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SubjectRe: [PATCH GHAK16 V5 00/10] capabilities: do not audit log BPRM_FCAPS on set*id
On 2017-10-11 20:57, Richard Guy Briggs wrote:
> The audit subsystem is adding a BPRM_FCAPS record when auditing setuid
> application execution (SYSCALL execve). This is not expected as it was
> supposed to be limited to when the file system actually had capabilities
> in an extended attribute. It lists all capabilities making the event
> really ugly to parse what is happening. The PATH record correctly
> records the setuid bit and owner. Suppress the BPRM_FCAPS record on
> set*id.

<crickets>

Serge? James? Can one of you two take this via your trees since Paul
has backed down citing (reasonably) that it is mostly capabilities
patches rather than audit?

> See: https://github.com/linux-audit/audit-kernel/issues/16
>
> The first to eighth patches just massage the logic to make it easier to
> understand. Some of them could be squashed together.
>
> The patch that resolves this issue is the ninth.
>
> It would be possible to address the original issue with a change of
> "!uid_eq(new->euid, root_uid) || !uid_eq(new->uid, root_uid)"
> to
> "!(uid_eq(new->euid, root_uid) || uid_eq(new->uid, root_uid))"
> but it took me long enough to understand this logic that I don't think
> I'd be doing any favours by leaving it this difficult to understand.
>
> The final patch attempts to address all the conditions that need logging
> based on mailing list conversations, recoginizing there is probably some
> duplication in the logic.
>
> Passes: (ltp 20170516)
> ./runltp -f syscalls -s cap
> ./runltp -f securebits
> ./runltp -f cap_bounds
> ./runltp -f filecaps
> make TARGETS=capabilities kselftest (when run locally, fails over nfs)
>
> Since this is mostly capabilities related rather than audit, could this go
> through the capabilites (Serge) or security (James) trees please? Thanks!
>
> v5
> rebase on linux-security/next 4.14-rc2
> added comment block header to handle_privileged_root()
> moved comment in handle_privileged_root()
> moved root_privileged() check back into handle_privileged_root()
>
> v4
> rebase on kees' 4.13 commoncap changes
> minor local func renames
>
> v3
> refactor into several sub-functions
> convert most macros to inline funcs
>
> v2
> use macros to clarify intent of calculations
> fix original logic error
> address additional audit logging conditions
>
> Richard Guy Briggs (10):
> capabilities: factor out cap_bprm_set_creds privileged root
> capabilities: intuitive names for cap gain status
> capabilities: rename has_cap to has_fcap
> capabilities: use root_priveleged inline to clarify logic
> capabilities: use intuitive names for id changes
> capabilities: move audit log decision to function
> capabilities: remove a layer of conditional logic
> capabilities: invert logic for clarity
> capabilities: fix logic for effective root or real root
> capabilities: audit log other surprising conditions
>
> security/commoncap.c | 193 ++++++++++++++++++++++++++++++++++-----------------
> 1 file changed, 128 insertions(+), 65 deletions(-)
>
> --
> 1.8.3.1
>
> --
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- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635

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