From patchwork Sat May 9 19:40:53 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 11538501 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3B13D92A for ; Sat, 9 May 2020 19:44:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 27961208DB for ; Sat, 9 May 2020 19:44:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728433AbgEIToY (ORCPT ); Sat, 9 May 2020 15:44:24 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:53380 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727938AbgEIToX (ORCPT ); Sat, 9 May 2020 15:44:23 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jXVOY-0000ls-R6; Sat, 09 May 2020 13:44:22 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jXVOX-0006Xr-QE; Sat, 09 May 2020 13:44:22 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Cc: Linus Torvalds , Oleg Nesterov , Jann Horn , Kees Cook , Greg Ungerer , Rob Landley , Bernd Edlinger , , Al Viro , Alexey Dobriyan , Andrew Morton , Casey Schaufler , linux-security-module@vger.kernel.org, James Morris , "Serge E. Hallyn" , Andy Lutomirski References: <87h7wujhmz.fsf@x220.int.ebiederm.org> <87sgga6ze4.fsf@x220.int.ebiederm.org> <87v9l4zyla.fsf_-_@x220.int.ebiederm.org> Date: Sat, 09 May 2020 14:40:53 -0500 In-Reply-To: <87v9l4zyla.fsf_-_@x220.int.ebiederm.org> (Eric W. Biederman's message of "Sat, 09 May 2020 14:40:17 -0500") Message-ID: <87pnbczyka.fsf_-_@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 X-XM-SPF: eid=1jXVOX-0006Xr-QE;;;mid=<87pnbczyka.fsf_-_@x220.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19q9NmVU84Mw9oy22ZcRjrINLYW7zrSIoA= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa03.xmission.com X-Spam-Level: ** X-Spam-Status: No, score=2.5 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TooManySym_01,XMGappySubj_01,XMNoVowels,XMSubLong autolearn=disabled version=3.4.2 X-Spam-Virus: No X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4999] * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.5 XMGappySubj_01 Very gappy subject * 0.7 XMSubLong Long Subject * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa03 0; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: ; sa03 0; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: **; X-Spam-Relay-Country: X-Spam-Timing: total 360 ms - load_scoreonly_sql: 0.03 (0.0%), signal_user_changed: 4.3 (1.2%), b_tie_ro: 2.9 (0.8%), parse: 1.09 (0.3%), extract_message_metadata: 12 (3.5%), get_uri_detail_list: 1.82 (0.5%), tests_pri_-1000: 11 (3.1%), tests_pri_-950: 1.06 (0.3%), tests_pri_-900: 0.82 (0.2%), tests_pri_-90: 56 (15.5%), check_bayes: 55 (15.2%), b_tokenize: 6 (1.8%), b_tok_get_all: 7 (2.0%), b_comp_prob: 1.86 (0.5%), b_tok_touch_all: 36 (10.1%), b_finish: 0.70 (0.2%), tests_pri_0: 262 (72.6%), check_dkim_signature: 0.38 (0.1%), check_dkim_adsp: 2.5 (0.7%), poll_dns_idle: 1.15 (0.3%), tests_pri_10: 2.6 (0.7%), tests_pri_500: 7 (1.8%), rewrite_mail: 0.00 (0.0%) Subject: [PATCH 1/5] exec: Call cap_bprm_set_creds directly from prepare_binprm X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The function cap_bprm_set_creds is the only instance of security_bprm_set_creds that does something for the primary executable file and for every interpreter the rest of the implementations of security_bprm_set_creds do something only for the primary executable file even if that file is a shell script. The function cap_bprm_set_creds is also special in that it is called even when CONFIG_SECURITY is unset. So calling cap_bprm_set_creds separately to make these two cases explicit, and allow future changes to take advantages of these differences to simplify the code. Signed-off-by: "Eric W. Biederman" --- fs/exec.c | 4 ++++ include/linux/security.h | 2 +- security/commoncap.c | 1 - 3 files changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index b0620d5ebc66..765bfd51a546 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1641,6 +1641,10 @@ int prepare_binprm(struct linux_binprm *bprm) return retval; bprm->called_set_creds = 1; + retval = cap_bprm_set_creds(bprm); + if (retval) + return retval; + memset(bprm->buf, 0, BINPRM_BUF_SIZE); return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos); } diff --git a/include/linux/security.h b/include/linux/security.h index a8d9310472df..c1aa1638429a 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -571,7 +571,7 @@ static inline int security_vm_enough_memory_mm(struct mm_struct *mm, long pages) static inline int security_bprm_set_creds(struct linux_binprm *bprm) { - return cap_bprm_set_creds(bprm); + return 0; } static inline int security_bprm_check(struct linux_binprm *bprm) diff --git a/security/commoncap.c b/security/commoncap.c index f4ee0ae106b2..3757988abe42 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -1346,7 +1346,6 @@ static struct security_hook_list capability_hooks[] __lsm_ro_after_init = { LSM_HOOK_INIT(ptrace_traceme, cap_ptrace_traceme), LSM_HOOK_INIT(capget, cap_capget), LSM_HOOK_INIT(capset, cap_capset), - LSM_HOOK_INIT(bprm_set_creds, cap_bprm_set_creds), LSM_HOOK_INIT(inode_need_killpriv, cap_inode_need_killpriv), LSM_HOOK_INIT(inode_killpriv, cap_inode_killpriv), LSM_HOOK_INIT(inode_getsecurity, cap_inode_getsecurity),