[PATCH bpf-next v7 07/24] bpf: prepare for more bpf syscall to be used from kernel and user space.

Benjamin Tissoires
2022-07-21T15:38:44Z

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.

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

no changes in v7

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 83c7136c5788..776c7a37c433 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1437,9 +1437,9 @@ 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;
@@ -1459,7 +1459,7 @@ 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;
@@ -4942,7 +4942,7 @@ 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);
@@ -5077,8 +5077,10 @@ 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