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

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

[Richard Guy Briggs]

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);
 	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

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

[Eric Paris]

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...


>  	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));

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@redhat.com>
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

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

[Richard Guy Briggs]

On 14/02/14, Richard Guy Briggs wrote:
> 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:

Sorry, pulled the trigger too fast:

---
 kernel/auditsc.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 6874c1f..3023d03 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2406,12 +2406,18 @@ 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, " 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


> - RGB

- RGB

--
Richard Guy Briggs <rbriggs@redhat.com>
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

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

[Eric Paris]

On Fri, 2014-02-14 at 15:52 -0500, Richard Guy Briggs wrote:
> On 14/02/14, Richard Guy Briggs wrote:
> > 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:
> 
> Sorry, pulled the trigger too fast:
> 
> ---
>  kernel/auditsc.c |    6 ++++++
>  1 files changed, 6 insertions(+), 0 deletions(-)
> 
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 6874c1f..3023d03 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -2406,12 +2406,18 @@ 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);

missing '='   but this isn't what audit_get_context() does...   it's
crappy naming...    I'd think a combo of audit_dummy_context() and
current->audit_context would be most appropriate.

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

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 15:52 -0500, Richard Guy Briggs wrote:
> > On 14/02/14, Richard Guy Briggs wrote:
> > > 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:
> > 
> > Sorry, pulled the trigger too fast:
> > 
> > ---
> >  kernel/auditsc.c |    6 ++++++
> >  1 files changed, 6 insertions(+), 0 deletions(-)
> > 
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index 6874c1f..3023d03 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -2406,12 +2406,18 @@ 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);
> 
> missing '='   but this isn't what audit_get_context() does...   it's
> crappy naming...    I'd think a combo of audit_dummy_context() and
> current->audit_context would be most appropriate.

Ok.  I think I finally understand audit_dummy_context().  Thanks for the
hint.  However, it appears it is not useful in this sitation, since if
there is an audit_context, even a dummy context, it appears arch is
filled in.

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
@@ -2406,12 +2406,18 @@ void audit_core_dumps(long signr)
 void __audit_seccomp(unsigned long syscall, long signr, int code)
 {
 	struct audit_buffer *ab;
+	struct audit_context *context = current->audit_context;
 
 	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, "%x", context->arch);
+	else
+		audit_log_format(ab, "(null)");
 	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@redhat.com>
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

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

[Eric Paris]

On Tue, 2014-02-18 at 15:50 -0500, Richard Guy Briggs wrote:
> On 14/02/14, Eric Paris wrote:
> > On Fri, 2014-02-14 at 15:52 -0500, Richard Guy Briggs wrote:
> > > On 14/02/14, Richard Guy Briggs wrote:
> > > > 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:
> > > 
> > > Sorry, pulled the trigger too fast:
> > > 
> > > ---
> > >  kernel/auditsc.c |    6 ++++++
> > >  1 files changed, 6 insertions(+), 0 deletions(-)
> > > 
> > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > index 6874c1f..3023d03 100644
> > > --- a/kernel/auditsc.c
> > > +++ b/kernel/auditsc.c
> > > @@ -2406,12 +2406,18 @@ 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);
> > 
> > missing '='   but this isn't what audit_get_context() does...   it's
> > crappy naming...    I'd think a combo of audit_dummy_context() and
> > current->audit_context would be most appropriate.
> 
> Ok.  I think I finally understand audit_dummy_context().  Thanks for the
> hint.  However, it appears it is not useful in this sitation, since if
> there is an audit_context, even a dummy context, it appears arch is
> filled in.

get a good commit message and feel free to add my Acked-by.

-Eric
> 
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> @@ -2406,12 +2406,18 @@ void audit_core_dumps(long signr)
>  void __audit_seccomp(unsigned long syscall, long signr, int code)
>  {
>  	struct audit_buffer *ab;
> +	struct audit_context *context = current->audit_context;
>  
>  	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, "%x", context->arch);
> +	else
> +		audit_log_format(ab, "(null)");
>  	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@redhat.com>
> 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

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

[Steve Grubb]

