[PATCH bpf-next v6 07/23] bpf: prepare for more bpf syscall to be used from kernel and user space.

From: Benjamin Tissoires <benjamin.tissoires@redhat.com>
To: Greg KH <gregkh@linuxfoundation.org>,
	Jiri Kosina <jikos@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
	Dave Marchevsky <davemarchevsky@fb.com>,
	Joe Stringer <joe@cilium.io>, Jonathan Corbet <corbet@lwn.net>
Cc: Tero Kristo <tero.kristo@linux.intel.com>,
	linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
	netdev@vger.kernel.org, bpf@vger.kernel.org,
	linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>
Subject: [PATCH bpf-next v6 07/23] bpf: prepare for more bpf syscall to be used from kernel and user space.
Date: Tue, 12 Jul 2022 16:58:34 +0200	[thread overview]
Message-ID: <20220712145850.599666-8-benjamin.tissoires@redhat.com> (raw)
In-Reply-To: <20220712145850.599666-1-benjamin.tissoires@redhat.com>

Add BPF_MAP_GET_FD_BY_ID and BPF_MAP_DELETE_PROG.

Only BPF_MAP_GET_FD_BY_ID needs to be amended to be able
to access the bpf pointer either from the userspace or the kernel.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

changes in v6:
- commit description change

new in v5
---
 kernel/bpf/syscall.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ab688d85b2c6..637765390c30 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1417,9 +1417,9 @@ static int map_update_elem(union bpf_attr *attr, bpfptr_t uattr)
 
 #define BPF_MAP_DELETE_ELEM_LAST_FIELD key
 
-static int map_delete_elem(union bpf_attr *attr)
+static int map_delete_elem(union bpf_attr *attr, bpfptr_t uattr)
 {
-	void __user *ukey = u64_to_user_ptr(attr->key);
+	bpfptr_t ukey = make_bpfptr(attr->key, uattr.is_kernel);
 	int ufd = attr->map_fd;
 	struct bpf_map *map;
 	struct fd f;
@@ -1439,7 +1439,7 @@ static int map_delete_elem(union bpf_attr *attr)
 		goto err_put;
 	}
 
-	key = __bpf_copy_key(ukey, map->key_size);
+	key = ___bpf_copy_key(ukey, map->key_size);
 	if (IS_ERR(key)) {
 		err = PTR_ERR(key);
 		goto err_put;
@@ -4922,7 +4922,7 @@ static int __sys_bpf(int cmd, bpfptr_t uattr, unsigned int size)
 		err = map_update_elem(&attr, uattr);
 		break;
 	case BPF_MAP_DELETE_ELEM:
-		err = map_delete_elem(&attr);
+		err = map_delete_elem(&attr, uattr);
 		break;
 	case BPF_MAP_GET_NEXT_KEY:
 		err = map_get_next_key(&attr);
@@ -5057,8 +5057,10 @@ BPF_CALL_3(bpf_sys_bpf, int, cmd, union bpf_attr *, attr, u32, attr_size)
 
 	switch (cmd) {
 	case BPF_MAP_CREATE:
+	case BPF_MAP_DELETE_ELEM:
 	case BPF_MAP_UPDATE_ELEM:
 	case BPF_MAP_FREEZE:
+	case BPF_MAP_GET_FD_BY_ID:
 	case BPF_PROG_LOAD:
 	case BPF_BTF_LOAD:
 	case BPF_LINK_CREATE:
-- 
2.36.1

