From 87e008d56de974947ebb99c2cc40b25d3c2cf43e Mon Sep 17 00:00:00 2001
From: Ophestra <cat@gensokyo.uk>
Date: Wed, 25 Jun 2025 03:59:52 +0900
Subject: treewide: rename to hakurei

Fortify makes little sense for a container tool.

Signed-off-by: Ophestra <cat@gensokyo.uk>
---
 cmd/fsu/main.go | 146 --------------------------------------------------------
 1 file changed, 146 deletions(-)
 delete mode 100644 cmd/fsu/main.go

(limited to 'cmd/fsu/main.go')

diff --git a/cmd/fsu/main.go b/cmd/fsu/main.go
deleted file mode 100644
index 33ecbf43..00000000
--- a/cmd/fsu/main.go
+++ /dev/null
@@ -1,146 +0,0 @@
-package main
-
-import (
-	"bytes"
-	"fmt"
-	"log"
-	"os"
-	"path"
-	"slices"
-	"strconv"
-	"strings"
-	"syscall"
-)
-
-const (
-	fsuConfFile = "/etc/fsurc"
-	envShim     = "FORTIFY_SHIM"
-	envAID      = "FORTIFY_APP_ID"
-	envGroups   = "FORTIFY_GROUPS"
-
-	PR_SET_NO_NEW_PRIVS = 0x26
-)
-
-func main() {
-	log.SetFlags(0)
-	log.SetPrefix("fsu: ")
-	log.SetOutput(os.Stderr)
-
-	if os.Geteuid() != 0 {
-		log.Fatal("this program must be owned by uid 0 and have the setuid bit set")
-	}
-
-	puid := os.Getuid()
-	if puid == 0 {
-		log.Fatal("this program must not be started by root")
-	}
-
-	var toolPath string
-	pexe := path.Join("/proc", strconv.Itoa(os.Getppid()), "exe")
-	if p, err := os.Readlink(pexe); err != nil {
-		log.Fatalf("cannot read parent executable path: %v", err)
-	} else if strings.HasSuffix(p, " (deleted)") {
-		log.Fatal("fortify executable has been deleted")
-	} else if p != mustCheckPath(fmain) && p != mustCheckPath(fpkg) {
-		log.Fatal("this program must be started by fortify")
-	} else {
-		toolPath = p
-	}
-
-	// uid = 1000000 +
-	//   fid * 10000 +
-	//           aid
-	uid := 1000000
-
-	// refuse to run if fsurc is not protected correctly
-	if s, err := os.Stat(fsuConfFile); err != nil {
-		log.Fatal(err)
-	} else if s.Mode().Perm() != 0400 {
-		log.Fatal("bad fsurc perm")
-	} else if st := s.Sys().(*syscall.Stat_t); st.Uid != 0 || st.Gid != 0 {
-		log.Fatal("fsurc must be owned by uid 0")
-	}
-
-	// authenticate before accepting user input
-	if f, err := os.Open(fsuConfFile); err != nil {
-		log.Fatal(err)
-	} else if fid, ok := mustParseConfig(f, puid); !ok {
-		log.Fatalf("uid %d is not in the fsurc file", puid)
-	} else {
-		uid += fid * 10000
-	}
-
-	// allowed aid range 0 to 9999
-	if as, ok := os.LookupEnv(envAID); !ok {
-		log.Fatal("FORTIFY_APP_ID not set")
-	} else if aid, err := parseUint32Fast(as); err != nil || aid < 0 || aid > 9999 {
-		log.Fatal("invalid aid")
-	} else {
-		uid += aid
-	}
-
-	// pass through setup fd to shim
-	var shimSetupFd string
-	if s, ok := os.LookupEnv(envShim); !ok {
-		// fortify requests target uid
-		// print resolved uid and exit
-		fmt.Print(uid)
-		os.Exit(0)
-	} else if len(s) != 1 || s[0] > '9' || s[0] < '3' {
-		log.Fatal("FORTIFY_SHIM holds an invalid value")
-	} else {
-		shimSetupFd = s
-	}
-
-	// supplementary groups
-	var suppGroups, suppCurrent []int
-
-	if gs, ok := os.LookupEnv(envGroups); ok {
-		if cur, err := os.Getgroups(); err != nil {
-			log.Fatalf("cannot get groups: %v", err)
-		} else {
-			suppCurrent = cur
-		}
-
-		// parse space-separated list of group ids
-		gss := bytes.Split([]byte(gs), []byte{' '})
-		suppGroups = make([]int, len(gss)+1)
-		for i, s := range gss {
-			if gid, err := strconv.Atoi(string(s)); err != nil {
-				log.Fatalf("cannot parse %q: %v", string(s), err)
-			} else if gid > 0 && gid != uid && gid != os.Getgid() && slices.Contains(suppCurrent, gid) {
-				suppGroups[i] = gid
-			} else {
-				log.Fatalf("invalid gid %d", gid)
-			}
-		}
-		suppGroups[len(suppGroups)-1] = uid
-	} else {
-		suppGroups = []int{uid}
-	}
-
-	// final bounds check to catch any bugs
-	if uid < 1000000 || uid >= 2000000 {
-		panic("uid out of bounds")
-	}
-
-	// careful! users in the allowlist is effectively allowed to drop groups via fsu
-
-	if err := syscall.Setresgid(uid, uid, uid); err != nil {
-		log.Fatalf("cannot set gid: %v", err)
-	}
-	if err := syscall.Setgroups(suppGroups); err != nil {
-		log.Fatalf("cannot set supplementary groups: %v", err)
-	}
-	if err := syscall.Setresuid(uid, uid, uid); err != nil {
-		log.Fatalf("cannot set uid: %v", err)
-	}
-	if _, _, errno := syscall.AllThreadsSyscall(syscall.SYS_PRCTL, PR_SET_NO_NEW_PRIVS, 1, 0); errno != 0 {
-		log.Fatalf("cannot set no_new_privs flag: %s", errno.Error())
-	}
-	if err := syscall.Exec(toolPath, []string{"fortify", "shim"}, []string{envShim + "=" + shimSetupFd}); err != nil {
-		log.Fatalf("cannot start shim: %v", err)
-	}
-
-	panic("unreachable")
-}
-- 
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