DW_FORM_flag_present dwarf attribute, so they do not print errors or
warnings on files that contain it. (This attribute can be emitted by
newer versions of clang and gcc.)
MFC after: 1 week
Removed the check for regex.h in configure in order
to disable regex syntax checking, as it exposes
BIND to a critical flaw in libregex on some
platforms. [RT #32688]
Security: CVE-2013-2266
Approved by: delphij (mentor)
Sponsored by: DK Hostmaster A/S
Limit write requests to at most INT_MAX.
This prevents a certain common programming error (passing -1 to write)
from leading to other problems deeper in the library.
References:
https://github.com/libarchive/libarchive/commit/22531545514043e0
Reported by: Xin Li <delphij@FreeBSD.org>
Obtained from: libarchive (master branch)
Update libarchive to 3.1.2
Some of new features:
- support for lrzip and grzip compression
- support for writing tar v7 format
- b64encode and uuencode filters
- support for __MACOSX directory in Zip archives
- support for lzop compresion (external utility)
register added to the symbol table by the assembler. On further
investigation it was found the problem was with the my_get_expression
function. This is called by parse_big_immediate.
Fix this by moving the call to parse_big_immediate to the end of the if,
else if, ..., else block.
match our import of the (un)vis(3) APIs.
This adds support for multibyte encoding and the -h and -m flags which
support HTTP and MIME encoding respectively.
PR: bin/175418
Obtained from: NetBSD
multibyte support[0] and the new functions strenvisx and strsenvisx.
Add MLINKS for vis(3) functions add by this and the initial import from
NetBSD[1].
PR: bin/166364, bin/175418
Submitted by: "J.R. Oldroyd" <fbsd@opal.com>[0]
stefanf[1]
Obtained from: NetBSD
MFC after: 2 weeks
LibYAML is a YAML 1.1 parser and emitter under MIT license which will
soon be used by the pkg boostrap (usr.bin/pkg) and bhyve
Reviewed by: roberto, antoine
int bindat(int fd, int s, const struct sockaddr *addr, socklen_t addrlen);
int connectat(int fd, int s, const struct sockaddr *name, socklen_t namelen);
which allow to bind and connect respectively to a UNIX domain socket with a
path relative to the directory associated with the given file descriptor 'fd'.
- Add manual pages for the new syscalls.
- Make the new syscalls available for processes in capability mode sandbox.
- Add capability rights CAP_BINDAT and CAP_CONNECTAT that has to be present on
the directory descriptor for the syscalls to work.
- Update audit(4) to support those two new syscalls and to handle path
in sockaddr_un structure relative to the given directory descriptor.
- Update procstat(1) to recognize the new capability rights.
- Document the new capability rights in cap_rights_limit(2).
Sponsored by: The FreeBSD Foundation
Discussed with: rwatson, jilles, kib, des
- Capability is no longer separate descriptor type. Now every descriptor
has set of its own capability rights.
- The cap_new(2) system call is left, but it is no longer documented and
should not be used in new code.
- The new syscall cap_rights_limit(2) should be used instead of
cap_new(2), which limits capability rights of the given descriptor
without creating a new one.
- The cap_getrights(2) syscall is renamed to cap_rights_get(2).
- If CAP_IOCTL capability right is present we can further reduce allowed
ioctls list with the new cap_ioctls_limit(2) syscall. List of allowed
ioctls can be retrived with cap_ioctls_get(2) syscall.
- If CAP_FCNTL capability right is present we can further reduce fcntls
that can be used with the new cap_fcntls_limit(2) syscall and retrive
them with cap_fcntls_get(2).
- To support ioctl and fcntl white-listing the filedesc structure was
heavly modified.
- The audit subsystem, kdump and procstat tools were updated to
recognize new syscalls.
- Capability rights were revised and eventhough I tried hard to provide
backward API and ABI compatibility there are some incompatible changes
that are described in detail below:
CAP_CREATE old behaviour:
- Allow for openat(2)+O_CREAT.
- Allow for linkat(2).
- Allow for symlinkat(2).
CAP_CREATE new behaviour:
- Allow for openat(2)+O_CREAT.
Added CAP_LINKAT:
- Allow for linkat(2). ABI: Reuses CAP_RMDIR bit.
- Allow to be target for renameat(2).
Added CAP_SYMLINKAT:
- Allow for symlinkat(2).
Removed CAP_DELETE. Old behaviour:
- Allow for unlinkat(2) when removing non-directory object.
