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transmission/libtransmission/bencode.c

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/*
* This file Copyright (C) Mnemosyne LLC
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id$
*/
#include <assert.h>
#include <ctype.h> /* isdigit() */
#include <errno.h>
#include <math.h> /* fabs() */
#include <stdio.h> /* rename() */
#include <string.h>
#ifdef WIN32 /* tr_mkstemp() */
#include <fcntl.h>
#define _S_IREAD 256
#define _S_IWRITE 128
#endif
#include <locale.h> /* setlocale() */
#include <unistd.h> /* write(), unlink() */
#include <event2/buffer.h>
#include "ConvertUTF.h"
#include "transmission.h"
#include "bencode.h"
#include "fdlimit.h" /* tr_close_file() */
#include "json.h"
#include "list.h"
#include "platform.h" /* TR_PATH_MAX */
#include "ptrarray.h"
#include "utils.h" /* tr_new(), tr_free() */
#ifndef ENODATA
#define ENODATA EIO
#endif
/**
***
**/
static tr_bool
isContainer( const tr_benc * val )
{
return tr_bencIsList( val ) || tr_bencIsDict( val );
}
static tr_bool
isSomething( const tr_benc * val )
{
return isContainer( val ) || tr_bencIsInt( val )
|| tr_bencIsString( val )
|| tr_bencIsReal( val )
|| tr_bencIsBool( val );
}
static void
tr_bencInit( tr_benc * val, char type )
{
memset( val, 0, sizeof( *val ) );
val->type = type;
}
/***
**** tr_bencParse()
**** tr_bencLoad()
***/
/**
* The initial i and trailing e are beginning and ending delimiters.
* You can have negative numbers such as i-3e. You cannot prefix the
* number with a zero such as i04e. However, i0e is valid.
* Example: i3e represents the integer "3"
* NOTE: The maximum number of bit of this integer is unspecified,
* but to handle it as a signed 64bit integer is mandatory to handle
* "large files" aka .torrent for more that 4Gbyte
*/
int
tr_bencParseInt( const uint8_t * buf,
const uint8_t * bufend,
const uint8_t ** setme_end,
int64_t * setme_val )
{
char * endptr;
const void * begin;
const void * end;
int64_t val;
if( buf >= bufend )
return EILSEQ;
if( *buf != 'i' )
return EILSEQ;
begin = buf + 1;
end = memchr( begin, 'e', ( bufend - buf ) - 1 );
if( end == NULL )
return EILSEQ;
errno = 0;
val = evutil_strtoll( begin, &endptr, 10 );
if( errno || ( endptr != end ) ) /* incomplete parse */
return EILSEQ;
if( val && *(const char*)begin == '0' ) /* no leading zeroes! */
return EILSEQ;
*setme_end = (const uint8_t*)end + 1;
*setme_val = val;
return 0;
}
/**
* Byte strings are encoded as follows:
* <string length encoded in base ten ASCII>:<string data>
* Note that there is no constant beginning delimiter, and no ending delimiter.
* Example: 4:spam represents the string "spam"
*/
int
tr_bencParseStr( const uint8_t * buf,
const uint8_t * bufend,
const uint8_t ** setme_end,
const uint8_t ** setme_str,
size_t * setme_strlen )
{
size_t len;
const void * end;
char * endptr;
if( buf >= bufend )
return EILSEQ;
if( !isdigit( *buf ) )
return EILSEQ;
end = memchr( buf, ':', bufend - buf );
if( end == NULL )
return EILSEQ;
errno = 0;
len = strtoul( (const char*)buf, &endptr, 10 );
if( errno || endptr != end )
return EILSEQ;
if( (const uint8_t*)end + 1 + len > bufend )
return EILSEQ;
*setme_end = (const uint8_t*)end + 1 + len;
*setme_str = (const uint8_t*)end + 1;
*setme_strlen = len;
return 0;
}
/* set to 1 to help expose bugs with tr_bencListAdd and tr_bencDictAdd */
#define LIST_SIZE 4 /* number of items to increment list/dict buffer by */
static int
makeroom( tr_benc * val,
size_t count )
{
assert( TR_TYPE_LIST == val->type || TR_TYPE_DICT == val->type );
if( val->val.l.count + count > val->val.l.alloc )
{
/* We need a bigger boat */
const int len = val->val.l.alloc + count +
( count % LIST_SIZE ? LIST_SIZE -
( count % LIST_SIZE ) : 0 );
void * tmp = realloc( val->val.l.vals, len * sizeof( tr_benc ) );
if( !tmp )
return 1;
val->val.l.alloc = len;
val->val.l.vals = tmp;
}
return 0;
}
static tr_benc*
getNode( tr_benc * top,
tr_ptrArray * parentStack,
int type )
{
tr_benc * parent;
assert( top );
assert( parentStack );
if( tr_ptrArrayEmpty( parentStack ) )
return top;
parent = tr_ptrArrayBack( parentStack );
assert( parent );
/* dictionary keys must be strings */
if( ( parent->type == TR_TYPE_DICT )
&& ( type != TR_TYPE_STR )
&& ( !( parent->val.l.count % 2 ) ) )
return NULL;
makeroom( parent, 1 );
return parent->val.l.vals + parent->val.l.count++;
}
/**
