[PATCH 5/5] fuse: propagate default and file acls on creation

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

For local filesystems, propagate the default and file access ACLs to new
children when creating them, just like the other in-kernel local
filesystems.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
 fs/fuse/fuse_i.h |    4 ++
 fs/fuse/acl.c    |   62 +++++++++++++++++++++++++++++++++
 fs/fuse/dir.c    |  101 +++++++++++++++++++++++++++++++++++++++++-------------
 3 files changed, 142 insertions(+), 25 deletions(-)


diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index a1880599455c0a..77b581ecf48a16 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1533,6 +1533,10 @@ struct posix_acl *fuse_get_acl(struct mnt_idmap *idmap,
 			       struct dentry *dentry, int type);
 int fuse_set_acl(struct mnt_idmap *, struct dentry *dentry,
 		 struct posix_acl *acl, int type);
+int fuse_acl_create(struct inode *dir, umode_t *mode,
+		    struct posix_acl **default_acl, struct posix_acl **acl);
+int fuse_init_acls(struct inode *inode, const struct posix_acl *default_acl,
+		   const struct posix_acl *acl);
 
 /* readdir.c */
 int fuse_readdir(struct file *file, struct dir_context *ctx);
diff --git a/fs/fuse/acl.c b/fs/fuse/acl.c
index f2b959efd67490..483ddf195d40a6 100644
--- a/fs/fuse/acl.c
+++ b/fs/fuse/acl.c
@@ -10,6 +10,7 @@
 
 #include <linux/posix_acl.h>
 #include <linux/posix_acl_xattr.h>
+#include <linux/fs_struct.h>
 
 /*
  * If this fuse server behaves like a local filesystem, we can implement the
@@ -202,3 +203,64 @@ int fuse_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 
 	return ret;
 }
+
+int fuse_acl_create(struct inode *dir, umode_t *mode,
+		    struct posix_acl **default_acl, struct posix_acl **acl)
+{
+	struct fuse_conn *fc = get_fuse_conn(dir);
+
+	if (fuse_is_bad(dir))
+		return -EIO;
+
+	if (IS_POSIXACL(dir) && fuse_inode_has_local_acls(dir))
+		return posix_acl_create(dir, mode, default_acl, acl);
+
+	if (!fc->dont_mask)
+		*mode &= ~current_umask();
+
+	*default_acl = NULL;
+	*acl = NULL;
+	return 0;
+}
+
+static int __fuse_set_acl(struct inode *inode, const char *name,
+			  const struct posix_acl *acl)
+{
+	struct fuse_conn *fc = get_fuse_conn(inode);
+	size_t size;
+	void *value = posix_acl_to_xattr(fc->user_ns, acl, &size, GFP_KERNEL);
+	int ret;
+
+	if (!value)
+		return -ENOMEM;
+
+	if (size > PAGE_SIZE) {
+		kfree(value);
+		return -E2BIG;
+	}
+
+	ret = fuse_setxattr(inode, name, value, size, 0, 0);
+	kfree(value);
+	return ret;
+}
+
+int fuse_init_acls(struct inode *inode, const struct posix_acl *default_acl,
+		   const struct posix_acl *acl)
+{
+	int ret;
+
+	if (default_acl) {
+		ret = __fuse_set_acl(inode, XATTR_NAME_POSIX_ACL_DEFAULT,
+				     default_acl);
+		if (ret)
+			return ret;
+	}
+
+	if (acl) {
+		ret = __fuse_set_acl(inode, XATTR_NAME_POSIX_ACL_ACCESS, acl);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 10fa47e969292f..9abec6f072ac73 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -821,26 +821,28 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir,
 	struct fuse_entry_out outentry;
 	struct fuse_inode *fi;
 	struct fuse_file *ff;
+	struct posix_acl *default_acl = NULL, *acl = NULL;
 	int epoch, err;
 	bool trunc = flags & O_TRUNC;
 
 	/* Userspace expects S_IFREG in create mode */
 	BUG_ON((mode & S_IFMT) != S_IFREG);
 
+	err = fuse_acl_create(dir, &mode, &default_acl, &acl);
+	if (err)
+		return err;
+
 	epoch = atomic_read(&fm->fc->epoch);
 	forget = fuse_alloc_forget();
 	err = -ENOMEM;
 	if (!forget)
-		goto out_err;
+		goto out_acl_release;
 
 	err = -ENOMEM;
 	ff = fuse_file_alloc(fm, true);
 	if (!ff)
 		goto out_put_forget_req;
 
