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ext/gd: Reject out-of-range XBM dimensions #25318

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ext/gd: Reject out-of-range XBM dimensions #25318

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4 changes: 4 additions & 0 deletions NEWS
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,10 @@ PHP NEWS
. Fixed bug GH-25268 (NULL php_libxml_ref_obj dereference in
dom_objects_store_clone_obj when cloning Dom\Notation). (David Carlier)

- GD:
. Fixed imagecreatefromxbm() accepting XBM files with out-of-range
dimensions. (Ilia Alshanetsky)

- MBString:
. Fixed stack overflow in mb_check_encoding() and mb_convert_encoding() with
deeply nested arrays. (Eyüp Can Akman)
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32 changes: 20 additions & 12 deletions ext/gd/libgd/gd_xbm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,8 @@
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <limits.h>
#include "gd.h"
#include "gdhelpers.h"
#include "gd_errors.h"
Expand All @@ -34,7 +36,9 @@ gdImagePtr gdImageCreateFromXbm(FILE * fd)
char fline[MAX_XBM_LINE_SIZE];
char iname[MAX_XBM_LINE_SIZE];
char *type;
int value;
char *end;
int offset;
long value;
unsigned int width = 0, height = 0;
int fail = 0;
int max_bit = 0;
Expand All @@ -52,18 +56,22 @@ gdImagePtr gdImageCreateFromXbm(FILE * fd)
if (strlen(fline) == MAX_XBM_LINE_SIZE-1) {
return 0;
}
if (sscanf(fline, "#define %s %d", iname, &value) == 2) {
if (!(type = strrchr(iname, '_'))) {
type = iname;
} else {
type++;
}
if (sscanf(fline, "#define %s %n", iname, &offset) == 1) {
errno = 0;
value = strtol(fline + offset, &end, 10);
if (end != fline + offset && errno == 0 && value > 0 && value <= INT_MAX) {
if (!(type = strrchr(iname, '_'))) {
type = iname;
} else {
type++;
}

if (!strcmp("width", type)) {
width = (unsigned int) value;
}
if (!strcmp("height", type)) {
height = (unsigned int) value;
if (!strcmp("width", type)) {
width = (unsigned int) value;
}
if (!strcmp("height", type)) {
height = (unsigned int) value;
}
}
} else {
if ( sscanf(fline, "static unsigned char %s = {", iname) == 1
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32 changes: 32 additions & 0 deletions ext/gd/tests/xbm_out_of_range.phpt
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@@ -0,0 +1,32 @@
--TEST--
imagecreatefromxbm() rejects out-of-range XBM dimensions
--EXTENSIONS--
gd
--SKIPIF--
<?php
if (!GD_BUNDLED) {
die("skip dimension range checks require bundled GD");
}
?>
--FILE--
<?php
$path = __DIR__ . '/xbm_out_of_range.tmp.xbm';
foreach ([['4294967298', '1'], ['1', '4294967298']] as [$w, $h]) {
file_put_contents($path, "#define x_width $w\n#define x_height $h\nstatic char x_bits[] = {\n0x00, 0x00 };\n");
echo "$w x $h\n";
var_dump(imagecreatefromxbm($path));
}
?>
--CLEAN--
<?php
@unlink(__DIR__ . '/xbm_out_of_range.tmp.xbm');
?>
--EXPECTF--
4294967298 x 1

Warning: imagecreatefromxbm(): "%s" is not a valid XBM file in %s on line %d
bool(false)
1 x 4294967298

Warning: imagecreatefromxbm(): "%s" is not a valid XBM file in %s on line %d
bool(false)
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