linux-kernel - [PATCH bpf-next v3 01/17] bpf: add new is_sys_admin_prog

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Date:   Fri, 18 Mar 2022 17:15:12 +0100
From:   Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:     Greg KH <gregkh@...uxfoundation.org>,
        Jiri Kosina <jikos@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>, Shuah Khan <shuah@...nel.org>,
        Dave Marchevsky <davemarchevsky@...com>,
        Joe Stringer <joe@...ium.io>, Jonathan Corbet <corbet@....net>
Cc:     Tero Kristo <tero.kristo@...ux.intel.com>,
        linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org,
        linux-kselftest@...r.kernel.org, linux-doc@...r.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Sean Young <sean@...s.org>
Subject: [PATCH bpf-next v3 01/17] bpf: add new is_sys_admin_prog_type() helper

LIRC_MODE2 does not really need net_admin capability, but only sys_admin.

Extract a new helper for it, it will be also used for the HID bpf
implementation.

Cc: Sean Young <sean@...s.org>
Acked-by: Sean Young <sean@...s.org>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@...hat.com>

---

changes in v3:
- dropped BPF_PROG_TYPE_EXT from the new helper

new in v2
---
 kernel/bpf/syscall.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 9beb585be5a6..b88688264ad0 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2165,7 +2165,6 @@ static bool is_net_admin_prog_type(enum bpf_prog_type prog_type)
 	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
 	case BPF_PROG_TYPE_SK_SKB:
 	case BPF_PROG_TYPE_SK_MSG:
-	case BPF_PROG_TYPE_LIRC_MODE2:
 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
 	case BPF_PROG_TYPE_CGROUP_DEVICE:
 	case BPF_PROG_TYPE_CGROUP_SOCK:
@@ -2202,6 +2201,16 @@ static bool is_perfmon_prog_type(enum bpf_prog_type prog_type)
 	}
 }
 
+static bool is_sys_admin_prog_type(enum bpf_prog_type prog_type)
+{
+	switch (prog_type) {
+	case BPF_PROG_TYPE_LIRC_MODE2:
+		return true;
+	default:
+		return false;
+	}
+}
+
 /* last field in 'union bpf_attr' used by this command */
 #define	BPF_PROG_LOAD_LAST_FIELD core_relo_rec_size
 
@@ -2252,6 +2261,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
 		return -EPERM;
 	if (is_perfmon_prog_type(type) && !perfmon_capable())
 		return -EPERM;
+	if (is_sys_admin_prog_type(type) && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
 
 	/* attach_prog_fd/attach_btf_obj_fd can specify fd of either bpf_prog
 	 * or btf, we need to check which one it is
-- 
2.35.1