linux-kernel - Re: [PATCH] param_sysfs_builtin memchr argument fix

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Date:	Tue, 9 Oct 2007 09:21:11 +0800
From:	Dave Young <hidave.darkstar@...il.com>
To:	Randy Dunlap <randy.dunlap@...cle.com>
Cc:	linux-kernel@...r.kernel.org, xiyou.wangcong@...il.com,
	akpm@...ux-foundation.org, gregkh@...e.de
Subject: Re: [PATCH] param_sysfs_builtin memchr argument fix

> > If memchr argument is longer than strlen(kp->name), there will be some
> > weird result.
> 
> Just to clarify:  this was causing duplicate filenames in sysfs ?
Yes, it will casuse duplicate filenames in sysfs. For me, the "nousb"
will cause the "usbcore" created twice. 
> 
> 
> > Signed-off-by: Dave Young <hidave.darkstar@...il.com>
> >
> > ---
> > kernel/params.c |    8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff -upr linux/kernel/params.c linux.new/kernel/params.c
> > --- linux/kernel/params.c     2007-10-08 14:30:06.000000000 +0800
> > +++ linux.new/kernel/params.c 2007-10-08 15:13:04.000000000 +0800
> > @@ -592,11 +592,17 @@ static void __init param_sysfs_builtin(v
> >
> >       for (i=0; i < __stop___param - __start___param; i++) {
> >               char *dot;
> > +             size_t kplen;
> >
> >               kp = &__start___param[i];
> > +             kplen = strlen(kp->name);
> >
> >               /* We do not handle args without periods. */
> > -             dot = memchr(kp->name, '.', MAX_KBUILD_MODNAME);
> > +             if (kplen > MAX_KBUILD_MODNAME) {
> > +                     DEBUGP("kernel parameter %s is too long\n", kp->name);
> 
> how about
>         kernel parameter name %s is too long
> or
>         kernel parameter name is too long: %s
> 
> (primary is addition of "name")
Yes, "name" should be added, thanks.
> 
> > +                     continue;
> > +             }
> > +             dot = memchr(kp->name, '.', kplen);
> >               if (!dot) {
> >                       DEBUGP("couldn't find period in %s\n", kp->name);
> >                       continue;
> > -
> 

Regards
dave

====================================================

Signed-off-by: Dave Young <hidave.darkstar@...il.com> 

---
kernel/params.c |    8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

diff -upr linux/kernel/params.c linux.new/kernel/params.c
--- linux/kernel/params.c	2007-10-08 14:30:06.000000000 +0800
+++ linux.new/kernel/params.c	2007-10-09 09:16:55.000000000 +0800
@@ -592,11 +592,17 @@ static void __init param_sysfs_builtin(v
 
 	for (i=0; i < __stop___param - __start___param; i++) {
 		char *dot;
+		size_t kplen;
 
 		kp = &__start___param[i];
+		kplen = strlen(kp->name);
 
 		/* We do not handle args without periods. */
-		dot = memchr(kp->name, '.', MAX_KBUILD_MODNAME);
+		if (kplen > MAX_KBUILD_MODNAME) {
+			DEBUGP("kernel parameter name is too long: %s\n", kp->name);
+			continue;
+		}
+		dot = memchr(kp->name, '.', kplen);
 		if (!dot) {
 			DEBUGP("couldn't find period in %s\n", kp->name);
 			continue;
-
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