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// Copyright 2018 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package linux
import "fmt"
// Seccomp constants taken from <linux/seccomp.h>.
const (
SECCOMP_MODE_NONE = 0
SECCOMP_MODE_FILTER = 2
SECCOMP_RET_ACTION_FULL = 0xffff0000
SECCOMP_RET_ACTION = 0x7fff0000
SECCOMP_RET_DATA = 0x0000ffff
SECCOMP_SET_MODE_FILTER = 1
SECCOMP_FILTER_FLAG_TSYNC = 1
SECCOMP_GET_ACTION_AVAIL = 2
)
// BPFAction is an action for a BPF filter.
type BPFAction uint32
// BPFAction definitions.
const (
SECCOMP_RET_KILL_PROCESS BPFAction = 0x80000000
SECCOMP_RET_KILL_THREAD BPFAction = 0x00000000
SECCOMP_RET_TRAP BPFAction = 0x00030000
SECCOMP_RET_ERRNO BPFAction = 0x00050000
SECCOMP_RET_TRACE BPFAction = 0x7ff00000
SECCOMP_RET_ALLOW BPFAction = 0x7fff0000
)
func (a BPFAction) String() string {
switch a & SECCOMP_RET_ACTION_FULL {
case SECCOMP_RET_KILL_PROCESS:
return "kill process"
case SECCOMP_RET_KILL_THREAD:
return "kill thread"
case SECCOMP_RET_TRAP:
return fmt.Sprintf("trap (%d)", a.Data())
case SECCOMP_RET_ERRNO:
return fmt.Sprintf("errno (%d)", a.Data())
case SECCOMP_RET_TRACE:
return fmt.Sprintf("trace (%d)", a.Data())
case SECCOMP_RET_ALLOW:
return "allow"
}
return fmt.Sprintf("invalid action: %#x", a)
}
// Data returns the SECCOMP_RET_DATA portion of the action.
func (a BPFAction) Data() uint16 {
return uint16(a & SECCOMP_RET_DATA)
}
// WithReturnCode sets the lower 16 bits of the SECCOMP_RET_ERRNO or
// SECCOMP_RET_TRACE actions to the provided return code, overwriting the previous
// action, and returns a new BPFAction. If not SECCOMP_RET_ERRNO or
// SECCOMP_RET_TRACE then this panics.
func (a BPFAction) WithReturnCode(code uint16) BPFAction {
// mask out the previous return value
baseAction := a & SECCOMP_RET_ACTION_FULL
if baseAction == SECCOMP_RET_ERRNO || baseAction == SECCOMP_RET_TRACE {
return BPFAction(uint32(baseAction) | uint32(code))
}
panic("WithReturnCode only valid for SECCOMP_RET_ERRNO and SECCOMP_RET_TRACE")
}
// SockFprog is sock_fprog taken from <linux/filter.h>.
type SockFprog struct {
Len uint16
pad [6]byte
Filter *BPFInstruction
}
// SeccompData is equivalent to struct seccomp_data, which contains the data
// passed to seccomp-bpf filters.
//
// +marshal
type SeccompData struct {
// Nr is the system call number.
Nr int32
// Arch is an AUDIT_ARCH_* value indicating the system call convention.
Arch uint32
// InstructionPointer is the value of the instruction pointer at the time
// of the system call.
InstructionPointer uint64
// Args contains the first 6 system call arguments.
Args [6]uint64
}
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