From Cppcheck:
Passing NULL after the last typed argument to a variadic function leads to
undefined behaviour. The C99 standard, in section 7.15.1.1, states that if the
type used by va_arg() is not compatible with the type of the actual next
argument (as promoted according to the default argument promotions), the
behavior is undefined. The value of the NULL macro is an implementation-defined
null pointer constant (7.17), which can be any integer constant expression with
the value 0, or such an expression casted to (void*) (6.3.2.3). This includes
values like 0, 0L, or even 0LL.In practice on common architectures, this will
cause real crashes if sizeof(int) != sizeof(void*), and NULL is defined to 0 or
any other null pointer constant that promotes to int. To reproduce you might be
able to use this little code example on 64bit platforms. If the output includes
"ERROR", the sentinel had only 4 out of 8 bytes initialized to zero and was not
detected as the final argument to stop argument processing via
va_arg(). Changing the 0 to (void*)0 or 0L will make the "ERROR" output go away.
void f(char *s, ...) {
va_list ap;
va_start(ap,s);
for (;;) {
char *p = va_arg(ap,char*);
printf("%018p, %s\n", p, (long)p & 255 ? p : "");
if(!p) break;
}
va_end(ap);
}
void g() {
char *s2 = "x";
char *s3 = "ERROR";
// changing 0 to 0L for the 7th argument (which is intended to act as
// sentinel) makes the error go away on x86_64
f("first", s2, s2, s2, s2, s2, 0, s3, (char*)0);
}
void h() {
int i;
volatile unsigned char a[1000];
for (i = 0; i<sizeof(a); i++)
a[i] = -1;
}
int main() {
h();
g();
return 0;
}
(cherry picked from commit d8879af877)
Until now, the build process for BIND on Windows involved upgrading the
solution file to the version of Visual Studio used on the build host.
Unfortunately, the executable used for that (devenv.exe) is not part of
Visual Studio Build Tools and thus there is no clean way to make that
executable part of a Windows Server container.
Luckily, the solution upgrade process boils down to just adding XML tags
to Visual Studio project files and modifying certain XML attributes - in
files which we pregenerate anyway using win32utils/Configure. Thus,
extend win32utils/Configure with three new command line parameters that
enable it to mimic what "devenv.exe bind9.sln /upgrade" does. This
makes the devenv.exe build step redundant and thus facilitates building
BIND in Windows Server containers.
(cherry picked from commit 0476e8f1ac)
when looking for a possible wildcard match in the RPZ summary database,
use an rbtnodechain to walk up label by label, rather than using the
node's parent pointer.
(cherry picked from commit 6e9be9a952)
When updating the statistics for RRset types, if a header is marked
stale or ancient, the appropriate statistic counters are decremented,
then incremented.
Also fix some out of date comments.
(cherry picked from commit a3af2c57e7)
Having the decrement/increment logic in stats makes the code hard
to follow. Remove it here and adjust the unit test. The caller
will be responsible for maintaining the correct increments and
decrements for statistics counters (in the following commit).
(cherry picked from commit 48332d4478)
The stale RR types are now printed with '#'. This used to be the
prefix for RR types that were marked ancient, but commit
df50751585 changed the meaning. It is
probably better to keep '#' for stale RR types and introduce a new
prefix for reintroducing ancient type stat counters.
(cherry picked from commit c9d56a8185)
There's a deadlock in BIND 9 code where (dns_view_t){ .lock } and
(dns_resolver_t){ .buckets[i].lock } gets locked in different order. When
view->weakrefs gets converted to a reference counting we can reduce the locking
in dns_view_weakdetach only to cases where it's the last instance of the
dns_view_t object.
(cherry picked from commit a7c9a52c89)
Make sure all unit tests include headers in a similar order:
1. Three headers which must be included before <cmocka.h>.
2. System headers.
3. UNIT_TESTING definition, followed by the <cmocka.h> header.
4. libisc headers.
5. Headers from other BIND libraries.
6. Local headers.
Also make sure header file names are sorted alphabetically within each
block of #include directives.
(cherry picked from commit 5381ac0fcc)
All unit tests define the UNIT_TESTING macro, which causes <cmocka.h> to
replace malloc(), calloc(), realloc(), and free() with its own functions
tracking memory allocations. In order for this not to break
compilation, the system header declaring the prototypes for these
standard functions must be included before <cmocka.h>.
Normally, these prototypes are only present in <stdlib.h>, so we make
sure it is included before <cmocka.h>. However, musl libc also defines
the prototypes for calloc() and free() in <sched.h>, which is included
by <pthread.h>, which is included e.g. by <isc/mutex.h>. Thus, unit
tests including "dnstest.h" (which includes <isc/mem.h>, which includes
<isc/mutex.h>) after <cmocka.h> will not compile with musl libc as for
these programs, <sched.h> will be included after <cmocka.h>.
Always including <cmocka.h> after all other header files is not a
feasible solution as that causes the mock assertion macros defined in
<isc/util.h> to mangle the contents of <cmocka.h>, thus breaking
compilation. We cannot really use the __noreturn__ or analyzer_noreturn
attributes with cmocka assertion functions because they do return if the
tested condition is true. The problem is that what BIND unit tests do
is incompatible with Clang Static Analyzer's assumptions: since we use
cmocka, our custom assertion handlers are present in a shared library
(i.e. it is the cmocka library that checks the assertion condition, not
a macro in unit test code). Redefining cmocka's assertion macros in
<isc/util.h> is an ugly hack to overcome that problem - unfortunately,
this is the only way we can think of to make Clang Static Analyzer
properly process unit test code. Giving up on Clang Static Analyzer
being able to properly process unit test code is not a satisfactory
solution.
Undefining _GNU_SOURCE for unit test code could work around the problem
(musl libc's <sched.h> only defines the prototypes for calloc() and
free() when _GNU_SOURCE is defined), but doing that could introduce
discrepancies for unit tests including entire *.c files, so it is also
not a good solution.
All in all, including <sched.h> before <cmocka.h> for all affected unit
tests seems to be the most benign way of working around this musl libc
quirk. While quite an ugly solution, it achieves our goals here, which
are to keep the benefit of proper static analysis of unit test code and
to fix compilation against musl libc.
(cherry picked from commit 59528d0e9d)
