Commit Graph

18 Commits

Author SHA1 Message Date
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
51ea07d722 Now that ioctl(2) is allowed in capability mode and we can limit ioctls for the
given descriptors, use Capsicum sandboxing for hastd in primary and secondary
modes. Allow for DIOCGDELETE and DIOCGFLUSH ioctls on provider descriptor and
for G_GATE_CMD_MODIFY, G_GATE_CMD_START, G_GATE_CMD_DONE and G_GATE_CMD_DESTROY
on GEOM Gate descriptor.

Sponsored by:	The FreeBSD Foundation
2013-03-14 23:14:47 +00:00
Pawel Jakub Dawidek
2b1b224d24 For functions that return -1 on failure check exactly for -1 and not for
any negative number.

MFC after:	3 days
2012-01-10 22:39:07 +00:00
Pawel Jakub Dawidek
f78fe2608a Constify argument.
MFC after:	3 days
2012-01-06 12:27:17 +00:00
Pawel Jakub Dawidek
1ebc0407fc No need to use KEEP_ERRNO() macro around pjdlog functions, as they don't
modify errno.

MFC after:	3 days
2011-09-27 07:52:39 +00:00
Pawel Jakub Dawidek
699b26bdce Compile capsicum support only if HAVE_CAPSICUM is defined.
MFC after:	3 days
2011-06-27 09:14:25 +00:00
Pawel Jakub Dawidek
133d75ed18 Log a warning if we cannot sandbox using capsicum, but only under debug level 1.
It would be too noisy to log it as a proper warning as CAPABILITIES are not
compiled into GENERIC by default.

MFC after:	3 days
2011-06-27 09:10:48 +00:00
Pawel Jakub Dawidek
1c6689d58d To handle BIO_FLUSH and BIO_DELETE requests in secondary worker we need
to use ioctl(2). This is why we can't use capsicum for now to sandbox
secondary. Capsicum is still used to sandbox hastctl.

MFC after:	1 week
2011-05-23 20:59:50 +00:00
Pawel Jakub Dawidek
0cddb12ffd Currently we are unable to use capsicum for the primary worker process,
because we need to do ioctl(2)s, which are not permitted in the capability
mode. What we do now is to chroot(2) to /var/empty, which restricts access
to file system name space and we drop privileges to hast user and hast
group.

This still allows to access to other name spaces, like list of processes,
network and sysvipc.

To address that, use jail(2) instead of chroot(2). Using jail(2) will restrict
access to process table, network (we use ip-less jails) and sysvipc (if
security.jail.sysvipc_allowed is turned off). This provides much better
separation.

MFC after:	1 week
2011-05-14 17:02:03 +00:00
Pawel Jakub Dawidek
bcc9f32110 When using capsicum to sanbox, still use other methods first, just in case
one of them have some problems.
2011-05-14 16:55:24 +00:00
Pawel Jakub Dawidek
6d51b7d530 Add my copyright.
MFC after:	1 week
2011-03-22 21:19:51 +00:00
Pawel Jakub Dawidek
cd72d521e3 White space cleanups.
MFC after:	1 week
2011-03-22 10:39:34 +00:00
Pawel Jakub Dawidek
4d8dc3b838 When dropping privileges prefer capsicum over chroot+setgid+setuid.
We can use capsicum for secondary worker processes and hastctl.
When working as primary we drop privileges using chroot+setgid+setuid
still as we need to send ioctl(2)s to ggate device, for which capsicum
doesn't allow (yet).

X-MFC after:	capsicum is merged to stable/8
2011-03-21 21:31:50 +00:00
Pawel Jakub Dawidek
9925a680a9 Add snprlcat() and vsnprlcat() - the functions I'm always missing.
They work as a combination of snprintf(3) and strlcat(3) - the caller
can append a string build based on the given format.

MFC after:	1 week
2011-03-21 08:36:50 +00:00
Pawel Jakub Dawidek
f4c96f944c Let the caller log info about successful privilege drop.
We don't want to log this in hastctl.

MFC after:	1 week
2011-02-03 10:37:44 +00:00
Pawel Jakub Dawidek
2ec483c58e - Use pjdlog for assertions and aborts as this will log assert/abort message
to syslog if we run in background.
- Asserts in proto.c that method we want to call is implemented and remove
  dummy methods from protocols implementation that are only there to abort
  the program with nice message.

MFC after:	1 week
2011-01-31 18:32:17 +00:00
Pawel Jakub Dawidek
49499e981e Implement function that drops privileges by:
- chrooting to /var/empty (user hast home directory),
- setting groups to 'hast' (user hast primary group),
- setting real group id, effective group id and saved group id to 'hast',
- setting real user id, effective user id and saved user id to 'hast'.
At the end verify that those operations where successfull.

MFC after:	1 week
2011-01-28 22:33:47 +00:00
Pawel Jakub Dawidek
32115b105a Please welcome HAST - Highly Avalable Storage.
HAST allows to transparently store data on two physically separated machines
connected over the TCP/IP network. HAST works in Primary-Secondary
(Master-Backup, Master-Slave) configuration, which means that only one of the
cluster nodes can be active at any given time. Only Primary node is able to
handle I/O requests to HAST-managed devices. Currently HAST is limited to two
cluster nodes in total.

HAST operates on block level - it provides disk-like devices in /dev/hast/
directory for use by file systems and/or applications. Working on block level
makes it transparent for file systems and applications. There in no difference
between using HAST-provided device and raw disk, partition, etc. All of them
are just regular GEOM providers in FreeBSD.

For more information please consult hastd(8), hastctl(8) and hast.conf(5)
manual pages, as well as http://wiki.FreeBSD.org/HAST.

Sponsored by:	FreeBSD Foundation
Sponsored by:	OMCnet Internet Service GmbH
Sponsored by:	TransIP BV
2010-02-18 23:16:19 +00:00