Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:53613 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751444AbbBYDy5 (ORCPT ); Tue, 24 Feb 2015 22:54:57 -0500 Message-ID: <1424836484.13431.36.camel@willson.usersys.redhat.com> Subject: Re: [patch v2] sunrpc: integer underflow in rsc_parse() From: Simo Sorce To: Dan Carpenter Cc: "J. Bruce Fields" , Trond Myklebust , Anna Schumaker , "David S. Miller" , Jeff Layton , Kinglong Mee , linux-nfs@vger.kernel.org, netdev@vger.kernel.org, "Eric W. Biederman" , Andrew Morton , Andy Lutomirski , Wang YanQing , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Date: Tue, 24 Feb 2015 22:54:44 -0500 In-Reply-To: <20150224153401.GA12218@mwanda> References: <20150224153401.GA12218@mwanda> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, 2015-02-24 at 18:34 +0300, Dan Carpenter wrote: > If we call groups_alloc() with invalid values then it's might lead to > memory corruption. For example, with a negative value then we might not > allocate enough for sizeof(struct group_info). > > Signed-off-by: Dan Carpenter > --- > v2: In v1, I changed groups_alloc(). The other places which call > groups_alloc() check the value before calling. Eric wanted that, either > have all the callers check, or all the callers rely on groups_alloc(). > In the end, Bruce Fields said adding the check here was probably > reasonable. > > diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c > index 224a82f..1095be9 100644 > --- a/net/sunrpc/auth_gss/svcauth_gss.c > +++ b/net/sunrpc/auth_gss/svcauth_gss.c > @@ -463,6 +463,8 @@ static int rsc_parse(struct cache_detail *cd, > /* number of additional gid's */ > if (get_int(&mesg, &N)) > goto out; > + if (N < 0 || N > NGROUPS_MAX) > + goto out; > status = -ENOMEM; > rsci.cred.cr_group_info = groups_alloc(N); > if (rsci.cred.cr_group_info == NULL) > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html I touched this code relatively recently, and this check looks correct. Feel free to add Reviewed-by: Simo Sorce Simo. -- Simo Sorce * Red Hat, Inc * New York