-	if (!fm->fc->dont_mask)
-		mode &= ~current_umask();
-
 	flags &= ~O_NOCTTY;
 	memset(&inarg, 0, sizeof(inarg));
 	memset(&outentry, 0, sizeof(outentry));
@@ -892,12 +894,17 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir,
 		fuse_sync_release(NULL, ff, flags);
 		fuse_queue_forget(fm->fc, forget, outentry.nodeid, 1);
 		err = -ENOMEM;
-		goto out_err;
+		goto out_acl_release;
 	}
 	kfree(forget);
 	d_instantiate(entry, inode);
 	entry->d_time = epoch;
 	fuse_change_entry_timeout(entry, &outentry);
+
+	err = fuse_init_acls(inode, default_acl, acl);
+	if (err)
+		goto out_acl_release;
+
 	fuse_dir_changed(dir);
 	err = generic_file_open(inode, file);
 	if (!err) {
@@ -913,13 +920,17 @@ static int fuse_create_open(struct mnt_idmap *idmap, struct inode *dir,
 		else if (!(ff->open_flags & FOPEN_KEEP_CACHE))
 			invalidate_inode_pages2(inode->i_mapping);
 	}
+	posix_acl_release(default_acl);
+	posix_acl_release(acl);
 	return err;
 
 out_free_ff:
 	fuse_file_free(ff);
 out_put_forget_req:
 	kfree(forget);
-out_err:
+out_acl_release:
+	posix_acl_release(default_acl);
+	posix_acl_release(acl);
 	return err;
 }
 
@@ -971,7 +982,9 @@ static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
  */
 static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_mount *fm,
 				       struct fuse_args *args, struct inode *dir,
-				       struct dentry *entry, umode_t mode)
+				       struct dentry *entry, umode_t mode,
+				       struct posix_acl *default_acl,
+				       struct posix_acl *acl)
 {
 	struct fuse_entry_out outarg;
 	struct inode *inode;
@@ -979,14 +992,18 @@ static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_moun
 	struct fuse_forget_link *forget;
 	int epoch, err;
 
-	if (fuse_is_bad(dir))
-		return ERR_PTR(-EIO);
+	if (fuse_is_bad(dir)) {
+		err = -EIO;
+		goto out_acl_release;
+	}
 
 	epoch = atomic_read(&fm->fc->epoch);
 
 	forget = fuse_alloc_forget();
-	if (!forget)
-		return ERR_PTR(-ENOMEM);
+	if (!forget) {
+		err = -ENOMEM;
+		goto out_acl_release;
+	}
 
 	memset(&outarg, 0, sizeof(outarg));
 	args->nodeid = get_node_id(dir);
@@ -1016,14 +1033,17 @@ static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_moun
 			  &outarg.attr, ATTR_TIMEOUT(&outarg), 0, 0);
 	if (!inode) {
 		fuse_queue_forget(fm->fc, forget, outarg.nodeid, 1);
-		return ERR_PTR(-ENOMEM);
+		err = -ENOMEM;
+		goto out_acl_release;
 	}
 	kfree(forget);
 
 	d_drop(entry);
 	d = d_splice_alias(inode, entry);
-	if (IS_ERR(d))
-		return d;
+	if (IS_ERR(d)) {
+		err = PTR_ERR(d);
+		goto out_acl_release;
+	}
 
 	if (d) {
 		d->d_time = epoch;
@@ -1032,19 +1052,31 @@ static struct dentry *create_new_entry(struct mnt_idmap *idmap, struct fuse_moun
 		entry->d_time = epoch;
 		fuse_change_entry_timeout(entry, &outarg);
 	}
+
+	err = fuse_init_acls(inode, default_acl, acl);
+	if (err)
+		goto out_acl_release;
 	fuse_dir_changed(dir);
+
+	posix_acl_release(default_acl);
+	posix_acl_release(acl);
 	return d;
 
  out_put_forget_req:
 	if (err == -EEXIST)
 		fuse_invalidate_entry(entry);
 	kfree(forget);
+ out_acl_release:
+	posix_acl_release(default_acl);
+	posix_acl_release(acl);
 	return ERR_PTR(err);
 }
 
 static int create_new_nondir(struct mnt_idmap *idmap, struct fuse_mount *fm,
 			     struct fuse_args *args, struct inode *dir,
-			     struct dentry *entry, umode_t mode)
+			     struct dentry *entry, umode_t mode,
+			     struct posix_acl *default_acl,
+			     struct posix_acl *acl)
 {
 	/*
 	 * Note that when creating anything other than a directory we
@@ -1055,7 +1087,8 @@ static int create_new_nondir(struct mnt_idmap *idmap, struct fuse_mount *fm,
 	 */
 	WARN_ON_ONCE(S_ISDIR(mode));
 
