Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC: r261566

Use CAP_EVENT instead of the deprecated CAP_POLL_EVENT.

PR: 185382 (based on)
Submitted by: Loganaden Velvindron
Reviewed by: pjd

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Change the cap_rights_t type from uint64_t to a structure that we can extend
in the future in a backward compatible (API and ABI) way.

The cap_rights_t represents capability rights. We used to use one bit to
represent one right, but we are running out of spare bits. Currently the new
structure provides place for 114 rights (so 50 more than the previous
cap_rights_t), but it is possible to grow the structure to hold at least 285
rights, although we can make it even larger if 285 rights won't be enough.

The structure definition looks like this:

struct cap_rights {
uint64_t cr_rights[CAP_RIGHTS_VERSION + 2];
};

The initial CAP_RIGHTS_VERSION is 0.

The top two bits in the first element of the cr_rights[] array contain total
number of elements in the array - 2. This means if those two bits are equal to
0, we have 2 array elements.

The top two bits in all remaining array elements should be 0.
The next five bits in all array elements contain array index. Only one bit is
used and bit position in this five-bits range defines array index. This means
there can be at most five array elements in the future.

To define new right the CAPRIGHT() macro must be used. The macro takes two
arguments - an array index and a bit to set, eg.

#define CAP_PDKILL CAPRIGHT(1, 0x0000000000000800ULL)

We still support aliases that combine few rights, but the rights have to belong
to the same array element, eg:

#define CAP_LOOKUP CAPRIGHT(0, 0x0000000000000400ULL)
#define CAP_FCHMOD CAPRIGHT(0, 0x0000000000002000ULL)

#define CAP_FCHMODAT (CAP_FCHMOD | CAP_LOOKUP)

There is new API to manage the new cap_rights_t structure:

cap_rights_t *cap_rights_init(cap_rights_t *rights, ...);
void cap_rights_set(cap_rights_t *rights, ...);
void cap_rights_clear(cap_rights_t *rights, ...);
bool cap_rights_is_set(const cap_rights_t *rights, ...);

bool cap_rights_is_valid(const cap_rights_t *rights);
void cap_rights_merge(cap_rights_t *dst, const cap_rights_t *src);
void cap_rights_remove(cap_rights_t *dst, const cap_rights_t *src);
bool cap_rights_contains(const cap_rights_t *big, const cap_rights_t *little);

Capability rights to the cap_rights_init(), cap_rights_set(),
cap_rights_clear() and cap_rights_is_set() functions are provided by
separating them with commas, eg:

cap_rights_t rights;

cap_rights_init(&rights, CAP_READ, CAP_WRITE, CAP_FSTAT);

There is no need to terminate the list of rights, as those functions are
actually macros that take care of the termination, eg:

#define cap_rights_set(rights, ...) \
__cap_rights_set((rights), __VA_ARGS__, 0ULL)
void __cap_rights_set(cap_rights_t *rights, ...);

Thanks to using one bit as an array index we can assert in those functions that
there are no two rights belonging to different array elements provided
together. For example this is illegal and will be detected, because CAP_LOOKUP
belongs to element 0 and CAP_PDKILL to element 1:

cap_rights_init(&rights, CAP_LOOKUP | CAP_PDKILL);

Providing several rights that belongs to the same array's element this way is
correct, but is not advised. It should only be used for aliases definition.

This commit also breaks compatibility with some existing Capsicum system calls,
but I see no other way to do that. This should be fine as Capsicum is still
experimental and this change is not going to 9.x.

Sponsored by: The FreeBSD Foundation

Fix dhclient for interfaces that are down. The discover_interfaces() function
that looks for interface skips interfaces that are not UP. We need to call
dhclient-script PREINIT before we call discover_interfaces(), so the script has
a chance to bring the interface UP.

Reported by: alfred

MFp4 @229488:

Sandbox unprivileged process using capability mode.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229487:

Revoke all capability rights from STDIN and allow only for write to STDOUT and
STDERR. All those descriptors are redirected to /dev/null.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229486:

Once PID is written to the pidfile, revoke all capability rights.
We just want to keep the pidfile open.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229485:

Only allow to overwrite lease file.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229484:

Limit routing socket so only poll(2) and read(2) are allowed (CAP_POLL_EVENT
and CAP_READ). This prevents unprivileged process from adding, removing or
modifying system routes.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229483:

Limit communication pipe with privileged process to CAP_READ and CAP_WRITE.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229481:

Currently it was allowed to send any UDP packets from unprivileged process and
possibly any packets because /dev/bpf was open for writing.

Move sending packets to privileged process. Unprivileged process has no longer
access to not connected UDP socket and has only access to /dev/bpf in read-only
mode.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229480:

Shutdown write direction of the routing socket. We only need to read from it.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229477:

The gethostname(3) function won't work in capability mode, because reading
kern.hostname sysctl is not permitted there. Cache hostname early and use
cached value later.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

Remove redundant white-spaces.

