From 16daaaacd12443f5d578f83cb835c68aec89822f Mon Sep 17 00:00:00 2001 From: Benoît Ganne Date: Thu, 26 Jan 2023 16:03:55 +0100 Subject: dns: keep AddressSanitizer happy MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Type: fix Change-Id: I0ae4071ee317f38daa882fec17087a55afe75d1d Signed-off-by: Benoît Ganne --- src/plugins/dns/dns.c | 28 ++++++++++++++++++---------- src/plugins/dns/request_node.c | 11 +++++------ 2 files changed, 23 insertions(+), 16 deletions(-) diff --git a/src/plugins/dns/dns.c b/src/plugins/dns/dns.c index 4a283bf298f..d07a1dac43b 100644 --- a/src/plugins/dns/dns.c +++ b/src/plugins/dns/dns.c @@ -38,6 +38,19 @@ dns_main_t dns_main; +/* the cache hashtable expects a NULL-terminated C-string but everywhere else + * expects a non-NULL terminated vector... The pattern of adding \0 but hiding + * it away drives AddressSanitizer crazy, this helper tries to bring some of + * its sanity back + */ +static_always_inline void +dns_terminate_c_string (u8 **v) +{ + vec_add1 (*v, 0); + vec_dec_len (*v, 1); + clib_mem_unpoison (vec_end (*v), 1); +} + static int dns_cache_clear (dns_main_t * dm) { @@ -826,8 +839,8 @@ re_resolve: pool_get (dm->entries, ep); clib_memset (ep, 0, sizeof (*ep)); - ep->name = format (0, "%s%c", name, 0); - vec_set_len (ep->name, vec_len (ep->name) - 1); + ep->name = format (0, "%s", name); + dns_terminate_c_string (&ep->name); hash_set_mem (dm->cache_entry_by_name, ep->name, ep - dm->entries); @@ -985,8 +998,7 @@ found_last_request: now = vlib_time_now (vm); cname = vnet_dns_labels_to_name (rr->rdata, reply, &pos2); /* Save the cname */ - vec_add1 (cname, 0); - vec_dec_len (cname, 1); + dns_terminate_c_string (&cname); ep = pool_elt_at_index (dm->entries, ep_index); ep->cname = cname; ep->flags |= (DNS_CACHE_ENTRY_FLAG_CNAME | DNS_CACHE_ENTRY_FLAG_VALID); @@ -1004,8 +1016,7 @@ found_last_request: clib_memset (next_ep, 0, sizeof (*next_ep)); next_ep->name = vec_dup (cname); - vec_add1 (next_ep->name, 0); - vec_dec_len (next_ep->name, 1); + dns_terminate_c_string (&next_ep->name); hash_set_mem (dm->cache_entry_by_name, next_ep->name, next_ep - dm->entries); @@ -2607,10 +2618,7 @@ test_dns_expire_command_fn (vlib_main_t * vm, dns_cache_entry_t *ep; if (unformat (input, "%v", &name)) - { - vec_add1 (name, 0); - vec_dec_len (name, 1); - } + dns_terminate_c_string (&name); else return clib_error_return (0, "no name provided"); diff --git a/src/plugins/dns/request_node.c b/src/plugins/dns/request_node.c index 9179bf8dbdd..9e76a56f961 100644 --- a/src/plugins/dns/request_node.c +++ b/src/plugins/dns/request_node.c @@ -208,13 +208,7 @@ dns46_request_inline (vlib_main_t * vm, label0 = (u8 *) (d0 + 1); - /* - * vnet_dns_labels_to_name produces a non NULL terminated vector - * vnet_dns_resolve_name expects a C-string. - */ name0 = vnet_dns_labels_to_name (label0, (u8 *) d0, (u8 **) & q0); - vec_add1 (name0, 0); - vec_dec_len (name0, 1); t0->request_type = DNS_PEER_PENDING_NAME_TO_IP; @@ -242,6 +236,11 @@ dns46_request_inline (vlib_main_t * vm, clib_memcpy_fast (t0->dst_address, ip40->src_address.as_u8, sizeof (ip4_address_t)); + /* + * vnet_dns_labels_to_name produces a non NULL terminated vector + * vnet_dns_resolve_name expects a C-string. + */ + vec_add1 (name0, 0); vnet_dns_resolve_name (vm, dm, name0, t0, &ep0); if (ep0) -- cgit 1.2.3-korg