pidgin/pidgin

certificate: Use public key fingerprint to compare certificates
release-2.x.y
2017-03-07, dx
887efbd652d8
certificate: Use public key fingerprint to compare certificates

This fixes an issue with google talk's certificates and gnutls, where the root
certificate in the provided chain is a slightly different version of the one
that is usually present in the certificate stores, but the SubjectPublicKeyInfo
section is the same.

This adds a PurpleCertificateScheme function, compare_pubkeys, and its wrapper
purple_certificate_compare_pubkeys().

This is only implemented for gnutls, since the NSS plugin only uses the NSS
certificate validation code. Even if that path was reachable from a plugin that
doesn't implement this method, it would return FALSE and behave as if this bug
was never fixed.

The gnutls implementation uses the gnutls_x509_crt_get_key_id() function,
which returns a hash of the SubjectPublicKeyInfo section of the certificate.

In gnutls versions older than 3.4.1, this may be a SHA1 hash, but after that
version SHA256 support was added (without much fanfare - the documentation
barely mentions this at all), and we just use the constant for the best known
algo, which for current versions is just SHA256. Older versions ignore that
flag parameter.

The whole comparison is modeled after the private _gnutls_check_if_same_key(),
which checks if both certificates have the same DN ("unique id") and does a
memcmp() of the raw SPKI section. We don't have direct access to the raw SPKI
section but comparing their fingerprints is good enough.
/**
* @file value.c Value wrapper API
* @ingroup core
*/
/* purple
*
* Purple is the legal property of its developers, whose names are too numerous
* to list here. Please refer to the COPYRIGHT file distributed with this
* source distribution.
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA
*/
#include "internal.h"
#include "value.h"
#define OUTGOING_FLAG 0x01
PurpleValue *
purple_value_new(PurpleType type, ...)
{
PurpleValue *value;
va_list args;
g_return_val_if_fail(type != PURPLE_TYPE_UNKNOWN, NULL);
value = g_new0(PurpleValue, 1);
value->type = type;
va_start(args, type);
if (type == PURPLE_TYPE_SUBTYPE)
value->u.subtype = va_arg(args, int);
else if (type == PURPLE_TYPE_BOXED)
value->u.specific_type = g_strdup(va_arg(args, char *));
va_end(args);
return value;
}
PurpleValue *
purple_value_new_outgoing(PurpleType type, ...)
{
PurpleValue *value;
va_list args;
g_return_val_if_fail(type != PURPLE_TYPE_UNKNOWN, NULL);
value = g_new0(PurpleValue, 1);
value->type = type;
va_start(args, type);
if (type == PURPLE_TYPE_SUBTYPE)
value->u.subtype = va_arg(args, int);
else if (type == PURPLE_TYPE_BOXED)
value->u.specific_type = g_strdup(va_arg(args, char *));
va_end(args);
value->flags |= OUTGOING_FLAG;
return value;
}
void
purple_value_destroy(PurpleValue *value)
{
g_return_if_fail(value != NULL);
if (purple_value_get_type(value) == PURPLE_TYPE_BOXED)
{
g_free(value->u.specific_type);
}
else if (purple_value_get_type(value) == PURPLE_TYPE_STRING)
{
g_free(value->data.string_data);
}
g_free(value);
}
PurpleValue *
purple_value_dup(const PurpleValue *value)
{
PurpleValue *new_value;
PurpleType type;
g_return_val_if_fail(value != NULL, NULL);
type = purple_value_get_type(value);
if (type == PURPLE_TYPE_SUBTYPE)
{
new_value = purple_value_new(PURPLE_TYPE_SUBTYPE,
purple_value_get_subtype(value));
}
else if (type == PURPLE_TYPE_BOXED)
{
new_value = purple_value_new(PURPLE_TYPE_BOXED,
purple_value_get_specific_type(value));
}
else
new_value = purple_value_new(type);
new_value->flags = value->flags;
switch (type)
{
case PURPLE_TYPE_CHAR:
purple_value_set_char(new_value, purple_value_get_char(value));
break;
case PURPLE_TYPE_UCHAR:
purple_value_set_uchar(new_value, purple_value_get_uchar(value));
break;
case PURPLE_TYPE_BOOLEAN:
purple_value_set_boolean(new_value, purple_value_get_boolean(value));
break;
case PURPLE_TYPE_SHORT:
purple_value_set_short(new_value, purple_value_get_short(value));
break;
case PURPLE_TYPE_USHORT:
purple_value_set_ushort(new_value, purple_value_get_ushort(value));
break;
case PURPLE_TYPE_INT:
purple_value_set_int(new_value, purple_value_get_int(value));
break;
case PURPLE_TYPE_UINT:
purple_value_set_uint(new_value, purple_value_get_uint(value));
break;
case PURPLE_TYPE_LONG:
purple_value_set_long(new_value, purple_value_get_long(value));
break;
case PURPLE_TYPE_ULONG:
purple_value_set_ulong(new_value, purple_value_get_ulong(value));
break;
case PURPLE_TYPE_INT64:
purple_value_set_int64(new_value, purple_value_get_int64(value));
break;
case PURPLE_TYPE_UINT64:
purple_value_set_uint64(new_value, purple_value_get_uint64(value));
break;
case PURPLE_TYPE_STRING:
purple_value_set_string(new_value, purple_value_get_string(value));
break;
case PURPLE_TYPE_OBJECT:
purple_value_set_object(new_value, purple_value_get_object(value));
break;
case PURPLE_TYPE_POINTER:
