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Validate large run map entries instead of assuming them #23366

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Validate large run map entries instead of assuming them #23366

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12 changes: 8 additions & 4 deletions Zend/zend_alloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1527,9 +1527,11 @@ static zend_always_inline void zend_mm_free_heap(zend_mm_heap *heap, void *ptr Z
ZEND_MM_CHECK(chunk->heap == heap, "zend_mm_heap corrupted");
if (EXPECTED(info & ZEND_MM_IS_SRUN)) {
zend_mm_free_small(heap, ptr, ZEND_MM_SRUN_BIN_NUM(info));
} else /* if (info & ZEND_MM_IS_LRUN) */ {
int pages_count = ZEND_MM_LRUN_PAGES(info);
} else {
/* A freed large run has a zeroed map entry, so this also rejects double frees. */
ZEND_MM_CHECK(info & ZEND_MM_IS_LRUN, "zend_mm_heap corrupted");

int pages_count = ZEND_MM_LRUN_PAGES(info);
ZEND_MM_CHECK(ZEND_MM_ALIGNED_OFFSET(page_offset, ZEND_MM_PAGE_SIZE) == 0, "zend_mm_heap corrupted");
zend_mm_free_large(heap, chunk, page_num, pages_count);
}
Expand Down Expand Up @@ -1557,7 +1559,8 @@ static size_t zend_mm_size(zend_mm_heap *heap, void *ptr ZEND_FILE_LINE_DC ZEND_
ZEND_MM_CHECK(chunk->heap == heap, "zend_mm_heap corrupted");
if (EXPECTED(info & ZEND_MM_IS_SRUN)) {
return bin_data_size[ZEND_MM_SRUN_BIN_NUM(info)];
} else /* if (info & ZEND_MM_IS_LARGE_RUN) */ {
} else {
ZEND_MM_CHECK(info & ZEND_MM_IS_LRUN, "zend_mm_heap corrupted");
return ZEND_MM_LRUN_PAGES(info) * ZEND_MM_PAGE_SIZE;
}
#endif
Expand Down Expand Up @@ -1752,7 +1755,8 @@ static zend_always_inline void *zend_mm_realloc_heap(zend_mm_heap *heap, void *p
return ret;
} while (0);

} else /* if (info & ZEND_MM_IS_LARGE_RUN) */ {
} else {
ZEND_MM_CHECK(info & ZEND_MM_IS_LRUN, "zend_mm_heap corrupted");
ZEND_MM_CHECK(ZEND_MM_ALIGNED_OFFSET(page_offset, ZEND_MM_PAGE_SIZE) == 0, "zend_mm_heap corrupted");
old_size = ZEND_MM_LRUN_PAGES(info) * ZEND_MM_PAGE_SIZE;
if (size > ZEND_MM_MAX_SMALL_SIZE && size <= ZEND_MM_MAX_LARGE_SIZE) {
Expand Down
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