1 files changed, 117 insertions, 47 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index cd1a071b625a..35bc174f9ba2 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -145,7 +145,7 @@ static void fuse_dir_changed(struct inode *dir)
 	inode_maybe_inc_iversion(dir, false);
 }
 
-/**
+/*
  * Mark the attributes as stale due to an atime change.  Avoid the invalidate if
  * atime is not used.
  */
@@ -466,7 +466,7 @@ static struct dentry *fuse_lookup(struct inode *dir, struct dentry *entry,
 }
 
 static int get_security_context(struct dentry *entry, umode_t mode,
-				void **security_ctx, u32 *security_ctxlen)
+				struct fuse_in_arg *ext)
 {
 	struct fuse_secctx *fctx;
 	struct fuse_secctx_header *header;
@@ -513,14 +513,100 @@ static int get_security_context(struct dentry *entry, umode_t mode,
 
 		memcpy(ptr, ctx, ctxlen);
 	}
-	*security_ctxlen = total_len;
-	*security_ctx = header;
+	ext->size = total_len;
+	ext->value = header;
 	err = 0;
 out_err:
 	kfree(ctx);
 	return err;
 }
 
+static void *extend_arg(struct fuse_in_arg *buf, u32 bytes)
+{
+	void *p;
+	u32 newlen = buf->size + bytes;
+
+	p = krealloc(buf->value, newlen, GFP_KERNEL);
+	if (!p) {
+		kfree(buf->value);
+		buf->size = 0;
+		buf->value = NULL;
+		return NULL;
+	}
+
+	memset(p + buf->size, 0, bytes);
+	buf->value = p;
+	buf->size = newlen;
+
+	return p + newlen - bytes;
+}
+
+static u32 fuse_ext_size(size_t size)
+{
+	return FUSE_REC_ALIGN(sizeof(struct fuse_ext_header) + size);
+}
+
+/*
+ * This adds just a single supplementary group that matches the parent's group.
+ */
+static int get_create_supp_group(struct inode *dir, struct fuse_in_arg *ext)
+{
+	struct fuse_conn *fc = get_fuse_conn(dir);
+	struct fuse_ext_header *xh;
+	struct fuse_supp_groups *sg;
+	kgid_t kgid = dir->i_gid;
+	gid_t parent_gid = from_kgid(fc->user_ns, kgid);
+	u32 sg_len = fuse_ext_size(sizeof(*sg) + sizeof(sg->groups[0]));
+
+	if (parent_gid == (gid_t) -1 || gid_eq(kgid, current_fsgid()) ||
+	    !in_group_p(kgid))
+		return 0;
+
+	xh = extend_arg(ext, sg_len);
+	if (!xh)
+		return -ENOMEM;
+
+	xh->size = sg_len;
+	xh->type = FUSE_EXT_GROUPS;
+
+	sg = (struct fuse_supp_groups *) &xh[1];
+	sg->nr_groups = 1;
+	sg->groups[0] = parent_gid;
+
+	return 0;
+}
+
+static int get_create_ext(struct fuse_args *args,
+			  struct inode *dir, struct dentry *dentry,
+			  umode_t mode)
+{
+	struct fuse_conn *fc = get_fuse_conn_super(dentry->d_sb);
+	struct fuse_in_arg ext = { .size = 0, .value = NULL };
+	int err = 0;
+
+	if (fc->init_security)
+		err = get_security_context(dentry, mode, &ext);
+	if (!err && fc->create_supp_group)
+		err = get_create_supp_group(dir, &ext);
+
+	if (!err && ext.size) {
+		WARN_ON(args->in_numargs >= ARRAY_SIZE(args->in_args));
+		args->is_ext = true;
+		args->ext_idx = args->in_numargs++;
+		args->in_args[args->ext_idx] = ext;
+	} else {
+		kfree(ext.value);
+	}
+
+	return err;
+}
+
+static void free_ext_value(struct fuse_args *args)
+{
+	if (args->is_ext)
+		kfree(args->in_args[args->ext_idx].value);
+}
+
 /*
  * Atomic create+open operation
  *
@@ -541,8 +627,6 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
 	struct fuse_entry_out outentry;
 	struct fuse_inode *fi;
 	struct fuse_file *ff;
-	void *security_ctx = NULL;
-	u32 security_ctxlen;
 	bool trunc = flags & O_TRUNC;
 