- Allow to be source for renameat(2).
Removed CAP_RMDIR. Old behaviour:
- Allow for unlinkat(2) when removing directory.
Added CAP_RENAMEAT:
- Required for source directory for the renameat(2) syscall.
Added CAP_UNLINKAT (effectively it replaces CAP_DELETE and CAP_RMDIR):
- Allow for unlinkat(2) on any object.
- Required if target of renameat(2) exists and will be removed by this
call.
Removed CAP_MAPEXEC.
CAP_MMAP old behaviour:
- Allow for mmap(2) with any combination of PROT_NONE, PROT_READ and
PROT_WRITE.
CAP_MMAP new behaviour:
- Allow for mmap(2)+PROT_NONE.
Added CAP_MMAP_R:
- Allow for mmap(PROT_READ).
Added CAP_MMAP_W:
- Allow for mmap(PROT_WRITE).
Added CAP_MMAP_X:
- Allow for mmap(PROT_EXEC).
Added CAP_MMAP_RW:
- Allow for mmap(PROT_READ | PROT_WRITE).
Added CAP_MMAP_RX:
- Allow for mmap(PROT_READ | PROT_EXEC).
Added CAP_MMAP_WX:
- Allow for mmap(PROT_WRITE | PROT_EXEC).
Added CAP_MMAP_RWX:
- Allow for mmap(PROT_READ | PROT_WRITE | PROT_EXEC).
Renamed CAP_MKDIR to CAP_MKDIRAT.
Renamed CAP_MKFIFO to CAP_MKFIFOAT.
Renamed CAP_MKNODE to CAP_MKNODEAT.
CAP_READ old behaviour:
- Allow pread(2).
- Disallow read(2), readv(2) (if there is no CAP_SEEK).
CAP_READ new behaviour:
- Allow read(2), readv(2).
- Disallow pread(2) (CAP_SEEK was also required).
CAP_WRITE old behaviour:
- Allow pwrite(2).
- Disallow write(2), writev(2) (if there is no CAP_SEEK).
CAP_WRITE new behaviour:
- Allow write(2), writev(2).
- Disallow pwrite(2) (CAP_SEEK was also required).
Added convinient defines:
#define CAP_PREAD (CAP_SEEK | CAP_READ)
#define CAP_PWRITE (CAP_SEEK | CAP_WRITE)
#define CAP_MMAP_R (CAP_MMAP | CAP_SEEK | CAP_READ)
#define CAP_MMAP_W (CAP_MMAP | CAP_SEEK | CAP_WRITE)
#define CAP_MMAP_X (CAP_MMAP | CAP_SEEK | 0x0000000000000008ULL)
#define CAP_MMAP_RW (CAP_MMAP_R | CAP_MMAP_W)
#define CAP_MMAP_RX (CAP_MMAP_R | CAP_MMAP_X)
#define CAP_MMAP_WX (CAP_MMAP_W | CAP_MMAP_X)
#define CAP_MMAP_RWX (CAP_MMAP_R | CAP_MMAP_W | CAP_MMAP_X)
#define CAP_RECV CAP_READ
#define CAP_SEND CAP_WRITE
#define CAP_SOCK_CLIENT \
(CAP_CONNECT | CAP_GETPEERNAME | CAP_GETSOCKNAME | CAP_GETSOCKOPT | \
CAP_PEELOFF | CAP_RECV | CAP_SEND | CAP_SETSOCKOPT | CAP_SHUTDOWN)
#define CAP_SOCK_SERVER \
(CAP_ACCEPT | CAP_BIND | CAP_GETPEERNAME | CAP_GETSOCKNAME | \
CAP_GETSOCKOPT | CAP_LISTEN | CAP_PEELOFF | CAP_RECV | CAP_SEND | \
CAP_SETSOCKOPT | CAP_SHUTDOWN)
Added defines for backward API compatibility:
#define CAP_MAPEXEC CAP_MMAP_X
#define CAP_DELETE CAP_UNLINKAT
#define CAP_MKDIR CAP_MKDIRAT
#define CAP_RMDIR CAP_UNLINKAT
#define CAP_MKFIFO CAP_MKFIFOAT
#define CAP_MKNOD CAP_MKNODAT
#define CAP_SOCK_ALL (CAP_SOCK_CLIENT | CAP_SOCK_SERVER)
Sponsored by: The FreeBSD Foundation
Reviewed by: Christoph Mallon <christoph.mallon@gmx.de>
Many aspects discussed with: rwatson, benl, jonathan
ABI compatibility discussed with: kib
reconnected in the meantime. Check if reset is set before opening next trail
file, as not doing so will result in sending OPEN message with the same
file name twice and this is illegal - the second OPEN is send without first
closing previous trail file.
