Commit Graph

57 Commits

Author SHA1 Message Date
Conrad Meyer
387016a576 dhclient: add support for interface-mtu (26)
Make dhclient set interface MTU if it was provided.

This version implements MTU setting in dhclient itself before it runs
dhclient-script.

PR:		206721
Submitted by:	novel@
Reported by:	Jarrod Petz <jlpetz at gmail.com>
Reviewed by:	cem, allanjude
Differential Revision:	https://reviews.freebsd.org/D5675
2016-09-02 21:14:29 +00:00
Conrad Meyer
fb0eab090e dhclient: Fix the trivial buffer overruns correctly
A DHCP client identifier is simply the hardware type (one byte) concatenated
with the hardware address (some variable number of bytes, but at most 16).
Limit the size of the temporary buffer to match and the rest of the
calculations shake out correctly.

This is a follow-up to the incorrect r299512, reverted in r300172.

CIDs:		1008682, 1305550
Sponsored by:	EMC / Isilon Storage Division
2016-05-18 23:41:55 +00:00
Conrad Meyer
4441bd735f Revert r299512
It broke client identifiers because I misunderstood the intent of the code.
There is still a minor issue detected by Coverity (at least, I can't find where
the code proves it isn't an issue).  I'll follow up with a better fix for the
CIDs.

Reported by:	Ian FREISLICH
Sponsored by:	EMC / Isilon Storage Division
2016-05-18 23:35:37 +00:00
Conrad Meyer
021b92e5ba dhclient: Fix some trivial buffer overruns
There was some confusion about how to limit a hardware address to at most 16
bytes.  In some cases it would overrun a byte off the end of the array.
Correct the types and rectify the overrun.

Reported by:	Coverity
CIDs:		1008682, 1305550
Sponsored by:	EMC / Isilon Storage Division
2016-05-12 04:28:22 +00:00
Sepherosa Ziehau
dd09ce3930 dhclient: Log a warning instead of bailing upon "illegal" options
In Azure, the DHCP servers add private option (id 0xf5), which contains
binary form of an IPv4 address. Once this option is converted to string
form, it could contain '$', e.g.

IPv4 address: 100.72.36.54
binary form: 0x64 0x48 0x24 0x36
string form: "dH$6"

dhclient bails upon "illegal" options like the above example, thus the
VM bring-up will fail.

Also as a side note, this "illegal" option detection was added in
OpenBSD ~11years ago:
http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sbin/dhclient/dhclient.c?rev=1.50&content-type=text/x-cvsweb-markup

And it was removed along with the removal of script support in OpenBSD
~3years ago:
http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sbin/dhclient/dhclient.c?rev=1.159&content-type=text/x-cvsweb-markup

Reported by:	Hongxiong Xian <v-hoxian microsoft com>
Reviewed by:	jhb, Dexuan Cui <decui microsoft com>
Tested by:	Hongxiong Xian <v-hoxian microsoft com>
Analyzed by:	Dong Liu <doliu microsoft com>
MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D5853
2016-04-20 23:56:25 +00:00
Patrick Kelsey
19342eee9d Add CAP_FCNTL to the lease file capsicum rights, and limit to
CAP_FCNTL_GETFL.  Without CAP_FCNTL_GETFL, the lease file truncation
in rewrite_client_leases() will fail to trim old data when rewriting
the file with a lesser amount of data.

Reviewed by: pjd, rwatson
Approved by: jmallett (mentor)
MFC after: 1 week
2015-05-28 05:38:07 +00:00
Pawel Jakub Dawidek
e16406c7ba Remove duplicated includes.
Submitted by:	Mariusz Zaborski <oshogbo@FreeBSD.org>
2014-06-26 13:57:44 +00:00
Robert Watson
b881b8be1d Update most userspace consumers of capability.h to use capsicum.h instead.
auditdistd is not updated as I will make the change upstream and then do a
vendor import sometime in the next week or two.

MFC after:	3 weeks
2014-03-16 11:04:44 +00:00
Christian Brueffer
bb7a82ac0d Use CAP_EVENT instead of the deprecated CAP_POLL_EVENT.
PR:		185382 (based on)
Submitted by:	Loganaden Velvindron
Reviewed by:	pjd
MFC after:	1 week
2014-02-06 21:36:14 +00:00
Eitan Adler
07561ab459 dhclient: change the pidfile's permissions to 644
This change permits non-root users to determine if dhclient is running
('service dhclient status wlan0').

Discussed with: mjg, cperciva
2014-02-03 04:22:29 +00:00
Pawel Jakub Dawidek
7008be5bd7 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
2013-09-05 00:09:56 +00:00
Pawel Jakub Dawidek
374a8a322b 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
2013-07-04 12:27:10 +00:00
Pawel Jakub Dawidek
8da93e6861 MFp4 @229488:
Sandbox unprivileged process using capability mode.

