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|
package seccomp
import (
"fmt"
"strconv"
"strings"
rspec "github.com/opencontainers/runtime-spec/specs-go"
)
// SyscallOpts contain options for parsing syscall rules
type SyscallOpts struct {
Action string
Syscall string
Index string
Value string
ValueTwo string
Operator string
}
// ParseSyscallFlag takes a SyscallOpts struct and the seccomp configuration
// and sets the new syscall rule accordingly
func ParseSyscallFlag(args SyscallOpts, config *rspec.LinuxSeccomp) error {
var arguments []string
if args.Index != "" && args.Value != "" && args.ValueTwo != "" && args.Operator != "" {
arguments = []string{args.Action, args.Syscall, args.Index, args.Value,
args.ValueTwo, args.Operator}
} else {
arguments = []string{args.Action, args.Syscall}
}
action, _ := parseAction(arguments[0])
if action == config.DefaultAction && args.argsAreEmpty() {
// default already set, no need to make changes
return nil
}
var newSyscall rspec.LinuxSyscall
numOfArgs := len(arguments)
if numOfArgs == 6 || numOfArgs == 2 {
argStruct, err := parseArguments(arguments[1:])
if err != nil {
return err
}
newSyscall = newSyscallStruct(arguments[1], action, argStruct)
} else {
return fmt.Errorf("incorrect number of arguments to ParseSyscall: %d", numOfArgs)
}
descison, err := decideCourseOfAction(&newSyscall, config.Syscalls)
if err != nil {
return err
}
delimDescison := strings.Split(descison, ":")
if delimDescison[0] == seccompAppend {
config.Syscalls = append(config.Syscalls, newSyscall)
}
if delimDescison[0] == seccompOverwrite {
indexForOverwrite, err := strconv.ParseInt(delimDescison[1], 10, 32)
if err != nil {
return err
}
config.Syscalls[indexForOverwrite] = newSyscall
}
return nil
}
var actions = map[string]rspec.LinuxSeccompAction{
"allow": rspec.ActAllow,
"errno": rspec.ActErrno,
"kill": rspec.ActKill,
"trace": rspec.ActTrace,
"trap": rspec.ActTrap,
}
// Take passed action, return the SCMP_ACT_<ACTION> version of it
func parseAction(action string) (rspec.LinuxSeccompAction, error) {
a, ok := actions[action]
if !ok {
return "", fmt.Errorf("unrecognized action: %s", action)
}
return a, nil
}
// ParseDefaultAction sets the default action of the seccomp configuration
// and then removes any rules that were already specified with this action
func ParseDefaultAction(action string, config *rspec.LinuxSeccomp) error {
if action == "" {
return nil
}
defaultAction, err := parseAction(action)
if err != nil {
return err
}
config.DefaultAction = defaultAction
err = RemoveAllMatchingRules(config, defaultAction)
if err != nil {
return err
}
return nil
}
// ParseDefaultActionForce simply sets the default action of the seccomp configuration
func ParseDefaultActionForce(action string, config *rspec.LinuxSeccomp) error {
if action == "" {
return nil
}
defaultAction, err := parseAction(action)
if err != nil {
return err
}
config.DefaultAction = defaultAction
return nil
}
func newSyscallStruct(name string, action rspec.LinuxSeccompAction, args []rspec.LinuxSeccompArg) rspec.LinuxSyscall {
syscallStruct := rspec.LinuxSyscall{
Names: []string{name},
Action: action,
Args: args,
}
return syscallStruct
}
func (s SyscallOpts) argsAreEmpty() bool {
return (s.Index == "" &&
s.Value == "" &&
s.ValueTwo == "" &&
s.Operator == "")
}
|