X86: Disable cmov-memory patterns on subtargets without cmov.
Fixes PR15115.
For the i386 arch, this should enable cmov instructions only on
-march=pentiumpro and higher. Since our default CPU is i486, cmov
instructions will now be disabled by default.
MFC after: 1 week
Refactor the x86 CPU name logic in the driver and pass -march and -mcpu
flag information down from the Clang driver into the Gold linker plugin
for LTO. This allows specifying -march on the linker commandline and
should hopefully have it pass all the way through to the LTO optimizer.
Fixes PR14697.
Pull in r175919 from upstream clang trunk:
Driver: Pass down the -march setting down to -cc1as on x86 too.
The assembler historically didn't make use of any target features, but this has
changed when support for old CPUs that don't support long nops was added.
This should fix the long nops that still occurred in crt*.o, and
possibly other object files, if the system was compiled for a CPU that
does not support those, such as Geode.
Note that gcc on i386 also does not pass through any -march, -mcpu or
-mtune setting to gas, but this has not caused any trouble yet, because
gas defaults to i386.
Reported by: lev
MFC after: 1 week
This fixes the problem on amd64 miscompiling mpboot.s causing boot
issues... We are still using gas for a few files in the kernel...
Submitted by: kib
MFC after: 1 month
Thanks to Mike Belopuhov for the pointer to the OpenBSD patch, though
OpenBSD's gcc is very different that it only helped w/ where to modify,
not how... Thanks to jhb for some early reviews...
Reviewed by: imp, kib
MFC after: 1 month
MCParser: Reject .balign with non-pow2 alignments.
GNU as rejects them and there are configure scripts in the wild that
check if the assembler rejects ".align 3" to determine whether the
alignment is in bytes or powers of two.
MFC after: 3 days
From: Jouni Malinen <j@w1.fi>
Date: Fri, 15 Jul 2011 13:42:06 +0300
Subject: [PATCH] MD5: Fix clearing of temporary stack memory to use correct length
sizeof of the structure instead of the pointer was supposed to be used
here. Fix this to clear the full structure at the end of MD5Final().
Found by: clang ToT
Reviewed by: rpaulo
MFC after: 3 days
X86: Disable generation of rep;movsl when %esi is used as a base pointer.
This happens when there is both stack realignment and a dynamic alloca in the
function. If we overwrite %esi (rep;movsl uses fixed registers) we'll lose the
base pointer and the next register spill will write into oblivion.
Fixes PR15249 and unbreaks firefox on i386/freebsd. Mozilla uses dynamic allocas
and freebsd a 4 byte stack alignment.
MFC after: 1 week
_Unwind_ForcedUnwind in libgcc_s takes as one of it's parameters a stop
function to tell it when to stop unwinding. One of the stop function's
parameters is a _Unwind_Exception_Class. On most architectures this is an
int64_t, however on ARM EABI the gcc developers have made this a char array
with 8 items. While both of these take the same space they are passed into
the stop function differently, an int64_t is passed in in registers r2 and
r3, while the char[8] is passed in as a pointer to the first item in
register r2.
Because libthr expects the value to be an int64_t we would get incorrect
results when it passes a function that take an int64_t but libgcc passes in
a pointer to a char array including crashing.
The fix is to update libgcc_s to make it pass an int64_t to the stop
function and to libstdc++ as it expects _Unwind_Exception_Class to be an
array.
.note.ABI-tag section.
This helps on ARM EABI where the OS/ABI field is zero. It would be better
to use the NOTES program header however this would require a more invasive
change.
Dont use/link ARCMT, StaticAnalyzer and Rewriter to clang when the user
specifies not to. Dont build ASTMatchers with Rewriter disabled and
StaticAnalyzer when it's disabled.
Without all those three, the clang binary shrinks (x86_64) from ~36MB
to ~32MB (unstripped).
To disable these clang components, and get a smaller clang binary built
and installed, set WITHOUT_CLANG_FULL in src.conf(5). During the
initial stages of buildworld, those extra components are already
disabled automatically, to save some build time.
