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[base, sfnt] Better checks for invalid cmaps (1/2).

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* src/base/ftobjs.c (FT_Get_Char_Index): Don't return out-of-bounds
glyph indices.
(FT_Get_First_Char): Updated.

* src/sfnt/ttcmap.c (tt_cmap6_char_next): Don't return character
codes greater than 0xFFFF.

(tt_cmap8_char_index): Avoid integer overflow in computation of
glyph index.
(tt_cmap8_char_next): Avoid integer overflows in computation of
both next character code and glyph index.

(tt_cmap10_char_index): Fix unsigned integer logic.
(tt_cmap10_char_next): Avoid integer overflow in computation of
next character code.

(tt_cmap12_next): Avoid integer overflows in computation of both
next character code and glyph index.
(tt_cmap12_char_map_binary): Ditto.
(tt_cmap12_char_next): Simplify.

(tt_cmap13_char_map_binary): Avoid integer overflow in computation
of next character code.
(tt_cmap13_char_next): Simplify.
This commit is contained in:
Werner Lemberg 2015-09-24 12:39:38 +02:00
parent cbdf13e5ca
commit c409eb18ae
3 changed files with 133 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
ChangeLog
View File

@ -1,3 +1,32 @@
2015-09-23 Werner Lemberg <wl@gnu.org>
[base, sfnt] Better checks for invalid cmaps (1/2).
* src/base/ftobjs.c (FT_Get_Char_Index): Don't return out-of-bounds
glyph indices.
(FT_Get_First_Char): Updated.
* src/sfnt/ttcmap.c (tt_cmap6_char_next): Don't return character
codes greater than 0xFFFF.
(tt_cmap8_char_index): Avoid integer overflow in computation of
glyph index.
(tt_cmap8_char_next): Avoid integer overflows in computation of
both next character code and glyph index.
(tt_cmap10_char_index): Fix unsigned integer logic.
(tt_cmap10_char_next): Avoid integer overflow in computation of
next character code.
(tt_cmap12_next): Avoid integer overflows in computation of both
next character code and glyph index.
(tt_cmap12_char_map_binary): Ditto.
(tt_cmap12_char_next): Simplify.
(tt_cmap13_char_map_binary): Avoid integer overflow in computation
of next character code.
(tt_cmap13_char_next): Simplify.
2015-09-21 suzuki toshiya <mpsuzuki@hiroshima-u.ac.jp>
[base] Check too long POST and sfnt resource (#45919).

6
src/base/ftobjs.c
View File

@ -3382,8 +3382,12 @@
FT_TRACE1(( "FT_Get_Char_Index: too large charcode" ));
FT_TRACE1(( " 0x%x is truncated\n", charcode ));
}
result = cmap->clazz->char_index( cmap, (FT_UInt32)charcode );
if ( result >= (FT_UInt)face->num_glyphs )
result = 0;
}
return result;
}
@ -3402,7 +3406,7 @@
if ( face && face->charmap && face->num_glyphs )
{
gindex = FT_Get_Char_Index( face, 0 );
if ( gindex == 0 || gindex >= (FT_UInt)face->num_glyphs )
if ( gindex == 0 )
result = FT_Get_Next_Char( face, 0, &gindex );
}

