RE: [PATCH v2 6/6] ima: Fix return value of ima_write_policy()

[Krzysztof Struczynski <krzysztof.struczynski@xxxxxxxxxx>]

Hi Mimi,

> -----Original Message-----
> From: Mimi Zohar [mailto:zohar@xxxxxxxxxxxxx]
> Sent: Tuesday, April 28, 2020 7:47 PM
> To: Roberto Sassu <roberto.sassu@xxxxxxxxxx>; Krzysztof Struczynski
> <krzysztof.struczynski@xxxxxxxxxx>
> Cc: linux-integrity@xxxxxxxxxxxxxxx; linux-security-module@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; Silviu Vlasceanu
> <Silviu.Vlasceanu@xxxxxxxxxx>; Krzysztof Struczynski
> <krzysztof.struczynski@xxxxxxxxxx>; stable@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 6/6] ima: Fix return value of ima_write_policy()
> 
> Hi Roberto,
> 
> On Mon, 2020-04-27 at 12:31 +0200, Roberto Sassu wrote:
> > This patch fixes the return value of ima_write_policy() when a new
> > policy is directly passed to IMA and the current policy requires
> > appraisal of the file containing the policy. Currently, if appraisal
> > is not in ENFORCE mode,
> > ima_write_policy() returns 0 and leads user space applications to an
> > endless loop. Fix this issue by denying the operation regardless of
> > the appraisal mode.
> >
> > Changelog
> >
> > v1:
> > - deny the operation in all cases (suggested by Mimi, Krzysztof)
> 
> Relatively recently, people have moved away from including the "Changelog"
> in the upstream commit. (I'm removing them now.)
> 
> >
> > Cc: stable@xxxxxxxxxxxxxxx # 4.10.x
> > Fixes: 19f8a84713edc ("ima: measure and appraise the IMA policy
> > itself")
> > Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
> 
> Without the Changelog, the only way of acknowledging people's contributions
> is by including their tags.  Krzysztof, did you want to add your "Reviewed-by"
> tag?

Please add:
Reviewed-by: Krzysztof Struczynski <krzysztof.struczynski@xxxxxxxxxx>

Thanks,
Krzysztof

> 
> > ---
> 
> People have started putting the Changelog or any comments immediately
> below the separator "---" here.
> 
> thanks,
> 
> Mimi
> 
> >  security/integrity/ima/ima_fs.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > diff --git a/security/integrity/ima/ima_fs.c
> > b/security/integrity/ima/ima_fs.c index 8b030a1c5e0d..e3fcad871861
> > 100644
> > --- a/security/integrity/ima/ima_fs.c
> > +++ b/security/integrity/ima/ima_fs.c
> > @@ -338,8 +338,7 @@ static ssize_t ima_write_policy(struct file *file, const
> char __user *buf,
> >  		integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
> >  				    "policy_update", "signed policy required",
> >  				    1, 0);
> > -		if (ima_appraise & IMA_APPRAISE_ENFORCE)
> > -			result = -EACCES;
> > +		result = -EACCES;
> >  	} else {
> >  		result = ima_parse_add_rule(data);
> >  	}