MFC after: 1 week
Since ARP and routing are separated, "proxy only" entries
don't have any meaning, thus we don't need additional field
in sockaddr to pass SIN_PROXY flag.
New kernel is binary compatible with old tools, since sizes
of sockaddr_inarp and sockaddr_in match, and sa_family are
filled with same value.
The structure declaration is left for compatibility with
third party software, but in tree code no longer use it.
Reviewed by: ru, andre, net@
an exception when you haven't caught one. This is largely a cosmetic fix, as
(unless you have a very unusual terminate handler installed) it will print a
nice error and then abort, rather than just aborting.
MFC after: 7 days
ARM EABI support is disabled by default and can be enabled by setting
WITH_ARM_EABI when building, however only the kernel-toolchain target will
work with this flag until the rest of the support is added.
- Don't treat pointers to members as pointers in catch blocks (they're usually
fat pointers).
- Correctly catch foreign exceptions in catchalls.
- Ensure that a happens-before relationship is established when setting
terminate handlers in one thread and calling them in another.
runtime on amd64, when it is compiled by clang. Some versions of clang
don't save and restore all callee registers, if a __builtin_eh_return()
intrinsic is used in a function. This is particularly bad on amd64.
Until the problem gets fixed by upstream, use an asm statement to force
clang to assume the registers in question are clobbered, when invoking
__builtin_eh_return(), so it will emit code to save and restore them.
This should fix the crashes reported on -current with some C++ programs,
particularly those that throw exceptions over multiple function
boundaries.
Reported by: stefanf
MFC after: 3 days
break mixed form dialogs in conjunction with the FreeBSD termcap, making
the bsdinstall partition editor Add dialog, among other things, completely
nonfunctional. This restores dialog 20110707.
There is a bug in gcc (GCC/35998) where dwarf reports
sizes of unsigned -1 (0xffffffff).
On NetBSD this generated a faulty CTF entry which then
caused a segfault in ctfmerge. The issue was worked
around in NetBSD's Dtrace but since the issue originated
in gcc, it seems reasonable to fix it here.
Upstream gcc has been slow to react to this issue and
the author that submitted the patch is not interested
in licensing the change to us, so I did an independent
workaround for the issue.
MFC after: 1 week
should never do so. This can cause global constructors and destructors
to not be executed at run-time, resulting in crashes and other strange
behaviour.
Reported by: rene
MFC after: 1 week
Fix another SROA crasher, PR14601.
This was a silly oversight, we weren't pruning allocas which were used
by variable-length memory intrinsics from the set that could be widened
and promoted as integers. Fix that.
This should fix the following assertion failure:
Assertion failed: (CanSROA), function visitUsers, file
/usr/src/lib/clang/libllvmscalaropts/../../../contrib/llvm/lib/Transforms/Scalar/SROA.cpp,
line 2395.
Reported by: gerald
towards replacing our mtree.
Sponsored by: DARPA, AFRL
Thanks to: cristos@NetBSD for reviewing and committing my patches
wiz@NetBSD for fixing typos in my patches
NetBSD's. This output size limited versions of vis and unvis functions
as well as a set of vis variants that allow arbitrary characters to be
specified for encoding.
Finally, MIME Quoted-Printable encoding as described in RFC 2045 is
supported.
built with clang. When these are defined the lists are defined similar to:
asm(".section .ctors");
STATIC func_ptr __CTOR_LIST__[1] = { (func_ptr) (-1) };
asm(".section .dtors");
STATIC func_ptr __DTOR_LIST__[1] = { (func_ptr) (-1) };
The problem is clang will move the two arrays out of the .ctors and .dtors
sections causing these sections to contain a single null address. By not
defining these macros we use the version of the code that places the arrays
is their sections by using __attribute__((section(".ctors"))) and similar
for .dtors.
Submitted by: Daisuke Aoyama <aoyama AT peach.ne.jp>
included various upstreamed patches from the FreeBSD base to make OpenBSM
compile more easily with bmake, higher warning levels, clang, and several
other loose ends.
Obtained from: TrustedBSD Project
Security Fixes
Prevents named from aborting with a require assertion failure
on servers with DNS64 enabled. These crashes might occur as a
result of specific queries that are received.
New Features
* Elliptic Curve Digital Signature Algorithm keys and signatures in
DNSSEC are now supported per RFC 6605. [RT #21918]
Feature Changes
* Improves OpenSSL error logging [RT #29932]
* nslookup now returns a nonzero exit code when it is unable to get
an answer. [RT #29492]
Other critical bug fixes are included.
