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vfs: canonicalize create mode in build_open_flags()

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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
This commit is contained in:
Miklos Szeredi 2012-08-15 13:01:24 +02:00
parent ddf343f635
commit e68726ff72
1 changed files with 4 additions and 3 deletions

7
fs/open.c
View File

@ -852,9 +852,10 @@ static inline int build_open_flags(int flags, umode_t mode, struct open_flags *o
int lookup_flags = 0; int lookup_flags = 0;
int acc_mode; int acc_mode;
if (!(flags & O_CREAT)) if (flags & O_CREAT)
mode = 0; op->mode = (mode & S_IALLUGO) | S_IFREG;
op->mode = mode; else
op->mode = 0;
/* Must never be set by userspace */ /* Must never be set by userspace */
flags &= ~FMODE_NONOTIFY; flags &= ~FMODE_NONOTIFY;