[PATCH v2] ima: instantiate the bprm_creds_for_exec() hook

[Mickaël Salaün]

On Thu, Dec 05, 2024 at 10:10:36PM -0500, Mimi Zohar wrote:
> On Thu, 2024-12-05 at 19:30 -0500, Paul Moore wrote:
> > On Dec  4, 2024 Mimi Zohar <zohar at linux.ibm.com> wrote:
> > > 
> > > Like direct file execution (e.g. ./script.sh), indirect file execution
> > > (e.g. sh script.sh) needs to be measured and appraised.  Instantiate
> > > the new security_bprm_creds_for_exec() hook to measure and verify the
> > > indirect file's integrity.  Unlike direct file execution, indirect file
> > > execution is optionally enforced by the interpreter.
> > > 
> > > Differentiate kernel and userspace enforced integrity audit messages.
> > > 
> > > Co-developed-by: Roberto Sassu <roberto.sassu at huawei.com>
> > > Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
> > > Signed-off-by: Mimi Zohar <zohar at linux.ibm.com>
> > > ---
> > > Changelog v3:
> > > - Mickael: add comment ima_bprm_creds_for_exec(), minor code cleanup,
> > >   add Co-developed-by tag.
> > > 
> > > Changelog v2:
> > > - Mickael: Use same audit messages with new audit message number
> > > - Stefan Berger: Return boolean from is_bprm_creds_for_exec()
> > > 
> > >  include/uapi/linux/audit.h            |  1 +
> > >  security/integrity/ima/ima_appraise.c | 27 +++++++++++++++++++++++--
> > >  security/integrity/ima/ima_main.c     | 29 +++++++++++++++++++++++++++
> > >  3 files changed, 55 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> > > index 75e21a135483..826337905466 100644
> > > --- a/include/uapi/linux/audit.h
> > > +++ b/include/uapi/linux/audit.h
> > > @@ -161,6 +161,7 @@
> > >  #define AUDIT_INTEGRITY_RULE	    1805 /* policy rule */
> > >  #define AUDIT_INTEGRITY_EVM_XATTR   1806 /* New EVM-covered xattr */
> > >  #define AUDIT_INTEGRITY_POLICY_RULE 1807 /* IMA policy rules */
> > > +#define AUDIT_INTEGRITY_DATA_CHECK  1808 /* Userspace enforced data integrity */
> > 
> > I worry that "DATA_CHECK" is a bit vague, should we change the name so
> > that there is some hint of either userspace enforcement or
> > AT_EXECVE_CHECK?
> > 
> > What about AUDIT_INTEGRITY_DATA_USER?
> 
> The emphasis should be on userspace - AUDIT_INTEGRITY_USERSPACE.

Looks good, I'll send a new patch series with this change, following
https://lore.kernel.org/all/20241205160925.230119-9-mic@digikod.net/