 	/* Userspace expects S_IFREG in create mode */
@@ -586,19 +670,12 @@ static int fuse_create_open(struct inode *dir, struct dentry *entry,
 	args.out_args[1].size = sizeof(outopen);
 	args.out_args[1].value = &outopen;
 
-	if (fm->fc->init_security) {
-		err = get_security_context(entry, mode, &security_ctx,
-					   &security_ctxlen);
-		if (err)
-			goto out_put_forget_req;
-
-		args.in_numargs = 3;
-		args.in_args[2].size = security_ctxlen;
-		args.in_args[2].value = security_ctx;
-	}
+	err = get_create_ext(&args, dir, entry, mode);
+	if (err)
+		goto out_put_forget_req;
 
 	err = fuse_simple_request(fm, &args);
-	kfree(security_ctx);
+	free_ext_value(&args);
 	if (err)
 		goto out_free_ff;
 
@@ -645,7 +722,7 @@ out_err:
 	return err;
 }
 
-static int fuse_mknod(struct user_namespace *, struct inode *, struct dentry *,
+static int fuse_mknod(struct mnt_idmap *, struct inode *, struct dentry *,
 		      umode_t, dev_t);
 static int fuse_atomic_open(struct inode *dir, struct dentry *entry,
 			    struct file *file, unsigned flags,
@@ -686,7 +763,7 @@ out_dput:
 	return err;
 
 mknod:
-	err = fuse_mknod(&init_user_ns, dir, entry, mode, 0);
+	err = fuse_mknod(&nop_mnt_idmap, dir, entry, mode, 0);
 	if (err)
 		goto out_dput;
 no_open:
@@ -705,8 +782,6 @@ static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args,
 	struct dentry *d;
 	int err;
 	struct fuse_forget_link *forget;
-	void *security_ctx = NULL;
-	u32 security_ctxlen;
 
 	if (fuse_is_bad(dir))
 		return -EIO;
@@ -721,21 +796,14 @@ static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args,
 	args->out_args[0].size = sizeof(outarg);
 	args->out_args[0].value = &outarg;
 
-	if (fm->fc->init_security && args->opcode != FUSE_LINK) {
-		err = get_security_context(entry, mode, &security_ctx,
-					   &security_ctxlen);
+	if (args->opcode != FUSE_LINK) {
+		err = get_create_ext(args, dir, entry, mode);
 		if (err)
 			goto out_put_forget_req;
-
-		BUG_ON(args->in_numargs != 2);
-
-		args->in_numargs = 3;
-		args->in_args[2].size = security_ctxlen;
-		args->in_args[2].value = security_ctx;
 	}
 
 	err = fuse_simple_request(fm, args);
-	kfree(security_ctx);
+	free_ext_value(args);
 	if (err)
 		goto out_put_forget_req;
 
@@ -773,7 +841,7 @@ static int create_new_entry(struct fuse_mount *fm, struct fuse_args *args,
 	return err;
 }
 
-static int fuse_mknod(struct user_namespace *mnt_userns, struct inode *dir,
+static int fuse_mknod(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *entry, umode_t mode, dev_t rdev)
 {
 	struct fuse_mknod_in inarg;
@@ -796,13 +864,13 @@ static int fuse_mknod(struct user_namespace *mnt_userns, struct inode *dir,
 	return create_new_entry(fm, &args, dir, entry, mode);
 }
 
-static int fuse_create(struct user_namespace *mnt_userns, struct inode *dir,
+static int fuse_create(struct mnt_idmap *idmap, struct inode *dir,
 		       struct dentry *entry, umode_t mode, bool excl)
 {
-	return fuse_mknod(&init_user_ns, dir, entry, mode, 0);
+	return fuse_mknod(&nop_mnt_idmap, dir, entry, mode, 0);
 }
 
-static int fuse_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
+static int fuse_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
 			struct file *file, umode_t mode)
 {
 	struct fuse_conn *fc = get_fuse_conn(dir);
@@ -819,7 +887,7 @@ static int fuse_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
 	return err;
 }
 
-static int fuse_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
+static int fuse_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 		      struct dentry *entry, umode_t mode)
 {
 	struct fuse_mkdir_in inarg;
@@ -841,7 +909,7 @@ static int fuse_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
 	return create_new_entry(fm, &args, dir, entry, S_IFDIR);
 }
 
-static int fuse_symlink(struct user_namespace *mnt_userns, struct inode *dir,
+static int fuse_symlink(struct mnt_idmap *idmap, struct inode *dir,
 			struct dentry *entry, const char *link)
 {
 	struct fuse_mount *fm = get_fuse_mount(dir);
@@ -998,7 +1066,7 @@ static int fuse_rename_common(struct inode *olddir, struct dentry *oldent,
 	return err;
 }
 