140
src/sfnt/ttcmap.c
View File

@ -51,6 +51,13 @@
#define TT_NEXT_ULONG FT_NEXT_ULONG
/* Too large glyph index return values are caught in `FT_Get_Char_Index' */
/* and `FT_Get_Next_Char' (the latter calls the internal `next' function */
/* again in this case). To mark character code return values as invalid */
/* it is sufficient to set the corresponding glyph index return value to */
/* zero. */
FT_CALLBACK_DEF( FT_Error )
tt_cmap_init( TT_CMap cmap,
FT_Byte* table )
@ -1533,7 +1540,7 @@
if ( char_code >= 0x10000UL )
goto Exit;
return 0;
if ( char_code < start )
char_code = start;
@ -1549,10 +1556,13 @@
result = char_code;
break;
}
if ( char_code >= 0xFFFFU )
return 0;
char_code++;
}
Exit:
*pchar_code = result;
return gindex;
}
@ -1772,7 +1782,10 @@
if ( char_code <= end )
{
result = (FT_UInt)( start_id + char_code - start );
if ( start_id > 0xFFFFFFFFUL - ( char_code - start ) )
return 0;
result = (FT_UInt)( start_id + ( char_code - start ) );
break;
}
}
@ -1785,7 +1798,7 @@
FT_UInt32 *pchar_code )
{
FT_UInt32 result = 0;
FT_UInt32 char_code = *pchar_code + 1;
FT_UInt32 char_code;
FT_UInt gindex = 0;
FT_Byte* table = cmap->data;
FT_Byte* p = table + 8204;
@ -1793,6 +1806,11 @@
FT_UInt32 start, end, start_id;
if ( *pchar_code >= 0xFFFFFFFFUL )
return 0;
char_code = *pchar_code + 1;
p = table + 8208;
for ( ; num_groups > 0; num_groups-- )
@ -1804,18 +1822,30 @@
if ( char_code < start )
char_code = start;
Again:
if ( char_code <= end )
{
gindex = (FT_UInt)( char_code - start + start_id );
if ( gindex != 0 )
/* ignore invalid group */
if ( start_id > 0xFFFFFFFFUL - ( char_code - start ) )
continue;
gindex = (FT_UInt)( start_id + ( char_code - start ) );
/* does first element of group point to `.notdef' glyph? */
if ( gindex == 0 )
{
result = char_code;
goto Exit;
if ( char_code >= 0xFFFFFFFFUL )
break;
char_code++;
goto Again;
}
result = char_code;
break;
}
}
Exit:
*pchar_code = result;
return gindex;
}
@ -1932,14 +1962,20 @@
FT_Byte* p = table + 12;
FT_UInt32 start = TT_NEXT_ULONG( p );
FT_UInt32 count = TT_NEXT_ULONG( p );
FT_UInt32 idx = (FT_ULong)( char_code - start );
FT_UInt32 idx;
if ( char_code < start )
return 0;
idx = char_code - start;
if ( idx < count )
{
p += 2 * idx;
result = TT_PEEK_USHORT( p );
}
return result;
}
@ -1949,7 +1985,7 @@
FT_UInt32 *pchar_code )
{
FT_Byte* table = cmap->data;
FT_UInt32 char_code = *pchar_code + 1;
FT_UInt32 char_code;
FT_UInt gindex = 0;
FT_Byte* p = table + 12;
FT_UInt32 start = TT_NEXT_ULONG( p );
@ -1957,10 +1993,15 @@
FT_UInt32 idx;
if ( *pchar_code >= 0xFFFFFFFFUL )
return 0;
char_code = *pchar_code + 1;
if ( char_code < start )
char_code = start;
idx = (FT_UInt32)( char_code - start );
idx = char_code - start;
p += 2 * idx;
for ( ; idx < count; idx++ )
@ -1968,6 +2009,10 @@
gindex = TT_NEXT_USHORT( p );
if ( gindex != 0 )
break;
if ( char_code >= 0xFFFFFFFFUL )
return 0;
char_code++;
}
@ -2157,18 +2202,30 @@
if ( char_code < start )
char_code = start;
for ( ; char_code <= end; char_code++ )
Again:
if ( char_code <= end )
{
gindex = (FT_UInt)( start_id + char_code - start );
/* ignore invalid group */
if ( start_id > 0xFFFFFFFFUL - ( char_code - start ) )
continue;
if ( gindex )
gindex = (FT_UInt)( start_id + ( char_code - start ) );
/* does first element of group point to `.notdef' glyph? */
if ( gindex == 0 )
{
cmap->cur_charcode = char_code;;
cmap->cur_gindex = gindex;
cmap->cur_group = n;
if ( char_code >= 0xFFFFFFFFUL )
goto Fail;
return;
char_code++;
goto Again;
}
cmap->cur_charcode = char_code;
cmap->cur_gindex = gindex;
cmap->cur_group = n;
return;
}
}
@ -2198,7 +2255,12 @@
end = 0xFFFFFFFFUL;
if ( next )
{
if ( char_code >= 0xFFFFFFFFUL )
return 0;
char_code++;
}
min = 0;
max = num_groups;
@ -2219,8 +2281,12 @@
else
{
start_id = TT_PEEK_ULONG( p );
gindex = (FT_UInt)( start_id + char_code - start );
/* reject invalid glyph index */
if ( start_id > 0xFFFFFFFFUL - ( char_code - start ) )
gindex = 0;
else
gindex = (FT_UInt)( start_id + ( char_code - start ) );
break;
}
}
@ -2254,8 +2320,7 @@
else
cmap12->cur_gindex = gindex;
if ( gindex )
*pchar_code = cmap12->cur_charcode;
*pchar_code = cmap12->cur_charcode;
}
return gindex;
@ -2275,23 +2340,17 @@
FT_UInt32 *pchar_code )
{
TT_CMap12 cmap12 = (TT_CMap12)cmap;
FT_ULong gindex;
FT_UInt gindex;
if ( cmap12->cur_charcode >= 0xFFFFFFFFUL )
return 0;
/* no need to search */
if ( cmap12->valid && cmap12->cur_charcode == *pchar_code )
{
tt_cmap12_next( cmap12 );
if ( cmap12->valid )
{
gindex = cmap12->cur_gindex;
/* XXX: check cur_charcode overflow is expected */
if ( gindex )
*pchar_code = (FT_UInt32)cmap12->cur_charcode;
gindex = cmap12->cur_gindex;
*pchar_code = (FT_UInt32)cmap12->cur_charcode;
}
else
gindex = 0;
@ -2299,8 +2358,7 @@
else
gindex = tt_cmap12_char_map_binary( cmap, pchar_code, 1 );
/* XXX: check gindex overflow is expected */
return (FT_UInt32)gindex;
return gindex;
}
@ -2521,7 +2579,12 @@
end = 0xFFFFFFFFUL;
if ( next )
{
if ( char_code >= 0xFFFFFFFFUL )
return 0;
char_code++;
}
min = 0;
max = num_groups;
@ -2576,8 +2639,7 @@
else
cmap13->cur_gindex = gindex;
if ( gindex )
*pchar_code = cmap13->cur_charcode;
*pchar_code = cmap13->cur_charcode;
}
return gindex;
@ -2600,18 +2662,14 @@
FT_UInt gindex;
if ( cmap13->cur_charcode >= 0xFFFFFFFFUL )
return 0;
/* no need to search */
if ( cmap13->valid && cmap13->cur_charcode == *pchar_code )
{
tt_cmap13_next( cmap13 );
if ( cmap13->valid )
{
gindex = cmap13->cur_gindex;
if ( gindex )
*pchar_code = cmap13->cur_charcode;
gindex = cmap13->cur_gindex;
*pchar_code = cmap13->cur_charcode;
}
else
gindex = 0;