It's wasteful to use 20 bytes and a pointer indirection to represent
two bits of information, so turn the struct into an enum. And change
the names of the enumeration constants to make the intent more clear.
This change introduces some inline functions into another header,
which confuses `gcovr` when it is trying to collect code coverage
statistics. So, in the CI job, copy more header files into a directory
where `gcovr` looks for them.
There was a proposal in the late 1990s that it might, but it turned
out to be unworkable. See RFC 6891, Extension Mechanisms for
DNS (EDNS(0)), section 5, Extended Label Types.
The remnants of the code that supported this in BIND are redundant.
From an attacker's point of view, a VLA declaration is essentially a
primitive for performing arbitrary arithmetic on the stack pointer. If
the attacker can control the size of a VLA they have a very powerful
tool for causing memory corruption.
To mitigate this kind of attack, and the more general class of stack
clash vulnerabilities, C compilers insert extra code when allocating a
VLA to probe the growing stack one page at a time. If these probes hit
the stack guard page, the program will crash.
From the point of view of a C programmer, there are a few things to
consider about VLAs:
* If it is important to handle allocation failures in a controlled
manner, don't use VLAs. You can use VLAs if it is OK for
unreasonable inputs to cause an uncontrolled crash.
* If the VLA is known to be smaller than some known fixed size,
use a fixed size array and a run-time check to ensure it is large
enough. This will be more efficient than the compiler's stack
probes that need to cope with arbitrary-size VLAs.
* If the VLA might be large, allocate it on the heap. The heap
allocator can allocate multiple pages in one shot, whereas the
stack clash probes work one page at a time.
Most of the existing uses of VLAs in BIND are in test code where they
are benign, but there was one instance in `named`, in the GSS-TSIG
verification code, which has now been removed.
This commit adjusts the style guide and the C compiler flags to allow
VLAs in test code but not elsewhere.
... along with dns_rdataclass_fromtext and dns_rdatatype_fromtext
Most of the test binary is modified named-rrchecker. Main differences:
- reads single RR and exists
- does not refuse meta classes and rr types
We actually do have some fromtext code for meta-things so erroring out
in named-rrchecker would prevent us from testing this code.
Corpus has examples of all currently supported RR types. I did not do
any minimization.
In future use command
diff -U0 \
<(sed -n -e 's/^.*fromtext_\(.*\)(.*$/\1/p' lib/dns/code.h | \
sort) \
<(ls fuzz/dns_rdata_fromtext.in/)
to check for missing RR types.
This commit converts the license handling to adhere to the REUSE
specification. It specifically:
1. Adds used licnses to LICENSES/ directory
2. Add "isc" template for adding the copyright boilerplate
3. Changes all source files to include copyright and SPDX license
header, this includes all the C sources, documentation, zone files,
configuration files. There are notes in the doc/dev/copyrights file
on how to add correct headers to the new files.
4. Handle the rest that can't be modified via .reuse/dep5 file. The
binary (or otherwise unmodifiable) files could have license places
next to them in <foo>.license file, but this would lead to cluttered
repository and most of the files handled in the .reuse/dep5 file are
system test files.
Unify the header guard style and replace the inconsistent include guards
with #pragma once.
The #pragma once is widely and very well supported in all compilers that
BIND 9 supports, and #pragma once was already in use in several new or
refactored headers.
Using simpler method will also allow us to automate header guard checks
as this is simpler to programatically check.
For reference, here are the reasons for the change taken from
Wikipedia[1]:
> In the C and C++ programming languages, #pragma once is a non-standard
> but widely supported preprocessor directive designed to cause the
> current source file to be included only once in a single compilation.
>
> Thus, #pragma once serves the same purpose as include guards, but with
> several advantages, including: less code, avoidance of name clashes,
> and sometimes improvement in compilation speed. On the other hand,
> #pragma once is not necessarily available in all compilers and its
> implementation is tricky and might not always be reliable.