MFp4 @229473:

No caller checks send_packet() return value, so make it void.

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229472:

Use the same type for 'from' and 'to' argument in send_packet().

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

MFp4 @229470:

Remove unused argument from send_packet().

Reviewed by: brooks
Sponsored by: The FreeBSD Foundation

When acquiring a lease, record the value of the BOOTP siaddr field
contained in the DHCP offer, and write it out to the lease file
as an unquoted value of the "next-server" keyword. The value is ignored
when the lease is read back by dhclient, however other applications
are free to parse it.

The intent behind this change is to allow easier interoperability
with automated installation systems e.g. Cobbler, Foreman, Razor;
FreeBSD installation kernels can automatically probe the network
to discover deployment servers. There are no plans to MFC this
change unless a backport is specifically requested.

The syntax of the "next-server <ip>" lease keyword is intended to be
identical to that used by the ISC DHCPD server in its configuration files.
The required defines are already present in dhclient but were unused before
this change. (Note: This is NOT the same as Option 66, tftp-server-name).

It has been exercised in a university protocol testbed environment, with
Cobbler and an mfsBSD image containing pc-sysinstall (driven by Cobbler
Cheetah templates). The SYSLINUX memdisk driver is used to boot mfsBSD.
Currently this approach requires that a dedicated system profile has
been created for the node where FreeBSD is to be deployed. If this
is not present, the pc-sysinstall wrapper will be unable to obtain
a node configuration. There is code in progress to allow mfsBSD images
to obtain the required hints from the memdisk environment by parsing
the MBFT ACPI chunk. This is non-standard as it is not linked into
the platform's ACPI RSDT.

Reviewed by: des

Revert r239356 and use an alternate algorithm.

First, don't exit when the link goes down on an interface. Instead,
teach dhclient to track changes in link state and to enter the reboot
state when the link on an interface goes up causing dhclient to attempt
to renew its existing lease.

Second, remove the change I added to clear the old lease when dhclient
exits due to an error (such as ifconfig down). If an interface is
using autoconfiguration it should keep its autoconfiguration as much as
possible. If the next time it needs a configuration it is able to reuse
the previous autoconfiguration, then leaving the settings intact allows
existing connections to survive temporary outages, etc.

PR: bin/166656
MFC after: 1 month

Fix dhclient to properly exit and teardown the configured lease when
link is lost. devd will start a new dhclient instance when link is
restored.

PR: bin/166656
Submitted by: Peter Jeremy (mostly)
Reviewed by: brooks (earlier version from Peter)
MFC after: 1 month

Support domain-search in dhclient(8)

The "domain-search" option (option 119) allows a DHCP server to publish
a list of implicit domain suffixes used during name lookup. This option
is described in RFC 3397.

For instance, if the domain-search option says:
".example.org .example.com"
and one wants to resolve "foobar", the resolver will try:
1. "foobar.example.org"
2. "foobar.example.com"

The file /etc/resolv.conf is updated with a "search" directive if the
DHCP server provides "domain-search".

A regression test suite is included in this patch under
tools/regression/sbin/dhclient.

PR: bin/151940
Sponsored by Yakaz (http://www.yakaz.com)

Make dhclient use a pid file. Modify the rc script accordingly; while
there, clean it up and add some error checks.

Glanced at by: brooks@
MFC after: 3 weeks

When dhclient obtains a lease, it runs dhclient-script and expects
it to configure the interface. When the script is complete, dhclient
monitors the routing socket and will terminate if its address is
deleted or if its interface is removed or brought down.

Because the routing socket is already open when dhclient-script is
run, dhclient ignores address deletions for 10 seconds after the
script was run.

If the address that will be obtained is already configured on the
interface before dhclient starts, and if dhclient-script takes more
than 10 seconds (perhaps due to dhclient-*-hooks latencies), on script
completion, dhclient will immediately and silently exit when it sees
the RTM_DELADDR routing message resulting from the script reassigning
the address to the interface.

This change logs dhclient's reason for exiting and also changes the
10 second timeout to be effective from completion of dhclient-script
rather than from when it was started.

We now ignore RTM_DELADDR and RTM_NEWADDR messages when the message
contains no interface address (which should not happen) rather than
exiting.

Not reviewed by: brooks (timeout)
MFC after: 3 weeks

Fix an off by one error when we limit append/prepend text sizes based on our
internal buffer sizes.

When we 'append', assume we're appending to text. Some MS dhcp servers will
give us a string with the length including the trailing NUL. when we 'append
domain-name', we get something like "search x.y\000 z" in resolv.conf :(

MFC after: 1 week
Security: A buffer overflow (by one NUL byte) was possible.

Support the remaining options listed in dhcp-options(5) and RFC 2132.

PR: bin/127076
Submitted by: jkim
MFC after: 1 week

Run the privileged dhclient process in its own session.

In the MPSAFE TTY branch, I noticed PTY's to be leaked, because
dhclient's privileged process was run inside the session of, say, the
login shell. Make sure we call setsid() here.

