userns: Convert stat to return values mapped from kuids and kgids

- Store uids and gids with kuid_t and kgid_t in struct kstat
- Convert uid and gids to userspace usable values with
  from_kuid and from_kgid

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

arch/arm/kernel/sys_oabi-compat.c

@@ -124,8 +124,8 @@ static long cp_oldabi_stat64(struct kstat *stat,
 	tmp.__st_ino = stat->ino;
 	tmp.st_mode = stat->mode;
 	tmp.st_nlink = stat->nlink;
-	tmp.st_uid = stat->uid;
-	tmp.st_gid = stat->gid;
+	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
+	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 	tmp.st_rdev = huge_encode_dev(stat->rdev);
 	tmp.st_size = stat->size;
 	tmp.st_blocks = stat->blocks;

arch/parisc/hpux/fs.c

@@ -159,8 +159,8 @@ static int cp_hpux_stat(struct kstat *stat, struct hpux_stat64 __user *statbuf)
 	tmp.st_ino = stat->ino;
 	tmp.st_mode = stat->mode;
 	tmp.st_nlink = stat->nlink;
-	tmp.st_uid = stat->uid;
-	tmp.st_gid = stat->gid;
+	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
+	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 	tmp.st_rdev = new_encode_dev(stat->rdev);
 	tmp.st_size = stat->size;
 	tmp.st_atime = stat->atime.tv_sec;

arch/s390/kernel/compat_linux.c

@@ -547,8 +547,8 @@ static int cp_stat64(struct stat64_emu31 __user *ubuf, struct kstat *stat)
 	tmp.__st_ino = (u32)stat->ino;
 	tmp.st_mode = stat->mode;
 	tmp.st_nlink = (unsigned int)stat->nlink;
-	tmp.st_uid = stat->uid;
-	tmp.st_gid = stat->gid;
+	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
+	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 	tmp.st_rdev = huge_encode_dev(stat->rdev);
 	tmp.st_size = stat->size;
 	tmp.st_blksize = (u32)stat->blksize;

arch/sparc/kernel/sys_sparc32.c

@@ -139,8 +139,8 @@ static int cp_compat_stat64(struct kstat *stat,
 	err |= put_user(stat->ino, &statbuf->st_ino);
 	err |= put_user(stat->mode, &statbuf->st_mode);
 	err |= put_user(stat->nlink, &statbuf->st_nlink);
-	err |= put_user(stat->uid, &statbuf->st_uid);
-	err |= put_user(stat->gid, &statbuf->st_gid);
+	err |= put_user(from_kuid_munged(current_user_ns(), stat->uid), &statbuf->st_uid);
+	err |= put_user(from_kgid_munged(current_user_ns(), stat->gid), &statbuf->st_gid);
 	err |= put_user(huge_encode_dev(stat->rdev), &statbuf->st_rdev);
 	err |= put_user(0, (unsigned long __user *) &statbuf->__pad3[0]);
 	err |= put_user(stat->size, &statbuf->st_size);

arch/x86/ia32/sys_ia32.c

@@ -71,8 +71,8 @@ static int cp_stat64(struct stat64 __user *ubuf, struct kstat *stat)
 {
 	typeof(ubuf->st_uid) uid = 0;
 	typeof(ubuf->st_gid) gid = 0;
-	SET_UID(uid, stat->uid);
-	SET_GID(gid, stat->gid);
+	SET_UID(uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(gid, from_kgid_munged(current_user_ns(), stat->gid));
 	if (!access_ok(VERIFY_WRITE, ubuf, sizeof(struct stat64)) ||
 	    __put_user(huge_encode_dev(stat->dev), &ubuf->st_dev) ||
 	    __put_user(stat->ino, &ubuf->__st_ino) ||

fs/compat.c

@@ -144,8 +144,8 @@ static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
 	tmp.st_nlink = stat->nlink;
 	if (tmp.st_nlink != stat->nlink)
 		return -EOVERFLOW;
-	SET_UID(tmp.st_uid, stat->uid);
-	SET_GID(tmp.st_gid, stat->gid);
+	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 	tmp.st_rdev = old_encode_dev(stat->rdev);
 	if ((u64) stat->size > MAX_NON_LFS)
 		return -EOVERFLOW;

fs/stat.c

@@ -137,8 +137,8 @@ static int cp_old_stat(struct kstat *stat, struct __old_kernel_stat __user * sta
 	tmp.st_nlink = stat->nlink;
 	if (tmp.st_nlink != stat->nlink)
 		return -EOVERFLOW;
-	SET_UID(tmp.st_uid, stat->uid);
-	SET_GID(tmp.st_gid, stat->gid);
+	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 	tmp.st_rdev = old_encode_dev(stat->rdev);
 #if BITS_PER_LONG == 32
 	if (stat->size > MAX_NON_LFS)
@@ -215,8 +215,8 @@ static int cp_new_stat(struct kstat *stat, struct stat __user *statbuf)
 	tmp.st_nlink = stat->nlink;
 	if (tmp.st_nlink != stat->nlink)
 		return -EOVERFLOW;
-	SET_UID(tmp.st_uid, stat->uid);
-	SET_GID(tmp.st_gid, stat->gid);
+	SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
+	SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
 #if BITS_PER_LONG == 32
 	tmp.st_rdev = old_encode_dev(stat->rdev);
 #else
@@ -350,8 +350,8 @@ static long cp_new_stat64(struct kstat *stat, struct stat64 __user *statbuf)
 #endif
 	tmp.st_mode = stat->mode;
 	tmp.st_nlink = stat->nlink;
-	tmp.st_uid = stat->uid;
-	tmp.st_gid = stat->gid;
+	tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid);
+	tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid);
 	tmp.st_atime = stat->atime.tv_sec;
 	tmp.st_atime_nsec = stat->atime.tv_nsec;
 	tmp.st_mtime = stat->mtime.tv_sec;

include/linux/stat.h

@@ -58,14 +58,15 @@
 
 #include <linux/types.h>
 #include <linux/time.h>
+#include <linux/uidgid.h>
 
 struct kstat {
 	u64		ino;
 	dev_t		dev;
 	umode_t		mode;
 	unsigned int	nlink;
-	uid_t		uid;
-	gid_t		gid;
+	kuid_t		uid;
+	kgid_t		gid;
 	dev_t		rdev;
 	loff_t		size;
 	struct timespec  atime;