tetragon
1// SPDX-License-Identifier: Apache-2.02// Copyright Authors of Tetragon3)21)27// GetLastCap() Returns unix.CAP_LAST_CAP unless the kernel29// defines another last cap which is the case for old kernels.30func GetLastCap() int32 {31lastCapOnce.Do(func() {32d, err := os.ReadFile(filepath.Join(option.Config.ProcFS, "/sys/kernel/cap_last_cap"))33if err != nil {34logger.GetLogger().WithError(err).Warnf("Could not read kernel cap_last_cap, using default '%d' as cap_last_cap", cap_last_cap)35}36val, err := strconv.ParseInt(strings.TrimRight(string(d), "\n"), 10, 32)37if err != nil {38logger.GetLogger().WithError(err).Warnf("Could not parse cap_last_cap, using default '%d' as cap_last_cap", cap_last_cap)39return40}41// just silence some CodeQL42if val >= 0 && val < unix.CAP_LAST_CAP {43cap_last_cap = int32(val)44}45})46return cap_last_cap47}48}56// AreSubset() Checks if "a" is a subset of "set"58// Rerturns true if all "a" capabilities are also in "set", otherwise59// false.60func AreSubset(a uint64, set uint64) bool {61return (!((a & ^uint64(set)) != 0))62}63// capToMask() returns the mask of the corresponding u3265func capToMask(cap int32) uint32 {66return uint32(1 << ((cap) & 31))67}68// GetCapsFullSet() Returns up to date (go unix library) full set.70func GetCapsFullSet() uint64 {71// Get last u32 bits72caps := uint64(capToMask(GetLastCap()+1)-1) << 3273// Get first u32 bits74caps |= uint64(^uint32(0))75}78}91}101}105/* uapi/linux/capability.h */107var capabilitiesString = map[uint64]string{108/* In a system with the [_POSIX_CHOWN_RESTRICTED] option defined, this109overrides the restriction of changing file ownership and group110ownership. */1110: "CAP_CHOWN",112/* Override all DAC access, including ACL execute access if113[_POSIX_ACL] is defined. Excluding DAC access covered by114CAP_LINUX_IMMUTABLE. */115and directories, including ACL restrictions if [_POSIX_ACL] is120defined. Excluding DAC access covered by "$1"_LINUX_IMMUTABLE. */1212: "CAP_DAC_READ_SEARCH",122file owner ID must be equal to the user ID, except where CAP_FSETID125is applicable. It doesn't override MAC and DAC restrictions. */126shall match the file owner ID when setting the S_ISUID and S_ISGID131bits on that file; that the effective group ID (or one of the132supplementary group IDs) shall match the file owner ID when setting133the S_ISGID bit on that file; that the S_ISUID and S_ISGID bits are134cleared on successful return from chown(2) (not implemented). */135process sending a signal must match the real or effective user ID140of the process receiving the signal. */141** Linux-specific capabilities157**/158* Transfer any capability in your permitted set to any pid,161* remove any capability in your permitted set from any pid162* With VFS support for capabilities (neither of above, but)163* Add any capability from current's capability bounding set164* to the current process' inheritable set165* Allow taking bits out of capability bounding set166* Allow modification of the securebits for a process167*/168sockets */190/* Allow binding to any address for transparent proxying (also via NET_RAW) */191/* Allow setting TOS (type of service) */192/* Allow setting promiscuous mode */193/* Allow clearing driver statistics */194/* Allow multicasting */195/* Allow read/write of device-specific registers */196/* Allow activation of ATM control sockets */197with IPC) */209and shared memory */251/* Allow locking/unlocking of shared memory segment */252/* Allow turning swap on/off */253/* Allow forged pids on socket credentials passing */254/* Allow setting readahead and flushing buffers on block devices */255/* Allow setting geometry in floppy driver */256/* Allow turning DMA on/off in xd driver */257/* Allow administration of md devices (mostly the above, but some258extra ioctls) */259/* Allow tuning the ide driver */260/* Allow access to the nvram device */261/* Allow administration of apm_bios, serial and bttv (TV) device */262/* Allow manufacturer commands in isdn CAPI support driver */263/* Allow reading non-standardized portions of pci configuration space */264/* Allow DDI debug ioctl on sbpcd driver */265/* Allow setting up serial ports */266/* Allow sending raw qic-117 commands */267/* Allow enabling/disabling tagged queuing on SCSI controllers and sending268arbitrary SCSI commands */269/* Allow setting encryption key on loopback filesystem */270/* Allow setting zone reclaim policy */271/* Allow everything under CAP_BPF and CAP_PERFMON for backward compatibility */272UID) processes */281/* Allow use of FIFO and round-robin (realtime) scheduling on own282processes and setting the scheduling algorithm used by another283process. */284/* Allow setting cpu affinity on other processes */285resources) */293/* NOTE: ext2 honors fsuid when checking for resource overrides, so294you can override using fsuid too */295/* Override size restrictions on IPC message queues */296/* Allow more than 64hz interrupts from the real-time clock */297/* Override max number of consoles on console allocation */298/* Override max number of keymaps */299/* Control memory reclaim behavior */300The base kernel enforces no MAC policy.336An LSM may enforce a MAC policy, and if it does and it chooses337to implement capability based overrides of that policy, this is338the capability it should use to do so. */339The base kernel requires no MAC configuration.344An LSM may enforce a MAC policy, and if it does and it chooses345to implement capability based checks on modifications to that346policy or the data required to maintain it, this is the347capability it should use to do so. */348* Allow system performance and observability privileged operations369* using perf_events, i915_perf and other kernel subsystems370*/371* CAP_BPF allows the following BPF operations:376* - Creating all types of BPF maps377* - Advanced verifier features378* - Indirect variable access379* - Bounded loops380* - BPF to BPF function calls381* - Scalar precision tracking382* - Larger complexity limits383* - Dead code elimination384* - And potentially other features385* - Loading BPF Type Format (BTF) data386* - Retrieve xlated and JITed code of BPF programs387* - Use bpf_spin_lock() helper388*389* CAP_PERFMON relaxes the verifier checks further:390* - BPF progs can use of pointer-to-integer conversions391* - speculation attack hardening measures are bypassed392* - bpf_probe_read to read arbitrary kernel memory is allowed393* - bpf_trace_printk to print kernel memory is allowed394*395* CAP_SYS_ADMIN is required to use bpf_probe_write_user.396*397* CAP_SYS_ADMIN is required to iterate system wide loaded398* programs, maps, links, BTFs and convert their IDs to file descriptors.399*400* CAP_PERFMON and CAP_BPF are required to load tracing programs.401* CAP_NET_ADMIN and CAP_BPF are required to load networking programs.402*/40339: "CAP_BPF",404}411}464}475}483}495}537}563