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improved security by encoding NULL values; double free mitigation on by default; more precise free list corruption detection

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This commit is contained in:
daan
2019-11-21 15:21:23 -08:00
parent 1674d551ff
commit 74dbfc30be
6 changed files with 49 additions and 36 deletions
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4
src/alloc.c
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@@ -157,7 +157,7 @@ static mi_decl_noinline bool mi_check_is_double_freex(const mi_page_t* page, con
}
static inline bool mi_check_is_double_free(const mi_page_t* page, const mi_block_t* block) {
mi_block_t* n = mi_block_nextx(page->cookie, block); // pretend it is freed, and get the decoded first field
mi_block_t* n = mi_block_nextx(page, block, page->cookie); // pretend it is freed, and get the decoded first field
if (((uintptr_t)n & (MI_INTPTR_SIZE-1))==0 && // quick check: aligned pointer?
(n==NULL || mi_is_in_same_segment(block, n))) // quick check: in same segment or NULL?
{
@@ -242,7 +242,7 @@ static mi_decl_noinline void _mi_free_block_mt(mi_page_t* page, mi_block_t* bloc
mi_block_t* dfree;
do {
dfree = (mi_block_t*)heap->thread_delayed_free;
mi_block_set_nextx(heap->cookie,block,dfree);
mi_block_set_nextx(heap,block,dfree, heap->cookie);
} while (!mi_atomic_cas_ptr_weak(mi_atomic_cast(void*,&heap->thread_delayed_free), block, dfree));
}