1. https://en.wikipedia.org/wiki/Pragma_once
Replace most "master/slave" terminology in tests with the preferred
"primary/secondary", with the following exceptions:
- When testing the old syntax
- When master is used in master file and master file format terms
- When master is used in hostmaster or postmaster terms
- When master used in legacy domain names (for example in dig.batch)
- When there is no replacement (for example default-masters)
Remove the dynamic registration of result codes. Convert isc_result_t
from unsigned + #defines into 32-bit enum type in grand unified
<isc/result.h> header. Keep the existing values of the result codes
even at the expense of the description and identifier tables being
unnecessary large.
Additionally, add couple of:
switch (result) {
[...]
default:
break;
}
statements where compiler now complains about missing enum values in the
switch statement.
The last remaining defines needed for platforms without NAME_MAX and
PATH_MAX (I'm looking at you, GNU Hurd) were moved to isc/dir.h where
it's prevalently used.
The Makefile.tests was modifying global AM_CFLAGS and LDADD and could
accidentally pull /usr/include to be listed before the internal
libraries, which is known to cause problems if the headers from the
previous version of BIND 9 has been installed on the build machine.
The dns_message_create() function cannot soft fail (as all memory
allocations either succeed or cause abort), so we change the function to
return void and cleanup the calls.
Since Mac OS X 10.1, Mach-O object files are by default built with a
so-called two-level namespace which prevents symbol lookups in BIND unit
tests that attempt to override the implementations of certain library
functions from working as intended. This feature can be disabled by
passing the "-flat_namespace" flag to the linker. Fix unit tests
affected by this issue on macOS by adding "-flat_namespace" to LDFLAGS
used for building all object files on that operating system (it is not
enough to only set that flag for the unit test executables).
The non-minimized corpus from https://github.com/CZ-NIC/dns-fuzzing was
used as input to afl-cmin, then every case were processed by afl-tmin
and then afl-cmin was used to further minimize the corpus again.
Previously, the bin/system/wire_test.c was optionally used as a fuzzer,
this commit extracts the parts relevant to the fuzzing into a
specialized fuzzer that can be used in oss-fuzz project.
The fuzzer parses the input as UDP DNS message, then prints parsed DNS
message, then renders the DNS message and then prints the rendered DNS
message. No part of the code should cause a assertion failure.
* Disallow compression pointers in names as we are not
reading from a packet and as a result length checks fail.
* Increase totext buffer size as fuzzer ran out of space on
big bitmaps.
* NUL terminate totext to make fault diagnosis easier.
* Add debugging messages to make fault diagnosie easier.
There was a copy&paste error in fuzz/isc_lex_getmastertoken.c where we
didn't really test the function we wanted to test. Update the test to
have the input data to always include expected 'tokentype' in the first
byte, `eol` argument in the second byte and the rest of the input is the
data to parse.
In this commit, the simple fuzzing tests for the isc_lex_gettoken() and
isc_lex_getmastertoken() functions have been added.
As part of this commit, the initialization has been moved from fuzz.h
constructor/destructor to LLVMFuzzerInitialize() in each fuzz test. The
main.c of no-fuzzing and AFL modes have been modified to run the
LLVMFuzzerInitialize() at the start of the main() function mimicking
the libfuzzer mode of operation.
The fuzzing tests were temporarily disabled when the build system has been
converted to automake. This commit restores the functionality to run the
fuzzing tests as part of the `make check`. When the afl or libfuzzer
is enabled via ./configure, it uses a custom LOG_DRIVER (fuzz/<fuzzer.sh>).
Currently only libfuzzer.sh has been implemented that runs each fuzz
test for 5 seconds each.
When --with-zlib is passed to ./configure (or when the latter
autodetects zlib's presence), libisc uses certain zlib functions and
thus libisc's users should be linked against zlib in that case. Adjust
Makefile variables appropriately to prevent shared build failures caused
by underlinking.
