linux-kernel - [PATCH] ramfs: ignore unknown mount options

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.64.0906142250590.6984@sister.anvils>
Date:	Sun, 14 Jun 2009 22:56:48 +0100 (BST)
From:	Hugh Dickins <hugh.dickins@...cali.co.uk>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
cc:	Matt Mackall <mpm@...enic.com>,
	Wu Fengguang <fengguang.wu@...el.com>,
	Mike Frysinger <vapier@...too.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] ramfs: ignore unknown mount options

From: Mike Frysinger <vapier@...too.org>

On systems where CONFIG_SHMEM is disabled, mounting tmpfs filesystems can
fail when tmpfs options are used.  This is because tmpfs creates a small
wrapper around ramfs which rejects unknown options, and ramfs itself only
supports a tiny subset of what tmpfs supports.  This makes it pretty hard
to use the same userspace systems across different configuration systems.
As such, ramfs should ignore the tmpfs options when tmpfs is merely a
wrapper around ramfs.

This used to work before commit c3b1b1cbf0 as previously, ramfs would
ignore all options.  But now, we get:
ramfs: bad mount option: size=10M
mount: mounting mdev on /dev failed: Invalid argument

Another option might be to restore the previous behavior, where ramfs
simply ignored all unknown mount options ... which is what Hugh prefers.

Signed-off-by: Mike Frysinger <vapier@...too.org>
Signed-off-by: Hugh Dickins <hugh.dickins@...cali.co.uk>
Acked-by: Matt Mackall <mpm@...enic.com>
Acked-by: Wu Fengguang <fengguang.wu@...el.com>
Cc: stable@...nel.org
---

 fs/ramfs/inode.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- 2.6.30/fs/ramfs/inode.c	2009-06-10 04:05:27.000000000 +0100
+++ linux/fs/ramfs/inode.c	2009-06-13 14:45:33.000000000 +0100
@@ -202,9 +202,12 @@ static int ramfs_parse_options(char *dat
 				return -EINVAL;
 			opts->mode = option & S_IALLUGO;
 			break;
-		default:
-			printk(KERN_ERR "ramfs: bad mount option: %s\n", p);
-			return -EINVAL;
+		/*
+		 * We might like to report bad mount options here;
+		 * but traditionally ramfs has ignored all mount options,
+		 * and as it is used as a !CONFIG_SHMEM simple substitute
+		 * for tmpfs, better continue to ignore other mount options.
+		 */
 		}
 	}

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/