* This function's previous recursive implementation was
* easier to read, but was vulnerable to a smash-stacking
* attack via maliciously-crafted bencoded data. (#667)
*/
static int
tr_bencParseImpl( const void * buf_in,
const void * bufend_in,
tr_benc * top,
tr_ptrArray * parentStack,
const uint8_t ** setme_end )
{
int err;
const uint8_t * buf = buf_in;
const uint8_t * bufend = bufend_in;
tr_bencInit( top, 0 );
while( buf != bufend )
{
if( buf > bufend ) /* no more text to parse... */
return 1;
if( *buf == 'i' ) /* int */
{
int64_t val;
const uint8_t * end;
tr_benc * node;
if( ( err = tr_bencParseInt( buf, bufend, &end, &val ) ) )
return err;
node = getNode( top, parentStack, TR_TYPE_INT );
if( !node )
return EILSEQ;
tr_bencInitInt( node, val );
buf = end;
if( tr_ptrArrayEmpty( parentStack ) )
break;
}
else if( *buf == 'l' ) /* list */
{
tr_benc * node = getNode( top, parentStack, TR_TYPE_LIST );
if( !node )
return EILSEQ;
tr_bencInit( node, TR_TYPE_LIST );
tr_ptrArrayAppend( parentStack, node );
++buf;
}
else if( *buf == 'd' ) /* dict */
{
tr_benc * node = getNode( top, parentStack, TR_TYPE_DICT );
if( !node )
return EILSEQ;
tr_bencInit( node, TR_TYPE_DICT );
tr_ptrArrayAppend( parentStack, node );
++buf;
}
else if( *buf == 'e' ) /* end of list or dict */
{
tr_benc * node;
++buf;
if( tr_ptrArrayEmpty( parentStack ) )
return EILSEQ;
node = tr_ptrArrayBack( parentStack );
if( tr_bencIsDict( node ) && ( node->val.l.count % 2 ) )
{
/* odd # of children in dict */
tr_bencFree( &node->val.l.vals[--node->val.l.count] );
return EILSEQ;
}
tr_ptrArrayPop( parentStack );
if( tr_ptrArrayEmpty( parentStack ) )
break;
}
else if( isdigit( *buf ) ) /* string? */
{
const uint8_t * end;
const uint8_t * str;
size_t str_len;
tr_benc * node;
if( ( err = tr_bencParseStr( buf, bufend, &end, &str, &str_len ) ) )
return err;
node = getNode( top, parentStack, TR_TYPE_STR );
if( !node )
return EILSEQ;
tr_bencInitStr( node, str, str_len );
buf = end;
if( tr_ptrArrayEmpty( parentStack ) )
break;
}
else /* invalid bencoded text... march past it */
{
++buf;
}
}
err = !isSomething( top ) || !tr_ptrArrayEmpty( parentStack );
if( !err && setme_end )
*setme_end = buf;
return err;
}
int
tr_bencParse( const void * buf,
const void * end,
tr_benc * top,
const uint8_t ** setme_end )
{
int err;
tr_ptrArray parentStack = TR_PTR_ARRAY_INIT;
top->type = 0; /* set to `uninitialized' */
err = tr_bencParseImpl( buf, end, top, &parentStack, setme_end );
if( err )
tr_bencFree( top );
tr_ptrArrayDestruct( &parentStack, NULL );
return err;
}
int
tr_bencLoad( const void * buf_in,
size_t buflen,
tr_benc * setme_benc,
char ** setme_end )
{
const uint8_t * buf = buf_in;
const uint8_t * end;
const int ret = tr_bencParse( buf, buf + buflen, setme_benc, &end );
if( !ret && setme_end )
*setme_end = (char*) end;
return ret;
}
/***
****
***/
/* returns true if the benc's string was malloced.
* this occurs when the string is too long for our string buffer */
static inline int
stringIsAlloced( const tr_benc * val )
{
return val->val.s.len >= sizeof( val->val.s.str.buf );
}
/* returns a const pointer to the benc's string */
static inline const char*
getStr( const tr_benc* val )
{
return stringIsAlloced(val) ? val->val.s.str.ptr : val->val.s.str.buf;
}
static int
dictIndexOf( const tr_benc * val, const char * key )
{
if( tr_bencIsDict( val ) )
{
size_t i;
const size_t len = strlen( key );
for( i = 0; ( i + 1 ) < val->val.l.count; i += 2 )
{
const tr_benc * child = val->val.l.vals + i;
if( ( child->type == TR_TYPE_STR )
&& ( child->val.s.len == len )
&& !memcmp( getStr(child), key, len ) )
return i;
}
}
return -1;
}
tr_benc *
tr_bencDictFind( tr_benc * val, const char * key )
{
const int i = dictIndexOf( val, key );
return i < 0 ? NULL : &val->val.l.vals[i + 1];
}
static tr_bool
tr_bencDictFindType( tr_benc * dict, const char * key, int type, tr_benc ** setme )
{
return tr_bencIsType( *setme = tr_bencDictFind( dict, key ), type );
}
size_t
tr_bencListSize( const tr_benc * list )
{
return tr_bencIsList( list ) ? list->val.l.count : 0;
}
tr_benc*
tr_bencListChild( tr_benc * val,
size_t i )
{
tr_benc * ret = NULL;
if( tr_bencIsList( val ) && ( i < val->val.l.count ) )
ret = val->val.l.vals + i;
return ret;
}
int
tr_bencListRemove( tr_benc * list, size_t i )
{
if( tr_bencIsList( list ) && ( i < list->val.l.count ) )
{
tr_bencFree( &list->val.l.vals[i] );
