This is a note to let you know that I've just added the patch titled
bpf: skip unnecessary capability check
to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-skip-unnecessary-capability-check.patch
and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0fa4fe85f4724fff89b09741c437cbee9cf8b008 Mon Sep 17 00:00:00 2001
From: Chenbo Feng <fengc@xxxxxxxxxx>
Date: Mon, 19 Mar 2018 17:57:27 -0700
Subject: bpf: skip unnecessary capability check
From: Chenbo Feng <fengc@xxxxxxxxxx>
commit 0fa4fe85f4724fff89b09741c437cbee9cf8b008 upstream.
The current check statement in BPF syscall will do a capability check
for CAP_SYS_ADMIN before checking sysctl_unprivileged_bpf_disabled. This
code path will trigger unnecessary security hooks on capability checking
and cause false alarms on unprivileged process trying to get CAP_SYS_ADMIN
access. This can be resolved by simply switch the order of the statement
and CAP_SYS_ADMIN is not required anyway if unprivileged bpf syscall is
allowed.
Signed-off-by: Chenbo Feng <fengc@xxxxxxxxxx>
Acked-by: Lorenzo Colitti <lorenzo@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/bpf/syscall.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1687,7 +1687,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf
union bpf_attr attr = {};
int err;
- if (!capable(CAP_SYS_ADMIN) && sysctl_unprivileged_bpf_disabled)
+ if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))
return -EPERM;
err = check_uarg_tail_zero(uattr, sizeof(attr), size);
Patches currently in stable-queue which might be from fengc@xxxxxxxxxx are
queue-4.15/kbuild-disable-clang-s-default-use-of-fmerge-all-constants.patch
queue-4.15/bpf-skip-unnecessary-capability-check.patch