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Fix overflow in memory limit checks

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Due to overflows in the memory limit checks, we were missing cases
where the allocation size was close to the address space size, and
caused an OOM condition rather than a memory limit error.
This commit is contained in:
Nikita Popov 2019-08-26 10:23:23 +02:00
parent 4b4a656d9e
commit 16d35eb643
2 changed files with 23 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

10
Zend/zend_alloc.c
View file

@ -980,7 +980,7 @@ get_chunk:
heap->cached_chunks = chunk->next;
} else {
#if ZEND_MM_LIMIT
if (UNEXPECTED(heap->real_size + ZEND_MM_CHUNK_SIZE > heap->limit)) {
if (UNEXPECTED(ZEND_MM_CHUNK_SIZE > heap->limit - heap->real_size)) {
if (zend_mm_gc(heap)) {
goto get_chunk;
} else if (heap->overflow == 0) {
@ -1484,8 +1484,8 @@ static void *zend_mm_realloc_heap(zend_mm_heap *heap, void *ptr, size_t size, si
}
} else /* if (new_size > old_size) */ {
#if ZEND_MM_LIMIT
if (UNEXPECTED(heap->real_size + (new_size - old_size) > heap->limit)) {
if (zend_mm_gc(heap) && heap->real_size + (new_size - old_size) <= heap->limit) {
if (UNEXPECTED(new_size - old_size > heap->limit - heap->real_size)) {
if (zend_mm_gc(heap) && new_size - old_size <= heap->limit - heap->real_size) {
/* pass */
} else if (heap->overflow == 0) {
#if ZEND_DEBUG
@ -1730,8 +1730,8 @@ static void *zend_mm_alloc_huge(zend_mm_heap *heap, size_t size ZEND_FILE_LINE_D
void *ptr;
#if ZEND_MM_LIMIT
if (UNEXPECTED(heap->real_size + new_size > heap->limit)) {
if (zend_mm_gc(heap) && heap->real_size + new_size <= heap->limit) {
if (UNEXPECTED(new_size > heap->limit - heap->real_size)) {
if (zend_mm_gc(heap) && new_size <= heap->limit - heap->real_size) {
/* pass */
} else if (heap->overflow == 0) {
#if ZEND_DEBUG

18
ext/standard/tests/strings/wordwrap_memory_limit.phpt Normal file
View file

@ -0,0 +1,18 @@
--TEST--
No overflow should occur during the memory_limit check for wordwrap()
--SKIPIF--
<?php
if (getenv("USE_ZEND_ALLOC") === "0") die("skip Zend MM disabled");
?>
--INI--
memory_limit=128M
--FILE--
<?php
$str = str_repeat('x', 65534);
$str2 = str_repeat('x', 65535);
wordwrap($str, 1, $str2);
?>
--EXPECTF--
Fatal error: Allowed memory size of 134217728 bytes exhausted%s(tried to allocate %d bytes) in %s on line %d