purple_value_set_pointer(new_value, purple_value_get_pointer(value));
break;
case PURPLE_TYPE_ENUM:
purple_value_set_enum(new_value, purple_value_get_enum(value));
break;
case PURPLE_TYPE_BOXED:
purple_value_set_boxed(new_value, purple_value_get_boxed(value));
break;
default:
break;
}
return new_value;
}
PurpleType
purple_value_get_type(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, PURPLE_TYPE_UNKNOWN);
return value->type;
}
unsigned int
purple_value_get_subtype(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
g_return_val_if_fail(purple_value_get_type(value) == PURPLE_TYPE_SUBTYPE, 0);
return value->u.subtype;
}
const char *
purple_value_get_specific_type(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, NULL);
g_return_val_if_fail(purple_value_get_type(value) == PURPLE_TYPE_BOXED, NULL);
return value->u.specific_type;
}
gboolean
purple_value_is_outgoing(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, FALSE);
return (value->flags & OUTGOING_FLAG);
}
void
purple_value_set_char(PurpleValue *value, char data)
{
g_return_if_fail(value != NULL);
value->data.char_data = data;
}
void
purple_value_set_uchar(PurpleValue *value, unsigned char data)
{
g_return_if_fail(value != NULL);
value->data.uchar_data = data;
}
void
purple_value_set_boolean(PurpleValue *value, gboolean data)
{
g_return_if_fail(value != NULL);
value->data.boolean_data = data;
}
void
purple_value_set_short(PurpleValue *value, short data)
{
g_return_if_fail(value != NULL);
value->data.short_data = data;
}
void
purple_value_set_ushort(PurpleValue *value, unsigned short data)
{
g_return_if_fail(value != NULL);
value->data.ushort_data = data;
}
void
purple_value_set_int(PurpleValue *value, int data)
{
g_return_if_fail(value != NULL);
value->data.int_data = data;
}
void
purple_value_set_uint(PurpleValue *value, unsigned int data)
{
g_return_if_fail(value != NULL);
value->data.int_data = data;
}
void
purple_value_set_long(PurpleValue *value, long data)
{
g_return_if_fail(value != NULL);
value->data.long_data = data;
}
void
purple_value_set_ulong(PurpleValue *value, unsigned long data)
{
g_return_if_fail(value != NULL);
value->data.long_data = data;
}
void
purple_value_set_int64(PurpleValue *value, gint64 data)
{
g_return_if_fail(value != NULL);
value->data.int64_data = data;
}
void
purple_value_set_uint64(PurpleValue *value, guint64 data)
{
g_return_if_fail(value != NULL);
value->data.uint64_data = data;
}
void
purple_value_set_string(PurpleValue *value, const char *data)
{
g_return_if_fail(value != NULL);
g_return_if_fail(data == NULL || g_utf8_validate(data, -1, NULL));
g_free(value->data.string_data);
value->data.string_data = g_strdup(data);
}
void
purple_value_set_object(PurpleValue *value, void *data)
{
g_return_if_fail(value != NULL);
value->data.object_data = data;
}
void
purple_value_set_pointer(PurpleValue *value, void *data)
{
g_return_if_fail(value != NULL);
value->data.pointer_data = data;
}
void
purple_value_set_enum(PurpleValue *value, int data)
{
g_return_if_fail(value != NULL);
value->data.enum_data = data;
}
void
purple_value_set_boxed(PurpleValue *value, void *data)
{
g_return_if_fail(value != NULL);
value->data.boxed_data = data;
}
char
purple_value_get_char(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.char_data;
}
unsigned char
purple_value_get_uchar(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.uchar_data;
}
gboolean
purple_value_get_boolean(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, FALSE);
return value->data.boolean_data;
}
short
purple_value_get_short(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.short_data;
}
unsigned short
purple_value_get_ushort(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.ushort_data;
}
int
purple_value_get_int(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.int_data;
}
unsigned int
purple_value_get_uint(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.int_data;
}
long
purple_value_get_long(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.long_data;
}
unsigned long
purple_value_get_ulong(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.long_data;
}
gint64
purple_value_get_int64(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.int64_data;
}
guint64
purple_value_get_uint64(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, 0);
return value->data.uint64_data;
}
const char *
purple_value_get_string(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, NULL);
return value->data.string_data;
}
void *
purple_value_get_object(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, NULL);
return value->data.object_data;
}
void *
purple_value_get_pointer(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, NULL);
return value->data.pointer_data;
}
int
purple_value_get_enum(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, -1);
return value->data.enum_data;
}
void *
purple_value_get_boxed(const PurpleValue *value)
{
g_return_val_if_fail(value != NULL, NULL);
return value->data.boxed_data;
}