From 180ff6921b1d995194c159729c5d494b07b802ca Mon Sep 17 00:00:00 2001
From: Miklos Szeredi <miklos@szeredi.hu>
Date: Mon, 1 Nov 2004 16:01:05 +0000
Subject: [PATCH] new mount option

---
 kernel/dir.c    |  7 +++++--
 kernel/fuse_i.h |  4 ++++
 kernel/inode.c  | 13 +++++++++++--
 3 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/kernel/dir.c b/kernel/dir.c
index 87dec6a..36eb3bf 100644
--- a/kernel/dir.c
+++ b/kernel/dir.c
@@ -505,7 +505,9 @@ static int fuse_revalidate(struct dentry *entry)
 
 	if (inode->i_ino == FUSE_ROOT_INO) {
 		if (!(fc->flags & FUSE_ALLOW_OTHER) &&
-		    current->fsuid != fc->uid)
+		    current->fsuid != fc->uid &&
+		    (!(fc->flags & FUSE_ALLOW_ROOT) ||
+		     current->fsuid != 0))
 			return -EACCES;
 	} else if (!fi->i_time || time_before_eq(jiffies, fi->i_time))
 		return 0;
@@ -517,7 +519,8 @@ static int _fuse_permission(struct inode *inode, int mask)
 {
 	struct fuse_conn *fc = INO_FC(inode);
 
-	if (!(fc->flags & FUSE_ALLOW_OTHER) && current->fsuid != fc->uid)
+	if (!(fc->flags & FUSE_ALLOW_OTHER) && current->fsuid != fc->uid &&
+	    (!(fc->flags & FUSE_ALLOW_ROOT) || current->fsuid != 0))
 		return -EACCES;
 	else if (fc->flags & FUSE_DEFAULT_PERMISSIONS) {
 		int err = vfs_permission(inode, mask);
diff --git a/kernel/fuse_i.h b/kernel/fuse_i.h
index 5a4d7e7..8e3b416 100644
--- a/kernel/fuse_i.h
+++ b/kernel/fuse_i.h
@@ -73,6 +73,10 @@ permission checking is done in the kernel */
 /** Bypass the page cache for read and write operations  */
 #define FUSE_DIRECT_IO           (1 << 3)
 
+/** Allow root and setuid-root programs to access fuse-mounted
+    filesystems */
+#define FUSE_ALLOW_ROOT		 (1 << 4)
+
 /** FUSE specific inode data */
 struct fuse_inode {
 	struct fuse_req *forget_req;
diff --git a/kernel/inode.c b/kernel/inode.c
index 09479e1..8de566c 100644
--- a/kernel/inode.c
+++ b/kernel/inode.c
@@ -33,7 +33,7 @@ module_param(user_allow_other, int, 0);
 MODULE_PARM(user_allow_other, "i");
 #endif
 
-MODULE_PARM_DESC(user_allow_other, "Allow non root user to specify the \"allow_other\" mount option");
+MODULE_PARM_DESC(user_allow_other, "Allow non root user to specify the \"allow_other\" or \"allow_root\" mount options");
 
 
 #define FUSE_SUPER_MAGIC 0x65735546
@@ -176,6 +176,7 @@ enum { opt_fd,
        opt_uid,
        opt_default_permissions, 
        opt_allow_other,
+       opt_allow_root,
        opt_kernel_cache,
        opt_large_read,
        opt_direct_io,
@@ -188,6 +189,7 @@ static match_table_t tokens = {
 	{opt_uid, "uid=%u"},
 	{opt_default_permissions, "default_permissions"},
 	{opt_allow_other, "allow_other"},
+	{opt_allow_root, "allow_root"},
 	{opt_kernel_cache, "kernel_cache"},
 	{opt_large_read, "large_read"},
 	{opt_direct_io, "direct_io"},
@@ -237,6 +239,10 @@ static int parse_fuse_opt(char *opt, struct fuse_mount_data *d)
 			d->flags |= FUSE_ALLOW_OTHER;
 			break;
 
+		case opt_allow_root:
+			d->flags |= FUSE_ALLOW_ROOT;
+			break;
+
 		case opt_kernel_cache:
 			d->flags |= FUSE_KERNEL_CACHE;
 			break;
@@ -284,6 +290,8 @@ static int fuse_show_options(struct seq_file *m, struct vfsmount *mnt)
 		seq_puts(m, ",default_permissions");
 	if (fc->flags & FUSE_ALLOW_OTHER)
 		seq_puts(m, ",allow_other");
+	if (fc->flags & FUSE_ALLOW_ROOT)
+		seq_puts(m, ",allow_root");
 	if (fc->flags & FUSE_KERNEL_CACHE)
 		seq_puts(m, ",kernel_cache");
 #ifndef KERNEL_2_6
@@ -375,7 +383,8 @@ static int fuse_read_super(struct super_block *sb, void *data, int silent)
 	if (!parse_fuse_opt((char *) data, &d))
 		return -EINVAL;
 
-	if (!user_allow_other && (d.flags & FUSE_ALLOW_OTHER) &&
+	if (!user_allow_other &&
+	    (d.flags & (FUSE_ALLOW_OTHER | FUSE_ALLOW_ROOT)) &&
 	    current->uid != 0)
 		return -EPERM;
 
-- 
2.30.2