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authorOndrej Mosnacek <omosnace@redhat.com>2021-11-19 14:45:20 +0100
committerPaul Moore <paul@paul-moore.com>2021-11-19 16:11:39 -0500
commitdc27f3c5d10c58069672215787a96b4fae01818b (patch)
tree63bd602b230581896d9723016253f9cadccc8e6d /security
parent32a370abf12f82c8383e430c21365f5355d8b288 (diff)
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: 03414a49ad5f ("selinux: do not allocate hashtabs dynamically") Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
Diffstat (limited to 'security')
-rw-r--r--security/selinux/ss/hashtab.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/security/selinux/ss/hashtab.c b/security/selinux/ss/hashtab.c
index 727c3b484bd3..0ae4e4e57a40 100644
--- a/security/selinux/ss/hashtab.c
+++ b/security/selinux/ss/hashtab.c
@@ -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,