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
- 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
a process has an auditid/preselection masks specified, and
is jailed, include the zonename (jailname) token as a
part of the audit record.
Reviewed by: pjd
MFC after: 2 weeks
Fix path handling for *at() syscalls.
Before the change directory descriptor was totally ignored,
so the relative path argument was appended to current working
directory path and not to the path provided by descriptor, thus
wrong paths were stored in audit logs.
Now that we use directory descriptor in vfs_lookup, move
AUDIT_ARG_UPATH1() and AUDIT_ARG_UPATH2() calls to the place where
we hold file descriptors table lock, so we are sure paths will
be resolved according to the same directory in audit record and
in actual operation.
Sponsored by: FreeBSD Foundation (auditdistd)
Reviewed by: rwatson
MFC after: 2 weeks
We wish to be able to audit capability rights arguments; this code
provides the necessary infrastructure.
This commit does not, of itself, turn on such auditing for any
system call; that should follow shortly.
Approved by: mentor (rwatson), re (Capsicum blanket)
Sponsored by: Google Inc
provide specific macros, AUDIT_ARG_UPATH1() and AUDIT_ARG_UPATH2()
to capture path information for audit records. This allows us to
move the definitions of ARG_* out of the public audit header file,
as they are an implementation detail of our current kernel-internal
audit record, which may change.
Approved by: re (kensmith)
Obtained from: TrustedBSD Project
MFC after: 1 month
to avoid exposing ARG_ macros/flag values outside of the audit code in
order to name which one of two possible vnodes will be audited for a
system call.
Approved by: re (kib)
Obtained from: TrustedBSD Project
MFC after: 1 month
instead of the root/current working directory as the starting point for
lookups. Up to two such descriptors can be audited. Add audit record
BSM encoding for fooat(2).
Note: due to an error in the OpenBSM 1.1p1 configuration file, a
further change is required to that file in order to fix openat(2)
auditing.
Approved by: re (kib)
Reviewed by: rdivacky (fooat(2) portions)
Obtained from: TrustedBSD Project
MFC after: 1 month
This fixes a problem created by the recent change that allows a large
number of groups per user. The gidset field in struct kaudit_record
is now dynamically allocated to the size needed rather than statically
(using NGROUPS).
Approved by: re@ (kensmith, rwatson), gnn (mentor)
- Add and use mapping of fcntl(2) commands to new BSM constant space.
- Adopt (int) rather than (long) arguments to a number of auditon(2)
commands, as has happened in Solaris, and add compatibility code to
handle the old comments.
Note that BSM_PF_IEEE80211 is partially but not fully removed, as the
userspace OpenBSM 1.1alpha5 code still depends on it. Once userspace
is updated, I'll GCC the kernel constant.
MFC after: 2 weeks
Sponsored by: Apple, Inc.
Obtained from: TrustedBSD Project
Portions submitted by: sson
queue length variables as well, avoiding storing the limit in a larger
type than the length.
Submitted by: sson
Sponsored by: Apple Inc.
MFC after: 1 week
regular header tokens. The extended header tokens contain an IP
or IPv6 address which makes it possible to identify which host an
audit record came from when audit records are centralized.
If the host information has not been specified, the system will
default to the old style headers. Otherwise, audit records that
are created as a result of system calls will contain host information.
This implemented has been designed to be consistent with the Solaris
implementation. Host information is set/retrieved using the A_GETKAUDIT
and A_SETKAUDIT auditon(2) commands. These commands require that a
pointer to a auditinfo_addr_t object is passed. Currently only IP and
IPv6 address families are supported.
The users pace bits associated with this change will follow in an
openbsm import.
Reviewed by: rwatson, (sson, wsalamon (older version))
MFC after: 1 month
remove associated comments.
Slip audit_file_rotate_wait assignment in audit_rotate_vnode() before
the drop of the global audit mutex.
Obtained from: TrustedBSD Project
tokens. Currently, we do not support the set{get}audit_addr(2) system
calls which allows processes like sshd to set extended or ip6
information for subject tokens.
