Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934957Ab3DHGdf (ORCPT ); Mon, 8 Apr 2013 02:33:35 -0400 Received: from ozlabs.org ([203.10.76.45]:46497 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934944Ab3DHGdd (ORCPT ); Mon, 8 Apr 2013 02:33:33 -0400 From: Rusty Russell To: Chen Gang Cc: "linux-kernel\@vger.kernel.org \>\> \"linux-kernel\@vger.kernel.org\"" Subject: Re: [PATCH] kernel: module: strncpy issue, using strlcpy instead of strncpy In-Reply-To: <51615AB0.9060502@asianux.com> References: <51615AB0.9060502@asianux.com> User-Agent: Notmuch/0.14 (http://notmuchmail.org) Emacs/23.4.1 (i686-pc-linux-gnu) Date: Mon, 08 Apr 2013 15:00:44 +0930 Message-ID: <87r4ila8sb.fsf@rustcorp.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1591 Lines: 49 Chen Gang writes: > ownername and namebuf are all NUL terminated string. > > need always let them ended by '\0'. > > Signed-off-by: Chen Gang > --- > kernel/module.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/module.c b/kernel/module.c > index 3c2c72d..597efd8 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -1283,7 +1283,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod, > > getname: > /* We must make copy under the lock if we failed to get ref. */ > - strncpy(ownername, module_name(owner), MODULE_NAME_LEN); > + strlcpy(ownername, module_name(owner), MODULE_NAME_LEN); This should just be strcpy(). > unlock: > mutex_unlock(&module_mutex); > return sym; > @@ -3464,7 +3464,7 @@ const char *module_address_lookup(unsigned long addr, > } > /* Make a copy in here where it's safe */ > if (ret) { > - strncpy(namebuf, ret, KSYM_NAME_LEN - 1); > + strlcpy(namebuf, ret, KSYM_NAME_LEN); This isn't a bug, because the caller (kallsyms_lookup) puts a NUL in ret[KSYM_NAME_LEN]. However, kallsyms_lookup also calls kallsyms_expand_symbol, which doesn't stop at KSYM_NAME_LEN, so if a name was longer than that we'd have a real bug. Would you like to take a look at that, too? Thanks, Rusty. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/