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Fix GH-20602: imagescale() overflow with large height values. #20605

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devnexen wants to merge 1 commit into from
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Fix GH-20602: imagescale() overflow with large height values. #20605

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8 changes: 8 additions & 0 deletions ext/gd/gd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3689,9 +3689,17 @@ PHP_FUNCTION(imagescale)
src_y = gdImageSY(im);

if (src_x && tmp_h < 0) {
if (tmp_w > (ZEND_LONG_MAX / src_y)) {
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@bukka bukka Nov 29, 2025

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You could allow a bit higher (multiple of src_x) value if it was changed to tmp_w * (src_y / src_x) but not sure if it's worth it...

zend_argument_value_error(2, "must be less than or equal to " ZEND_LONG_FMT, (zend_long)(ZEND_LONG_MAX / src_y));
RETURN_THROWS();
}
tmp_h = tmp_w * src_y / src_x;
}
if (src_y && tmp_w < 0) {
if (tmp_h > (ZEND_LONG_MAX / src_x)) {
zend_argument_value_error(3, "must be less than or equal to " ZEND_LONG_FMT, (zend_long)(ZEND_LONG_MAX / src_x));
RETURN_THROWS();
}
tmp_w = tmp_h * src_x / src_y;
}
}
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22 changes: 22 additions & 0 deletions ext/gd/tests/gh20602.phpt
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@@ -0,0 +1,22 @@
--TEST--
GH-20551: (imagegammacorrect out of range input/output value)
--EXTENSIONS--
gd
--FILE--
<?php
$im = imagecreatetruecolor(16, 16);

try {
imagescale($im, PHP_INT_MAX, -1);
} catch (\ValueError $e) {
echo $e->getMessage(), PHP_EOL;
}
try {
imagescale($im, -1, PHP_INT_MAX);
} catch (\ValueError $e) {
echo $e->getMessage(), PHP_EOL;
}
?>
--EXPECTF--
imagescale(): Argument #2 ($width) must be less than or equal to %d
imagescale(): Argument #3 ($height) must be less than or equal to %d
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