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add an extra sanity check for unallocated metadata

pull/50/head
Daniel Micay 2018-08-24 05:18:20 -04:00
parent bde8c3c29b
commit 805bdc6087
1 changed files with 4 additions and 0 deletions
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4
malloc.c
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@ -276,6 +276,10 @@ static void *get_slab(struct size_class *c, size_t slab_size, struct slab_metada
static struct slab_metadata *get_metadata(struct size_class *c, size_t slab_size, void *p) { static struct slab_metadata *get_metadata(struct size_class *c, size_t slab_size, void *p) {
size_t offset = (char *)p - (char *)c->class_region_start; size_t offset = (char *)p - (char *)c->class_region_start;
size_t index = offset / slab_size; size_t index = offset / slab_size;
// still caught without this check either as a read access violation or "double free"
if (index >= c->metadata_allocated) {
fatal_error("invalid free within a slab yet to be used");
}
return c->slab_info + index; return c->slab_info + index;
} }