From: Christoph Hellwig <hch@infradead.org>
To: torvalds@osdl.org, Gergely Nagy <algernon@gandalph.mad.hu>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [devfs] Use before initialisation in devfs_mk_cdev()
Date: Fri, 18 Jul 2003 12:33:14 +0100 [thread overview]
Message-ID: <20030718123314.A24143@infradead.org> (raw)
In-Reply-To: <83he5mm3jt.wl@iluvatar.bonehunter.rulez.org>; from algernon@gandalph.mad.hu on Thu, Jul 17, 2003 at 01:53:42AM +0200
On Thu, Jul 17, 2003 at 01:53:42AM +0200, Gergely Nagy wrote:
> Hi!
>
> While playing around with implementing my first linux 2.5 module, I
> stumbled upon a buglet in devfs (though, if used properly, it probably
> won't surface ever). The problem - as I see it - is that
> devfs_mk_cdev() first checks the mode passed to it, and if it thinks
> it is not a char device, it prints a warning and aborts. Now, this
> printing involves the local variable `buf' (char buf[64]), which is
> not initialised at that point.
Sorry, my fault. I had a report on this earlier but didn't submit
a patch yet. The same problem also affects devfs_mk_bdev.
Linus, please apply the patch below.
--- 1.95/fs/devfs/base.c Fri Jul 11 01:24:00 2003
+++ edited/fs/devfs/base.c Fri Jul 18 11:36:24 2003
@@ -1432,12 +1432,6 @@
va_list args;
int error, n;
- if (!S_ISBLK(mode)) {
- printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
- __FUNCTION__, mode, buf);
- return -EINVAL;
- }
-
va_start(args, fmt);
n = vsnprintf(buf, 64, fmt, args);
if (n >= 64 || !buf[0]) {
@@ -1445,6 +1439,12 @@
__FUNCTION__);
return -EINVAL;
}
+
+ if (!S_ISBLK(mode)) {
+ printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+ __FUNCTION__, mode, buf);
+ return -EINVAL;
+ }
de = _devfs_prepare_leaf(&dir, buf, mode);
if (!de) {
@@ -1478,17 +1478,17 @@
va_list args;
int error, n;
- if (!S_ISCHR(mode)) {
- printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
- __FUNCTION__, mode, buf);
- return -EINVAL;
- }
-
va_start(args, fmt);
n = vsnprintf(buf, 64, fmt, args);
if (n >= 64 || !buf[0]) {
printk(KERN_WARNING "%s: invalid format string\n",
__FUNCTION__);
+ return -EINVAL;
+ }
+
+ if (!S_ISCHR(mode)) {
+ printk(KERN_WARNING "%s: invalide mode (%u) for %s\n",
+ __FUNCTION__, mode, buf);
return -EINVAL;
}
prev parent reply other threads:[~2003-07-18 11:18 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-16 23:53 [devfs] Use before initialisation in devfs_mk_cdev() Gergely Nagy
2003-07-18 11:33 ` Christoph Hellwig [this message]
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