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ext/standard: getimagesizefromstring() overflow. #22574

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ext/standard: getimagesizefromstring() overflow. #22574

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2 changes: 1 addition & 1 deletion ext/standard/image.c
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Original file line number Diff line number Diff line change
Expand Up @@ -874,7 +874,7 @@ static struct gfxinfo *php_handle_iff(php_stream * stream)
if (size < 0) {
return NULL;
}
if ((size & 1) == 1) {
if ((size & 1) == 1 && size < INT_MAX) {
size++;
}
if (chunkId == 0x424d4844) { /* BMHD chunk */
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14 changes: 14 additions & 0 deletions ext/standard/tests/image/getimagesizefromstring_iff_overflow.phpt
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@@ -0,0 +1,14 @@
--TEST--
getimagesizefromstring() IFF chunk size integer overflow (GH-getimagesize_oflow)
--CREDITS--
Alexandre Daubois
--FILE--
<?php
// IFF/ILBM with a chunk size of INT_MAX (0x7fffffff), an odd value.
// The parser rounds odd chunk sizes up to even via size++, which overflowed
// when size == INT_MAX. It must be handled gracefully rather than triggering UB.
$payload = "FORM" . "\x00\x00\x00\x00" . "ILBM" . "ABCD" . "\x7f\xff\xff\xff";
var_dump(getimagesizefromstring($payload));
?>
--EXPECT--
bool(false)
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