netdev - [PATCH net-next v2 2/2] bpf: Remove the capability check for cgroup skb eBPF program

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Date:   Wed, 31 May 2017 18:16:00 -0700
From:   Chenbo Feng <chenbofeng.kernel@...il.com>
To:     netdev@...r.kernel.org, David Miller <davem@...emloft.net>
Cc:     Lorenzo Colitti <lorenzo@...gle.com>,
        Chenbo Feng <fengc@...gle.com>
Subject: [PATCH net-next v2 2/2] bpf: Remove the capability check for cgroup skb eBPF program

From: Chenbo Feng <fengc@...gle.com>

Currently loading a cgroup skb eBPF program require a CAP_SYS_ADMIN
capability while attaching the program to a cgroup only requires the
user have CAP_NET_ADMIN privilege. We can escape the capability
check when load the program just like socket filter program to make
the capability requirement consistent.

Change since v1:
Change the code style in order to be compliant with checkpatch.pl
preference

Signed-off-by: Chenbo Feng <fengc@...gle.com>
---
 kernel/bpf/syscall.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 265a0d8..59da103 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -815,7 +815,9 @@ static int bpf_prog_load(union bpf_attr *attr)
 	    attr->kern_version != LINUX_VERSION_CODE)
 		return -EINVAL;
 
-	if (type != BPF_PROG_TYPE_SOCKET_FILTER && !capable(CAP_SYS_ADMIN))
+	if (type != BPF_PROG_TYPE_SOCKET_FILTER &&
+	    type != BPF_PROG_TYPE_CGROUP_SKB &&
+	    !capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
 	/* plain bpf_prog allocation */
-- 
2.7.4