Commit ddd0d356 authored by Ondřej Surý's avatar Ondřej Surý

Fix 'Dereference of null pointer' from scan-build-10

These are mostly false positives, the clang-analyzer FAQ[1] specifies
why and how to fix it:

> The reason the analyzer often thinks that a pointer can be null is
> because the preceding code checked compared it against null. So if you
> are absolutely sure that it cannot be null, remove the preceding check
> and, preferably, add an assertion as well.

The 4 warnings reported are:

dnssec-cds.c:781:4: warning: Access to field 'base' results in a dereference of a null pointer (loaded from variable 'buf')
                        isc_buffer_availableregion(buf, &r);
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/builds/isc-projects/bind9/lib/isc/include/isc/buffer.h:996:36: note: expanded from macro 'isc_buffer_availableregion'
                                   ^
/builds/isc-projects/bind9/lib/isc/include/isc/buffer.h:821:16: note: expanded from macro 'ISC__BUFFER_AVAILABLEREGION'
                (_r)->base = isc_buffer_used(_b);              \
                             ^~~~~~~~~~~~~~~~~~~
/builds/isc-projects/bind9/lib/isc/include/isc/buffer.h:152:29: note: expanded from macro 'isc_buffer_used'
        ((void *)((unsigned char *)(b)->base + (b)->used)) /*d*/
                                   ^~~~~~~~~
1 warning generated.

--

byname_test.c:308:34: warning: Access to field 'fwdtable' results in a dereference of a null pointer (loaded from variable 'view')
                RUNTIME_CHECK(dns_fwdtable_add(view->fwdtable, dns_rootname,
                                               ^~~~~~~~~~~~~~
/builds/isc-projects/bind9/lib/isc/include/isc/util.h:318:52: note: expanded from macro 'RUNTIME_CHECK'
                                                   ^~~~
/builds/isc-projects/bind9/lib/isc/include/isc/error.h:50:21: note: expanded from macro 'ISC_ERROR_RUNTIMECHECK'
        ((void)(ISC_LIKELY(cond) ||  \
                           ^~~~
/builds/isc-projects/bind9/lib/isc/include/isc/likely.h:23:43: note: expanded from macro 'ISC_LIKELY'
                                            ^
1 warning generated.

--

./rndc.c:255:6: warning: Dereference of null pointer (loaded from variable 'host')
        if (*host == '/') {
            ^~~~~
1 warning generated.

--

./main.c:1254:9: warning: Access to field 'sctx' results in a dereference of a null pointer (loaded from variable 'named_g_server')
        sctx = named_g_server->sctx;
               ^~~~~~~~~~~~~~~~~~~~
1 warning generated.

References:
1. https://clang-analyzer.llvm.org/faq.html#null_pointer
parent 262f087b
Pipeline #37582 failed with stages
in 24 minutes and 9 seconds
......@@ -754,6 +754,8 @@ ds_from_cds(dns_rdatalist_t *dslist, isc_buffer_t *buf, dns_rdata_t *cds) {
dns_rdata_ds_t ds;
dns_rdata_t *rdata;
REQUIRE(buf != NULL);
rdata = rdata_get();
result = dns_rdata_tostruct(cds, &ds, NULL);
......@@ -772,6 +774,8 @@ ds_from_cdnskey(dns_rdatalist_t *dslist, isc_buffer_t *buf,
isc_result_t result;
unsigned i, n;
REQUIRE(buf != NULL);
n = sizeof(dtype) / sizeof(dtype[0]);
for (i = 0; i < n; i++) {
if (dtype[i] != 0) {
......
......@@ -1251,6 +1251,7 @@ setup(void) {
#endif /* if CONTRIB_DLZ */
named_server_create(named_g_mctx, &named_g_server);
ENSURE(named_g_server != NULL);
sctx = named_g_server->sctx;
/*
......
......@@ -252,6 +252,8 @@ get_addresses(const char *host, in_port_t port) {
isc_result_t result;
int found = 0, count;
REQUIRE(host != NULL);
if (*host == '/') {
result = isc_sockaddr_frompath(&serveraddrs[nserveraddrs],
host);
......@@ -1036,7 +1038,7 @@ main(int argc, char **argv) {
fatal("'%s' is not implemented", command);
}
if (nserveraddrs == 0) {
if (nserveraddrs == 0 && servername != NULL) {
get_addresses(servername, (in_port_t)remoteport);
}
......
......@@ -305,6 +305,7 @@ main(int argc, char *argv[]) {
isc_sockaddr_fromin(&sa, &ina, 53);
ISC_LIST_APPEND(sal, &sa, link);
REQUIRE(DNS_VIEW_VALID(view));
RUNTIME_CHECK(dns_fwdtable_add(view->fwdtable, dns_rootname,
&sal, dns_fwdpolicy_only) ==
ISC_R_SUCCESS);
......
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