From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= <maze@google.com>
Date: Sat, 20 Jun 2020 14:26:16 -0700
Subject: bpf: Restore behaviour of CAP_SYS_ADMIN allowing the loading of
 networking bpf programs
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Patch-mainline: v5.8-rc5
Git-commit: b338cb921e6739ff59ce32f43342779fe5ffa732
References: bsc#1177028

This is a fix for a regression in commit 2c78ee898d8f ("bpf: Implement CAP_BPF").
Before the above commit it was possible to load network bpf programs
with just the CAP_SYS_ADMIN privilege.

The Android bpfloader happens to run in such a configuration (it has
SYS_ADMIN but not NET_ADMIN) and creates maps and loads bpf programs
for later use by Android's netd (which has NET_ADMIN but not SYS_ADMIN).

Fixes: 2c78ee898d8f ("bpf: Implement CAP_BPF")
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/bpf/20200620212616.93894-1-zenczykowski@gmail.com
Acked-by: Gary Lin <glin@suse.com>
---
 kernel/bpf/syscall.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2118,7 +2118,7 @@ static int bpf_prog_load(union bpf_attr
 	    !bpf_capable())
 		return -EPERM;
 
-	if (is_net_admin_prog_type(type) && !capable(CAP_NET_ADMIN))
+	if (is_net_admin_prog_type(type) && !capable(CAP_NET_ADMIN) && !capable(CAP_SYS_ADMIN))
 		return -EPERM;
 	if (is_perfmon_prog_type(type) && !perfmon_capable())
 		return -EPERM;