1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
// +build linux,seccomp
package chroot
import (
"github.com/opencontainers/runtime-spec/specs-go"
"github.com/pkg/errors"
libseccomp "github.com/seccomp/libseccomp-golang"
"github.com/sirupsen/logrus"
)
// setSeccomp sets the seccomp filter for ourselves and any processes that we'll start.
func setSeccomp(spec *specs.Spec) error {
logrus.Debugf("setting seccomp configuration")
if spec.Linux.Seccomp == nil {
return nil
}
mapAction := func(specAction specs.LinuxSeccompAction) libseccomp.ScmpAction {
switch specAction {
case specs.ActKill:
return libseccomp.ActKill
case specs.ActTrap:
return libseccomp.ActTrap
case specs.ActErrno:
return libseccomp.ActErrno
case specs.ActTrace:
return libseccomp.ActTrace
case specs.ActAllow:
return libseccomp.ActAllow
}
return libseccomp.ActInvalid
}
mapArch := func(specArch specs.Arch) libseccomp.ScmpArch {
switch specArch {
case specs.ArchX86:
return libseccomp.ArchX86
case specs.ArchX86_64:
return libseccomp.ArchAMD64
case specs.ArchX32:
return libseccomp.ArchX32
case specs.ArchARM:
return libseccomp.ArchARM
case specs.ArchAARCH64:
return libseccomp.ArchARM64
case specs.ArchMIPS:
return libseccomp.ArchMIPS
case specs.ArchMIPS64:
return libseccomp.ArchMIPS64
case specs.ArchMIPS64N32:
return libseccomp.ArchMIPS64N32
case specs.ArchMIPSEL:
return libseccomp.ArchMIPSEL
case specs.ArchMIPSEL64:
return libseccomp.ArchMIPSEL64
case specs.ArchMIPSEL64N32:
return libseccomp.ArchMIPSEL64N32
case specs.ArchPPC:
return libseccomp.ArchPPC
case specs.ArchPPC64:
return libseccomp.ArchPPC64
case specs.ArchPPC64LE:
return libseccomp.ArchPPC64LE
case specs.ArchS390:
return libseccomp.ArchS390
case specs.ArchS390X:
return libseccomp.ArchS390X
case specs.ArchPARISC:
/* fallthrough */ /* for now */
case specs.ArchPARISC64:
/* fallthrough */ /* for now */
}
return libseccomp.ArchInvalid
}
mapOp := func(op specs.LinuxSeccompOperator) libseccomp.ScmpCompareOp {
switch op {
case specs.OpNotEqual:
return libseccomp.CompareNotEqual
case specs.OpLessThan:
return libseccomp.CompareLess
case specs.OpLessEqual:
return libseccomp.CompareLessOrEqual
case specs.OpEqualTo:
return libseccomp.CompareEqual
case specs.OpGreaterEqual:
return libseccomp.CompareGreaterEqual
case specs.OpGreaterThan:
return libseccomp.CompareGreater
case specs.OpMaskedEqual:
return libseccomp.CompareMaskedEqual
}
return libseccomp.CompareInvalid
}
filter, err := libseccomp.NewFilter(mapAction(spec.Linux.Seccomp.DefaultAction))
if err != nil {
return errors.Wrapf(err, "error creating seccomp filter with default action %q", spec.Linux.Seccomp.DefaultAction)
}
for _, arch := range spec.Linux.Seccomp.Architectures {
if err = filter.AddArch(mapArch(arch)); err != nil {
return errors.Wrapf(err, "error adding architecture %q(%q) to seccomp filter", arch, mapArch(arch))
}
}
for _, rule := range spec.Linux.Seccomp.Syscalls {
scnames := make(map[libseccomp.ScmpSyscall]string)
for _, name := range rule.Names {
scnum, err := libseccomp.GetSyscallFromName(name)
if err != nil {
logrus.Debugf("error mapping syscall %q to a syscall, ignoring %q rule for %q", name, rule.Action)
continue
}
scnames[scnum] = name
}
for scnum := range scnames {
if len(rule.Args) == 0 {
if err = filter.AddRule(scnum, mapAction(rule.Action)); err != nil {
return errors.Wrapf(err, "error adding a rule (%q:%q) to seccomp filter", scnames[scnum], rule.Action)
}
continue
}
var conditions []libseccomp.ScmpCondition
for _, arg := range rule.Args {
condition, err := libseccomp.MakeCondition(arg.Index, mapOp(arg.Op), arg.Value, arg.ValueTwo)
if err != nil {
return errors.Wrapf(err, "error building a seccomp condition %d:%v:%d:%d", arg.Index, arg.Op, arg.Value, arg.ValueTwo)
}
conditions = append(conditions, condition)
}
if err = filter.AddRuleConditional(scnum, mapAction(rule.Action), conditions); err != nil {
return errors.Wrapf(err, "error adding a conditional rule (%q:%q) to seccomp filter", scnames[scnum], rule.Action)
}
}
}
if err = filter.SetNoNewPrivsBit(spec.Process.NoNewPrivileges); err != nil {
return errors.Wrapf(err, "error setting no-new-privileges bit to %v", spec.Process.NoNewPrivileges)
}
err = filter.Load()
filter.Release()
if err != nil {
return errors.Wrapf(err, "error activating seccomp filter")
}
return nil
}
|