tr_removeElementFromArray( list->val.l.vals, i, sizeof( tr_benc ), list->val.l.count-- );
return 1;
}
return 0;
}
static void
tr_benc_warning( const char * err )
{
fprintf( stderr, "warning: %s\n", err );
}
tr_bool
tr_bencGetInt( const tr_benc * val,
int64_t * setme )
{
tr_bool success = FALSE;
if( !success && (( success = tr_bencIsInt( val ))))
if( setme )
*setme = val->val.i;
if( !success && (( success = tr_bencIsBool( val )))) {
tr_benc_warning( "reading bool as an int" );
if( setme )
*setme = val->val.b ? 1 : 0;
}
return success;
}
tr_bool
tr_bencGetStr( const tr_benc * val, const char ** setme )
{
const tr_bool success = tr_bencIsString( val );
if( success )
*setme = getStr( val );
return success;
}
tr_bool
tr_bencGetBool( const tr_benc * val, tr_bool * setme )
{
const char * str;
tr_bool success = FALSE;
if(( success = tr_bencIsBool( val )))
*setme = val->val.b;
if( !success && tr_bencIsInt( val ) )
if(( success = ( val->val.i==0 || val->val.i==1 ) ))
*setme = val->val.i!=0;
if( !success && tr_bencGetStr( val, &str ) )
if(( success = ( !strcmp(str,"true") || !strcmp(str,"false"))))
*setme = !strcmp(str,"true");
return success;
}
tr_bool
tr_bencGetReal( const tr_benc * val, double * setme )
{
tr_bool success = FALSE;
if( !success && (( success = tr_bencIsReal( val ))))
*setme = val->val.d;
if( !success && (( success = tr_bencIsInt( val ))))
*setme = val->val.i;
if( !success && tr_bencIsString(val) )
{
char * endptr;
char locale[128];
double d;
/* the json spec requires a '.' decimal point regardless of locale */
tr_strlcpy( locale, setlocale( LC_NUMERIC, NULL ), sizeof( locale ) );
setlocale( LC_NUMERIC, "POSIX" );
d = strtod( getStr(val), &endptr );
setlocale( LC_NUMERIC, locale );
if(( success = ( getStr(val) != endptr ) && !*endptr ))
*setme = d;
}
return success;
}
tr_bool
tr_bencDictFindInt( tr_benc * dict, const char * key, int64_t * setme )
{
return tr_bencGetInt( tr_bencDictFind( dict, key ), setme );
}
tr_bool
tr_bencDictFindBool( tr_benc * dict, const char * key, tr_bool * setme )
{
return tr_bencGetBool( tr_bencDictFind( dict, key ), setme );
}
tr_bool
tr_bencDictFindReal( tr_benc * dict, const char * key, double * setme )
{
return tr_bencGetReal( tr_bencDictFind( dict, key ), setme );
}
tr_bool
tr_bencDictFindStr( tr_benc * dict, const char * key, const char ** setme )
{
return tr_bencGetStr( tr_bencDictFind( dict, key ), setme );
}
tr_bool
tr_bencDictFindList( tr_benc * dict, const char * key, tr_benc ** setme )
{
return tr_bencDictFindType( dict, key, TR_TYPE_LIST, setme );
}
tr_bool
tr_bencDictFindDict( tr_benc * dict, const char * key, tr_benc ** setme )
{
return tr_bencDictFindType( dict, key, TR_TYPE_DICT, setme );
}
tr_bool
tr_bencDictFindRaw( tr_benc * dict,
const char * key,
const uint8_t ** setme_raw,
size_t * setme_len )
{
tr_benc * child;
const tr_bool found = tr_bencDictFindType( dict, key, TR_TYPE_STR, &child );
if( found ) {
*setme_raw = (uint8_t*) getStr(child);
*setme_len = child->val.s.len;
}
return found;
}
/***
****
***/
void
tr_bencInitRaw( tr_benc * val, const void * src, size_t byteCount )
{
char * setme;
tr_bencInit( val, TR_TYPE_STR );
/* There's no way in benc notation to distinguish between
* zero-terminated strings and raw byte arrays.
* Because of this, tr_bencMergeDicts() and tr_bencListCopy()
* don't know whether or not a TR_TYPE_STR node needs a '\0'.
* Append one, een to the raw arrays, just to be safe. */
if( byteCount < sizeof( val->val.s.str.buf ) )
setme = val->val.s.str.buf;
else
setme = val->val.s.str.ptr = tr_new( char, byteCount + 1 );
memcpy( setme, src, byteCount );
setme[byteCount] = '\0';
val->val.s.len = byteCount;
}
void
tr_bencInitStr( tr_benc * val, const void * str, int len )
{
if( str == NULL )
len = 0;
else if( len < 0 )
len = strlen( str );
tr_bencInitRaw( val, str, len );
}
void
tr_bencInitBool( tr_benc * b, int value )
{
tr_bencInit( b, TR_TYPE_BOOL );
b->val.b = value != 0;
}
void
tr_bencInitReal( tr_benc * b, double value )
{
tr_bencInit( b, TR_TYPE_REAL );
b->val.d = value;
}
void
tr_bencInitInt( tr_benc * b, int64_t value )
{
tr_bencInit( b, TR_TYPE_INT );
b->val.i = value;
}
int
tr_bencInitList( tr_benc * b, size_t reserveCount )
{
tr_bencInit( b, TR_TYPE_LIST );
return tr_bencListReserve( b, reserveCount );
}
int
tr_bencListReserve( tr_benc * b, size_t count )
{
assert( tr_bencIsList( b ) );
return makeroom( b, count );
