec);
if (!res)
rc = do_check_sig(c, node, NULL, &is_expkey, &is_revkey );
}
}
}
/* If the preferred keyserver thing above didn't work and we got
no information from the DNS PKA, this is a third try. */
if( rc == G10ERR_NO_PUBKEY && opt.keyserver
&& (opt.keyserver_options.options&KEYSERVER_AUTO_KEY_RETRIEVE))
@ -1673,8 +1779,11 @@ check_sig_and_print( CTX c, KBNODE node )
free_public_key( vpk );
}
if( !rc )
if (!rc)
{
pka_uri_from_sig (sig); /* Make sure PKA info is available. */
rc = check_signatures_trust( sig );
}
if(sig->flags.expired)
{

25
g10/misc.c
View file

@ -1065,6 +1065,31 @@ unescape_percent_string (const unsigned char *s)
int
has_invalid_email_chars (const char *s)
{
int at_seen=0;
static char valid_chars[] = ("01234567890_-."
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ");
for ( ; *s; s++ )
{
if ( *s & 0x80 )
return 1;
if ( *s == '@' )
at_seen=1;
else if ( !at_seen && !( !!strchr( valid_chars, *s ) || *s == '+' ) )
return 1;
else if ( at_seen && !strchr( valid_chars, *s ) )
return 1;
}
return 0;
}
/* This is a helper function to load a Windows function from either of
one DLLs. */
#ifdef HAVE_W32_SYSTEM

80
g10/packet.h
View file

@ -122,36 +122,56 @@ struct revocation_key {
byte fpr[MAX_FINGERPRINT_LEN];
};
typedef struct {
struct {
unsigned checked:1; /* signature has been checked */
unsigned valid:1; /* signature is good (if checked is set) */
unsigned chosen_selfsig:1; /* a selfsig that is the chosen one */
unsigned unknown_critical:1;
unsigned exportable:1;
unsigned revocable:1;
unsigned policy_url:1; /* At least one policy URL is present */
unsigned notation:1; /* At least one notation is present */
unsigned pref_ks:1; /* At least one preferred keyserver is present */
unsigned expired:1;
} flags;
u32 keyid[2]; /* 64 bit keyid */
u32 timestamp; /* signature made */
u32 expiredate; /* expires at this date or 0 if not at all */
byte version;
byte sig_class; /* sig classification, append for MD calculation*/
byte pubkey_algo; /* algorithm used for public key scheme */
/* (PUBKEY_ALGO_xxx) */
byte digest_algo; /* algorithm used for digest (DIGEST_ALGO_xxxx) */
byte trust_depth;
byte trust_value;
const byte *trust_regexp;
struct revocation_key **revkey;
int numrevkeys;
subpktarea_t *hashed; /* all subpackets with hashed data (v4 only) */
subpktarea_t *unhashed; /* ditto for unhashed data */
byte digest_start[2]; /* first 2 bytes of the digest */
MPI data[PUBKEY_MAX_NSIG];
/* Object to keep information about a PKA DNS record. */
typedef struct
{
int valid; /* An actual PKA record exists for EMAIL. */
int checked; /* Set to true if the FPR has been checked against the
actual key. */
char *uri; /* Malloced string with the URI. NULL if the URI is
not available.*/
unsigned char fpr[20]; /* The fingerprint as stored in the PKA RR. */
char email[1];/* The email address from the notation data. */
} pka_info_t;
/* Object to keep information pertaining to a signature. */
typedef struct
{
struct
{
unsigned checked:1; /* Signature has been checked. */
unsigned valid:1; /* Signature is good (if checked is set). */
unsigned chosen_selfsig:1; /* A selfsig that is the chosen one. */
unsigned unknown_critical:1;
unsigned exportable:1;
unsigned revocable:1;
unsigned policy_url:1; /* At least one policy URL is present */
unsigned notation:1; /* At least one notation is present */
unsigned pref_ks:1; /* At least one preferred keyserver is present */
unsigned expired:1;
unsigned pka_tried:1; /* Set if we tried to retrieve the PKA record. */
} flags;
u32 keyid[2]; /* 64 bit keyid */
u32 timestamp; /* Signature made (seconds since Epoch). */
u32 expiredate; /* Expires at this date or 0 if not at all. */
byte version;
byte sig_class; /* Sig classification, append for MD calculation. */
byte pubkey_algo; /* Algorithm used for public key scheme */
/* (PUBKEY_ALGO_xxx) */
byte digest_algo; /* Algorithm used for digest (DIGEST_ALGO_xxxx). */
byte trust_depth;
byte trust_value;
const byte *trust_regexp;
struct revocation_key **revkey;
int numrevkeys;
pka_info_t *pka_info; /* Malloced PKA data or NULL if not
available. See also flags.pka_tried. */
subpktarea_t *hashed; /* All subpackets with hashed data (v4 only). */
subpktarea_t *unhashed; /* Ditto for unhashed data. */
byte digest_start[2]; /* First 2 bytes of the digest. */
MPI data[PUBKEY_MAX_NSIG];
} PKT_signature;
#define ATTRIB_IMAGE 1

2
g10/parse-packet.c
View file

@ -1042,6 +1042,8 @@ can_handle_critical_notation(const byte *name,size_t len)
{
if(len==32 && memcmp(name,"preferred-email-encoding@pgp.com",32)==0)
return 1;
if(len==21 && memcmp(name,"pka-address@gnupg.org",21)==0)
return 1;
return 0;
}

42
g10/pkclist.c
View file

@ -532,6 +532,48 @@ check_signatures_trust( PKT_signature *sig )
if ((trustlevel & TRUST_FLAG_DISABLED))
log_info (_("Note: This key has been disabled.\n"));
/* If we have PKA information adjust the trustlevel. */
if (sig->pka_info && sig->pka_info->valid)
{
unsigned char fpr[MAX_FINGERPRINT_LEN];
PKT_public_key *primary_pk;
size_t fprlen;
int okay;
log_info (_("Note: Verified address is `%s'\n"), sig->pka_info->email);
primary_pk = xmalloc_clear (sizeof *primary_pk);
get_pubkey (primary_pk, pk->main_keyid);
fingerprint_from_pk (primary_pk, fpr, &fprlen);
free_public_key (primary_pk);
if ( fprlen == 20 && !memcmp (sig->pka_info->fpr, fpr, 20) )
okay = 1;
else
okay = 0;
switch ( (trustlevel & TRUST_MASK) )
{
case TRUST_UNKNOWN:
case TRUST_UNDEFINED:
case TRUST_MARGINAL:
if (okay)
{
trustlevel = ((trustlevel & ~TRUST_MASK) | TRUST_FULLY);
log_info ("trustlevel adjusted to FULL due to valid PKA info\n");
}
/* (fall through) */
case TRUST_FULLY:
if (!okay)
{
trustlevel = ((trustlevel & ~TRUST_MASK) | TRUST_NEVER);
log_info ("trustlevel adjusted to NEVER due to bad PKA info\n");
}
break;
}
}
/* Now let the user know what up with the trustlevel. */
switch ( (trustlevel & TRUST_MASK) )
{
case TRUST_EXPIRED: