Messages in this thread | | | From | Todd Kjos <> | Date | Fri, 8 Oct 2021 14:24:15 -0700 | Subject | Re: [PATCH v4 3/3] binder: use euid from cred instead of using task |
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On Fri, Oct 8, 2021 at 2:12 PM Paul Moore <paul@paul-moore.com> wrote: > > On Wed, Oct 6, 2021 at 8:46 PM Todd Kjos <tkjos@google.com> wrote: > > > > Set a transaction's sender_euid from the 'struct cred' > > saved at binder_open() instead of looking up the euid > > from the binder proc's 'struct task'. This ensures > > the euid is associated with the security context that > > of the task that opened binder. > > > > Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") > > Signed-off-by: Todd Kjos <tkjos@google.com> > > Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com> > > Cc: stable@vger.kernel.org # 4.4+ > > --- > > v3: added this patch to series > > > > drivers/android/binder.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > This is an interesting ordering of the patches. Unless I'm missing > something I would have expected patch 3/3 to come first, followed by > 2/3, with patch 1/3 at the end; basically the reverse of what was > posted here.
2/3 and 3/3 both depend on 1/3 (add "cred" member of struct binder_proc). I kept that in 1/3 to keep that patch the same as what had already been reviewed. I didn't think much about the ordering between 2/3 and 3/3 -- but I agree that it would have been sensible to reverse their order.
> > My reading of the previous thread was that Casey has made his peace > with these changes so unless anyone has any objections I'll plan on > merging 2/3 and 3/3 into selinux/stable-5.15 and merging 1/3 into > selinux/next.
Thanks Paul. I'm not familiar with the branch structure, but you need 1/3 in selinux/stable-5.15 to resolve the dependency on proc->cred.
> > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > > index 989afd0804ca..26382e982c5e 100644 > > --- a/drivers/android/binder.c > > +++ b/drivers/android/binder.c > > @@ -2711,7 +2711,7 @@ static void binder_transaction(struct binder_proc *proc, > > t->from = thread; > > else > > t->from = NULL; > > - t->sender_euid = task_euid(proc->tsk); > > + t->sender_euid = proc->cred->euid; > > t->to_proc = target_proc; > > t->to_thread = target_thread; > > t->code = tr->code; > > -- > > 2.33.0.800.g4c38ced690-goog > > -- > paul moore > www.paul-moore.com
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