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[cff] Fix memory overflow.

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Reported as

  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=9869
  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10869

* src/cff/cffparse.c (destruct_t2s_item, cff_parser_run): Store
evaluated T2 charstrings in separately allocated memory.
This commit is contained in:
Armin Hasitzka 2018-11-22 10:29:35 +00:00
parent 81f43a9d36
commit 642bc7590c
2 changed files with 57 additions and 13 deletions
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12
ChangeLog
View File

@ -1,3 +1,15 @@
2018-11-22 Armin Hasitzka <prince.cherusker@gmail.com>
[cff] Fix memory overflow.
Reported as
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=9869
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10869
* src/cff/cffparse.c (destruct_t2s_item, cff_parser_run): Store
evaluated T2 charstrings in separately allocated memory.
2018-11-18 Alexei Podtelezhnikov <apodtele@gmail.com>
* builds/windows/{visualc,vc2005,vc2008}/freetype.vcproj: Fix it.

58
src/cff/cffparse.c
View File

@ -1121,22 +1121,36 @@
#endif /* FT_DEBUG_LEVEL_TRACE */
static void
destruct_t2s_item( FT_Memory memory,
void* data,
void* user )
{
FT_UNUSED( user );
memory->free( memory, data );
}
FT_LOCAL_DEF( FT_Error )
cff_parser_run( CFF_Parser parser,
FT_Byte* start,
FT_Byte* limit )
{
FT_Byte* p = start;
FT_Error error = FT_Err_Ok;
#ifdef CFF_CONFIG_OPTION_OLD_ENGINE
PSAux_Service psaux;
#endif
FT_Byte* p = start;
FT_Error error = FT_Err_Ok;
FT_Library library = parser->library;
FT_Memory memory = library->memory;
FT_UNUSED( library );
FT_ListRec t2s;
FT_ZERO( &t2s );
#endif
parser->top = parser->stack;
parser->start = start;
parser->limit = limit;
@ -1195,8 +1209,9 @@
FT_Byte* charstring_base;
FT_ULong charstring_len;
FT_Fixed* stack;
FT_Byte* q;
FT_Fixed* stack;
FT_ListNode node;
FT_Byte* q;
charstring_base = ++p;
@ -1237,13 +1252,23 @@
/* Now copy the stack data in the temporary decoder object, */
/* converting it back to charstring number representations */
/* (this is ugly, I know). */
/* */
/* We overwrite the original top DICT charstring under the */
/* assumption that the charstring representation of the result */
/* of `cff_decoder_parse_charstrings' is shorter, which should */
/* be always true. */
q = charstring_base - 1;
node = (FT_ListNode)memory->alloc( memory,
sizeof ( FT_ListNodeRec ) );
if ( !node )
goto Out_Of_Memory_Error;
/* `5' is the conservative upper bound of required bytes per stack */
/* element. */
q = (FT_Byte*)memory->alloc( memory,
5 * ( decoder.top - decoder.stack ) );
if ( !q )
goto Out_Of_Memory_Error;
node->data = q;
FT_List_Add( &t2s, node );
stack = decoder.stack;
while ( stack < decoder.top )
@ -1500,11 +1525,18 @@
parser->top = parser->stack;
}
p++;
}
} /* while ( p < limit ) */
Exit:
#ifdef CFF_CONFIG_OPTION_OLD_ENGINE
FT_List_Finalize( &t2s, destruct_t2s_item, memory, NULL );
#endif
return error;
Out_Of_Memory_Error:
error = FT_THROW( Out_Of_Memory );
goto Exit;
Stack_Overflow:
error = FT_THROW( Invalid_Argument );
goto Exit;