}
int
tr_bencInitDict( tr_benc * b, size_t reserveCount )
{
tr_bencInit( b, TR_TYPE_DICT );
return tr_bencDictReserve( b, reserveCount );
}
int
tr_bencDictReserve( tr_benc * b, size_t reserveCount )
{
assert( tr_bencIsDict( b ) );
return makeroom( b, reserveCount * 2 );
}
tr_benc *
tr_bencListAdd( tr_benc * list )
{
tr_benc * item;
assert( tr_bencIsList( list ) );
if( list->val.l.count == list->val.l.alloc )
tr_bencListReserve( list, LIST_SIZE );
assert( list->val.l.count < list->val.l.alloc );
item = &list->val.l.vals[list->val.l.count];
list->val.l.count++;
tr_bencInit( item, TR_TYPE_INT );
return item;
}
tr_benc *
tr_bencListAddInt( tr_benc * list, int64_t val )
{
tr_benc * node = tr_bencListAdd( list );
tr_bencInitInt( node, val );
return node;
}
tr_benc *
tr_bencListAddReal( tr_benc * list, double val )
{
tr_benc * node = tr_bencListAdd( list );
tr_bencInitReal( node, val );
return node;
}
tr_benc *
tr_bencListAddBool( tr_benc * list, tr_bool val )
{
tr_benc * node = tr_bencListAdd( list );
tr_bencInitBool( node, val );
return node;
}
tr_benc *
tr_bencListAddStr( tr_benc * list, const char * val )
{
tr_benc * node = tr_bencListAdd( list );
tr_bencInitStr( node, val, -1 );
return node;
}
tr_benc *
tr_bencListAddRaw( tr_benc * list, const uint8_t * val, size_t len )
{
tr_benc * node = tr_bencListAdd( list );
tr_bencInitRaw( node, val, len );
return node;
}
tr_benc*
tr_bencListAddList( tr_benc * list,
size_t reserveCount )
{
tr_benc * child = tr_bencListAdd( list );
tr_bencInitList( child, reserveCount );
return child;
}
tr_benc*
tr_bencListAddDict( tr_benc * list,
size_t reserveCount )
{
tr_benc * child = tr_bencListAdd( list );
tr_bencInitDict( child, reserveCount );
return child;
}
tr_benc *
tr_bencDictAdd( tr_benc * dict,
const char * key )
{
tr_benc * keyval, * itemval;
assert( tr_bencIsDict( dict ) );
if( dict->val.l.count + 2 > dict->val.l.alloc )
makeroom( dict, 2 );
assert( dict->val.l.count + 2 <= dict->val.l.alloc );
keyval = dict->val.l.vals + dict->val.l.count++;
tr_bencInitStr( keyval, key, -1 );
itemval = dict->val.l.vals + dict->val.l.count++;
tr_bencInit( itemval, TR_TYPE_INT );
return itemval;
}
static tr_benc*
dictFindOrAdd( tr_benc * dict, const char * key, int type )
{
tr_benc * child;
/* see if it already exists, and if so, try to reuse it */
if(( child = tr_bencDictFind( dict, key ))) {
if( !tr_bencIsType( child, type ) ) {
tr_bencDictRemove( dict, key );
child = NULL;
}
}
/* if it doesn't exist, create it */
if( child == NULL )
child = tr_bencDictAdd( dict, key );
return child;
}
tr_benc*
tr_bencDictAddInt( tr_benc * dict,
const char * key,
int64_t val )
{
tr_benc * child = dictFindOrAdd( dict, key, TR_TYPE_INT );
tr_bencInitInt( child, val );
return child;
}
tr_benc*
tr_bencDictAddBool( tr_benc * dict, const char * key, tr_bool val )
{
tr_benc * child = dictFindOrAdd( dict, key, TR_TYPE_BOOL );
tr_bencInitBool( child, val );
return child;
}
tr_benc*
tr_bencDictAddReal( tr_benc * dict, const char * key, double val )
{
tr_benc * child = dictFindOrAdd( dict, key, TR_TYPE_REAL );
tr_bencInitReal( child, val );
return child;
}
tr_benc*
tr_bencDictAddStr( tr_benc * dict, const char * key, const char * val )
{
tr_benc * child;
/* see if it already exists, and if so, try to reuse it */
if(( child = tr_bencDictFind( dict, key ))) {
if( tr_bencIsString( child ) ) {
if( stringIsAlloced( child ) )
tr_free( child->val.s.str.ptr );
} else {
tr_bencDictRemove( dict, key );
child = NULL;
}
}
/* if it doesn't exist, create it */
if( child == NULL )
child = tr_bencDictAdd( dict, key );
/* set it */
tr_bencInitStr( child, val, -1 );
return child;
}
tr_benc*
tr_bencDictAddRaw( tr_benc * dict,
const char * key,
const void * src,
size_t len )
{
tr_benc * child;
/* see if it already exists, and if so, try to reuse it */
if(( child = tr_bencDictFind( dict, key ))) {
if( tr_bencIsString( child ) ) {
if( stringIsAlloced( child ) )
tr_free( child->val.s.str.ptr );
} else {
tr_bencDictRemove( dict, key );
child = NULL;
}
}
/* if it doesn't exist, create it */
if( child == NULL )
child = tr_bencDictAdd( dict, key );
/* set it */
tr_bencInitRaw( child, src, len );
return child;
}
tr_benc*
tr_bencDictAddList( tr_benc * dict,
const char * key,
size_t reserveCount )
{
tr_benc * child = tr_bencDictAdd( dict, key );
tr_bencInitList( child, reserveCount );
return child;
}
tr_benc*
