Backport Coverity fix to hide detected issue

Backport already accepted upstream patch.

Fixes:
1. Defect type: GCC_ANALYZER_WARNING
2. dnsmasq-2.85/src/forward.c:2335:18: warning[-Wanalyzer-null-dereference]: dereference of NULL 'rfd'

Related: rhbz#2156789

dnsmasq-2.87-coverity-forward-cache.patch

@@ -0,0 +1,77 @@
+From 2f45670951d2159ebf588e1e4943c0bc9e1cd20b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
+Date: Wed, 18 Aug 2021 14:59:23 +0200
+Subject: [PATCH] Add safety checks to places pointed by Coverity
+
+GCC Analyzer (experimental)
+
+1. dnsmasq-2.85/src/forward.c:0: scope_hint: In function 'allocate_rfd.part.0'
+2. dnsmasq-2.85/src/forward.c:2321:18: warning[-Wanalyzer-null-dereference]: dereference of NULL 'rfd'
+ #  2319|     *fdlp = rfl;
+ #  2320|
+ #  2321|->   return rfl->rfd->fd;
+ #  2322|   }
+ #  2323|
+
+1. dnsmasq-2.85/src/cache.c:0: scope_hint: In function 'log_query'
+2. dnsmasq-2.85/src/cache.c:1969:20: warning[-Wanalyzer-null-dereference]: dereference of NULL 'name'
+ #  1967|       source = "cached";
+ #  1968|
+ #  1969|->   if (strlen(name) == 0)
+ #  1970|       name = ".";
+ #  1971|
+
+1. dnsmasq-2.85/src/cache.c:0: scope_hint: In function 'cache_scan_free'
+2. dnsmasq-2.85/src/cache.c:436:20: warning[-Wanalyzer-null-argument]: use of NULL 'addr' where non-null expected
+40. /usr/include/sys/un.h:37: included_from: Included from here.
+41. dnsmasq-2.85/src/dnsmasq.h:101: included_from: Included from here.
+42. dnsmasq-2.85/src/cache.c:17: included_from: Included from here.
+43. /usr/include/string.h:64:12: note: argument 2 of 'memcmp' must be non-null
+ #   434|   		   (flags & crecp->flags & F_REVERSE) &&
+ #   435|   		   (flags & crecp->flags & (F_IPV4 | F_IPV6)) &&
+ #   436|-> 		   memcmp(&crecp->addr, addr, addrlen) == 0)
+ #   437|   	    {
+ #   438|   	      *up = crecp->hash_next;
+---
+ src/cache.c   | 4 ++--
+ src/forward.c | 2 +-
+ 2 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/src/cache.c b/src/cache.c
+index b3b3c7c..8f97947 100644
+--- a/src/cache.c
++++ b/src/cache.c
+@@ -483,7 +483,7 @@ static struct crec *cache_scan_free(char *name, union all_addr *addr, unsigned s
+ 	  else if (!(crecp->flags & (F_HOSTS | F_DHCP | F_CONFIG)) &&
+ 		   (flags & crecp->flags & F_REVERSE) && 
+ 		   (flags & crecp->flags & (F_IPV4 | F_IPV6)) &&
+-		   memcmp(&crecp->addr, addr, addrlen) == 0)
++		   addr && memcmp(&crecp->addr, addr, addrlen) == 0)
+ 	    {
+ 	      *up = crecp->hash_next;
+ 	      cache_unlink(crecp);
+@@ -2067,7 +2067,7 @@ void log_query(unsigned int flags, char *name, union all_addr *addr, char *arg,
+   else
+     source = "cached";
+   
+-  if (strlen(name) == 0)
++  if (name && !name[0])
+     name = ".";
+ 
+   if (option_bool(OPT_EXTRALOG))
+diff --git a/src/forward.c b/src/forward.c
+index 434ba77..f3c38d7 100644
+--- a/src/forward.c
++++ b/src/forward.c
+@@ -2274,7 +2274,7 @@ int allocate_rfd(struct randfd_list **fdlp, struct server *serv)
+ 	  }
+       }
+ 
+-  if (j == daemon->numrrand)
++  if (!rfd) /* should be when j == daemon->numrrand */
+     {
+       struct randfd_list *rfl_poll;
+ 
+-- 
+2.41.0
+

dnsmasq.spec

@@ -20,7 +20,7 @@
 
 Name:           dnsmasq
 Version:        2.85
-Release:        13%{?extraversion:.%{extraversion}}%{?dist}
+Release:        14%{?extraversion:.%{extraversion}}%{?dist}
 Summary:        A lightweight DHCP/caching DNS server
 
 License:        GPLv2 or GPLv3
@@ -67,6 +67,8 @@ Patch13:        dnsmasq-2.87-log-root-writeable.patch
 # Downstream only patch; https://bugzilla.redhat.com/show_bug.cgi?id=2209031
 # complements patch12
 Patch14:        dnsmasq-2.85-domain-blocklist-speedup.patch
+# https://thekelleys.org.uk/gitweb/?p=dnsmasq.git;h=9bbf098a970c9e5fa251939208e25fb21064d1be
+Patch15:        dnsmasq-2.87-coverity-forward-cache.patch
 
 # This is workaround to nettle bug #1549190
 # https://bugzilla.redhat.com/show_bug.cgi?id=1549190
@@ -210,6 +212,9 @@ install -Dpm 644 %{SOURCE2} %{buildroot}%{_sysusersdir}/%{name}.conf
 %{_mandir}/man1/dhcp_*
 
 %changelog
+* Fri Jul 28 2023 Petr Menšík <pemensik@redhat.com> - 2.85-14
+- Backport Coverity fix to hide detected issue (#2156789)
+
 * Thu Jul 20 2023 Petr Menšík <pemensik@redhat.com> - 2.85-13
 - Rebuild with modified gating settings