/*****************************************************************************
* acl.c:
*****************************************************************************
* Copyright © 2005-2007 Rémi Denis-Courmont
* $Id$
*
* Authors: Rémi Denis-Courmont <rem # videolan.org>
*
* 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 02110-1301, USA.
*****************************************************************************/
/*****************************************************************************
* Preamble
*****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "vlc_common.h"
#include <ctype.h>
#include "vlc_acl.h"
#include <errno.h>
#include "vlc_network.h"
#include "vlc_charset.h"
/* FIXME: rwlock on acl, but libvlc doesn't implement rwlock */
typedef struct vlc_acl_entry_t
{
uint8_t host[17];
uint8_t i_bytes_match;
uint8_t i_bits_mask;
bool b_allow;
} vlc_acl_entry_t;
struct vlc_acl_t
{
vlc_object_t *p_owner;
unsigned i_size;
vlc_acl_entry_t *p_entries;
bool b_allow_default;
};
static int ACL_Resolve( vlc_object_t *p_this, uint8_t *p_bytes,
const char *psz_ip )
{
struct addrinfo hints, *res;
int i_family;
memset (&hints, 0, sizeof (hints));
hints.ai_socktype = SOCK_STREAM; /* doesn't matter */
hints.ai_flags = AI_NUMERICHOST;
if( vlc_getaddrinfo( p_this, psz_ip, 0, &hints, &res ) )
{
msg_Err( p_this, "invalid IP address %s", psz_ip );
return -1;
}
p_bytes[16] = 0; /* avoids overflowing when i_bytes_match = 16 */
i_family = res->ai_addr->sa_family;
switch( i_family )
{
case AF_INET:
{
struct sockaddr_in *addr;
addr = (struct sockaddr_in *)res->ai_addr;
memset( p_bytes, 0, 12 );
memcpy( p_bytes + 12, &addr->sin_addr, 4 );
break;
}
#if defined (HAVE_GETADDRINFO) || defined (WIN32)
/* unfortunately many people define AF_INET6
though they don't have struct sockaddr_in6 */
case AF_INET6:
{
struct sockaddr_in6 *addr;
addr = (struct sockaddr_in6 *)res->ai_addr;
memcpy( p_bytes, &addr->sin6_addr, 16 );
break;
}
#endif
default:
msg_Err( p_this, "unknown address family" );
vlc_freeaddrinfo( res );
return -1;
}
vlc_freeaddrinfo( res );
return i_family;
}
/**
* Check if a given address passes an access control list.
*
* @param p_acl pre-existing ACL to match the address against
* @param psz_ip numeric IPv4/IPv6 address
*
* @return 0 if the first matching ACL entry is an access grant,
* 1 if the first matching ACL entry is a denial of access,
* -1 on error.
*/
int ACL_Check( vlc_acl_t *p_acl, const char *psz_ip )
{
const vlc_acl_entry_t *p_cur, *p_end;
uint8_t host[17];
if( p_acl == NULL )
return -1;
p_cur = p_acl->p_entries;
p_end = p_cur + p_acl->i_size;
if( ACL_Resolve( p_acl->p_owner, host, psz_ip ) < 0 )
return -1;
while (p_cur < p_end)
{
unsigned i;
i = p_cur->i_bytes_match;
if( (memcmp( p_cur->host, host, i ) == 0)
&& (((p_cur->host[i] ^ host[i]) & p_cur->i_bits_mask) == 0) )
return !p_cur->b_allow;
p_cur++;
}
return !p_acl->b_allow_default;
}
/**
* Adds an item to an ACL.
* Items are always matched in the same order as they are added.
*/
int ACL_AddNet( vlc_acl_t *p_acl, const char *psz_ip, int i_len,
bool b_allow )
{
vlc_acl_entry_t *p_ent;
unsigned i_size;
div_t d;
int i_family;
i_size = p_acl->i_size;
p_ent = (vlc_acl_entry_t *)realloc( p_acl->p_entries,
++p_acl->i_size * sizeof( *p_ent ) );
if( p_ent == NULL )
return -1;
p_acl->p_entries = p_ent;
p_ent += i_size;
i_family = ACL_Resolve( p_acl->p_owner, p_ent->host, psz_ip );
if( i_family < 0 )
{
/*
* I'm lazy : memory space will be re-used in the next ACL_Add call...
* or not.
*/
p_acl->i_size--;
return -1;
}
if( i_len >= 0 )
{
if( i_family == AF_INET )
i_len += 96;
if( i_len > 128 )
i_len = 128;
}
else
i_len = 128; /* ACL_AddHost */
d = div( i_len, 8 );
p_ent->i_bytes_match = d.quot;
p_ent->i_bits_mask = 0xff << (8 - d.rem);
p_ent->b_allow = b_allow;
return 0;
}
/**
* Creates an empty ACL.
*
* @param b_allow whether to grant (true) or deny (false) access
* by default (ie if none of the ACL entries matched).
*
* @return an ACL object. NULL in case of error.
*/
vlc_acl_t *__ACL_Create( vlc_object_t *p_this, bool b_allow )
{
vlc_acl_t *p_acl;
p_acl = (vlc_acl_t *)malloc( sizeof( *p_acl ) );
if( p_acl == NULL )
return NULL;
vlc_object_yield( p_this );
p_acl->p_owner = p_this;
p_acl->i_size = 0;
p_acl->p_entries = NULL;
p_acl->b_allow_default = b_allow;
return p_acl;
}
/**
* Perform a deep copy of an existing ACL.
*
* @param p_this object to attach the copy to.
* @param p_acl ACL object to be copied.
*
* @return a new ACL object, or NULL on error.
*/
vlc_acl_t *__ACL_Duplicate( vlc_object_t *p_this, const vlc_acl_t *p_acl )
{
vlc_acl_t *p_dupacl;
if( p_acl == NULL )
return NULL;
p_dupacl = (vlc_acl_t *)malloc( sizeof( *p_dupacl ) );
if( p_dupacl == NULL )
return NULL;
if( p_acl->i_size )
{
p_dupacl->p_entries = (vlc_acl_entry_t *)
malloc( p_acl->i_size * sizeof( vlc_acl_entry_t ) );
if( p_dupacl->p_entries == NULL )
{
free( p_dupacl );
return NULL;
}
memcpy( p_dupacl->p_entries, p_acl->p_entries,
p_acl->i_size * sizeof( vlc_acl_entry_t ) );
}
else
p_dupacl->p_entries = NULL;
vlc_object_yield( p_this );
p_dupacl->p_owner = p_this;
p_dupacl->i_size = p_acl->i_size;
p_dupacl->b_allow_default = p_acl->b_allow_default;
return p_dupacl;
}
/**
* Releases all resources associated with an ACL object.
*/
void ACL_Destroy( vlc_acl_t *p_acl )
{
if( p_acl != NULL )
{
if( p_acl->p_entries != NULL )
free( p_acl->p_entries );
vlc_object_release( p_acl->p_owner );
free( p_acl );
}
}
/**
* Reads ACL entries from a file.
*
* @param p_acl ACL object in which to insert parsed entries.
* @param psz_patch filename from which to parse entries.
*
* @return 0 on success, -1 on error.
*/
int ACL_LoadFile( vlc_acl_t *p_acl, const char *psz_path )
{
FILE *file;
if( p_acl == NULL )
return -1;
file = utf8_fopen( psz_path, "r" );
if( file == NULL )
return -1;
msg_Dbg( p_acl->p_owner, "find .hosts in dir=%s", psz_path );
while( !feof( file ) )
{
char line[1024], *psz_ip, *ptr;
if( fgets( line, sizeof( line ), file ) == NULL )
{
if( ferror( file ) )
{
msg_Err( p_acl->p_owner, "error reading %s : %m", psz_path );
goto error;
}
continue;
}
/* fgets() is cool : never overflow, always nul-terminate */
psz_ip = line;
/* skips blanks - cannot overflow given '\0' is not space */
while( isspace( *psz_ip ) )
psz_ip++;
if( *psz_ip == '\0' ) /* empty/blank line */
continue;
ptr = strchr( psz_ip, '\n' );
if( ptr == NULL )
{
msg_Warn( p_acl->p_owner, "skipping overly long line in %s",
psz_path);
do
{
if( fgets( line, sizeof( line ), file ) == NULL )
{
if( ferror( file ) )
{
msg_Err( p_acl->p_owner, "error reading %s : %m",
psz_path );
}
goto error;
}
}
while( strchr( line, '\n' ) == NULL);
continue; /* skip unusable line */
}
/* skips comment-only line */
if( *psz_ip == '#' )
continue;
/* looks for first space, CR, LF, etc. or end-of-line comment */
/* (there is at least a linefeed) */
for( ptr = psz_ip; ( *ptr != '#' ) && !isspace( *ptr ); ptr++ );
*ptr = '\0';
msg_Dbg( p_acl->p_owner, "restricted to %s", psz_ip );
ptr = strchr( psz_ip, '/' );
if( ptr != NULL )
*ptr++ = '\0'; /* separate address from mask length */
if( (ptr != NULL)
? ACL_AddNet( p_acl, psz_ip, atoi( ptr ), true )
: ACL_AddHost( p_acl, psz_ip, true ) )
{
msg_Err( p_acl->p_owner, "cannot add ACL from %s", psz_path );
continue;
}
}
fclose( file );
return 0;
error:
fclose( file );
return -1;
}
