The goal here is to provide one place altering process credentials.
This eases debugging and opens up posibilities to do additional work when such
an action is performed.
This is (yet another) step towards the removal of device
cloning from our kernel.
CR: https://reviews.freebsd.org/D441
Reviewed by: kib, rwatson
Tested by: pho
dev_ref() in the clone handlers that still use it.
- Don't set SI_CHEAPCLONE flag, it's not used anywhere neither in devfs
(for anything real)
Reviewed by: kib
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
int bindat(int fd, int s, const struct sockaddr *addr, socklen_t addrlen);
int connectat(int fd, int s, const struct sockaddr *name, socklen_t namelen);
which allow to bind and connect respectively to a UNIX domain socket with a
path relative to the directory associated with the given file descriptor 'fd'.
- Add manual pages for the new syscalls.
- Make the new syscalls available for processes in capability mode sandbox.
- Add capability rights CAP_BINDAT and CAP_CONNECTAT that has to be present on
the directory descriptor for the syscalls to work.
- Update audit(4) to support those two new syscalls and to handle path
in sockaddr_un structure relative to the given directory descriptor.
- Update procstat(1) to recognize the new capability rights.
- Document the new capability rights in cap_rights_limit(2).
Sponsored by: The FreeBSD Foundation
Discussed with: rwatson, jilles, kib, des
- 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
implement the BSM audit trail format. Rename the kernel versions of the
files to match the userspace filenames so that it's easier to work out
what they correspond to, and therefore ensure they are kept in-sync.
Obtained from: TrustedBSD Project
src/sys/{bsm,security/audit}. There are a few tweaks to help with the
FreeBSD build environment that will be merged back to OpenBSM. No
significant functional changes appear on the kernel side.
Obtained from: TrustedBSD Project
Sponsored by: The FreeBSD Foundation (auditdistd)
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
Currently when we discover that trail file is greater than configured
limit we send AUDIT_TRIGGER_ROTATE_KERNEL trigger to the auditd daemon
once. If for some reason auditd didn't rotate trail file it will never
be rotated.
Change it by sending the trigger when trail file size grows by the
configured limit. For example if the limit is 1MB, we will send trigger
on 1MB, 2MB, 3MB, etc.
This is also needed for the auditd change that will be committed soon
where auditd may ignore the trigger - it might be ignored if kernel
requests the trail file to be rotated too quickly (often than once a second)
which would result in overwriting previous trail file.
Sponsored by: FreeBSD Foundation (auditdistd)
MFC after: 2 weeks
Currently on each record write we call VFS_STATFS() to get available space
on the file system as well as VOP_GETATTR() to get trail file size.
We can assume that trail file is only updated by the audit worker, so instead
of asking for file size on every write, get file size on trail switch only
(it should be zero, but it's not expensive) and use global variable audit_size
protected by the audit worker lock to keep track of trail file's size.
This eliminates VOP_GETATTR() call for every write. VFS_STATFS() is satisfied
from in-memory data (mount->mnt_stat), so shouldn't be expensive.
Sponsored by: FreeBSD Foundation (auditdistd)
MFC after: 2 weeks
In particular, do not lock Giant conditionally when calling into the
filesystem module, remove the VFS_LOCK_GIANT() and related
macros. Stop handling buffers belonging to non-mpsafe filesystems.
The VFS_VERSION is bumped to indicate the interface change which does
not result in the interface signatures changes.
Conducted and reviewed by: attilio
Tested by: pho
The SYSCTL_NODE macro defines a list that stores all child-elements of
that node. If there's no SYSCTL_DECL macro anywhere else, there's no
reason why it shouldn't be static.
It seems the D_PSEUDO flag was meant to allow make_dev() to return NULL.
Nowadays we have a different interface for that; make_dev_p(). There's
no need to keep it there.
While there, remove an unneeded D_NEEDMINOR from the gpio driver.
Discussed with: gonzo@ (gpio)
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.
Reviewed by: rwatson
Approved by: re (bz)
If a selinfo object is recorded (via selrecord()) and then it is
quickly destroyed, with the waiters missing the opportunity to awake,
at the next iteration they will find the selinfo object destroyed,
causing a PF#.