-static int fuse_rename2(struct user_namespace *mnt_userns, struct inode *olddir,
+static int fuse_rename2(struct mnt_idmap *idmap, struct inode *olddir,
 			struct dentry *oldent, struct inode *newdir,
 			struct dentry *newent, unsigned int flags)
 {
@@ -1156,7 +1224,7 @@ static int fuse_update_get_attr(struct inode *inode, struct file *file,
 		forget_all_cached_acls(inode);
 		err = fuse_do_getattr(inode, stat, file);
 	} else if (stat) {
-		generic_fillattr(&init_user_ns, inode, stat);
+		generic_fillattr(&nop_mnt_idmap, inode, stat);
 		stat->mode = fi->orig_i_mode;
 		stat->ino = fi->orig_ino;
 	}
@@ -1326,7 +1394,7 @@ static int fuse_perm_getattr(struct inode *inode, int mask)
  * access request is sent.  Execute permission is still checked
  * locally based on file mode.
  */
-static int fuse_permission(struct user_namespace *mnt_userns,
+static int fuse_permission(struct mnt_idmap *idmap,
 			   struct inode *inode, int mask)
 {
 	struct fuse_conn *fc = get_fuse_conn(inode);
@@ -1358,7 +1426,7 @@ static int fuse_permission(struct user_namespace *mnt_userns,
 	}
 
 	if (fc->default_permissions) {
-		err = generic_permission(&init_user_ns, inode, mask);
+		err = generic_permission(&nop_mnt_idmap, inode, mask);
 
 		/* If permission is denied, try to refresh file
 		   attributes.  This is also needed, because the root
@@ -1366,7 +1434,7 @@ static int fuse_permission(struct user_namespace *mnt_userns,
 		if (err == -EACCES && !refreshed) {
 			err = fuse_perm_getattr(inode, mask);
 			if (!err)
-				err = generic_permission(&init_user_ns,
+				err = generic_permission(&nop_mnt_idmap,
 							 inode, mask);
 		}
 
@@ -1690,7 +1758,7 @@ int fuse_do_setattr(struct dentry *dentry, struct iattr *attr,
 	if (!fc->default_permissions)
 		attr->ia_valid |= ATTR_FORCE;
 
-	err = setattr_prepare(&init_user_ns, dentry, attr);
+	err = setattr_prepare(&nop_mnt_idmap, dentry, attr);
 	if (err)
 		return err;
 
@@ -1837,7 +1905,7 @@ error:
 	return err;
 }
 
-static int fuse_setattr(struct user_namespace *mnt_userns, struct dentry *entry,
+static int fuse_setattr(struct mnt_idmap *idmap, struct dentry *entry,
 			struct iattr *attr)
 {
 	struct inode *inode = d_inode(entry);
@@ -1900,7 +1968,7 @@ static int fuse_setattr(struct user_namespace *mnt_userns, struct dentry *entry,
 	return ret;
 }
 
-static int fuse_getattr(struct user_namespace *mnt_userns,
+static int fuse_getattr(struct mnt_idmap *idmap,
 			const struct path *path, struct kstat *stat,
 			u32 request_mask, unsigned int flags)
 {
@@ -1942,7 +2010,8 @@ static const struct inode_operations fuse_dir_inode_operations = {
 	.permission	= fuse_permission,
 	.getattr	= fuse_getattr,
 	.listxattr	= fuse_listxattr,
-	.get_inode_acl	= fuse_get_acl,
+	.get_inode_acl	= fuse_get_inode_acl,
+	.get_acl	= fuse_get_acl,
 	.set_acl	= fuse_set_acl,
 	.fileattr_get	= fuse_fileattr_get,
 	.fileattr_set	= fuse_fileattr_set,
@@ -1964,7 +2033,8 @@ static const struct inode_operations fuse_common_inode_operations = {
 	.permission	= fuse_permission,
 	.getattr	= fuse_getattr,
 	.listxattr	= fuse_listxattr,
-	.get_inode_acl	= fuse_get_acl,
+	.get_inode_acl	= fuse_get_inode_acl,
+	.get_acl	= fuse_get_acl,
 	.set_acl	= fuse_set_acl,
 	.fileattr_get	= fuse_fileattr_get,
 	.fileattr_set	= fuse_fileattr_set,