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[raster] Fix uninitialized memory access.

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Apparently `ras.cProfile' might be uninitialized.  This will be the
case if `ras.top == ras.cProfile->offset', as can be seen in
`End_Profile'.  The overshoot code introduced in a change `Fix B/W
rasterization of subglyphs with different drop-out modes.' (from
2009-06-18) violated this, accessing `ras.cProfile->flags'
unconditionally just before calling `End_Profile' (which then
detected that `cProfile' is uninitialized and didn't touch it).

This was harmless, and was not detected by valgrind before because
the objects were allocated on the `raster_pool', which was always
initialized.  With recent change to allocate raster buffers on the
stack, valgrind now reported this invalid access.

* src/raster/ftraster.c (Convert_Glyph): Don't access an
uninitialized `cProfile'.
This commit is contained in:
Behdad Esfahbod 2015-01-14 18:48:14 +01:00 committed by Werner Lemberg
parent b2ba68665f
commit c242fe41ec
2 changed files with 22 additions and 1 deletions
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20
ChangeLog
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@ -1,3 +1,23 @@
2015-01-14 Behdad Esfahbod <behdad@behdad.org>
[raster] Fix uninitialized memory access.
Apparently `ras.cProfile' might be uninitialized. This will be the
case if `ras.top == ras.cProfile->offset', as can be seen in
`End_Profile'. The overshoot code introduced in a change `Fix B/W
rasterization of subglyphs with different drop-out modes.' (from
2009-06-18) violated this, accessing `ras.cProfile->flags'
unconditionally just before calling `End_Profile' (which then
detected that `cProfile' is uninitialized and didn't touch it).
This was harmless, and was not detected by valgrind before because
the objects were allocated on the `raster_pool', which was always
initialized. With recent change to allocate raster buffers on the
stack, valgrind now reported this invalid access.
* src/raster/ftraster.c (Convert_Glyph): Don't access an
uninitialized `cProfile'.
2015-01-14 Behdad Esfahbod <behdad@behdad.org>
[smooth] Fix uninitialized memory access.

3
src/raster/ftraster.c
View File

@ -1982,7 +1982,8 @@
/* to be drawn. */
lastProfile = ras.cProfile;
if ( ras.cProfile->flags & Flow_Up )
if ( ras.top != ras.cProfile->offset &&
( ras.cProfile->flags & Flow_Up ) )
o = IS_TOP_OVERSHOOT( ras.lastY );
else
o = IS_BOTTOM_OVERSHOOT( ras.lastY );