That happens because the selinfo interface has no way to drain the
waiters before to destroy the registered selinfo object. Also this
race is quite rare to get in practice, because it would require a
selrecord(), a poll request by another thread and a quick destruction
of the selrecord()'ed selinfo object.
Fix this by adding the seldrain() routine which should be called
before to destroy the selinfo objects (in order to avoid such case),
and fix the present cases where it might have already been called.
Sometimes, the context is safe enough to prevent this type of race,
like it happens in device drivers which installs selinfo objects on
poll callbacks. There, the destruction of the selinfo object happens
at driver detach time, when all the filedescriptors should be already
closed, thus there cannot be a race.
For this case, mfi(4) device driver can be set as an example, as it
implements a full correct logic for preventing this from happening.
Sponsored by: Sandvine Incorporated
Reported by: rstone
Tested by: pluknet
Reviewed by: jhb, kib
Approved by: re (bz)
MFC after: 3 weeks
kernel for FreeBSD 9.0:
Add a new capability mask argument to fget(9) and friends, allowing system
call code to declare what capabilities are required when an integer file
descriptor is converted into an in-kernel struct file *. With options
CAPABILITIES compiled into the kernel, this enforces capability
protection; without, this change is effectively a no-op.
Some cases require special handling, such as mmap(2), which must preserve
information about the maximum rights at the time of mapping in the memory
map so that they can later be enforced in mprotect(2) -- this is done by
narrowing the rights in the existing max_protection field used for similar
purposes with file permissions.
In namei(9), we assert that the code is not reached from within capability
mode, as we're not yet ready to enforce namespace capabilities there.
This will follow in a later commit.
Update two capability names: CAP_EVENT and CAP_KEVENT become
CAP_POST_KEVENT and CAP_POLL_KEVENT to more accurately indicate what they
represent.
Approved by: re (bz)
Submitted by: jonathan
Sponsored by: Google Inc
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
constant to indicate that a system call (or perhaps an operation requested
via a system call) is not permitted for a capability mode process.
Submitted by: anderson
Sponsored by: Google, Inc.
Obtained from: Capsicum Project
MFC after: 1 week
PMC/SYSV/...).
No FreeBSD version bump, the userland application to query the features will
be committed last and can serve as an indication of the availablility if
needed.
Sponsored by: Google Summer of Code 2010
Submitted by: kibab
Reviewed by: arch@ (parts by rwatson, trasz, jhb)
X-MFC after: to be determined in last commit with code from this project
code associated with overflow or with the drain function. While this
function is not expected to be used often, it produces more information
in the form of an errno that sbuf_overflowed() did.
kern.ngroups+1. kern.ngroups can range from NGROUPS_MAX=1023 to
INT_MAX-1. Given that the Windows group limit is 1024, this range
should be sufficient for most applications.
MFC after: 1 month
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
contrib/openbsm and a subset also imported into sys/security/audit.
This patch release addresses several minor issues:
- Fixes to AUT_SOCKUNIX token parsing.
- IPv6 support for au_to_me(3).
- Improved robustness in the parsing of audit_control, especially long
flags/naflags strings and whitespace in all fields.
- Add missing conversion of a number of FreeBSD/Mac OS X errnos to/from BSM
error number space.
MFC after: 3 weeks
Obtained from: TrustedBSD Project
Sponsored by: Apple, Inc.
Approved by: re (kib)
system calls:
- Centralize generation of argument tokens for VM addresses in a macro,
ADDR_TOKEN(), and properly encode 64-bit addresses in 64-bit arguments.
- Fix up argument numbers across a large number of syscalls so that they
match the numeric argument into the system call.
- Don't audit the address argument to ioctl(2) or ptrace(2), but do keep
generating tokens for mmap(2), minherit(2), since they relate to passing
object access across execve(2).
Approved by: re (audit argument blanket)
Obtained from: TrustedBSD Project
MFC after: 1 week
rather than as paths, which would lead to them being treated as relative
pathnames and hence confusingly converted into absolute pathnames.
Capture flags to unmount(2) via an argument token.
Approved by: re (audit argument blanket)
MFC after: 3 days
