480409 - integer overflow on allocation in harfbuzz on 64-bit systems

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Karl Tomlinson (:karlt)]

HB_INTERNAL HB_Pointer
_hb_realloc( HB_Pointer block,
	     HB_UInt    new_size,
	     HB_Error  *perror_ );

typedef unsigned int HB_UInt;

Comment 1

[Behdad Esfahbod]

Committed to pango:

commit caaa5d09e10d4fe01ef986c9a95826c3cbb13cfa
Author: Behdad Esfahbod <[e-mail]>
Date:   Mon Mar 2 14:20:20 2009 +0330

    [opentype] Use size_t instead of uint for malloc wrappers


Though the macros still do multiplication without checking for overflow.  I don't expect it to be a major issue though as most (all?) numbers coming from the font file are 16-bit ints.

Comment 2

[Karl Tomlinson (:karlt)]

Thanks, Behdad.  My concern was HB_Buffer, which Pango uses with string lengths.  But callers of hb_buffer_ensure seem to only ever increment the buffer by what can be stored in an HB_UShort, so allocation should fail, limiting the length of the buffer, before size_t multiplication overflow occurs, even on 32-bit systems.