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
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