tr_bencDictAddDict( tr_benc * dict,
const char * key,
size_t reserveCount )
{
tr_benc * child = tr_bencDictAdd( dict, key );
tr_bencInitDict( child, reserveCount );
return child;
}
int
tr_bencDictRemove( tr_benc * dict,
const char * key )
{
int i = dictIndexOf( dict, key );
if( i >= 0 )
{
const int n = dict->val.l.count;
tr_bencFree( &dict->val.l.vals[i] );
tr_bencFree( &dict->val.l.vals[i + 1] );
if( i + 2 < n )
{
dict->val.l.vals[i] = dict->val.l.vals[n - 2];
dict->val.l.vals[i + 1] = dict->val.l.vals[n - 1];
}
dict->val.l.count -= 2;
}
return i >= 0; /* return true if found */
}
/***
**** BENC WALKING
***/
struct KeyIndex
{
const char * key;
int index;
};
static int
compareKeyIndex( const void * va,
const void * vb )
{
const struct KeyIndex * a = va;
const struct KeyIndex * b = vb;
return strcmp( a->key, b->key );
}
struct SaveNode
{
const tr_benc * val;
int valIsVisited;
int childCount;
int childIndex;
int * children;
};
static void
nodeInitDict( struct SaveNode * node, const tr_benc * val, tr_bool sort_dicts )
{
const int n = val->val.l.count;
const int nKeys = n / 2;
assert( tr_bencIsDict( val ) );
node->val = val;
node->children = tr_new0( int, n );
if( sort_dicts )
{
int i, j;
struct KeyIndex * indices = tr_new( struct KeyIndex, nKeys );
for( i=j=0; i<n; i+=2, ++j )
{
indices[j].key = getStr(&val->val.l.vals[i]);
indices[j].index = i;
}
qsort( indices, j, sizeof( struct KeyIndex ), compareKeyIndex );
for( i = 0; i < j; ++i )
{
const int index = indices[i].index;
node->children[node->childCount++] = index;
node->children[node->childCount++] = index + 1;
}
tr_free( indices );
}
else
{
int i;
for( i=0; i<n; ++i )
node->children[node->childCount++] = i;
}
assert( node->childCount == n );
}
static void
nodeInitList( struct SaveNode * node, const tr_benc * val )
{
int i, n;
assert( tr_bencIsList( val ) );
n = val->val.l.count;
node->val = val;
node->childCount = n;
node->children = tr_new0( int, n );
for( i = 0; i < n; ++i ) /* a list's children don't need to be reordered */
node->children[i] = i;
}
static void
nodeInitLeaf( struct SaveNode * node, const tr_benc * val )
{
assert( !isContainer( val ) );
node->val = val;
}
static void
nodeInit( struct SaveNode * node, const tr_benc * val, tr_bool sort_dicts )
{
static const struct SaveNode INIT_NODE = { NULL, 0, 0, 0, NULL };
*node = INIT_NODE;
if( tr_bencIsList( val ) ) nodeInitList( node, val );
else if( tr_bencIsDict( val ) ) nodeInitDict( node, val, sort_dicts );
else nodeInitLeaf( node, val );
}
typedef void ( *BencWalkFunc )( const tr_benc * val, void * user_data );
struct WalkFuncs
{
BencWalkFunc intFunc;
BencWalkFunc boolFunc;
BencWalkFunc realFunc;
BencWalkFunc stringFunc;
BencWalkFunc dictBeginFunc;
BencWalkFunc listBeginFunc;
BencWalkFunc containerEndFunc;
};
/**
* This function's previous recursive implementation was
* easier to read, but was vulnerable to a smash-stacking
* attack via maliciously-crafted bencoded data. (#667)
*/
static void
bencWalk( const tr_benc * top,
const struct WalkFuncs * walkFuncs,
void * user_data,
tr_bool sort_dicts )
{
int stackSize = 0;
int stackAlloc = 64;
struct SaveNode * stack = tr_new( struct SaveNode, stackAlloc );
nodeInit( &stack[stackSize++], top, sort_dicts );
while( stackSize > 0 )
{
struct SaveNode * node = &stack[stackSize-1];
const tr_benc * val;
if( !node->valIsVisited )
{
val = node->val;
node->valIsVisited = TRUE;
}
else if( node->childIndex < node->childCount )
{
const int index = node->children[node->childIndex++];
val = node->val->val.l.vals + index;
}
else /* done with this node */
{
if( isContainer( node->val ) )
walkFuncs->containerEndFunc( node->val, user_data );
--stackSize;
tr_free( node->children );
continue;
}
if( val ) switch( val->type )
{
case TR_TYPE_INT:
walkFuncs->intFunc( val, user_data );
break;
case TR_TYPE_BOOL:
walkFuncs->boolFunc( val, user_data );
break;
case TR_TYPE_REAL:
walkFuncs->realFunc( val, user_data );
break;
case TR_TYPE_STR:
walkFuncs->stringFunc( val, user_data );
break;
case TR_TYPE_LIST:
if( val == node->val )
walkFuncs->listBeginFunc( val, user_data );
else {
if( stackAlloc == stackSize ) {
stackAlloc *= 2;
stack = tr_renew( struct SaveNode, stack, stackAlloc );
}
nodeInit( &stack[stackSize++], val, sort_dicts );
}
break;
case TR_TYPE_DICT:
if( val == node->val )
walkFuncs->dictBeginFunc( val, user_data );
else {
if( stackAlloc == stackSize ) {