On Tuesday, February 18, 2014 03:50:44 PM Richard Guy Briggs wrote:
> > missing '='   but this isn't what audit_get_context() does...   it's
> > crappy naming...    I'd think a combo of audit_dummy_context() and
> > current->audit_context would be most appropriate.
> 
> Ok.  I think I finally understand audit_dummy_context().  Thanks for the
> hint.  However, it appears it is not useful in this sitation, since if
> there is an audit_context, even a dummy context, it appears arch is
> filled in.
> 
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> @@ -2406,12 +2406,18 @@ void audit_core_dumps(long signr)
>  void __audit_seccomp(unsigned long syscall, long signr, int code)
>  {
>         struct audit_buffer *ab;
> +       struct audit_context *context = current->audit_context;
>  
>         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, "%x", context->arch);
> +       else
> +               audit_log_format(ab, "(null)");
>         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));

Is there anything that could be passed by the caller that might identify the 
syscall ABI when this call was blocked? '(null)' still makes syscall number 
uninterpretable.

-Steve

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

[Richard Guy Briggs]

On 14/02/18, Steve Grubb wrote:
> On Tuesday, February 18, 2014 03:50:44 PM Richard Guy Briggs wrote:
> > > missing '='   but this isn't what audit_get_context() does...   it's
> > > crappy naming...    I'd think a combo of audit_dummy_context() and
> > > current->audit_context would be most appropriate.
> > 
> > Ok.  I think I finally understand audit_dummy_context().  Thanks for the
> > hint.  However, it appears it is not useful in this sitation, since if
> > there is an audit_context, even a dummy context, it appears arch is
> > filled in.
> > 
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > @@ -2406,12 +2406,18 @@ void audit_core_dumps(long signr)
> >  void __audit_seccomp(unsigned long syscall, long signr, int code)
> >  {
> >         struct audit_buffer *ab;
> > +       struct audit_context *context = current->audit_context;
> >  
> >         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, "%x", context->arch);
> > +       else
> > +               audit_log_format(ab, "(null)");
> >         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));
> 
> Is there anything that could be passed by the caller that might identify the 
> syscall ABI when this call was blocked? '(null)' still makes syscall number 
> uninterpretable.

This is the way it is done in the existing record that prints a syscall
record in audit_log_exit().

It is set by the arch-dependent assembler linkage for
__audit_syscall_entry() or set by the arch-dependent ptrace code that
calls audit_syscall_entry().  In some arches there are a couple of
choices.


To pass this in to __audit_seccomp() as an arg, I'd have to add that arg
to:
	__audit_seccomp()
	audit_seccomp()
	__secure_computing()
	secure_computing()


As you've pointed out in IRC, there is a syscall_get_arch(current, regs)
that could be used to get the arch when an audit context is not yet created.

I was just looking for something like that...  I am noticing that all
arches call a variant of syscall_trace_enter() which first calls
secure_computing() [which eventually calls __audit_seccomp()] *before*
calling audit_syscall_entry() [which eventually sets context->arch].  So
I'm not sure how task->audit_context->arch got set...  Perhaps
__audit_syscall_entry() should just call syscall_get_arch() instead of
lugging it through the stack like it presently does.

Is this going to give the same information?  (I guess I should be able
to answer that question...)

> -Steve

- RGB

--
Richard Guy Briggs <rbriggs@redhat.com>
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

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

[Richard Guy Briggs]

On 14/02/18, Richard Guy Briggs wrote:
> On 14/02/18, Steve Grubb wrote:
> > On Tuesday, February 18, 2014 03:50:44 PM Richard Guy Briggs wrote:
> > > > missing '='   but this isn't what audit_get_context() does...   it's
> > > > crappy naming...    I'd think a combo of audit_dummy_context() and
> > > > current->audit_context would be most appropriate.
> > > 
> > > Ok.  I think I finally understand audit_dummy_context().  Thanks for the
> > > hint.  However, it appears it is not useful in this sitation, since if
> > > there is an audit_context, even a dummy context, it appears arch is
> > > filled in.
> > > 
> > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > @@ -2406,12 +2406,18 @@ void audit_core_dumps(long signr)
> > >  void __audit_seccomp(unsigned long syscall, long signr, int code)
> > >  {
> > >         struct audit_buffer *ab;
> > > +       struct audit_context *context = current->audit_context;
> > >  
> > >         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, "%x", context->arch);
> > > +       else
> > > +               audit_log_format(ab, "(null)");
> > >         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));
> > 
> > Is there anything that could be passed by the caller that might identify the 
> > syscall ABI when this call was blocked? '(null)' still makes syscall number 
> > uninterpretable.
> 
> This is the way it is done in the existing record that prints a syscall
> record in audit_log_exit().
> 
> It is set by the arch-dependent assembler linkage for
> __audit_syscall_entry() or set by the arch-dependent ptrace code that
> calls audit_syscall_entry().  In some arches there are a couple of
> choices.
> 
> 
> To pass this in to __audit_seccomp() as an arg, I'd have to add that arg
> to:
> 	__audit_seccomp()
> 	audit_seccomp()
> 	__secure_computing()
> 	secure_computing()
> 
> 
> As you've pointed out in IRC, there is a syscall_get_arch(current, regs)
> that could be used to get the arch when an audit context is not yet created.

