[PATCH ghak82 v3] audit: Fix extended comparison of GID/EGID

[Paul Moore]

On Tue, Jun 5, 2018 at 5:00 AM Ondrej Mosnacek <omosnace at redhat.com> wrote:
> The audit_filter_rules() function in auditsc.c used the in_[e]group_p()
> functions to check GID/EGID match, but these functions use the current
> task's credentials, while the comparison should use the credentials of
> the task given to audit_filter_rules() as a parameter (tsk).
>
> Note that we can use group_search(cred->group_info, ...) as a
> replacement for both in_group_p and in_egroup_p as these functions only
> compare the parameter to cred->fsgid/egid and then call group_search.
>
> In fact, the usage of in_group_p was even more incorrect: it compares to
> cred->fsgid (which is usually equal to cred->egid) and not cred->gid.
>
> GitHub issue:
> https://github.com/linux-audit/audit-kernel/issues/82
>
> Fixes: 37eebe39c973 ("audit: improve GID/EGID comparation logic")
> Signed-off-by: Ondrej Mosnacek <omosnace at redhat.com>
> ---
>  kernel/auditsc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Merged, thanks.

> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index ceb1c4596c51..518a3336a697 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -494,20 +494,20 @@ static int audit_filter_rules(struct task_struct *tsk,
>                         result = audit_gid_comparator(cred->gid, f->op, f->gid);
>                         if (f->op == Audit_equal) {
>                                 if (!result)
> -                                       result = in_group_p(f->gid);
> +                                       result = groups_search(cred->group_info, f->gid);
>                         } else if (f->op == Audit_not_equal) {
>                                 if (result)
> -                                       result = !in_group_p(f->gid);
> +                                       result = !groups_search(cred->group_info, f->gid);
>                         }
>                         break;
>                 case AUDIT_EGID:
>                         result = audit_gid_comparator(cred->egid, f->op, f->gid);
>                         if (f->op == Audit_equal) {
>                                 if (!result)
> -                                       result = in_egroup_p(f->gid);
> +                                       result = groups_search(cred->group_info, f->gid);
>                         } else if (f->op == Audit_not_equal) {
>                                 if (result)
> -                                       result = !in_egroup_p(f->gid);
> +                                       result = !groups_search(cred->group_info, f->gid);
>                         }
>                         break;
>                 case AUDIT_SGID:
> --
> 2.17.1
>


-- 
paul moore
www.paul-moore.com