Approved by: philip (mentor), brooks

Defer state change on disassociate to avoid unnecessarily dropping the
lease: track the current bssid and if it changes (as reported in an
assoc/reassoc) event only then kick the state machine. This gives us
immediate response when roaming but otherwise causes us to fallback on
the normal state machine.

Reviewed by: brooks, jhb
MFC after: 3 weeks

correct syslog mask so LOG_DEBUG msgs are not lost

MFC after: 2 weeks

Implement RFC3442, the Classless Static Route option.

The original DHCP specification includes a route option but it supports
only class-based routes. RFC3442 adds support for specifying the netmask
width for each static route. A variable length encoding is used to minimize
the size of this option.

PR: bin/99534
Submitted by: Andrey V. Elsukov <bu7cher@yandex.ru>
Reviewed by: brooks

Actually implement rev 1.12 for host names and NIS domain names. We
were removing the invalid option, but still rejecting the lease.

Reported by: Yoshihiko Sarumaru <mistral at imasy dot or dot jp>

Revert the addition of -p. It's flawed in that dhclient should not run
on an interface without carrier. devd should be used instead to handle
link up/down events.

Put on the right path by: brooks, sam

Correct usage()

Add a -p switch to dhclient. The switch tells dhclient to persist
despite the interface link status.

Add dhclient_flags_iface and background_dhclient_iface rc.conf options.
(where iface is a specific interface). These can be used to give
interface specific flags to dhclient.

Reviewed by: brooks@

Send client identifier unconditionally. My ancient D-Link router response
with NACK if I don't set it. Setting 'option dhcp-client-identifier' is
alternative but it is inconvenient because I have to keep the list of
all MAC addresses. As bin/94743 pointed out, it is always sent from
Windows clients and I found Mac OS X does the same.

OK'd by: brooks

Remove 'n' from the getopt string. There's no -n option that is
parsed, so it winds up at usage anyway.

Add 'b' to the usage summary. Noticed by Ben Mesander.

Be more like Windows and Linux and send our hostname in the host-name
option if none is given in the config file. Also add #ifdefd out
support for sending a client ID based on our MAC address.

PR: bin/94743, bin/76401
Submitted by: Frank Behrens <frank at pinky dot sax dot de>
X-MFC after: 6.1-RELEASE

Allow users to add aliases to the interface.

PR: bin/87465 (different solution used)
MFC after: 1 week

When we get a bogus hostname in an option, drop the option rather than
refusing the lease. This allow obtaining leases on misadministered
networks that use host names with underscores in them.

MFC After: 3 days

When we supersed the subnet-mask, write the forced value to the lease
file. This is what the ISC client does.

Submitted by: Rostislav Krasny <rosti dot bsd at gmail dot com>

Introduce a new helper function check_search() derived for res_hnok to
check the domain-name parameter according to the rules for "search"
strings as documented in resolv.conf(5). Specifically, the string must
be no more than 256 bytes long and contain no more than six valid domain
names separated by white space.

The previous unchecked values could result in a mangled resolv.conf
file which could effectively deny access to local sites. This is not
a security issue as rogue dhcp servers could already do this without
sending invalid strings.

Reviewed by: cperciva
MFC After: 3 days

Add __FBSDID to all .c files in dhclient to aid in determining file
versions when dealing with user problems.

Don't reject packets with server names containing characters that are
not allowed in domain names. RFC 2132 does not list valid or invalid
characters and the ISC client accepts anything here.

Reported by: ps

treat REASSOC events just like ASSOC

MFC after: 3 days

Don't complain when we receive smtp, pop, nntp, www, finger, and irc
server options.

Reported by: Max Boyarov <max_b at tut dot by>
Approved by: re (dhclient blanket)

People like to do RFC violating things with the domain-name option and
include a space seperated list of domains instead of the domain of the
host. This is supported on too many platforms to break for now so,
remove validation of this option for the moment.

The correct solution longer term is to implement RFC 3397 support and
then treat domain-name options containing space seperated lists of
domains as domain-search options for backwards compatability.

Approved by: re (dhclient blanket)

Avoid a null pointer dereference by not expiring our lease if we don't
have an active one.

Submitted by: sam
Reported by: James Snow <snow at teardrop dot org>
Approved by: re (dhclient blanket)

Fix build on 64-bit platforms where time_t is 64 bit. Since where
talking about time related to leases, it should be OK to cast these to
(int)s rather than using intmax_t.

Submitted by: ru
Pointy hat: brooks

Define _PATH_VAREMPTY.

Add a -b option to background immediatly.

Add support for 802.11 routing messages to "instantly" renegotiate
at lease when we associate with a new network.

Submitted by: sam

This commit was generated by cvs2svn to compensate for changes in r147072,
which included commits to RCS files with non-trunk default branches.

Import the OpenBSD dhclient as shipped with OpenBSD-3.7 (the tag
OPENBSD_3_7).