The approach that was taken was to change the process audit state
slightly to use an extended terminal ID in the kernel. This allows
us to store both IPv4 IPv6 addresses. In the case that an IPv4 address
is in use, we convert the terminal ID from an struct auditinfo_addr to
a struct auditinfo.
If getaudit(2) is called when the subject is bound to an ip6 address,
we return E2BIG.
- Change the internal audit record to store an extended terminal ID
- Introduce ARG_TERMID_ADDR
- Change the kaudit <-> BSM conversion process so that we are using
the appropriate subject token. If the address associated with the
subject is IPv4, we use the standard subject32 token. If the subject
has an IPv6 address associated with them, we use an extended subject32
token.
- Fix a couple of endian issues where we do a couple of byte swaps when
we shouldn't be. IP addresses are already in the correct byte order,
so reading the ip6 address 4 bytes at a time and swapping them results
in in-correct address data. It should be noted that the same issue was
found in the openbsm library and it has been changed there too on the
vendor branch
- Change A_GETPINFO to use the appropriate structures
- Implement A_GETPINFO_ADDR which basically does what A_GETPINFO does,
but can also handle ip6 addresses
- Adjust get{set}audit(2) syscalls to convert the data
auditinfo <-> auditinfo_addr
- Fully implement set{get}audit_addr(2)
NOTE: This adds the ability for processes to correctly set extended subject
information. The appropriate userspace utilities still need to be updated.
MFC after: 1 month
Reviewed by: rwatson
Obtained from: TrustedBSD
sockaddr_storage. This structure is defined in RFC 2553 and is a more
semantically correct structure for holding IP and IP6 sockaddr information.
struct sockaddr is not big enough to hold all the required information for
IP6, resulting in truncated addresses et al when auditing IP6 sockaddr
information.
We also need to assume that the sa->sa_len has been validated before the call to
audit_arg_sockaddr() is made, otherwise it could result in a buffer overflow.
This is being done to accommodate auditing of network related arguments (like
connect, bind et al) that will be added soon.
Discussed with: rwatson
Obtained from: TrustedBSD Project
MFC after: 2 weeks
audit pipes. If the kernel record was not selected for the trail or the pipe,
any user supplied record attached to it would be tossed away, resulting in
otherwise selected events being lost.
- Introduce two new masks: AR_PRESELECT_USER_TRAIL AR_PRESELECT_USER_PIPE,
currently we have AR_PRESELECT_TRAIL and AR_PRESELECT_PIPE, which tells
the audit worker that we are interested in the kernel record, with
the additional masks we can determine if either the pipe or trail is
interested in seeing the kernel or user record.
- In audit(2), we unconditionally set the AR_PRESELECT_USER_TRAIL and
AR_PRESELECT_USER_PIPE masks under the assumption that userspace has
done the preselection [1].
Currently, there is work being done that allows the kernel to parse and
preselect user supplied records, so in the future preselection could occur
in either layer. But there is still a few details to work out here.
[1] At some point we need to teach au_preselect(3) about the interests of
all the individual audit pipes.
This is a RELENG_6 candidate.
Reviewed by: rwatson
Obtained from: TrustedBSD Project
MFC after: 1 week
Add the argument auditing functions for argv and env.
Add kernel-specific versions of the tokenizer functions for the
arg and env represented as a char array.
Implement the AUDIT_ARGV and AUDIT_ARGE audit policy commands to
enable/disable argv/env auditing.
Call the argument auditing from the exec system calls.
Obtained from: TrustedBSD Project
Approved by: rwatson (mentor)
global audit trail configuration. This allows applications consuming
audit trails to specify parameters for which audit records are of
interest, including selecting records not required by the global trail.
Allowing application interest specification without changing the global
configuration allows intrusion detection systems to run without
interfering with global auditing or each other (if multiple are
present). To implement this:
- Kernel audit records now carry a flag to indicate whether they have
been selected by the global trail or by the audit pipe subsystem,
set during record commit, so that this information is available
after BSM conversion when delivering the BSM to the trail and audit
pipes in the audit worker thread asynchronously. Preselection by
either record target will cause the record to be kept.