Approved by: delphij (mentor)
MFC after: 3 days
Security: CVE-2012-5688
Sponsored by: DK Hostmaster A/S
share/mk/sys.mk instead.
This is part of a medium term project to permit deterministic builds of
FreeBSD.
Submitted by: Erik Cederstrand <erik@cederstrand.dk>
Reviewed by: imp, toolchain@
Approved by: cperciva
MFC after: 2 weeks
When using libc++ headers on FreeBSD, in combination with -std=c++98,
-ansi or -std=c++03, the long long type is not supported. So in this
case, several functions and types, like lldiv_t, strtoll(), are not
declared.
This should make it possible to use the libc++ headers in c++98 mode.
Note: libc++ is originally designed as a c++0x or higher library, so you
should still take care when using it with c++98 or c++03.
Noted by: Yamaya Takashi <yamayan@kbh.biglobe.ne.jp>
MFC after: 1 week
This improves GDB usability when debugging code compiled with
optimization.
Upstream GDB revision f0031b6d3ae9b164b3747986ab898190bd4dcf8c (prior
to GDB's switch to GPLv3), with frame_debug_got_null_frame expanded
inline.
| 2004-12-12 Andrew Cagney <cagney@gnu.org>
|
| * frame.c (get_prev_frame): When unwinding normal frames, check
| that the PC isn't zero.
Sponsored by: ADARA Networks
MFC After: 1 month
X86: fcmov doesn't handle all possible EFLAGS, fall back to a branch
for the others.
Otherwise it will try to use SSE patterns and fail horribly if sse is
disabled.
Fixes PR14035.
This should fix the following assertion failure:
Assertion failed: (Reg >= X86::FP0 && Reg <= X86::FP6 && "Expected FP
register!"), function getFPReg, file
contrib/llvm/lib/Target/X86/X86FloatingPoint.cpp, line 330.
which can show up when compiling contrib/compiler-rt, using -march=i686
through -march=pentium3 (CPU's which do support fcmov, but don't support
SSE2).
MFC after: 1 week
Add a new warning -Wmissing-variable-declarations, to warn about variables
defined without a previous declaration. This is similar to
-Wmissing-prototypes, but for variables instead of functions.
Make sure always-inline functions get inlined. <rdar://problem/12423986>
Without this change, when the estimated cost for inlining a function with
an "alwaysinline" attribute was lower than the inlining threshold, the
getInlineCost function was returning that estimated cost rather than the
special InlineCost::AlwaysInlineCost value. That is fine in the normal
inlining case, but it can fail when the inliner considers the opportunity
cost of inlining into an internal or linkonce-odr function. It may decide
not to inline the always-inline function in that case. The fix here is just
to make getInlineCost always return the special value for always-inline
functions. I ran into this building clang with libc++. Tablegen failed to
link because of an always-inline function that was not inlined. I have been
unable to reduce the testcase down to a reasonable size.
This should fix the link errors that were reported when atf-run was
compiled with clang -stdlib=libc++. In this case, at -O3 optimization,
some calls to basic_ios::clear() were not inlined, even when the
function was marked __always_inline__.
Reported by: Jan Beich <jbeich@tormail.org>
MFC after: 1 week
when building other C++ software with it. Also fix one actual bug in
libsupc++, which was exposed by such a warning. This latter fix is the
only functional change.
MFC after: 1 week
this has many visibility problems fixed, which should help with
compiling certain ports that exercise C++11 mode (i.e. Firefox).
Also, belatedly add the LICENSE.TXT and accompanying CREDITS.TXT files,
which are referred to in all the source files.
MFC after: 1 month
X86: Disable long nops for all cpus prior to pentiumpro/i686.
This is the safest approach for now. If you think long nops matter a
lot for performance, compile with -march=i686 or higher. :)
MFC after: 3 days
This adds two features:
* uid_from_user() and gid_from_group() as the reverse of user_from_uid()
and groups_from_gid().
* pwcache_userdb() and pwcache_groupdb() which allow alternative lookup
functions to be used. For example lookups from passwd and group
databases in a non-standard location.
When creating MCAsmBackend pass the CPU string as well. In X86AsmBackend
store this and use it to not emit long nops when the CPU is geode which
doesnt support them.
Fixes PR11212.
Pull in r164133 from upstream clang trunk:
Follow up on llvm r164132.
This should prevent illegal instructions when building world on Geode
CPUs (e.g. Soekris).
