From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752181AbdJKXav (ORCPT ); Wed, 11 Oct 2017 19:30:51 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:31767 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750999AbdJKXar (ORCPT ); Wed, 11 Oct 2017 19:30:47 -0400 Date: Thu, 12 Oct 2017 10:30:36 +1100 (AEDT) From: James Morris X-X-Sender: james.l.morris@t440.gateway.2wire.net To: "Serge E. Hallyn" cc: Colin King , linux-security-module@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference In-Reply-To: <20171011204809.GD8207@mail.hallyn.com> Message-ID: References: <20170904175005.29871-1-colin.king@canonical.com> <20170904185339.GA11576@mail.hallyn.com> <20171011204809.GD8207@mail.hallyn.com> User-Agent: Alpine 2.20 (LFD 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 11 Oct 2017, Serge E. Hallyn wrote: > Hi James, > > it doesn't look like this has been picked up yet. Assuming I'm not looking > in the wrong place, can you pull it into the security tree? Sure, Colin, can you please resend this? > > Quoting Serge E. Hallyn (serge@hallyn.com): > > On Mon, Sep 04, 2017 at 06:50:05PM +0100, Colin King wrote: > > > From: Colin Ian King > > > > > > The pointer fs_ns is assigned from inode->i_ib->s_user_ns before > > > a null pointer check on inode, hence if inode is actually null we > > > will get a null pointer dereference on this assignment. Fix this > > > by only dereferencing inode after the null pointer check on > > > inode. > > > > > > Detected by CoverityScan CID#1455328 ("Dereference before null check") > > > > > > Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities") > > > Signed-off-by: Colin Ian King > > > > thanks! > > > > Acked-by: Serge Hallyn > > > > > --- > > > security/commoncap.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/security/commoncap.c b/security/commoncap.c > > > index c25e0d27537f..fc46f5b85251 100644 > > > --- a/security/commoncap.c > > > +++ b/security/commoncap.c > > > @@ -585,13 +585,14 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data > > > struct vfs_ns_cap_data data, *nscaps = &data; > > > struct vfs_cap_data *caps = (struct vfs_cap_data *) &data; > > > kuid_t rootkuid; > > > - struct user_namespace *fs_ns = inode->i_sb->s_user_ns; > > > + struct user_namespace *fs_ns; > > > > > > memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); > > > > > > if (!inode) > > > return -ENODATA; > > > > > > + fs_ns = inode->i_sb->s_user_ns; > > > size = __vfs_getxattr((struct dentry *)dentry, inode, > > > XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ); > > > if (size == -ENODATA || size == -EOPNOTSUPP) > > > -- > > > 2.14.1 > -- > To unsubscribe from this list: send the line "unsubscribe linux-security-module" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >