Re: [RFC PATCH ghak59 V1 3/6] audit: exclude user records from syscall context

On 2018-07-12 17:46, Richard Guy Briggs wrote: > On 2018-06-28 18:11, Paul Moore wrote: > > On Thu, Jun 14, 2018 at 4:23 PM Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: > > > Since the function audit_log_common_recv_msg() is shared by a number of > > > AUDIT_CONFIG_CHANGE and the entire range of AUDIT_USER_* record types, > > > and since the AUDIT_CONFIG_CHANGE message type has been converted to a > > > syscall accompanied record type, special-case the AUDIT_USER_* range of > > > messages so they remain standalone records. > > > > > > See: https://github.com/linux-audit/audit-kernel/issues/59 > > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > > > --- > > > kernel/audit.c | 12 +++++++++--- > > > 1 file changed, 9 insertions(+), 3 deletions(-) > > > > I think this is fine, but see my previous comment about combining 2/6 > > and 3/6 as a safety measure. > > This one I left as a seperate patch for discussion. We'd previously > talked about connecting all possible records with syscall records if > they exist, but this one I'm unsure about, since we don't really care > what userspace process is issuing this message. It is just the message > content itself that is important. Or is it? Are we concerned about > CAP_AUDIT_WRITE holders/abusers and want as much info about them as we > can get in case they go rogue or pear-shaped? I'm waiting on re-spinning this patchset because of this open question. Is connecting AUDIT_USER* records desirable or a liability?

> > > diff --git a/kernel/audit.c b/kernel/audit.c > > > index e469234..c8c2efc 100644 > > > --- a/kernel/audit.c > > > +++ b/kernel/audit.c > > > @@ -1057,7 +1057,8 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) > > > return err; > > > } > > > > > > -static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) > > > +static void __audit_log_common_recv_msg(struct audit_context *context, > > > + struct audit_buffer **ab, u16 msg_type) > > > { > > > uid_t uid = from_kuid(&init_user_ns, current_uid()); > > > pid_t pid = task_tgid_nr(current); > > > @@ -1067,7 +1068,7 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) > > > return; > > > } > > > > > > - *ab = audit_log_start(audit_context(), GFP_KERNEL, msg_type); > > > + *ab = audit_log_start(context, GFP_KERNEL, msg_type); > > > if (unlikely(!*ab)) > > > return; > > > audit_log_format(*ab, "pid=%d uid=%u", pid, uid); > > > @@ -1075,6 +1076,11 @@ static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) > > > audit_log_task_context(*ab); > > > } > > > > > > +static inline void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type) > > > +{ > > > + __audit_log_common_recv_msg(audit_context(), ab, msg_type); > > > +} > > > + > > > int is_audit_feature_set(int i) > > > { > > > return af.features & AUDIT_FEATURE_TO_MASK(i); > > > @@ -1341,7 +1347,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) > > > if (err) > > > break; > > > } > > > - audit_log_common_recv_msg(&ab, msg_type); > > > + __audit_log_common_recv_msg(NULL, &ab, msg_type); > > > if (msg_type != AUDIT_USER_TTY) > > > audit_log_format(ab, " msg='%.*s'", > > > AUDIT_MESSAGE_TEXT_MAX, > > > -- > > > 1.8.3.1 > > > > > > > > > -- > > paul moore > > www.paul-moore.com > > > > -- > > Linux-audit mailing list > > Linux-audit(a)redhat.com > > https://www.redhat.com/mailman/listinfo/linux-audit > > - RGB > > -- > Richard Guy Briggs <rgb(a)redhat.com&gt; > Sr. S/W Engineer, Kernel Security, Base Operating Systems > Remote, Ottawa, Red Hat Canada > IRC: rgb, SunRaycer > Voice: +1.647.777.2635, Internal: (81) 32635 > > -- > Linux-audit mailing list > Linux-audit(a)redhat.com > https://www.redhat.com/mailman/listinfo/linux-audit - RGB -- Richard Guy Briggs <rgb(a)redhat.com&gt; Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635