From 0b6216d1c702ef0aaa66a2a1bea70cfb12c81468 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= Date: Wed, 25 Nov 2020 12:45:47 +0100 Subject: [PATCH] Silence cppcheck 2.2 false positive in udp_recv() cppcheck 2.2 reports the following false positive: lib/dns/dispatch.c:1239:14: warning: Either the condition 'resp==NULL' is redundant or there is possible null pointer dereference: resp. [nullPointerRedundantCheck] if (disp != resp->disp) { ^ lib/dns/dispatch.c:1210:11: note: Assuming that condition 'resp==NULL' is not redundant if (resp == NULL) { ^ lib/dns/dispatch.c:1239:14: note: Null pointer dereference if (disp != resp->disp) { ^ Apparently this version of cppcheck gets confused about conditional "goto" statements because line 1239 can never be reached if 'resp' is NULL. Move a code block to prevent the above false positive from being reported without affecting the processing logic. --- lib/dns/dispatch.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/lib/dns/dispatch.c b/lib/dns/dispatch.c index 82c019168d..f226d156bf 100644 --- a/lib/dns/dispatch.c +++ b/lib/dns/dispatch.c @@ -1217,11 +1217,6 @@ udp_recv(isc_event_t *ev_in, dns_dispatch_t *disp, dispsocket_t *dispsock) { "search for response in bucket %d: %s", bucket, (resp == NULL ? "not found" : "found")); - if (resp == NULL) { - inc_stats(mgr, dns_resstatscounter_mismatch); - free_buffer(disp, ev->region.base, ev->region.length); - goto unlock; - } } else if (resp->id != id || !isc_sockaddr_equal(&ev->address, &resp->host)) { dispatch_log(disp, LVL(90), @@ -1231,6 +1226,12 @@ udp_recv(isc_event_t *ev_in, dns_dispatch_t *disp, dispsocket_t *dispsock) { goto unlock; } + if (resp == NULL) { + inc_stats(mgr, dns_resstatscounter_mismatch); + free_buffer(disp, ev->region.base, ev->region.length); + goto unlock; + } + /* * Now that we have the original dispatch the query was sent * from check that the address and port the response was