MFC after: 3 days
Prevents a lockup when queried a deliberately constructed combination
of records. [CVE-2012-5166]
For more information: https://kb.isc.org/article/AA-00801
doesn't mean supporting IFT_PFSYNC (which I hope will eventually
die). This means decoding packets with IP protocol of 240 caught
on any normal interface like Ethernet.
The code is based on couple of files from OpenBSD, significantly
modified by myself.
Parser differentiates for four levels of verbosity: no -v, -v,
-vv and -vvv.
We don't yet forward this code upstream, because currently it
strongly relies on if_pfsync.h and even on pfvar.h. I hope that
this can be fixed in future.
Reviewed by: gnn, delphij
- Set IP_RECVDSTADDR sockopt on the socket only in case if
it is INADDR_ANY bound.
- Supply IP_SENDSRCADDR control message only if we did receive
IP_RECVDSTADDR control message.
This fixes operation of snmpd bound to a specific local IP address.
PR: bin/171279
Prevents a crash when queried for a record whose RDATA exceeds
65535 bytes.
Prevents a crash when validating caused by using "Bad cache" data
before it has been initialized.
ISC_QUEUE handling for recursive clients was updated to address
a race condition that could cause a memory leak. This rarely
occurred with UDP clients, but could be a significant problem
for a server handling a steady rate of TCP queries.
A condition has been corrected where improper handling of
zero-length RDATA could cause undesirable behavior, including
termination of the named process.
For more information: https://kb.isc.org/article/AA-00788
X86: Emitting x87 fsin/fcos for sinf/cosf is not safe without unsafe
fp math.
This should make clang emit calls to libm for sinf/cosf by default.
MFC after: 1 week
reside, and move there ipfw(4) and pf(4).
o Move most modified parts of pf out of contrib.
Actual movements:
sys/contrib/pf/net/*.c -> sys/netpfil/pf/
sys/contrib/pf/net/*.h -> sys/net/
contrib/pf/pfctl/*.c -> sbin/pfctl
contrib/pf/pfctl/*.h -> sbin/pfctl
contrib/pf/pfctl/pfctl.8 -> sbin/pfctl
contrib/pf/pfctl/*.4 -> share/man/man4
contrib/pf/pfctl/*.5 -> share/man/man5
sys/netinet/ipfw -> sys/netpfil/ipfw
The arguable movement is pf/net/*.h -> sys/net. There are
future plans to refactor pf includes, so I decided not to
break things twice.
Not modified bits of pf left in contrib: authpf, ftp-proxy,
tftp-proxy, pflogd.
The ipfw(4) movement is planned to be merged to stable/9,
to make head and stable match.
Discussed with: bz, luigi
- Pacific/Fiji will go into DST from 21 October 2012 till 20 January 2013.
- Fix offset for Pacific/Tokelau.
- Gaza and West Bank had DST from 29 March to 28 September 2012.
- Syria has DST from April till October
- Morocco had DST from April to September 2012 except for 20 July to 20 August.
- Cuba changed to DST from 1 April 2012 only.
- Haiti has DST between 8 March and 1 November in 2012.
Obtained from: ftp://ftp.iana.org/tz/releases/
IP_SENDSRCADDR control with datagram message we reply with. This makes
bsnmpd reply from exactly same address that request was sent to, thus
successfully bypassing stateful firewalls or other kinds of strict checking.
PR: bin/171279
from the control message, actually never worked. This means check_priv()
didn't work for local dgram sockets.
The SCM_CREDS control messages is received only in two cases:
1) If we did setsockopt(LOCAL_CREDS) on our socket, and in this case
the message is struct sockcred.
2) If sender did supplied SCM_CREDS control message in his sendmsg()
syscall. In this case the message is struct cmsgcred.
We can't rely on 2), so we will use 1) for dgram sockets. For stream
sockets it is more reliable to obtain accept-time credentials, since
SCM_CREDS control message is attached only on first read. Thus:
o Do setsockopt(LOCAL_CREDS) on local dgram sockets.
o Split check_priv() into check_priv_stream() and check_priv_dgram(),
and call them from recv_stream() and recv_dgram() respectively.
o Don't provide space for SCM_CREDS control message in recv_stream().
o Provide space for SCM_CREDS control message in recv_dgram(), but there
is no need to initialize anything in it.
o In recv_dgram() do not blindly expect that first message is SCM_CREDS,
instead use correct search cycle through control messages.
