1 files changed, 53 insertions, 33 deletions

diff --git a/fs/inode.c b/fs/inode.c
index 6598ea2bb097..a047ab306f9a 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1494,7 +1494,7 @@ struct inode *find_inode_rcu(struct super_block *sb, unsigned long hashval,
 EXPORT_SYMBOL(find_inode_rcu);
 
 /**
- * find_inode_by_rcu - Find an inode in the inode cache
+ * find_inode_by_ino_rcu - Find an inode in the inode cache
  * @sb:		Super block of file system to search
  * @ino:	The inode number to match
  *
@@ -1744,24 +1744,26 @@ static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
 
 int generic_update_time(struct inode *inode, struct timespec64 *time, int flags)
 {
-	int iflags = I_DIRTY_TIME;
-	bool dirty = false;
-
-	if (flags & S_ATIME)
-		inode->i_atime = *time;
-	if (flags & S_VERSION)
-		dirty = inode_maybe_inc_iversion(inode, false);
-	if (flags & S_CTIME)
-		inode->i_ctime = *time;
-	if (flags & S_MTIME)
-		inode->i_mtime = *time;
-	if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
-	    !(inode->i_sb->s_flags & SB_LAZYTIME))
-		dirty = true;
-
-	if (dirty)
-		iflags |= I_DIRTY_SYNC;
-	__mark_inode_dirty(inode, iflags);
+	int dirty_flags = 0;
+
+	if (flags & (S_ATIME | S_CTIME | S_MTIME)) {
+		if (flags & S_ATIME)
+			inode->i_atime = *time;
+		if (flags & S_CTIME)
+			inode->i_ctime = *time;
+		if (flags & S_MTIME)
+			inode->i_mtime = *time;
+
+		if (inode->i_sb->s_flags & SB_LAZYTIME)
+			dirty_flags |= I_DIRTY_TIME;
+		else
+			dirty_flags |= I_DIRTY_SYNC;
+	}
+
+	if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false))
+		dirty_flags |= I_DIRTY_SYNC;
+
+	__mark_inode_dirty(inode, dirty_flags);
 	return 0;
 }
 EXPORT_SYMBOL(generic_update_time);
@@ -1778,7 +1780,7 @@ static int update_time(struct inode *inode, struct timespec64 *time, int flags)
 }
 
 /**
- *	touch_atime	-	update the access time
+ *	atime_needs_update	-	update the access time
  *	@path: the &struct path to update
  *	@inode: inode to update
  *
@@ -1797,7 +1799,7 @@ bool atime_needs_update(const struct path *path, struct inode *inode)
 	/* Atime updates will likely cause i_uid and i_gid to be written
 	 * back improprely if their true value is unknown to the vfs.
 	 */
-	if (HAS_UNMAPPED_ID(inode))
+	if (HAS_UNMAPPED_ID(mnt_user_ns(mnt), inode))
 		return false;
 
 	if (IS_NOATIME(inode))
@@ -1904,7 +1906,8 @@ int dentry_needs_remove_privs(struct dentry *dentry)
 	return mask;
 }
 
-static int __remove_privs(struct dentry *dentry, int kill)
+static int __remove_privs(struct user_namespace *mnt_userns,
+			  struct dentry *dentry, int kill)
 {
 	struct iattr newattrs;
 
@@ -1913,7 +1916,7 @@ static int __remove_privs(struct dentry *dentry, int kill)
 	 * Note we call this on write, so notify_change will not
 	 * encounter any conflicting delegations:
 	 */
-	return notify_change(dentry, &newattrs, NULL);
+	return notify_change(mnt_userns, dentry, &newattrs, NULL);
 }
 
 /*
@@ -1940,7 +1943,7 @@ int file_remove_privs(struct file *file)
 	if (kill < 0)
 		return kill;
 	if (kill)
-		error = __remove_privs(dentry, kill);
+		error = __remove_privs(file_mnt_user_ns(file), dentry, kill);
 	if (!error)
 		inode_has_no_xattr(inode);
 
@@ -2131,14 +2134,21 @@ EXPORT_SYMBOL(init_special_inode);
 
 /**
  * inode_init_owner - Init uid,gid,mode for new inode according to posix standards
+ * @mnt_userns:	User namespace of the mount the inode was created from
  * @inode: New inode
  * @dir: Directory inode
  * @mode: mode of the new inode
+ *
+ * If the inode has been created through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions
+ * and initializing i_uid and i_gid. On non-idmapped mounts or if permission
+ * checking is to be performed on the raw inode simply passs init_user_ns.
  */
-void inode_init_owner(struct inode *inode, const struct inode *dir,
-			umode_t mode)
+void inode_init_owner(struct user_namespace *mnt_userns, struct inode *inode,
+		      const struct inode *dir, umode_t mode)
 {
-	inode->i_uid = current_fsuid();
+	inode->i_uid = fsuid_into_mnt(mnt_userns);
 	if (dir && dir->i_mode & S_ISGID) {
 		inode->i_gid = dir->i_gid;
 
@@ -2146,31 +2156,41 @@ void inode_init_owner(struct inode *inode, const struct inode *dir,
 		if (S_ISDIR(mode))
 			mode |= S_ISGID;
 		else if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP) &&
-			 !in_group_p(inode->i_gid) &&
-			 !capable_wrt_inode_uidgid(dir, CAP_FSETID))
+			 !in_group_p(i_gid_into_mnt(mnt_userns, dir)) &&
+			 !capable_wrt_inode_uidgid(mnt_userns, dir, CAP_FSETID))
 			mode &= ~S_ISGID;
 	} else
-		inode->i_gid = current_fsgid();
+		inode->i_gid = fsgid_into_mnt(mnt_userns);
 	inode->i_mode = mode;
 }
 EXPORT_SYMBOL(inode_init_owner);
 
 /**
  * inode_owner_or_capable - check current task permissions to inode
+ * @mnt_userns:	user namespace of the mount the inode was found from
  * @inode: inode being checked
  *
  * Return true if current either has CAP_FOWNER in a namespace with the
  * inode owner uid mapped, or owns the file.
+ *
+ * If the inode has been found through an idmapped mount the user namespace of
+ * the vfsmount must be passed through @mnt_userns. This function will then take
+ * care to map the inode according to @mnt_userns before checking permissions.
+ * On non-idmapped mounts or if permission checking is to be performed on the
+ * raw inode simply passs init_user_ns.
  */
-bool inode_owner_or_capable(const struct inode *inode)
+bool inode_owner_or_capable(struct user_namespace *mnt_userns,
+			    const struct inode *inode)
 {
+	kuid_t i_uid;
 	struct user_namespace *ns;
 
-	if (uid_eq(current_fsuid(), inode->i_uid))
+	i_uid = i_uid_into_mnt(mnt_userns, inode);
+	if (uid_eq(current_fsuid(), i_uid))
 		return true;
 
 	ns = current_user_ns();
-	if (kuid_has_mapping(ns, inode->i_uid) && ns_capable(ns, CAP_FOWNER))
+	if (kuid_has_mapping(ns, i_uid) && ns_capable(ns, CAP_FOWNER))
 		return true;
 	return false;
 }