diff --git a/hkexshd/hkexshd.go b/hkexshd/hkexshd.go index 5776001..05aa355 100755 --- a/hkexshd/hkexshd.go +++ b/hkexshd/hkexshd.go @@ -35,9 +35,11 @@ import ( ) var ( - version string - gitCommit string // set in -ldflags by build - + version string + gitCommit string // set in -ldflags by build + + useSysLogin bool + // Log - syslog output (with no -d) Log *logger.Writer ) @@ -276,8 +278,18 @@ func runShellAs(who, hname, ttype, cmd string, interactive bool, conn *hkexnet.C var c *exec.Cmd if interactive { - //c = exec.Command("/bin/login", "-f", "-p", who) // nolint: gosec - c = exec.Command("/bin/bash", "-i", "-l") // nolint: gosec + if useSysLogin { + // Use the server's login binary (post-auth + // which is still done via our own bcrypt file) + // Things UNIX login does, like print the 'motd', + // and use the shell specified by /etc/passwd, will be done + // automagically, at the cost of another external tool + // dependency. + // + c = exec.Command("/bin/login", "-f", "-p", who) // nolint: gosec + } else { + c = exec.Command("/bin/bash", "-i", "-l") // nolint: gosec + } } else { c = exec.Command("/bin/bash", "-c", cmd) // nolint: gosec } @@ -286,8 +298,13 @@ func runShellAs(who, hname, ttype, cmd string, interactive bool, conn *hkexnet.C //c.Env = []string{"HOME=" + u.HomeDir, "SUDO_GID=", "SUDO_UID=", "SUDO_USER=", "SUDO_COMMAND=", "MAIL=", "LOGNAME="+who} c.Dir = u.HomeDir c.SysProcAttr = &syscall.SysProcAttr{} - //c.SysProcAttr.Credential = &syscall.Credential{} - c.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid} + if useSysLogin { + // If using server's login binary, drop to user creds + // is taken care of by it. + c.SysProcAttr.Credential = &syscall.Credential{} + } else { + c.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid} + } c.Stdin = conn c.Stdout = conn c.Stderr = conn @@ -426,6 +443,7 @@ func main() { flag.BoolVar(&vopt, "v", false, "show version") flag.StringVar(&laddr, "l", ":2000", "interface[:port] to listen") + flag.BoolVar(&useSysLogin, "L", false, "use system login") flag.BoolVar(&chaffEnabled, "e", true, "enable chaff pkts") flag.UintVar(&chaffFreqMin, "f", 100, "chaff pkt freq min (msecs)") flag.UintVar(&chaffFreqMax, "F", 5000, "chaff pkt freq max (msecs)")