feat: procfs增加TrustedExe方法

procfs/procfs.go

@@ -5,13 +5,16 @@
 package procfs
 
 import (
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
-	"github.com/linuxdeepin/go-lib/encoding/kv"
 	"strconv"
 	"strings"
+	"sync"
+
+	"github.com/linuxdeepin/go-lib/encoding/kv"
 )
 
 type Process uint
@@ -53,6 +56,20 @@ func (p Process) Exe() (string, error) {
 	return exe, err
 }
 
+func (p Process) TrustedExe() (string, error) {
+	exeFile := p.getFile("exe")
+	exe, err := filepath.EvalSymlinks(exeFile)
+	if err != nil {
+		return "", err
+	}
+	if os.Getuid() == 0 {
+		if !checkSenderNsMntValid(uint32(p)) {
+			return "", errors.New("due to the difference between the current process's ns mnt and the init process's ns mnt, the exe field is not reliable")
+		}
+	}
+	return exe, nil
+}
+
 type EnvVars []string
 
 func (p Process) Environ() (EnvVars, error) {
@@ -145,3 +162,27 @@ func (st Status) PPid() (uint, error) {
 	}
 	return uint(v), nil
 }
+
+var _initProcNsMnt string
+var _once sync.Once
+
+// 通过判断/proc/pid/ns/mnt 和 /proc/1/ns/mnt是否相同，如果不相同，则进程exe字段不可信
+func checkSenderNsMntValid(pid uint32) bool {
+	_once.Do(func() {
+		out, err := os.Readlink("/proc/1/ns/mnt")
+		if err != nil {
+			fmt.Println(err)
+			return
+		}
+		_initProcNsMnt = strings.TrimSpace(out)
+	})
+	c, err := os.Readlink(fmt.Sprintf("/proc/%v/ns/mnt", pid))
+	if err != nil {
+		fmt.Println(err)
+		return false
+	}
+	defer func() {
+		fmt.Printf("pid 1 mnt ns is %v,pid %v mnt ns is %v\n", _initProcNsMnt, pid, strings.TrimSpace(c))
+	}()
+	return strings.TrimSpace(c) == _initProcNsMnt
+}

users/passwd/passwd.go

@@ -10,9 +10,12 @@ import "C"
 
 import (
 	"fmt"
+	"sync"
 	"unsafe"
 )
 
+var mutex sync.Mutex
+
 // Passwd wraps up `passwd` struct used in kernel
 type Passwd struct {
 	Name    string
@@ -53,6 +56,8 @@ func (err *UserNotFoundError) Error() string {
 // GetPasswdByName wraps up `getpwnam` system call.
 // It retrieves records from the password file based on username.
 func GetPasswdByName(name string) (*Passwd, error) {
+	mutex.Lock()
+	defer mutex.Unlock()
 	nameC := C.CString(name)
 	defer C.free(unsafe.Pointer(nameC))
 	passwdC, err := C.getpwnam(nameC)
@@ -70,6 +75,8 @@ func GetPasswdByName(name string) (*Passwd, error) {
 // GetPasswdByUid wraps up `getpwuid` system call.
 // It retrieves records from the password file based on uid.
 func GetPasswdByUid(uid uint32) (*Passwd, error) {
+	mutex.Lock()
+	defer mutex.Unlock()
 	uidC := C.__uid_t(uid)
 	passwdC, err := C.getpwuid(uidC)
 	if passwdC == nil {
@@ -86,6 +93,8 @@ func GetPasswdByUid(uid uint32) (*Passwd, error) {
 // GetPasswdEntry wraps up `getpwent` system call
 // It performs sequential scans of the records in the password file.
 func GetPasswdEntry() []*Passwd {
+	mutex.Lock()
+	defer mutex.Unlock()
 	var passwds []*Passwd
 
 	// Restart scanning from the begging of the password file.