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Fix integer overflow vulnerability in exportImagePixels #775

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Fix integer overflow vulnerability in exportImagePixels #775

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31 changes: 29 additions & 2 deletions imagick_class.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2661,7 +2661,7 @@ PHP_METHOD(Imagick, exportImagePixels)
MagickBooleanType status;
im_long x, y, width, height, storage;
char *map;
int map_size, i = 0;
size_t map_size, i = 0;
IM_LEN_TYPE map_len;
double *double_array;
float *float_array;
Expand Down Expand Up @@ -2702,7 +2702,34 @@ PHP_METHOD(Imagick, exportImagePixels)
intern = Z_IMAGICK_P(getThis());
IMAGICK_NOT_EMPTY(intern);

map_size = (map_len * width * height);
// Check for integer overflow in map_size calculation
// map_size = map_len * width * height
if (width > 0 && map_len > SIZE_MAX / (size_t)width) {
php_imagick_throw_exception(IMAGICK_CLASS, "Integer overflow detected in pixel calculation (width * map_len)" TSRMLS_CC);
RETURN_THROWS();
}

size_t temp = (size_t)map_len * (size_t)width;
if (height > 0 && temp > SIZE_MAX / (size_t)height) {
php_imagick_throw_exception(IMAGICK_CLASS, "Integer overflow detected in pixel calculation (width * height * map_len)" TSRMLS_CC);
RETURN_THROWS();
}

map_size = temp * (size_t)height;

// Check for overflow in memory allocation
// The largest pixel type is either double (8 bytes) or unsigned long long int (8 bytes)
// We check against the largest to ensure safety for all types
size_t max_element_size = sizeof(double);
#if MagickLibVersion >= 0x700
if (sizeof(unsigned long long int) > max_element_size) {
max_element_size = sizeof(unsigned long long int);
}
#endif
if (map_size > SIZE_MAX / max_element_size) {
php_imagick_throw_exception(IMAGICK_CLASS, "Memory allocation would overflow (pixel buffer too large)" TSRMLS_CC);
RETURN_THROWS();
}

switch (storage) {
case FloatPixel:
Expand Down