From: Miklos Szeredi <mszeredi@suse.cz>
Date: Wed, 15 Aug 2012 11:01:24 +0000 (+0200)
Subject: vfs: canonicalize create mode in build_open_flags()
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=e68726ff72cf7ba5e7d789857fcd9a75ca573f03;p=openwrt%2Fstaging%2Fblogic.git

vfs: canonicalize create mode in build_open_flags()

Userspace can pass weird create mode in open(2) that we canonicalize to
"(mode & S_IALLUGO) | S_IFREG" in vfs_create().

The problem is that we use the uncanonicalized mode before calling vfs_create()
with unforseen consequences.

So do the canonicalization early in build_open_flags().

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
CC: stable@vger.kernel.org
---

diff --git a/fs/open.c b/fs/open.c
index bc132e167d2d..e1f2cdb91a4d 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -852,9 +852,10 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
 	int lookup_flags = 0;
 	int acc_mode;
 
-	if (!(flags & O_CREAT))
-		mode = 0;
-	op->mode = mode;
+	if (flags & O_CREAT)
+		op->mode = (mode & S_IALLUGO) | S_IFREG;
+	else
+		op->mode = 0;
 
 	/* Must never be set by userspace */
 	flags &= ~FMODE_NONOTIFY;