From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Moore Subject: Re: [PATCH ghak95] audit: Do not log full CWD path on empty relative paths Date: Fri, 24 Aug 2018 11:00:35 -0400 Message-ID: References: <20180802114436.1209-1-omosnace@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com (ext-mx01.extmail.prod.ext.phx2.redhat.com [10.5.110.25]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9FD639A546 for ; Fri, 24 Aug 2018 15:00:50 +0000 (UTC) Received: from mail-lf1-f66.google.com (mail-lf1-f66.google.com [209.85.167.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 00F577F6B3 for ; Fri, 24 Aug 2018 15:00:49 +0000 (UTC) Received: by mail-lf1-f66.google.com with SMTP id g6-v6so6897951lfb.11 for ; Fri, 24 Aug 2018 08:00:48 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-audit-bounces@redhat.com Errors-To: linux-audit-bounces@redhat.com To: omosnace@redhat.com Cc: rgb@redhat.com, linux-audit@redhat.com List-Id: linux-audit@redhat.com On Thu, Aug 2, 2018 at 8:03 PM Paul Moore wrote: > > On Thu, Aug 2, 2018 at 7:45 AM Ondrej Mosnacek wrote: > > When a relative path has just a single component and we want to emit a > > nametype=PARENT record, the current implementation just reports the full > > CWD path (which is alrady available in the audit context). > > > > This is wrong for three reasons: > > 1. Wasting log space for redundant data (CWD path is already in the CWD > > record). > > 2. Inconsistency with other PATH records (if a relative PARENT directory > > path contains at least one component, only the verbatim relative path > > is logged). > > 3. In some syscalls (e.g. openat(2)) the relative path may not even be > > relative to the CWD, but to another directory specified as a file > > descriptor. In that case the logged path is simply plain wrong. > > > > This patch modifies this behavior to simply report "." in the > > aforementioned case, which is equivalent to an "empty" directory path > > and can be concatenated with the actual base directory path (CWD or > > dirfd from openat(2)-like syscall) once support for its logging is added > > later. In the meantime, defaulting to CWD as base directory on relative > > paths (as already done by the userspace tools) will be enough to achieve > > results equivalent to the current behavior. > > I have to ask the obvious question, if we already have the necessary > parent path in the CWD record, why do we need a nametype=parent PATH > record anyway? Can we safely remove it or will that cause problems > for Steve's userspace tools? As a reminder, these questions still need answers. > > See: https://github.com/linux-audit/audit-kernel/issues/95 > > > > Fixes: 9c937dcc7102 ("[PATCH] log more info for directory entry change events") > > Signed-off-by: Ondrej Mosnacek > > --- > > kernel/audit.c | 9 ++++----- > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/kernel/audit.c b/kernel/audit.c > > index 2a8058764aa6..4f18bd48eb4b 100644 > > --- a/kernel/audit.c > > +++ b/kernel/audit.c > > @@ -2127,28 +2127,27 @@ void audit_log_name(struct audit_context *context, struct audit_names *n, > > > > audit_log_format(ab, "item=%d", record_num); > > > > + audit_log_format(ab, " name="); > > if (path) > > - audit_log_d_path(ab, " name=", path); > > + audit_log_d_path(ab, NULL, path); > > else if (n->name) { > > switch (n->name_len) { > > case AUDIT_NAME_FULL: > > /* log the full path */ > > - audit_log_format(ab, " name="); > > audit_log_untrustedstring(ab, n->name->name); > > break; > > case 0: > > /* name was specified as a relative path and the > > * directory component is the cwd */ > > - audit_log_d_path(ab, " name=", &context->pwd); > > + audit_log_untrustedstring(ab, "."); > > break; > > default: > > /* log the name's directory component */ > > - audit_log_format(ab, " name="); > > audit_log_n_untrustedstring(ab, n->name->name, > > n->name_len); > > } > > } else > > - audit_log_format(ab, " name=(null)"); > > + audit_log_format(ab, "(null)"); > > > > if (n->ino != AUDIT_INO_UNSET) > > audit_log_format(ab, " inode=%lu" > > -- > > 2.17.1 > > > > > -- > paul moore > www.paul-moore.com -- paul moore www.paul-moore.com