s390x architecture doesn't have it defined.  :(

> I was just looking for something like that...  I am noticing that all
> arches call a variant of syscall_trace_enter() which first calls
> secure_computing() [which eventually calls __audit_seccomp()] *before*
> calling audit_syscall_entry() [which eventually sets context->arch].  So
> I'm not sure how task->audit_context->arch got set...  Perhaps
> __audit_syscall_entry() should just call syscall_get_arch() instead of
> lugging it through the stack like it presently does.
> 
> Is this going to give the same information?  (I guess I should be able
> to answer that question...)
> 
> > -Steve
> 
> - RGB

- RGB

--
Richard Guy Briggs <rbriggs@redhat.com>
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

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

[Richard Guy Briggs]

On 14/02/19, Richard Guy Briggs wrote:
> On 14/02/18, Richard Guy Briggs wrote:
> > On 14/02/18, Steve Grubb wrote:
> > > On Tuesday, February 18, 2014 03:50:44 PM Richard Guy Briggs wrote:
> > > > > missing '='   but this isn't what audit_get_context() does...   it's
> > > > > crappy naming...    I'd think a combo of audit_dummy_context() and
> > > > > current->audit_context would be most appropriate.
> > > > 
> > > > Ok.  I think I finally understand audit_dummy_context().  Thanks for the
> > > > hint.  However, it appears it is not useful in this sitation, since if
> > > > there is an audit_context, even a dummy context, it appears arch is
> > > > filled in.
> > > > 
> > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > > > @@ -2406,12 +2406,18 @@ void audit_core_dumps(long signr)
> > > >  void __audit_seccomp(unsigned long syscall, long signr, int code)
> > > >  {
> > > >         struct audit_buffer *ab;
> > > > +       struct audit_context *context = current->audit_context;
> > > >  
> > > >         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, "%x", context->arch);
> > > > +       else
> > > > +               audit_log_format(ab, "(null)");
> > > >         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));
> > > 
> > > Is there anything that could be passed by the caller that might identify the 
> > > syscall ABI when this call was blocked? '(null)' still makes syscall number 
> > > uninterpretable.
> > 
> > This is the way it is done in the existing record that prints a syscall
> > record in audit_log_exit().
> > 
> > It is set by the arch-dependent assembler linkage for
> > __audit_syscall_entry() or set by the arch-dependent ptrace code that
> > calls audit_syscall_entry().  In some arches there are a couple of
> > choices.
> > 
> > 
> > To pass this in to __audit_seccomp() as an arg, I'd have to add that arg
> > to:
> > 	__audit_seccomp()
> > 	audit_seccomp()
> > 	__secure_computing()
> > 	secure_computing()
> > 
> > 
> > As you've pointed out in IRC, there is a syscall_get_arch(current, regs)
> > that could be used to get the arch when an audit context is not yet created.
> 
> s390x architecture doesn't have it defined.  :(

It is defined, but is having trouble finding it...

> > I was just looking for something like that...  I am noticing that all
> > arches call a variant of syscall_trace_enter() which first calls
> > secure_computing() [which eventually calls __audit_seccomp()] *before*
> > calling audit_syscall_entry() [which eventually sets context->arch].  So
> > I'm not sure how task->audit_context->arch got set...  Perhaps
> > __audit_syscall_entry() should just call syscall_get_arch() instead of
> > lugging it through the stack like it presently does.
> > 
> > Is this going to give the same information?  (I guess I should be able
> > to answer that question...)
> > 
> > > -Steve
> > 
> > - RGB
> 
> - RGB

- RGB

--
Richard Guy Briggs <rbriggs@redhat.com>
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