Commit dc27f3c5 authored by Ondrej Mosnacek's avatar Ondrej Mosnacek Committed by Paul Moore
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selinux: fix NULL-pointer dereference when hashtab allocation fails 



When the hash table slot array allocation fails in hashtab_init(),
h->size is left initialized with a non-zero value, but the h->htable
pointer is NULL. This may then cause a NULL pointer dereference, since
the policydb code relies on the assumption that even after a failed
hashtab_init(), hashtab_map() and hashtab_destroy() can be safely called
on it. Yet, these detect an empty hashtab only by looking at the size.

Fix this by making sure that hashtab_init() always leaves behind a valid
empty hashtab when the allocation fails.

Cc: stable@vger.kernel.org
Fixes: 03414a49 ("selinux: do not allocate hashtabs dynamically")
Signed-off-by: default avatarOndrej Mosnacek <omosnace@redhat.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 32a370ab

security/selinux/ss/hashtab.c

+12 −5
Original line number Diff line number Diff line
@@ -31,13 +31,20 @@ static u32 hashtab_compute_size(u32 nel) 


int hashtab_init(struct hashtab *h, u32 nel_hint)

{

	h->size = hashtab_compute_size(nel_hint);

	u32 size = hashtab_compute_size(nel_hint);



	/* should already be zeroed, but better be safe */

	h->nel = 0;

	if (!h->size)

		return 0;

	h->size = 0;

	h->htable = NULL;



	h->htable = kcalloc(h->size, sizeof(*h->htable), GFP_KERNEL);

	return h->htable ? 0 : -ENOMEM;

	if (size) {

		h->htable = kcalloc(size, sizeof(*h->htable), GFP_KERNEL);

		if (!h->htable)

			return -ENOMEM;

		h->size = size;

	}

	return 0;

}



int __hashtab_insert(struct hashtab *h, struct hashtab_node **dst,