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
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
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
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
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
- Limit bpf descriptor in unprivileged process to CAP_POLL_EVENT, CAP_READ and
allow for SIOCGIFFLAGS, SIOCGIFMEDIA ioctls.
- While here limit bpf descriptor in privileged process to only CAP_WRITE.
Reviewed by: brooks
Sponsored by: The FreeBSD Foundation
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
- Add new request (IMSG_SEND_PACKET) that will be handled by privileged process.
- Add $FreeBSD$.
Reviewed by: brooks
Sponsored by: The FreeBSD Foundation
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
Make use of two fields: rfdesc and wfdesc to keep bpf descriptor open for
reading only in rfdesc and bpf descriptor open for writing only in wfdesc.
In the end they will be used by two different processes.
Reviewed by: brooks
Sponsored by: The FreeBSD Foundation
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
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
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
In the original Domain Search option patch, an invalid option value
would cause the whole lease to be rejected. However, DHCP servers who
emit such an invalid value are more common than I thought. With this new
patch, just the option is rejected, not the entire lease.
PR: bin/163431
Submitted by: Fabian Keil <fk@fabiankeil.de> (earlier version)
Reviewed by: Fabian Keil <fk@fabiankeil.de>
Sponsored by: Yakaz (http://www.yakaz.com)
that changed 0.0.0.0/0.0.0.0 prefix to 0.0.0.0/255.0.0.0.
In the r228313 this behavior was fixed, and since dhclient-script
got broken.
I'm not sure this fix is a perfect one, it just changes
dhclient-script to set 0.0.0.0/255.0.0.0 explicitly.
PR: kern/163206
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)
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
packets instead of allowing the protocol stack to pick a random source port.
This fixes the behaviour where dhclient would never transition from RENEWING
to BOUND without going through REBINDING in networks which are paranoid about
DHCP spoofing, such as most mainstream cable-broadband ISP networks.
Reviewed by: brooks
Obtained from: OpenBSD (partly - I'm not convinced their solution can work)
MFC after: 1 week (pending re approval)
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.
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
interface is one with the default route (or there isn't one). Use it to
decide if we should adjust the default route and /etc/resolv.conf.
Fix the delete of the default route. The if statement was totally bogus
and the delete only worked due to a typo. [1]
Reported by: Jordan Coleman <jordan at JordanColeman dot com> [1]
MFC after: 1 week
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
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
length != BPF_WORDALIGN(length)
This meeans that it is possible for this to be true:
interface->rbuf_offset > interface->rbuf_len
Handle this case in the test for running out of packets. While
OpenBSD's solution of setting interface->rbuf_len to
BPF_WORDALIGN(length) is safe due to the size of the buffer, I think
this solution results in less hidden assumptions.
This should fix the problem of dhclient running away and consuming 100%
CPU.
PR: bin/102226
Submitted by: Joost Bekkers <joost at jodocus.org>
MFC after: 3 days
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@
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
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
/tmp may not be writeable yet when dhclient is first run via
/etc/rc.d/netif so using it may not work. Also, writing to a
predictable file in /tmp as root is a really bad idea since a malicious
user may be able to win a race and insert a symlink which will allow
them to cause any file to be overwritten. To solve these problems,
create the tempory file in /var/run which will exist this early and is
writable only by root.
Security: Local risk if users can cause dhclient to run on demand
(such as by unplugging and replugging the network cable).
entries from the interface rather than using ifconfig's delete command.
This preserves non-dhclient configured addresses (though they are wiped
out when dhclient is restarted).
MFC after: 1 week
renewal, or we lose link, be more forceful about clearing interface
state so another interface that connects to the same network has a
chance of working. This doesn't address attemping to connect to both at
once, but appears to allow unplugging from a wired interface and then
inserting a wireless card that associates with an AP bridged to the same
LAN.
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
