diff options
| author | Alistair Delva <[email protected]> | 2021-11-15 18:16:55 +0000 |
|---|---|---|
| committer | Jens Axboe <[email protected]> | 2021-11-15 14:28:59 -0700 |
| commit | 94c4b4fd25e6c3763941bdec3ad54f2204afa992 (patch) | |
| tree | 1781f563bb78fffa586da1a565b59308d009dbd8 | |
| parent | fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff) | |
block: Check ADMIN before NICE for IOPRIO_CLASS_RT
Booting to Android userspace on 5.14 or newer triggers the following
SELinux denial:
avc: denied { sys_nice } for comm="init" capability=23
scontext=u:r:init:s0 tcontext=u:r:init:s0 tclass=capability
permissive=0
Init is PID 0 running as root, so it already has CAP_SYS_ADMIN. For
better compatibility with older SEPolicy, check ADMIN before NICE.
Fixes: 9d3a39a5f1e4 ("block: grant IOPRIO_CLASS_RT to CAP_SYS_NICE")
Signed-off-by: Alistair Delva <[email protected]>
Cc: Khazhismel Kumykov <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: Serge Hallyn <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Paul Moore <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected] # v5.14+
Reviewed-by: Bart Van Assche <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>
| -rw-r--r-- | block/ioprio.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/block/ioprio.c b/block/ioprio.c index 0e4ff245f2bf..313c14a70bbd 100644 --- 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 */ |