The 'restrict' keyword was introduced in C99 and provides a hint to
the compiler that can be used to better optimized code. The 'restrict'
keyword results in build failures when the compiler is not C99.
auditdns.c:101:37: error: expected ‘;’, ‘,’ or ‘)’ before ‘hints’
const struct addrinfo *restrict hints,
^
auditdns.c:409:45: error: expected ‘;’, ‘,’ or ‘)’ before ‘sa’
getnameinfo(const struct sockaddr *restrict sa, socklen_t salen,
^
This change defines 'register' to nothing if the compiler does not
implement the C99 standard.
Observed with gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44).
This change has two parts:
1. Provide our own local implementation of numeric-only getaddrinfo
in auditdns.c used to audit for DNS leaks, rather than deferring
to dlsym(RTLD_NEXT, "getaddrinfo"), in terms of inet_pton.
To keep review and implementation simple, this is limited to
AI_NUMERICHOST _and_ AI_NUMERICSERV -- this requires that we
arrange to pass AI_NUMERICSERV in callers too.
2. Wherever we implement block_dns, set AI_NUMERICSERV in addition to
AI_NUMERICHOST as needed by the new auditdns.c getaddrinfo.
(In principle this might also avoid other network leaks -- POSIX
guarantees no name resolution service will be invoked, and gives
NIS+ as an example.)
One tiny semantic change to avoid tripping over the auditor:
kadmin(8) now uses the string "749" rather than the string
"kerberos-adm". (Currently we don't audit kadmin(8) for DNS leaks
but let's avoid leaving a rake to step on.) Every other caller I
found is already guaranteed to pass a numeric service rather than
named service to getaddrinfo.
fix https://github.com/heimdal/heimdal/issues/1212
We build variants of kinit and test_acquire_cred that define their
own symbols rk_dns_lookup, gethostbyname, gethostbyname2, and
getaddrinfo to print a message and abort. For getaddrinfo, we abort
only if the caller failed to specify AI_NUMERICHOST; otherwise we use
dlsym(RTLD_NEXT, "getaddrinfo") instead.
The new test tests/gss/check-nodns is like tests/gss/check-basic, but
uses kinit_auditdns and test_acquire_cred_auditdns to verify that no
DNS resolution happens.
This test should work and be effective on ELF platforms where the
getaddrinfo function is implemented by the symbol `getaddrinfo'. On
non-ELF platforms it may not be effective -- and on platforms where
the getaddrinfo function is implemented by another symbol (like
`__getaddrinfo50') it may not work, but we can cross that bridge when
we come to it.
Verified manually that the test fails, with the expected error
message and abort, without `block_dns = yes' in krb5-nodns.conf. No
automatic test of the mechanism for now because it might not work on
some platforms.
XXX check-nodns.in is copypasta of check-basic.in, should factor out
the common parts so they don't get out of sync.
appl/test/tcp_server and gssapi_server try to open the keytab file only when processing a connection.
This patch verifies the existence of the keytab file on program startup, so that troubleshooting is easier. In addition it adds some comments.
Signed-off-by: Love Hornquist Astrand <lha@h5l.org>
We turn on a few extra warnings and fix the fallout that occurs
when building with --enable-developer. Note that we get different
warnings on different machines and so this will be a work in
progress. So far, we have built on NetBSD/amd64 5.99.64 (which
uses gcc 4.5.3) and Ubuntu 10.04.3 LTS (which uses gcc 4.4.3).
Notably, we fixed
1. a lot of missing structure initialisers,
2. unchecked return values for functions that glibc
marks as __attribute__((warn-unused-result)),
3. made minor modifications to slc and asn1_compile
which can generate code which generates warnings,
and
4. a few stragglers here and there.
We turned off the extended warnings for many programs in appl/ as
they are nearing the end of their useful lifetime, e.g. rsh, rcp,
popper, ftp and telnet.
Interestingly, glibc's strncmp() macro needed to be worked around
whereas the function calls did not.
We have not yet tried this on 32 bit platforms, so there will be
a few more warnings when we do.