-	return PTR_ERR(create_new_entry(idmap, fm, args, dir, entry, mode));
+	return PTR_ERR(create_new_entry(idmap, fm, args, dir, entry, mode,
+					default_acl, acl));
 }
 
 static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
@@ -1063,10 +1096,13 @@ static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
 {
 	struct fuse_mknod_in inarg;
 	struct fuse_mount *fm = get_fuse_mount(dir);
+	struct posix_acl *default_acl, *acl;
 	FUSE_ARGS(args);
+	int err;
 
-	if (!fm->fc->dont_mask)
-		mode &= ~current_umask();
+	err = fuse_acl_create(dir, &mode, &default_acl, &acl);
+	if (err)
+		return err;
 
 	memset(&inarg, 0, sizeof(inarg));
 	inarg.mode = mode;
@@ -1078,7 +1114,8 @@ static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	args.in_args[0].value = &inarg;
 	args.in_args[1].size = entry->d_name.len + 1;
 	args.in_args[1].value = entry->d_name.name;
-	return create_new_nondir(idmap, fm, &args, dir, entry, mode);
+	return create_new_nondir(idmap, fm, &args, dir, entry, mode,
+				 default_acl, acl);
 }
 
 static int fuse_create(struct mnt_idmap *idmap, struct inode *dir,
@@ -1110,13 +1147,17 @@ static struct dentry *fuse_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 {
 	struct fuse_mkdir_in inarg;
 	struct fuse_mount *fm = get_fuse_mount(dir);
+	struct posix_acl *default_acl, *acl;
 	FUSE_ARGS(args);
+	int err;
 
-	if (!fm->fc->dont_mask)
-		mode &= ~current_umask();
+	mode |= S_IFDIR;	/* vfs doesn't set S_IFDIR for us */
+	err = fuse_acl_create(dir, &mode, &default_acl, &acl);
+	if (err)
+		return ERR_PTR(err);
 
 	memset(&inarg, 0, sizeof(inarg));
-	inarg.mode = mode;
+	inarg.mode = mode & ~S_IFDIR;
 	inarg.umask = current_umask();
 	args.opcode = FUSE_MKDIR;
 	args.in_numargs = 2;
@@ -1124,7 +1165,8 @@ static struct dentry *fuse_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 	args.in_args[0].value = &inarg;
 	args.in_args[1].size = entry->d_name.len + 1;
 	args.in_args[1].value = entry->d_name.name;
-	return create_new_entry(idmap, fm, &args, dir, entry, S_IFDIR);
+	return create_new_entry(idmap, fm, &args, dir, entry, S_IFDIR,
+				default_acl, acl);
 }
 
 static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
@@ -1132,7 +1174,14 @@ static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
 {
 	struct fuse_mount *fm = get_fuse_mount(dir);
 	unsigned len = strlen(link) + 1;
+	struct posix_acl *default_acl, *acl;
+	umode_t mode = S_IFLNK | 0777;
 	FUSE_ARGS(args);
+	int err;
+
+	err = fuse_acl_create(dir, &mode, &default_acl, &acl);
+	if (err)
+		return err;
 
 	args.opcode = FUSE_SYMLINK;
 	args.in_numargs = 3;
@@ -1141,7 +1190,8 @@ static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	args.in_args[1].value = entry->d_name.name;
 	args.in_args[2].size = len;
 	args.in_args[2].value = link;
-	return create_new_nondir(idmap, fm, &args, dir, entry, S_IFLNK);
+	return create_new_nondir(idmap, fm, &args, dir, entry, S_IFLNK,
+				 default_acl, acl);
 }
 
 void fuse_flush_time_update(struct inode *inode)
@@ -1341,7 +1391,8 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
 	args.in_args[0].value = &inarg;
 	args.in_args[1].size = newent->d_name.len + 1;
 	args.in_args[1].value = newent->d_name.name;
-	err = create_new_nondir(&invalid_mnt_idmap, fm, &args, newdir, newent, inode->i_mode);
+	err = create_new_nondir(&invalid_mnt_idmap, fm, &args, newdir, newent,
+				inode->i_mode, NULL, NULL);
 	if (!err)
 		fuse_update_ctime_in_cache(inode);
 	else if (err == -EINTR)