mirror of
https://github.com/criyle/go-sandbox.git
synced 2025-11-04 14:49:53 +08:00
149 lines
3.5 KiB
Go
149 lines
3.5 KiB
Go
package main
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import (
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"fmt"
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"os"
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"syscall"
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tracer "github.com/criyle/go-judger/tracer"
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libseccomp "github.com/seccomp/libseccomp-golang"
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)
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type handler struct {
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fs *fileSets
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sc syscallCounter
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showDetails bool
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}
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func softBanSyscall(ctx *tracer.Context) tracer.TraceAction {
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ctx.SetReturnValue(-int(syscall.EACCES))
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return tracer.TraceBan
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}
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func getFileMode(flags uint) string {
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switch flags & syscall.O_ACCMODE {
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case syscall.O_RDONLY:
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return "r "
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case syscall.O_WRONLY:
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return "w "
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case syscall.O_RDWR:
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return "wr"
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default:
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return "??"
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}
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}
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func (h *handler) print(v ...interface{}) {
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if h.showDetails {
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fmt.Fprintln(os.Stderr, v...)
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}
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}
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func (h *handler) onDgsFileDetect(ctx *tracer.Context, name string) tracer.TraceAction {
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if h.fs.isSoftBanFile(name) {
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return softBanSyscall(ctx)
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}
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h.print("Dangerous fileopen: (killed)", name)
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return tracer.TraceKill
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}
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func (h *handler) checkOpen(ctx *tracer.Context, addr uint, flags uint) tracer.TraceAction {
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fn := ctx.GetString(uintptr(addr))
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isReadOnly := (flags&syscall.O_ACCMODE == syscall.O_RDONLY) &&
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(flags&syscall.O_CREAT == 0) &&
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(flags&syscall.O_EXCL == 0) &&
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(flags&syscall.O_TRUNC == 0)
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h.print("open: ", fn, getFileMode(flags))
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if isReadOnly {
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if realPath(fn) != "" && !h.fs.isReadableFile(fn) {
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return h.onDgsFileDetect(ctx, fn)
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}
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} else {
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if realPath(fn) != "" && !h.fs.isWritableFile(fn) {
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return h.onDgsFileDetect(ctx, fn)
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}
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}
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return tracer.TraceAllow
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}
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func (h *handler) checkRead(ctx *tracer.Context, addr uint) tracer.TraceAction {
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fn := ctx.GetString(uintptr(addr))
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h.print("check read: ", fn)
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if !h.fs.isReadableFile(fn) {
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return h.onDgsFileDetect(ctx, fn)
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}
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return tracer.TraceAllow
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}
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func (h *handler) checkWrite(ctx *tracer.Context, addr uint) tracer.TraceAction {
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fn := ctx.GetString(uintptr(addr))
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h.print("check write: ", fn)
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if !h.fs.isWritableFile(fn) {
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return h.onDgsFileDetect(ctx, fn)
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}
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return tracer.TraceAllow
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}
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func (h *handler) checkStat(ctx *tracer.Context, addr uint) tracer.TraceAction {
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fn := ctx.GetString(uintptr(addr))
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h.print("check stat: ", fn)
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if !h.fs.isStatableFile(fn) {
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return h.onDgsFileDetect(ctx, fn)
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}
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return tracer.TraceAllow
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}
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func (h *handler) Handle(ctx *tracer.Context) tracer.TraceAction {
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syscallNo := ctx.SyscallNo()
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syscallName, err := libseccomp.ScmpSyscall(syscallNo).GetName()
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h.print("syscall: ", syscallNo, syscallName, err)
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switch syscallName {
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case "open":
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return h.checkOpen(ctx, ctx.Arg0(), ctx.Arg1())
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case "openat":
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return h.checkOpen(ctx, ctx.Arg1(), ctx.Arg2())
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case "readlink":
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return h.checkRead(ctx, ctx.Arg0())
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case "readlinkat":
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return h.checkRead(ctx, ctx.Arg1())
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case "unlink":
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return h.checkWrite(ctx, ctx.Arg0())
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case "unlinkat":
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return h.checkWrite(ctx, ctx.Arg1())
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case "access":
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return h.checkStat(ctx, ctx.Arg0())
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case "stat", "stat64":
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return h.checkStat(ctx, ctx.Arg0())
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case "lstat", "lstat64":
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return h.checkStat(ctx, ctx.Arg0())
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case "execve":
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return h.checkRead(ctx, ctx.Arg0())
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case "chmod":
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return h.checkWrite(ctx, ctx.Arg0())
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case "rename":
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return h.checkWrite(ctx, ctx.Arg0())
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default:
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// if it is traced, then try to count syscall
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if inside, allow := h.sc.check(syscallName); !allow {
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return tracer.TraceKill
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} else if !inside {
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// if it is traced but not counted, it should be soft banned
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return softBanSyscall(ctx)
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}
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}
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return tracer.TraceAllow
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}
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func (h *handler) GetSyscallName(ctx *tracer.Context) (string, error) {
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syscallNo := ctx.SyscallNo()
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return libseccomp.ScmpSyscall(syscallNo).GetName()
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}
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