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authorSebastian Lackner2019-01-13 18:12:00 +0100
committerrfjakob2019-01-14 21:27:28 +0100
commitd7be76685128cb2cdca01becd856ea57cc18ef34 (patch)
tree4e31b55e780bf528ce1b688b27396a19744969c4 /internal/syscallcompat
parente885f087462338b4d65f0c12a004f57dc513b839 (diff)
syscallcompat: Use pthread_setugid_np() to implement *User() functions on macOS.
Fixes -allow_other mode on macOS.
Diffstat (limited to 'internal/syscallcompat')
-rw-r--r--internal/syscallcompat/sys_darwin.go71
1 files changed, 56 insertions, 15 deletions
diff --git a/internal/syscallcompat/sys_darwin.go b/internal/syscallcompat/sys_darwin.go
index 5c855d8..a260db6 100644
--- a/internal/syscallcompat/sys_darwin.go
+++ b/internal/syscallcompat/sys_darwin.go
@@ -2,6 +2,7 @@ package syscallcompat
import (
"log"
+ "runtime"
"syscall"
"golang.org/x/sys/unix"
@@ -16,8 +17,22 @@ const (
// O_PATH is only defined on Linux
O_PATH = 0
+
+ // KAUTH_UID_NONE and KAUTH_GID_NONE are special values to
+ // revert permissions to the process credentials.
+ KAUTH_UID_NONE = ^uint32(0) - 100
+ KAUTH_GID_NONE = ^uint32(0) - 100
)
+// Unfortunately pthread_setugid_np does not have a syscall wrapper yet.
+func pthread_setugid_np(uid uint32, gid uint32) (err error) {
+ _, _, e1 := syscall.RawSyscall(syscall.SYS_SETTID, uintptr(uid), uintptr(gid), 0)
+ if e1 != 0 {
+ err = e1
+ }
+ return
+}
+
// Sorry, fallocate is not available on OSX at all and
// fcntl F_PREALLOCATE is not accessible from Go.
// See https://github.com/rfjakob/gocryptfs/issues/18 if you want to help.
@@ -47,9 +62,16 @@ func Openat(dirfd int, path string, flags int, mode uint32) (fd int, err error)
}
func OpenatUser(dirfd int, path string, flags int, mode uint32, context *fuse.Context) (fd int, err error) {
- // FIXME: take into account context.Owner
- // Until we have that, filter SUID and SGID bits:
- mode = filterSuidSgid(mode)
+ if context != nil {
+ runtime.LockOSThread()
+ defer runtime.UnlockOSThread()
+
+ err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
+ if err != nil {
+ return -1, err
+ }
+ defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
+ }
return Openat(dirfd, path, flags, mode)
}
@@ -67,9 +89,16 @@ func Mknodat(dirfd int, path string, mode uint32, dev int) (err error) {
}
func MknodatUser(dirfd int, path string, mode uint32, dev int, context *fuse.Context) (err error) {
- // FIXME: take into account context.Owner
- // Until we have that, filter SUID and SGID bits:
- mode = filterSuidSgid(mode)
+ if context != nil {
+ runtime.LockOSThread()
+ defer runtime.UnlockOSThread()
+
+ err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
+ if err != nil {
+ return err
+ }
+ defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
+ }
return Mknodat(dirfd, path, mode, dev)
}
@@ -87,7 +116,17 @@ func Symlinkat(oldpath string, newdirfd int, newpath string) (err error) {
}
func SymlinkatUser(oldpath string, newdirfd int, newpath string, context *fuse.Context) (err error) {
- // FIXME: take into account context.Owner
+ if context != nil {
+ runtime.LockOSThread()
+ defer runtime.UnlockOSThread()
+
+ err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
+ if err != nil {
+ return err
+ }
+ defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
+ }
+
return Symlinkat(oldpath, newdirfd, newpath)
}
@@ -96,9 +135,16 @@ func Mkdirat(dirfd int, path string, mode uint32) (err error) {
}
func MkdiratUser(dirfd int, path string, mode uint32, context *fuse.Context) (err error) {
- // FIXME: take into account context.Owner
- // Until we have that, filter SUID and SGID bits:
- mode = filterSuidSgid(mode)
+ if context != nil {
+ runtime.LockOSThread()
+ defer runtime.UnlockOSThread()
+
+ err = pthread_setugid_np(context.Owner.Uid, context.Owner.Gid)
+ if err != nil {
+ return err
+ }
+ defer pthread_setugid_np(KAUTH_UID_NONE, KAUTH_GID_NONE)
+ }
return Mkdirat(dirfd, path, mode)
}
@@ -110,8 +156,3 @@ func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
func Getdents(fd int) ([]fuse.DirEntry, error) {
return emulateGetdents(fd)
}
-
-// filterSuidSgid removes SUID and SGID bits from "mode".
-func filterSuidSgid(mode uint32) uint32 {
- return mode & ^uint32(syscall.S_ISGID|syscall.S_ISUID)
-}