AuroraMiddleware/qt5base-lts
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Fix a division by zero when processing malformed BMP files.

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This fixes a division by 0 when processing a maliciously crafted BMP
file. No impact beyond DoS.

Task-number: QTBUG-44547
Change-Id: Ifcded2c0aa712e90d23e6b3969af0ec3add53973
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
This commit is contained in:
Richard J. Moore 2015-02-21 17:43:21 +00:00
parent 1afe110b8f
commit 661f6bfd03
1 changed files with 8 additions and 0 deletions
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8
src/gui/image/qbmphandler.cpp
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@ -314,12 +314,20 @@ static bool read_dib_body(QDataStream &s, const BMP_INFOHDR &bi, int offset, int
}
} else if (comp == BMP_BITFIELDS && (nbits == 16 || nbits == 32)) {
red_shift = calc_shift(red_mask);
if (((red_mask >> red_shift) + 1) == 0)
return false;
red_scale = 256 / ((red_mask >> red_shift) + 1);
green_shift = calc_shift(green_mask);
if (((green_mask >> green_shift) + 1) == 0)
return false;
green_scale = 256 / ((green_mask >> green_shift) + 1);
blue_shift = calc_shift(blue_mask);
if (((blue_mask >> blue_shift) + 1) == 0)
return false;
blue_scale = 256 / ((blue_mask >> blue_shift) + 1);
alpha_shift = calc_shift(alpha_mask);
if (((alpha_mask >> alpha_shift) + 1) == 0)
return false;
alpha_scale = 256 / ((alpha_mask >> alpha_shift) + 1);
} else if (comp == BMP_RGB && (nbits == 24 || nbits == 32)) {
blue_mask = 0x000000ff;