- Similar changes to preselection when the audit record is created
when the system call is entering: consult both the global trail and
pipes.
- au_preselect() now accepts the class in order to avoid repeatedly
looking up the mask for each preselection test.
- Define a series of ioctls that allow applications to specify whether
they want to track the global trail, or program their own
preselection parameters: they may specify their own flags and naflags
masks, similar to the global masks of the same name, as well as a set
of per-auid masks. They also set a per-pipe mode specifying whether
they track the global trail, or user their own -- the door is left
open for future additional modes. A new ioctl is defined to allow a
user process to flush the current audit pipe queue, which can be used
after reprogramming pre-selection to make sure that only records of
interest are received in future reads.
- Audit pipe data structures are extended to hold the additional fields
necessary to support preselection. By default, audit pipes track the
global trail, so "praudit /dev/auditpipe" will track the global audit
trail even though praudit doesn't program the audit pipe selection
model.
- Comment about the complexities of potentially adding partial read
support to audit pipes.
By using a set of ioctls, applications can select which records are of
interest, and toggle the preselection mode.
Obtained from: TrustedBSD Project
worker.
Rename audit_commit_cv to audit_watermark_cv, since it is there to
wake up threads waiting on hitting the low watermark. Describe
properly in comment.
Obtained from: TrustedBSD Project
branch:
Integrate audit.c to audit_worker.c, so as to migrate the worker
thread implementation to its own .c file.
Populate audit_worker.c using parts now removed from audit.c:
- Move audit rotation global variables.
- Move audit_record_write(), audit_worker_rotate(),
audit_worker_drain(), audit_worker(), audit_rotate_vnode().
- Create audit_worker_init() from relevant parts of audit_init(),
which now calls this routine.
- Recreate audit_free(), which wraps uma_zfree() so that
audit_record_zone can be static to audit.c.
- Unstaticize various types and variables relating to the audit
record queue so that audit_worker can get to them. We may want
to wrap these in accessor methods at some point.
- Move AUDIT_PRINTF() to audit_private.h.
Addition of audit_worker.c to kernel configuration, missed in
earlier submit.
Obtained from: TrustedBSD Project
Change send_trigger() prototype to return an int, so that user
space callers can tell if the message was successfully placed
in the trigger queue. This isn't quite the same as it being
successfully received, but is close enough that we can generate
a more useful warning message in audit(8).
Obtained from: TrustedBSD Project
- Include audit_internal.h to get definition of internal audit record
structures, as it's no longer in audit.h. Forward declare au_record
in audit_private.h as not all audit_private.h consumers care about
it.
- Remove __APPLE__ compatibility bits that are subsumed by configure
for user space.
- Don't expose in6_addr internals (non-portable, but also cleaner
looking).
- Avoid nested include of audit.h in audit_private.h.
Obtained from: TrustedBSD Project
applications to insert a "tee" in the live audit event stream. Records
are inserted into a per-clone queue so that user processes can pull
discreet records out of the queue. Unlike delivery to disk, audit pipes
are "lossy", dropping records in low memory conditions or when the
process falls behind real-time events. This mechanism is appropriate
for use by live monitoring systems, host-based intrusion detection, etc,
and avoids applications having to dig through active on-disk trails that
are owned by the audit daemon.
Obtained from: TrustedBSD Project
- Management of audit state on processes.
- Audit system calls to configure process and system audit state.
- Reliable audit record queue implementation, audit_worker kernel
thread to asynchronously store records on disk.
- Audit event argument.
- Internal audit data structure -> BSM audit trail conversion library.
- Audit event pre-selection.
- Audit pseudo-device permitting kernel->user upcalls to notify auditd
of kernel audit events.
Much work by: wsalamon
Obtained from: TrustedBSD Project, Apple Computer, Inc.
