lib: fixed possible null pointers passed to nonnull arguments

lib/dnssec/nsec3.c

@@ -222,7 +222,7 @@ static int covers_name(int *flags, const knot_rrset_t *nsec3, const knot_dname_t
 	uint8_t *next_hash = NULL;
 	knot_nsec3_next_hashed(&nsec3->rrs, 0, &next_hash, &next_size);
 
-	if ((owner_hash.size == next_size) && (name_hash.size == next_size)) {
+	if ((next_size > 0) && (owner_hash.size == next_size) && (name_hash.size == next_size)) {
 		/* All hash lengths must be same. */
 		const uint8_t *ownrd = owner_hash.data;
 		const uint8_t *nextd = next_hash;

lib/generic/lru.c

@@ -152,7 +152,7 @@ KR_EXPORT void * lru_get_impl(struct lru *lru, const char *key, uint key_len,
 		if (g->hashes[i] == khash_top) {
 			it = g->items[i];
 			if (likely(it && it->key_len == key_len
-					&& memcmp(it->data, key, key_len) == 0))
+					&& (key_len == 0 || memcmp(it->data, key, key_len) == 0)))
 				goto found; // to reduce huge nesting depth
 		}
 	}
@@ -200,7 +200,9 @@ KR_EXPORT void * lru_get_impl(struct lru *lru, const char *key, uint key_len,
 	}
 	it->key_len = key_len;
 	it->val_len = val_len;
-	memcpy(it->data, key, key_len);
+	if (key_len > 0) {
+		memcpy(it->data, key, key_len);
+	}
 	memset(item_val(it), 0, val_len); // clear the value
 found: // key and hash OK on g->items[i]; now update stamps
 	assert(i < LRU_ASSOC);