Re: [PATCH] audit: add arch field to seccomp event log

[Richard Guy Briggs]

On 14/02/14, Eric Paris wrote:
> On Fri, 2014-02-14 at 15:23 -0500, Richard Guy Briggs wrote:
> > The AUDIT_SECCOMP record looks something like this:
> > 
> > type=SECCOMP msg=audit(1373478171.953:32775): auid=4325 uid=4325 gid=4325 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0 pid=12381 comm="test" sig=31 syscall=231 compat=0 ip=0x39ea8bca89 code=0x0
> > 
> > In order to determine what syscall 231 maps to, we need to have the arch= field right before it.
> > 
> > To see the event, compile this test.c program:
> > 
> > =====
> > int main(void)
> > {
> >         return seccomp_load(seccomp_init(SCMP_ACT_KILL));
> > }
> > =====
> > 
> > gcc -g test.c -o test -lseccomp
> > 
> > After running the program, find the record by:  ausearch --start recent -m SECCOMP -i
> > ---
> >  kernel/auditsc.c |    1 +
> >  1 files changed, 1 insertions(+), 0 deletions(-)
> > 
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 6874c1f..c464d44 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -2412,6 +2412,7 @@ void __audit_seccomp(unsigned long syscall, long signr, int code)
> >  		return;
> >  	audit_log_task(ab);
> >  	audit_log_format(ab, " sig=%ld", signr);
> > +	audit_log_format(ab, " arch=%x", current->audit_context->arch);
> 
> 
> What happens if the task does not have current->audit_context allocated?
> Seems possible if signr is non-zero...

I had assumed that since we got this far, that there was an audit
context.  This was my first patch:

---
 kernel/auditsc.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 6874c1f..ef16e02 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2406,12 +2406,19 @@ void audit_core_dumps(long signr)
 void __audit_seccomp(unsigned long syscall, long signr, int code)
 {
        struct audit_buffer *ab;
+       //struct audit_context *context audit_get_context(current, 0,
0);
 
        ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_SECCOMP);
        if (unlikely(!ab))
                return;
        audit_log_task(ab);
        audit_log_format(ab, " sig=%ld", signr);
+       //audit_log_format(ab, " arch=");
+       //if (context)
+               //audit_log_format(ab, "(null)");
+       //else
+               //audit_log_format(ab, "%x", context->arch);
+       audit_log_format(ab, " arch=%x", current->audit_context->arch);
        audit_log_format(ab, " syscall=%ld", syscall);
        audit_log_format(ab, " compat=%d", is_compat_task());
        audit_log_format(ab, " ip=0x%lx", KSTK_EIP(current));
-- 
1.7.1

> >  	audit_log_format(ab, " syscall=%ld", syscall);
> >  	audit_log_format(ab, " compat=%d", is_compat_task());
> >  	audit_log_format(ab, " ip=0x%lx", KSTK_EIP(current));
> 
> 

- RGB

--
Richard Guy Briggs <rbriggs@xxxxxxxxxx>
Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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