stackAlloc *= 2;
stack = tr_renew( struct SaveNode, stack, stackAlloc );
}
nodeInit( &stack[stackSize++], val, sort_dicts );
}
break;
default:
/* did caller give us an uninitialized val? */
tr_err( "%s", _( "Invalid metadata" ) );
break;
}
}
tr_free( stack );
}
/****
*****
****/
static void
saveIntFunc( const tr_benc * val, void * evbuf )
{
evbuffer_add_printf( evbuf, "i%" PRId64 "e", val->val.i );
}
static void
saveBoolFunc( const tr_benc * val, void * evbuf )
{
if( val->val.b )
evbuffer_add( evbuf, "i1e", 3 );
else
evbuffer_add( evbuf, "i0e", 3 );
}
static void
saveRealFunc( const tr_benc * val, void * evbuf )
{
char buf[128];
char locale[128];
size_t len;
/* always use a '.' decimal point s.t. locale-hopping doesn't bite us */
tr_strlcpy( locale, setlocale( LC_NUMERIC, NULL ), sizeof( locale ) );
setlocale( LC_NUMERIC, "POSIX" );
tr_snprintf( buf, sizeof( buf ), "%f", val->val.d );
setlocale( LC_NUMERIC, locale );
len = strlen( buf );
evbuffer_add_printf( evbuf, "%lu:", (unsigned long)len );
evbuffer_add( evbuf, buf, len );
}
static void
saveStringFunc( const tr_benc * val, void * evbuf )
{
evbuffer_add_printf( evbuf, "%lu:", (unsigned long)val->val.s.len );
evbuffer_add( evbuf, getStr(val), val->val.s.len );
}
static void
saveDictBeginFunc( const tr_benc * val UNUSED, void * evbuf )
{
evbuffer_add( evbuf, "d", 1 );
}
static void
saveListBeginFunc( const tr_benc * val UNUSED, void * evbuf )
{
evbuffer_add( evbuf, "l", 1 );
}
static void
saveContainerEndFunc( const tr_benc * val UNUSED, void * evbuf )
{
evbuffer_add( evbuf, "e", 1 );
}
static const struct WalkFuncs saveFuncs = { saveIntFunc,
saveBoolFunc,
saveRealFunc,
saveStringFunc,
saveDictBeginFunc,
saveListBeginFunc,
saveContainerEndFunc };
/***
****
***/
static void
freeDummyFunc( const tr_benc * val UNUSED, void * buf UNUSED )
{}
static void
freeStringFunc( const tr_benc * val, void * unused UNUSED )
{
if( stringIsAlloced( val ) )
tr_free( val->val.s.str.ptr );
}
static void
freeContainerEndFunc( const tr_benc * val, void * unused UNUSED )
{
tr_free( val->val.l.vals );
}
static const struct WalkFuncs freeWalkFuncs = { freeDummyFunc,
freeDummyFunc,
freeDummyFunc,
freeStringFunc,
freeDummyFunc,
freeDummyFunc,
freeContainerEndFunc };
void
tr_bencFree( tr_benc * val )
{
if( isSomething( val ) )
bencWalk( val, &freeWalkFuncs, NULL, FALSE );
}
/***
****
***/
/** @brief Implementation helper class for tr_bencToBuffer(TR_FMT_JSON) */
struct ParentState
{
int bencType;
int childIndex;
int childCount;
};
/** @brief Implementation helper class for tr_bencToBuffer(TR_FMT_JSON) */
struct jsonWalk
{
tr_bool doIndent;
tr_list * parents;
struct evbuffer * out;
};
static void
jsonIndent( struct jsonWalk * data )
{
if( data->doIndent )
{
char buf[1024];
const int width = tr_list_size( data->parents ) * 4;
buf[0] = '\n';
memset( buf+1, ' ', width );
evbuffer_add( data->out, buf, 1+width );
}
}
static void
jsonChildFunc( struct jsonWalk * data )
{
if( data->parents )
{
struct ParentState * parentState = data->parents->data;
switch( parentState->bencType )
{
case TR_TYPE_DICT:
{
const int i = parentState->childIndex++;
if( !( i % 2 ) )
evbuffer_add( data->out, ": ", data->doIndent ? 2 : 1 );
else {
const tr_bool isLast = parentState->childIndex == parentState->childCount;
if( !isLast ) {
evbuffer_add( data->out, ", ", data->doIndent ? 2 : 1 );
jsonIndent( data );
}
}
break;
}
case TR_TYPE_LIST:
{
const tr_bool isLast = ++parentState->childIndex == parentState->childCount;
if( !isLast ) {
evbuffer_add( data->out, ", ", data->doIndent ? 2 : 1 );
jsonIndent( data );
}
break;
}
default:
break;
}
}
}
static void
jsonPushParent( struct jsonWalk * data,
const tr_benc * benc )
{
struct ParentState * parentState = tr_new( struct ParentState, 1 );
parentState->bencType = benc->type;
parentState->childIndex = 0;
parentState->childCount = benc->val.l.count;
tr_list_prepend( &data->parents, parentState );
}
static void
jsonPopParent( struct jsonWalk * data )
{
tr_free( tr_list_pop_front( &data->parents ) );
}
static void
jsonIntFunc( const tr_benc * val,
void * vdata )
{
struct jsonWalk * data = vdata;
evbuffer_add_printf( data->out, "%" PRId64, val->val.i );
jsonChildFunc( data );
}
static void
jsonBoolFunc( const tr_benc * val, void * vdata )
{
struct jsonWalk * data = vdata;
if( val->val.b )
evbuffer_add( data->out, "true", 4 );
else
