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refresh canary value when allocating free slabs

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This commit is contained in:
Daniel Micay 2018-09-06 15:07:01 -04:00
parent a875951e82
commit 8624201f06
1 changed files with 2 additions and 1 deletions
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3
malloc.c
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@ -152,7 +152,6 @@ static struct slab_metadata *alloc_metadata(struct size_class *c, size_t slab_si
} }
struct slab_metadata *metadata = c->slab_info + c->metadata_count; struct slab_metadata *metadata = c->slab_info + c->metadata_count;
metadata->canary_value = get_random_u64(&c->rng);
c->metadata_count++; c->metadata_count++;
return metadata; return metadata;
} }
@ -271,6 +270,7 @@ static inline void *slab_allocate(size_t requested_size) {
return p; return p;
} else if (c->free_slabs_head != NULL) { } else if (c->free_slabs_head != NULL) {
struct slab_metadata *metadata = c->free_slabs_head; struct slab_metadata *metadata = c->free_slabs_head;
metadata->canary_value = get_random_u64(&c->rng);
void *slab = get_slab(c, slab_size, metadata); void *slab = get_slab(c, slab_size, metadata);
if (requested_size != 0 && memory_protect_rw(slab, slab_size)) { if (requested_size != 0 && memory_protect_rw(slab, slab_size)) {
@ -302,6 +302,7 @@ static inline void *slab_allocate(size_t requested_size) {
pthread_mutex_unlock(&c->mutex); pthread_mutex_unlock(&c->mutex);
return NULL; return NULL;
} }
metadata->canary_value = get_random_u64(&c->rng);
void *slab = get_slab(c, slab_size, metadata); void *slab = get_slab(c, slab_size, metadata);
if (requested_size != 0 && memory_protect_rw(slab, slab_size)) { if (requested_size != 0 && memory_protect_rw(slab, slab_size)) {