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
tcpdump will print an error message saying rfmon is not supported.
Give a concise explanation as to how one might solve this problem by
creating a monitor mode VAP.
For now, sandboxing is done only if -n option was specified and neither -z nor
-V options were given. Because it is very common to run tcpdump(8) with the -n
option for speed, I decided to commit sandboxing now. To also support
sandboxing when -n option wasn't specified, we need Casper daemon and its
services that are not available in FreeBSD yet.
- Limit file descriptors of a file specified by -r option or files specified
via -V option to CAP_READ only.
- If neither -r nor -V options were specified, we operate on /dev/bpf.
Limit its descriptor to CAP_READ and CAP_IOCTL plus limit allowed ioctls to
BIOCGSTATS only.
- Limit file descriptor of a file specified by -w option to CAP_SEEK and
CAP_WRITE.
- If either -C or -G options were specified, we open directory containing
destination file and we limit directory descriptor to CAP_CREATE, CAP_FCNTL,
CAP_FTRUNCATE, CAP_LOOKUP, CAP_SEEK and CAP_WRITE. Newly opened/created
files are limited to CAP_SEEK and CAP_WRITE only.
- Enter capability mode if -n option was specified and neither -z nor -V
options were specified.
Approved by: delphij, wxs
Sponsored by: The FreeBSD Foundation
share/mk/sys.mk instead.
This is part of a medium term project to permit deterministic builds of
FreeBSD.
Submitted by: Erik Cederstrand <erik@cederstrand.dk>
Reviewed by: imp, toolchain@
Approved by: cperciva
MFC after: 2 weeks
doesn't mean supporting IFT_PFSYNC (which I hope will eventually
die). This means decoding packets with IP protocol of 240 caught
on any normal interface like Ethernet.
The code is based on couple of files from OpenBSD, significantly
modified by myself.
Parser differentiates for four levels of verbosity: no -v, -v,
-vv and -vvv.
We don't yet forward this code upstream, because currently it
strongly relies on if_pfsync.h and even on pfvar.h. I hope that
this can be fixed in future.
Reviewed by: gnn, delphij
against icmp6_hdr::icmp6_type is done incorrectly. (This fix has
already been applied upstream, but we do not have the latest version of
tcpdump.)
MFC after: 1 week
o add missing Status and Reason codes
o parse/display Action frames
o parse/display Mesh data frames
o parse/display BA frames
Reviewed by: rpaulo
Approved by: re (kib)
o print-fr.c returned to code on vendor branch
o remove pmap_prot.h include from print-sunrprc.c
o remove gcc/i386-specific ntoh* write-arounds from tcpdump-stdinc.h
Reviewed by: bms
