From dcd532e2e416aa81ca9ac42dc153731855f91418 Mon Sep 17 00:00:00 2001 From: Ian Lewis Date: Tue, 15 Sep 2020 23:17:36 -0700 Subject: Add support for OCI seccomp filters in the sandbox. OCI configuration includes support for specifying seccomp filters. In runc, these filter configurations are converted into seccomp BPF programs and loaded into the kernel via libseccomp. runsc needs to be a static binary so, for runsc, we cannot rely on a C library and need to implement the functionality in Go. The generator added here implements basic support for taking OCI seccomp configuration and converting it into a seccomp BPF program with the same behavior as a program generated by libseccomp. - New conditional operations were added to pkg/seccomp to support operations available in OCI. - AllowAny and AllowValue were renamed to MatchAny and EqualTo to better reflect that syscalls matching the conditionals result in the provided action not simply SCMP_RET_ALLOW. - BuildProgram in pkg/seccomp no longer panics if provided an empty list of rules. It now builds a program with the architecture sanity check only. - ProgramBuilder now allows adding labels that are unused. However, backwards jumps are still not permitted. Fixes #510 PiperOrigin-RevId: 331938697 --- pkg/bpf/decoder.go | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'pkg/bpf/decoder.go') diff --git a/pkg/bpf/decoder.go b/pkg/bpf/decoder.go index c8ee0c3b1..069d0395d 100644 --- a/pkg/bpf/decoder.go +++ b/pkg/bpf/decoder.go @@ -21,10 +21,15 @@ import ( "gvisor.dev/gvisor/pkg/abi/linux" ) -// DecodeProgram translates an array of BPF instructions into text format. -func DecodeProgram(program []linux.BPFInstruction) (string, error) { +// DecodeProgram translates a compiled BPF program into text format. +func DecodeProgram(p Program) (string, error) { + return DecodeInstructions(p.instructions) +} + +// DecodeInstructions translates an array of BPF instructions into text format. +func DecodeInstructions(instns []linux.BPFInstruction) (string, error) { var ret bytes.Buffer - for line, s := range program { + for line, s := range instns { ret.WriteString(fmt.Sprintf("%v: ", line)) if err := decode(s, line, &ret); err != nil { return "", err @@ -34,7 +39,7 @@ func DecodeProgram(program []linux.BPFInstruction) (string, error) { return ret.String(), nil } -// Decode translates BPF instruction into text format. +// Decode translates a single BPF instruction into text format. func Decode(inst linux.BPFInstruction) (string, error) { var ret bytes.Buffer err := decode(inst, -1, &ret) -- cgit v1.2.3