From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3259C76186 for ; Tue, 23 Jul 2019 23:13:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF1372253D for ; Tue, 23 Jul 2019 23:13:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726550AbfGWXNS (ORCPT ); Tue, 23 Jul 2019 19:13:18 -0400 Received: from vmicros1.altlinux.org ([194.107.17.57]:42980 "EHLO vmicros1.altlinux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725884AbfGWXNS (ORCPT ); Tue, 23 Jul 2019 19:13:18 -0400 Received: from imap.altlinux.org (imap.altlinux.org [194.107.17.38]) by vmicros1.altlinux.org (Postfix) with ESMTP id 5447D72CCDF; Wed, 24 Jul 2019 02:13:16 +0300 (MSK) Received: from altlinux.org (sole.flsd.net [185.75.180.6]) by imap.altlinux.org (Postfix) with ESMTPSA id 4290F4A4AE8; Wed, 24 Jul 2019 02:13:16 +0300 (MSK) Date: Wed, 24 Jul 2019 02:13:16 +0300 From: Vitaly Chikunov To: Mimi Zohar Cc: linux-integrity@vger.kernel.org Subject: Re: [PATCH v3 2/2] ima-evm-utils: log unknown keyid's as errors Message-ID: <20190723231316.rnngionrm4lrtyct@altlinux.org> Mail-Followup-To: Mimi Zohar , linux-integrity@vger.kernel.org References: <1563460194-21569-1-git-send-email-zohar@linux.ibm.com> <1563460194-21569-2-git-send-email-zohar@linux.ibm.com> <20190723221801.ycvdj5eajlrozxf6@altlinux.org> <1563922756.4294.16.camel@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1563922756.4294.16.camel@linux.ibm.com> User-Agent: NeoMutt/20171215-106-ac61c7 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Mimi, On Tue, Jul 23, 2019 at 06:59:16PM -0400, Mimi Zohar wrote: > On Wed, 2019-07-24 at 01:18 +0300, Vitaly Chikunov wrote: > > On Thu, Jul 18, 2019 at 10:29:54AM -0400, Mimi Zohar wrote: > > > Each tima a new unknown key is encountered, emit a message of the format > > > "key #: unknown". The individual files using unknown keys are > > > then only logged in verbose mode. > > > > > > Signed-off-by: Mimi Zohar > > > --- > > > src/libimaevm.c | 21 +++++++++++++++++---- > > > 1 file changed, 17 insertions(+), 4 deletions(-) > > > > > > diff --git a/src/libimaevm.c b/src/libimaevm.c > > > index 43eb4ef2412c..d2194a6ca0f8 100644 > > > --- a/src/libimaevm.c > > > +++ b/src/libimaevm.c > > > @@ -402,13 +402,26 @@ static struct public_key_entry *public_keys = NULL; > > > > > > static EVP_PKEY *find_keyid(uint32_t keyid) > > > { > > > - struct public_key_entry *entry; > > > + struct public_key_entry *entry, *tail = public_keys; > > > > If user specified in `-k` filename that does not exist no key is added > > into public_keys and it remains NULL. > > Right, just the keyid is added and an error message is emitted. > > > > > > + int i = 1; > > > > > > for (entry = public_keys; entry != NULL; entry = entry->next) { > > > if (entry->keyid == keyid) > > > return entry->key; > > > + i++; > > > + tail = entry; > > > } > > > - return NULL; > > > + > > > + /* add unknown keys to list */ > > > + entry = calloc(1, sizeof(struct public_key_entry)); > > > + if (!entry) { > > > + perror("calloc"); > > > + return 0; > > > + } > > > + entry->keyid = keyid; > > > + tail->next = entry; > > > > In that case here is SIGSEGV when user try to ima_verify. > > find_keyid() returns NULL, which is checked before being used. > šThere's only one caller of this function. find_keyid does not return since tail is NULL, thus there is null dereference in `tail->next`. > Do you have a test case to reproduce this bug? ima-evm-utils/tests ((31b5f50...))$ rm sha1.txt ima-evm-utils/tests ((31b5f50...))$ touch sha1.txt ima-evm-utils/tests ((31b5f50...))$ evmctl ima_sign -k test-rsa1024.key -a sha1 --xattr-user sha1.txt ima-evm-utils/tests ((31b5f50...))$ evmctl ima_verify -k /absent --xattr-user sha1.txt Failed to open keyfile: /absent Segmentation fault 31b5f50 is head of your git next branch. I temporary fixed like this: - tail->next = entry; + if (tail) + tail->next = entry; + else + public_keys = entry;