linux-kernel - Re: [PATCH] FUSE: Validate rootmode mount option

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Date:	Tue, 03 Apr 2007 00:31:55 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	tsavola@...ial.fi
CC:	linux-kernel@...r.kernel.org, fuse-devel@...ts.sourceforge.net
Subject: Re: [PATCH] FUSE: Validate rootmode mount option

> If rootmode doesn't include any file type bits, we hit the BUG() in
> fuse_init_inode.  Now EINVAL is returned.

Thanks, well spotted.

I'll queue this more complete fix.

Miklos

----
From: Timo Savola <tsavola@...ial.fi>
Subject: fuse: validate rootmode mount option

If rootmode isn't valid, we hit the BUG() in fuse_init_inode.  Now
EINVAL is returned.

Signed-off-by: Timo Savola <tsavola@...ial.fi>
Signed-off-by: Miklos Szeredi <mszeredi@...e.cz>
---

Index: linux/fs/fuse/inode.c
===================================================================
--- linux.orig/fs/fuse/inode.c	2007-03-21 18:44:43.000000000 +0100
+++ linux/fs/fuse/inode.c	2007-04-03 00:01:07.000000000 +0200
@@ -330,6 +330,8 @@ static int parse_fuse_opt(char *opt, str
 		case OPT_ROOTMODE:
 			if (match_octal(&args[0], &value))
 				return 0;
+			if (!fuse_valid_type(value))
+				return 0;
 			d->rootmode = value;
 			d->rootmode_present = 1;
 			break;
Index: linux/fs/fuse/dir.c
===================================================================
--- linux.orig/fs/fuse/dir.c	2007-03-21 18:44:43.000000000 +0100
+++ linux/fs/fuse/dir.c	2007-04-03 00:00:00.000000000 +0200
@@ -195,7 +195,7 @@ static struct dentry_operations fuse_den
 	.d_revalidate	= fuse_dentry_revalidate,
 };
 
-static int valid_mode(int m)
+int fuse_valid_type(int m)
 {
 	return S_ISREG(m) || S_ISDIR(m) || S_ISLNK(m) || S_ISCHR(m) ||
 		S_ISBLK(m) || S_ISFIFO(m) || S_ISSOCK(m);
@@ -248,7 +248,8 @@ static struct dentry *fuse_lookup(struct
 	fuse_put_request(fc, req);
 	/* Zero nodeid is same as -ENOENT, but with valid timeout */
 	if (!err && outarg.nodeid &&
-	    (invalid_nodeid(outarg.nodeid) || !valid_mode(outarg.attr.mode)))
+	    (invalid_nodeid(outarg.nodeid) ||
+	     !fuse_valid_type(outarg.attr.mode)))
 		err = -EIO;
 	if (!err && outarg.nodeid) {
 		inode = fuse_iget(dir->i_sb, outarg.nodeid, outarg.generation,
Index: linux/fs/fuse/fuse_i.h
===================================================================
--- linux.orig/fs/fuse/fuse_i.h	2007-02-04 19:44:54.000000000 +0100
+++ linux/fs/fuse/fuse_i.h	2007-04-03 00:01:20.000000000 +0200
@@ -552,3 +552,8 @@ int fuse_ctl_add_conn(struct fuse_conn *
  * Remove connection from control filesystem
  */
 void fuse_ctl_remove_conn(struct fuse_conn *fc);
+
+/**
+ * Is file type valid?
+ */
+int fuse_valid_type(int m);
-
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