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 addresses part of https://github.com/heimdal/heimdal/issues/1214
to audit potential network leaks with [libdefaults] block_dns = yes.
NI_NUMERICHOST is _probably_ sufficient -- we probably won't see many
systems using NIS to look up service names by number if we fail to
specify NI_NUMERICSERV, and such systems probably require careful
auditing of their own. And I don't know of any way NI_NUMERICSCOPE
could trigger network leaks. But named scope ids are such a niche
option with IPv6 that setting it to forestall concerns can't hurt
much, and it makes reviewing easier if we just unconditionally flip
on all the numeric-only options.
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.
This way there is no truncation and no build failure due to
-Werror=format-truncation as is the default in some compilers, such
as gcc7.4 with -Wall -Werror.
This is presumably not space-constrained or performance-critical; the
very next thing it does is another asprintf and frees it immediately.
And uname is not usually under any adversary's control.
fix https://github.com/heimdal/heimdal/issues/1105
In function ‘afslog_cell.isra’:
afslog.c:144:13: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
144 | warnx("No cell matching \"%s\" found.", cell);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
caused by expand_cell_name() returning the input pointer.
Alter the behavior of expand_cell_name() to match its usage.
Change-Id: I3b15c4b3e59b597af5351e5e62f5d7751be50feb
Although not required to address bad code generation in
some versions of gcc 9 and 10, a coding style that requires
explicit comparison of the result to zero before use is
both clearer and would have avoided the generation of bad
code.
This change converts all use of cmp function usage from
```
if (strcmp(a, b) || !strcmp(c, d)) ...
```
to
```
if (strcmp(a, b) != 0 || strcmp(c, d)) == 0
```
for all C library cmp functions and related:
- strcmp(), strncmp()
- strcasecmp(), strncasecmp()
- stricmp(), strnicmp()
- memcmp()
Change-Id: Ic60c15e1e3a07e4faaf10648eefe3adae2543188
Using non-reentrant getpwuid() (or getpwnam(), or getspnam()) can be
dangerous. We had a report of a login application / PAM that calls
those, and Heimdal, by calling them too, clobbered the cached struct
passwd used by the login app / PAM.
In client_connect() getaddrinfo() stores the head of the allocated
addrinfo structure list in 'res0'. 'res' is used to walk the list
and will be NULL at the end of the for() loop when freeaddrinfo(res)
is executed. Pass 'res0' to freeaddrinfo() instead of 'res'.
Change-Id: Ie1358c0356b6b0f98470e46e25216cfa0ab4adac
This adds a new backend for libhcrypto: the OpenSSL backend.
Now libhcrypto has these backends:
- hcrypto itself (i.e., the algorithms coded in lib/hcrypto)
- Common Crypto (OS X)
- PKCS#11 (specifically for Solaris, but not Solaris-specific)
- Windows CNG (Windows)
- OpenSSL (generic)
The ./configure --with-openssl=... option no longer disables the use of
hcrypto. Instead it enables the use of OpenSSL as a (and the default)
backend in libhcrypto. The libhcrypto framework is now always used.
OpenSSL should no longer be used directly within Heimdal, except in the
OpenSSL hcrypto backend itself, and files where elliptic curve (EC)
crypto is needed.
Because libhcrypto's EC support is incomplete, we can only use OpenSSL
for EC. Currently that means separating all EC-using code so that it
does not use hcrypto, thus the libhx509/hxtool and PKINIT EC code has
been moved out of the files it used to be in.
On Windows a file descriptor is an int value allocated by the
local module instance of the C Run Time Library. A socket handle is a
SOCKET value allocated by a Winsock Provider for the requested family and
protocol. These two values cannot be mixed and there is no mechanism for
converting between the two. The _get_osfhandle() and _open_osfhandle()
functions can work with a standard HANDLE (file, pipe, etc) but cannot be
used for a SOCKET.
The Heimdal krb5_storage_from_fd() routine counted on the osf conversion
functions working on SOCKET values. Since they do not any attempt to call
krb5_storage_from_fd() on a socket resulted in an assertion being thrown
by the C RTL.
Another problem is SOCKET value truncation when storing a 64-bit value
into a 32-bit int.
To address these problems a new krb5_storage_from_socket() routine is
introduced. This routine setups a krb5_storage that stores a socket value
as a rk_socket_t and provides a set of helper routines that always use
network ready functions.
The krb5_storage_from_fd() routines no longer use net_read() and
net_write() but provide helpers that follow their logic so that pipes can
be processed.
All call sites that allocate a socket now store the socket as rk_socket_t
and call krb5_storage_from_socket().
All locations that previously called the bare close() on a socket value
now call rk_closesocket().
Change-Id: I045f775b2a5dbf5cf803751409490bc27fffe597
