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

From: Chenbo Feng <[email-masked]>
Date: Wed, 31 May 2017 11:06:53 -0700

From: Chenbo Feng <[email-masked]>

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.

Signed-off-by: Chenbo Feng <[email-masked]>
---
 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..021c0b4 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