| Date | Wed, 24 Nov 2021 16:22:50 +0200 | From | Jari Ruusu <> | Subject | Re: [PATCH 5.10 130/154] block: Check ADMIN before NICE for IOPRIO_CLASS_RT |
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Greg Kroah-Hartman wrote: > From: Alistair Delva <adelva@google.com> > > commit 94c4b4fd25e6c3763941bdec3ad54f2204afa992 upstream. [SNIP] > --- a/block/ioprio.c > +++ b/block/ioprio.c > @@ -69,7 +69,14 @@ int ioprio_check_cap(int ioprio) > > switch (class) { > case IOPRIO_CLASS_RT: > - if (!capable(CAP_SYS_NICE) && !capable(CAP_SYS_ADMIN)) > + /* > + * Originally this only checked for CAP_SYS_ADMIN, > + * which was implicitly allowed for pid 0 by security > + * modules such as SELinux. Make sure we check > + * CAP_SYS_ADMIN first to avoid a denial/avc for > + * possibly missing CAP_SYS_NICE permission. > + */ > + if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_NICE)) > return -EPERM; > fallthrough; > /* rt has prio field too */
What exactly is above patch trying to fix? It does not change control flow at all, and added comment is misleading.
-- Jari Ruusu 4096R/8132F189 12D6 4C3A DCDA 0AA4 27BD ACDF F073 3C80 8132 F189
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