evbuffer_add( data->out, "false", 5 );
jsonChildFunc( data );
}
static void
jsonRealFunc( const tr_benc * val, void * vdata )
{
struct jsonWalk * data = vdata;
char locale[128];
if( fabs( val->val.d - (int)val->val.d ) < 0.00001 )
evbuffer_add_printf( data->out, "%d", (int)val->val.d );
else {
/* json requires a '.' decimal point regardless of locale */
tr_strlcpy( locale, setlocale( LC_NUMERIC, NULL ), sizeof( locale ) );
setlocale( LC_NUMERIC, "POSIX" );
evbuffer_add_printf( data->out, "%.4f", tr_truncd( val->val.d, 4 ) );
setlocale( LC_NUMERIC, locale );
}
jsonChildFunc( data );
}
static void
jsonStringFunc( const tr_benc * val, void * vdata )
{
char * out;
char * outwalk;
char * outend;
struct evbuffer_iovec vec[1];
struct jsonWalk * data = vdata;
const unsigned char * it = (const unsigned char *) getStr(val);
const unsigned char * end = it + val->val.s.len;
const int safeguard = 512; /* arbitrary margin for escapes and unicode */
evbuffer_reserve_space( data->out, val->val.s.len+safeguard, vec, 1 );
out = vec[0].iov_base;
outend = out + vec[0].iov_len;
outwalk = out;
*outwalk++ = '"';
for( ; it!=end; ++it )
{
switch( *it )
{
case '\b': *outwalk++ = '\\'; *outwalk++ = 'b'; break;
case '\f': *outwalk++ = '\\'; *outwalk++ = 'f'; break;
case '\n': *outwalk++ = '\\'; *outwalk++ = 'n'; break;
case '\r': *outwalk++ = '\\'; *outwalk++ = 'r'; break;
case '\t': *outwalk++ = '\\'; *outwalk++ = 't'; break;
case '"' : *outwalk++ = '\\'; *outwalk++ = '"'; break;
case '\\': *outwalk++ = '\\'; *outwalk++ = '\\'; break;
default:
if( isascii( *it ) )
*outwalk++ = *it;
else {
const UTF8 * tmp = it;
UTF32 buf = 0;
UTF32 * u32 = &buf;
ConversionResult result = ConvertUTF8toUTF32( &tmp, end, &u32, &buf + 1, 0 );
if((( result==conversionOK ) || (result==targetExhausted)) && (tmp!=it)) {
outwalk += tr_snprintf( outwalk, outend-outwalk, "\\u%04x", (unsigned int)buf );
it = tmp - 1;
}
}
}
}
*outwalk++ = '"';
vec[0].iov_len = outwalk - out;
evbuffer_commit_space( data->out, vec, 1 );
jsonChildFunc( data );
}
static void
jsonDictBeginFunc( const tr_benc * val,
void * vdata )
{
struct jsonWalk * data = vdata;
jsonPushParent( data, val );
evbuffer_add( data->out, "{", 1 );
if( val->val.l.count )
jsonIndent( data );
}
static void
jsonListBeginFunc( const tr_benc * val,
void * vdata )
{
const size_t nChildren = tr_bencListSize( val );
struct jsonWalk * data = vdata;
jsonPushParent( data, val );
evbuffer_add( data->out, "[", 1 );
if( nChildren )
jsonIndent( data );
}
static void
jsonContainerEndFunc( const tr_benc * val,
void * vdata )
{
struct jsonWalk * data = vdata;
int emptyContainer = FALSE;
jsonPopParent( data );
if( !emptyContainer )
jsonIndent( data );
if( tr_bencIsDict( val ) )
evbuffer_add( data->out, "}", 1 );
else /* list */
evbuffer_add( data->out, "]", 1 );
jsonChildFunc( data );
}
static const struct WalkFuncs jsonWalkFuncs = { jsonIntFunc,
jsonBoolFunc,
jsonRealFunc,
jsonStringFunc,
jsonDictBeginFunc,
jsonListBeginFunc,
jsonContainerEndFunc };
/***
****
***/
static void
tr_bencListCopy( tr_benc * target, const tr_benc * src )
{
int i = 0;
const tr_benc * val;
while(( val = tr_bencListChild( (tr_benc*)src, i++ )))
{
if( tr_bencIsBool( val ) )
{
tr_bool boolVal = 0;
tr_bencGetBool( val, &boolVal );
tr_bencListAddBool( target, boolVal );
}
else if( tr_bencIsReal( val ) )
{
double realVal = 0;
tr_bencGetReal( val, &realVal );
tr_bencListAddReal( target, realVal );
}
else if( tr_bencIsInt( val ) )
{
int64_t intVal = 0;
tr_bencGetInt( val, &intVal );
tr_bencListAddInt( target, intVal );
}
else if( tr_bencIsString( val ) )
{
tr_bencListAddRaw( target, (const uint8_t*)getStr( val ), val->val.s.len );
}
else if( tr_bencIsDict( val ) )
{
tr_bencMergeDicts( tr_bencListAddDict( target, 0 ), val );
}
else if ( tr_bencIsList( val ) )
{
tr_bencListCopy( tr_bencListAddList( target, 0 ), val );
}
else
{
tr_err( "tr_bencListCopy skipping item" );
}
}
}
static size_t
tr_bencDictSize( const tr_benc * dict )
{
size_t count = 0;
if( tr_bencIsDict( dict ) )
count = dict->val.l.count / 2;
return count;
}
tr_bool
tr_bencDictChild( tr_benc * dict, size_t n, const char ** key, tr_benc ** val )
{
tr_bool success = 0;
assert( tr_bencIsDict( dict ) );
if( tr_bencIsDict( dict ) && (n*2)+1 <= dict->val.l.count )
{
tr_benc * k = dict->val.l.vals + (n*2);
tr_benc * v = dict->val.l.vals + (n*2) + 1;
if(( success = tr_bencGetStr( k, key ) && isSomething( v )))
