Re: [PATCH v3 2/3] IMA: Add log statements for failure conditions.

[Tushar Sugandhi]

On 2020-02-12 6:47 a.m., Mimi Zohar wrote:
> Hi Tushar,
>
> Please remove the period at the end of the ÂSubject line.
Thanks. I will fix it in the next iteration.
> On Tue, 2020-02-11 at 15:14 -0800, Tushar Sugandhi wrote:
> > process_buffer_measurement() does not have log messages for failure
> > conditions.
> >
> > This change adds a log statement in the above function.
>
> I agree some form of notification needs to be added. ÂThe question is
> whether the failure should be audited or a kernel message emitted.
>  ÂIMA emits audit messages (integrity_audit_msg) for a number of
> reasons - on failure to calculate a file hash, invalid policy rules,
> failure to communicate with the TPM, signature verification errors,
> etc.
I believe both IMA audit messages and kernel message should be emitted -
for better discoverability and diagnosability.
> > Signed-off-by: Tushar Sugandhi <tusharsu@xxxxxxxxxxxxxxxxxxx>
> > Reviewed-by: Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx>
> > Suggested-by: Joe Perches <joe@xxxxxxxxxxx>
> > ---
> >   security/integrity/ima/ima_main.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> > index 9fe949c6a530..6e1576d9eb48 100644
> > --- a/security/integrity/ima/ima_main.c
> > +++ b/security/integrity/ima/ima_main.c
> > @@ -757,6 +757,9 @@ void process_buffer_measurement(const void *buf, int size,
> >   		ima_free_template_entry(entry);
> >   
> >   out:
> > +	if (ret < 0)
> > +		pr_err("%s: failed, result: %d\n", __func__, ret);
> > +
> >   	return;
> >   }
> >   
>
> With 3/3 "IMA: Add module name and base name prefix to log", the
> resulting message will be "KBUILD_MODNAME: KBUILD_BASENAME: func:".
>  ÂIsn't that a bit much?
For this specific message, it will look like below.
"ima: ima_main: process_buffer_measurement: failed, result: %d"

In general, adding KBUILD_BASENAME seems helpful to pinpoint the 
location of the issue.


> Mimi