From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from h2.hallyn.com ([78.46.35.8]:56842 "EHLO mail.hallyn.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753423AbeDJOph (ORCPT ); Tue, 10 Apr 2018 10:45:37 -0400 Date: Tue, 10 Apr 2018 09:45:36 -0500 From: "Serge E. Hallyn" To: Tetsuo Handa Cc: syzbot , "Serge E. Hallyn" , "Eric W. Biederman" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk Subject: Re: KASAN: null-ptr-deref Read in xattr_getsecurity Message-ID: <20180410144536.GA13386@mail.hallyn.com> References: <0000000000008d2e0d05697a693d@google.com> <9d192497-8b1e-ca8d-0ed8-b3324ee1e361@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9d192497-8b1e-ca8d-0ed8-b3324ee1e361@I-love.SAKURA.ne.jp> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Apr 10, 2018 at 07:13:23PM +0900, Tetsuo Handa wrote: > syzbot is reporting NULL pointer dereference at xattr_getsecurity() [1], > for cap_inode_getsecurity() is returning sizeof(struct vfs_cap_data) when > memory allocation failed. Return -ENOMEM if memory allocation failed. > > [1] https://syzkaller.appspot.com/bug?id=a55ba438506fe68649a5f50d2d82d56b365e0107 > > Signed-off-by: Tetsuo Handa > Fixes: 8db6c34f1dbc8e06 ("Introduce v3 namespaced file capabilities") > Reported-by: syzbot > Cc: stable # 4.14+ > Cc: Serge E. Hallyn Acked-by: Serge Hallyn thanks! -serge > Cc: Eric W. Biederman > --- > security/commoncap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/security/commoncap.c b/security/commoncap.c > index 48620c9..1ce701f 100644 > --- a/security/commoncap.c > +++ b/security/commoncap.c > @@ -449,6 +449,8 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, > magic |= VFS_CAP_FLAGS_EFFECTIVE; > memcpy(&cap->data, &nscap->data, sizeof(__le32) * 2 * VFS_CAP_U32); > cap->magic_etc = cpu_to_le32(magic); > + } else { > + size = -ENOMEM; > } > } > kfree(tmpbuf); > -- > 1.8.3.1