*val = v;
}
return success;
}
void
tr_bencMergeDicts( tr_benc * target, const tr_benc * source )
{
size_t i;
const size_t sourceCount = tr_bencDictSize( source );
assert( tr_bencIsDict( target ) );
assert( tr_bencIsDict( source ) );
for( i=0; i<sourceCount; ++i )
{
const char * key;
tr_benc * val;
tr_benc * t;
if( tr_bencDictChild( (tr_benc*)source, i, &key, &val ) )
{
if( tr_bencIsBool( val ) )
{
tr_bool boolVal;
tr_bencGetBool( val, &boolVal );
tr_bencDictAddBool( target, key, boolVal );
}
else if( tr_bencIsReal( val ) )
{
double realVal = 0;
tr_bencGetReal( val, &realVal );
tr_bencDictAddReal( target, key, realVal );
}
else if( tr_bencIsInt( val ) )
{
int64_t intVal = 0;
tr_bencGetInt( val, &intVal );
tr_bencDictAddInt( target, key, intVal );
}
else if( tr_bencIsString( val ) )
{
tr_bencDictAddRaw( target, key, getStr( val ), val->val.s.len );
}
else if( tr_bencIsDict( val ) && tr_bencDictFindDict( target, key, &t ) )
{
tr_bencMergeDicts( t, val );
}
else if( tr_bencIsList( val ) )
{
if( tr_bencDictFind( target, key ) == NULL )
{
tr_bencListCopy( tr_bencDictAddList( target, key, tr_bencListSize( val ) ), val );
}
}
else
{
tr_dbg( "tr_bencMergeDicts skipping \"%s\"", key );
}
}
}
}
/***
****
***/
void
tr_bencToBuf( const tr_benc * top, tr_fmt_mode mode, struct evbuffer * buf )
{
evbuffer_drain( buf, evbuffer_get_length( buf ) );
evbuffer_expand( buf, 4096 ); /* alloc a little memory to start off with */
switch( mode )
{
case TR_FMT_BENC:
bencWalk( top, &saveFuncs, buf, TRUE );
break;
case TR_FMT_JSON:
case TR_FMT_JSON_LEAN: {
struct jsonWalk data;
data.doIndent = mode==TR_FMT_JSON;
data.out = buf;
data.parents = NULL;
bencWalk( top, &jsonWalkFuncs, &data, TRUE );
if( evbuffer_get_length( buf ) )
evbuffer_add_printf( buf, "\n" );
break;
}
}
}
char*
tr_bencToStr( const tr_benc * top, tr_fmt_mode mode, int * len )
{
char * ret;
struct evbuffer * buf = evbuffer_new( );
size_t n;
tr_bencToBuf( top, mode, buf );
n = evbuffer_get_length( buf );
ret = evbuffer_free_to_str( buf );
if( len != NULL )
*len = (int) n;
return ret;
}
/* portability wrapper for mkstemp(). */
static int
tr_mkstemp( char * template )
{
#ifdef WIN32
const int flags = O_RDWR | O_BINARY | O_CREAT | O_EXCL | _O_SHORT_LIVED;
const mode_t mode = _S_IREAD | _S_IWRITE;
mktemp( template );
return open( template, flags, mode );
#else
return mkstemp( template );
#endif
}
int
tr_bencToFile( const tr_benc * top, tr_fmt_mode mode, const char * filename )
{
char * tmp;
int fd;
int err = 0;
char buf[TR_PATH_MAX];
/* follow symlinks to find the "real" file, to make sure the temporary
* we build with tr_mkstemp() is created on the right partition */
if( tr_realpath( filename, buf ) != NULL )
filename = buf;
/* if the file already exists, try to move it out of the way & keep it as a backup */
tmp = tr_strdup_printf( "%s.tmp.XXXXXX", filename );
fd = tr_mkstemp( tmp );
tr_set_file_for_single_pass( fd );
if( fd >= 0 )
{
int nleft;
/* save the benc to a temporary file */
{
char * buf = tr_bencToStr( top, mode, &nleft );
const char * walk = buf;
while( nleft > 0 ) {
const int n = write( fd, walk, nleft );
if( n >= 0 ) {
nleft -= n;
walk += n;
}
else if( errno != EAGAIN ) {
err = errno;
break;
}
}
tr_free( buf );
}
if( nleft > 0 )
{
tr_err( _( "Couldn't save temporary file \"%1$s\": %2$s" ), tmp, tr_strerror( err ) );
tr_close_file( fd );
unlink( tmp );
}
else
{
tr_fsync( fd );
tr_close_file( fd );
#ifdef WIN32
if( MoveFileEx( tmp, filename, MOVEFILE_REPLACE_EXISTING ) )
#else
if( !rename( tmp, filename ) )
#endif
{
tr_inf( _( "Saved \"%s\"" ), filename );
}
else
{
err = errno;
tr_err( _( "Couldn't save file \"%1$s\": %2$s" ), filename, tr_strerror( err ) );
unlink( tmp );
}
}
}
else
{
err = errno;
tr_err( _( "Couldn't save temporary file \"%1$s\": %2$s" ), tmp, tr_strerror( err ) );
}
tr_free( tmp );
return err;
}
/***
****
***/
int
tr_bencLoadFile( tr_benc * setme, tr_fmt_mode mode, const char * filename )
{
int err;
size_t contentLen;
uint8_t * content;
content = tr_loadFile( filename, &contentLen );
if( !content && errno )
err = errno;
else if( !content )
err = ENODATA;
else {
if( mode == TR_FMT_BENC )
err = tr_bencLoad( content, contentLen, setme, NULL );
else
err = tr_jsonParse( filename, content, contentLen, setme, NULL );
}
tr_free( content );
return err;
}
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