Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755843AbbLGVa6 (ORCPT ); Mon, 7 Dec 2015 16:30:58 -0500 Received: from mail-ig0-f179.google.com ([209.85.213.179]:37346 "EHLO mail-ig0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932972AbbLGVay (ORCPT ); Mon, 7 Dec 2015 16:30:54 -0500 MIME-Version: 1.0 In-Reply-To: <1449523512-29200-2-git-send-email-jann@thejh.net> References: <20151207203824.GA27364@pc.thejh.net> <1449523512-29200-1-git-send-email-jann@thejh.net> <1449523512-29200-2-git-send-email-jann@thejh.net> Date: Mon, 7 Dec 2015 13:30:53 -0800 Message-ID: Subject: Re: [PATCH 1/2] security: let security modules use PTRACE_MODE_* with bitmasks From: Kees Cook To: Jann Horn Cc: Andrew Morton , Casey Schaufler , Oleg Nesterov , Ingo Molnar , James Morris , "Serge E. Hallyn" , Andy Shevchenko , Andy Lutomirski , Al Viro , "Eric W. Biederman" , Joe Perches , Thomas Gleixner , Michael Kerrisk , LKML , Linux-MM , linux-security-module , Linux API , "security@kernel.org" , Willy Tarreau Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2494 Lines: 73 On Mon, Dec 7, 2015 at 1:25 PM, Jann Horn wrote: > It looks like smack and yama weren't aware that the ptrace mode > can have flags ORed into it - PTRACE_MODE_NOAUDIT until now, but > only for /proc/$pid/stat, and with the PTRACE_MODE_*CREDS patch, > all modes have flags ORed into them. > > Signed-off-by: Jann Horn Acked-by: Kees Cook -Kees > --- > security/smack/smack_lsm.c | 8 +++----- > security/yama/yama_lsm.c | 4 ++-- > 2 files changed, 5 insertions(+), 7 deletions(-) > > diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c > index ff81026..7c57c7f 100644 > --- a/security/smack/smack_lsm.c > +++ b/security/smack/smack_lsm.c > @@ -398,12 +398,10 @@ static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead, > */ > static inline unsigned int smk_ptrace_mode(unsigned int mode) > { > - switch (mode) { > - case PTRACE_MODE_READ: > - return MAY_READ; > - case PTRACE_MODE_ATTACH: > + if (mode & PTRACE_MODE_ATTACH) > return MAY_READWRITE; > - } > + if (mode & PTRACE_MODE_READ) > + return MAY_READ; > > return 0; > } > diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c > index d3c19c9..cb6ed10 100644 > --- a/security/yama/yama_lsm.c > +++ b/security/yama/yama_lsm.c > @@ -281,7 +281,7 @@ static int yama_ptrace_access_check(struct task_struct *child, > int rc = 0; > > /* require ptrace target be a child of ptracer on attach */ > - if (mode == PTRACE_MODE_ATTACH) { > + if (mode & PTRACE_MODE_ATTACH) { > switch (ptrace_scope) { > case YAMA_SCOPE_DISABLED: > /* No additional restrictions. */ > @@ -307,7 +307,7 @@ static int yama_ptrace_access_check(struct task_struct *child, > } > } > > - if (rc) { > + if (rc && (mode & PTRACE_MODE_NOAUDIT) == 0) { > printk_ratelimited(KERN_NOTICE > "ptrace of pid %d was attempted by: %s (pid %d)\n", > child->pid, current->comm, current->pid); > -- > 2.1.4 > -- Kees Cook Chrome OS & Brillo Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/