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
2013-07-03 22:23:25 +00:00
Pawel Jakub Dawidek
a6f38228d4 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
2013-07-03 22:22:29 +00:00
Pawel Jakub Dawidek
4c7a48b7a9 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
2013-07-03 22:21:11 +00:00
Pawel Jakub Dawidek
fe5c716394 MFp4 @229485:
Only allow to overwrite lease file.

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
2013-07-03 22:19:43 +00:00
Pawel Jakub Dawidek
f73ac8b9de 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
2013-07-03 22:18:40 +00:00
Pawel Jakub Dawidek
de2c882f5c MFp4 @229483:
Limit communication pipe with privileged process to CAP_READ and CAP_WRITE.

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
2013-07-03 22:17:29 +00:00
Pawel Jakub Dawidek
235eb53002 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
2013-07-03 22:12:54 +00:00
Pawel Jakub Dawidek
e374cef518 MFp4 @229480:
Shutdown write direction of the routing socket. We only need to read from it.

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
2013-07-03 22:09:02 +00:00
Pawel Jakub Dawidek
0bbe83068e 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
2013-07-03 22:05:36 +00:00
Pawel Jakub Dawidek
c786bc9089 Remove redundant white-spaces. 2013-07-03 22:03:19 +00:00
Pawel Jakub Dawidek
e8da500388 MFp4 @229473:
No caller checks send_packet() return value, so make it void.

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
2013-07-03 21:57:24 +00:00
Pawel Jakub Dawidek
ba019ae51f MFp4 @229472:
Use the same type for 'from' and 'to' argument in send_packet().

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
2013-07-03 21:53:54 +00:00
Pawel Jakub Dawidek
592291c1e7 MFp4 @229470:
Remove unused argument from send_packet().

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation
2013-07-03 21:45:29 +00:00
Bruce M Simpson
d32438c3f1 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
2013-07-02 13:24:37 +00:00
John Baldwin
0a26f85822 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
2012-08-22 13:53:37 +00:00
John Baldwin
83f745b8b9 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
2012-08-17 15:53:43 +00:00
Jean-Sébastien Pédron
409139f051 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)
2011-12-04 14:44:31 +00:00
Dag-Erling Smørgrav
23f39c906b 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
2011-10-13 17:20:45 +00:00
Brian Somers
6964abef83 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
2010-07-07 06:06:54 +00:00
Brian Somers
043bcc8d44 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.
2009-06-08 21:42:30 +00:00
Brooks Davis
38e755fd40 Support the remaining options listed in dhcp-options(5) and RFC 2132.
PR:		bin/127076
Submitted by:	jkim
MFC after:	1 week
2008-10-17 13:28:53 +00:00
Ed Schouten
708925463e 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
2008-06-30 20:23:49 +00:00
Sam Leffler
61063e478a 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
2008-03-22 16:24:02 +00:00
Sam Leffler
043f1935e0 correct syslog mask so LOG_DEBUG msgs are not lost
MFC after:	2 weeks
2008-03-22 16:18:07 +00:00
Ed Maste
2fcc737008 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
2007-02-09 17:50:26 +00:00
Brooks Davis
a0b5cadc42 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>
2007-01-29 15:55:13 +00:00
Brian Somers
3dd3357a13 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
2006-08-21 16:31:31 +00:00
Brian Somers
43cb852dc0 Correct usage() 2006-08-17 17:27:42 +00:00
Brian Somers
9341e8dd88 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@
2006-08-17 17:12:27 +00:00
Jung-uk Kim
473c2d129b 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
2006-07-03 22:05:38 +00:00
Warner Losh
649482853c 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.
2006-05-23 16:57:47 +00:00
Brooks Davis
fcab8addcf 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
2006-05-07 23:31:10 +00:00
Brooks Davis
dfad96ea18 Allow users to add aliases to the interface.
PR:		bin/87465 (different solution used)
MFC after:	1 week
2006-01-10 04:53:20 +00:00
Brooks Davis
82dbbc4120 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
2005-12-10 03:46:14 +00:00
Brooks Davis
40767e22ea 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>
2005-09-02 17:35:35 +00:00
Brooks Davis
f954ec0bcf 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
2005-08-30 18:20:46 +00:00
Brooks Davis
8794fdbb48 Add __FBSDID to all .c files in dhclient to aid in determining file
versions when dealing with user problems.
2005-08-23 23:59:55 +00:00
Brooks Davis
acccb9aa83 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
2005-07-28 00:24:39 +00:00