[PATCHv5 bpf-next 02/28] bpf: Add attach_type checks under bpf_prog_attach_check_attach_type

Jiri Olsa
2023-07-30T13:42:49Z

Add extra attach_type checks from link_create under
bpf_prog_attach_check_attach_type.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
kernel/bpf/syscall.c | 120 +++++++++++++++++++------------------------
1 file changed, 52 insertions(+), 68 deletions(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 7f4e8c357a6a..7c01186d4078 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3656,34 +3656,6 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
return fd;
}

-static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
- enum bpf_attach_type attach_type)
-{
- switch (prog->type) {
- case BPF_PROG_TYPE_CGROUP_SOCK:
- case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
- case BPF_PROG_TYPE_CGROUP_SOCKOPT:
- case BPF_PROG_TYPE_SK_LOOKUP:
- return attach_type == prog->expected_attach_type ? 0 : -EINVAL;
- case BPF_PROG_TYPE_CGROUP_SKB:
- if (!capable(CAP_NET_ADMIN))
- /* cg-skb progs can be loaded by unpriv user.
- * check permissions at attach time.
- */
- return -EPERM;
- return prog->enforce_expected_attach_type &&
- prog->expected_attach_type != attach_type ?
- -EINVAL : 0;
- case BPF_PROG_TYPE_KPROBE:
- if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI &&
- attach_type != BPF_TRACE_KPROBE_MULTI)
- return -EINVAL;
- return 0;
- default:
- return 0;
- }
-}
-
static enum bpf_prog_type
attach_type_to_prog_type(enum bpf_attach_type attach_type)
{
@@ -3750,6 +3722,58 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type)
}
}

+static int bpf_prog_attach_check_attach_type(const struct bpf_prog *prog,
+ enum bpf_attach_type attach_type)
+{
+ enum bpf_prog_type ptype;
+
+ switch (prog->type) {
+ case BPF_PROG_TYPE_CGROUP_SOCK:
+ case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+ case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+ case BPF_PROG_TYPE_SK_LOOKUP:
+ return attach_type == prog->expected_attach_type ? 0 : -EINVAL;
+ case BPF_PROG_TYPE_CGROUP_SKB:
+ if (!capable(CAP_NET_ADMIN))
+ /* cg-skb progs can be loaded by unpriv user.
+ * check permissions at attach time.
+ */
+ return -EPERM;
+ return prog->enforce_expected_attach_type &&
+ prog->expected_attach_type != attach_type ?
+ -EINVAL : 0;
+ case BPF_PROG_TYPE_EXT:
+ return 0;
+ case BPF_PROG_TYPE_NETFILTER:
+ if (attach_type != BPF_NETFILTER)
+ return -EINVAL;
+ return 0;
+ case BPF_PROG_TYPE_PERF_EVENT:
+ case BPF_PROG_TYPE_TRACEPOINT:
+ if (attach_type != BPF_PERF_EVENT)
+ return -EINVAL;
+ return 0;
+ case BPF_PROG_TYPE_KPROBE:
+ if (prog->expected_attach_type == BPF_TRACE_KPROBE_MULTI &&
+ attach_type != BPF_TRACE_KPROBE_MULTI)
+ return -EINVAL;
+ if (attach_type != BPF_PERF_EVENT &&
+ attach_type != BPF_TRACE_KPROBE_MULTI)
+ return -EINVAL;
+ return 0;
+ case BPF_PROG_TYPE_SCHED_CLS:
+ if (attach_type != BPF_TCX_INGRESS &&
+ attach_type != BPF_TCX_EGRESS)
+ return -EINVAL;
+ return 0;
+ default:
+ ptype = attach_type_to_prog_type(attach_type);
+ if (ptype == BPF_PROG_TYPE_UNSPEC || ptype != prog->type)
+ return -EINVAL;
+ return 0;
+ }
+}
+
#define BPF_PROG_ATTACH_LAST_FIELD expected_revision

#define BPF_F_ATTACH_MASK_BASE \
@@ -4856,7 +4880,6 @@ static int bpf_map_do_batch(const union bpf_attr *attr,
#define BPF_LINK_CREATE_LAST_FIELD link_create.kprobe_multi.cookies
static int link_create(union bpf_attr *attr, bpfptr_t uattr)
{
- enum bpf_prog_type ptype;
struct bpf_prog *prog;
int ret;

@@ -4875,45 +4898,6 @@ static int link_create(union bpf_attr *attr, bpfptr_t uattr)
if (ret)
goto out;

- switch (prog->type) {
- case BPF_PROG_TYPE_EXT:
- break;
- case BPF_PROG_TYPE_NETFILTER:
- if (attr->link_create.attach_type != BPF_NETFILTER) {
- ret = -EINVAL;
- goto out;
- }
- break;
- case BPF_PROG_TYPE_PERF_EVENT:
- case BPF_PROG_TYPE_TRACEPOINT:
- if (attr->link_create.attach_type != BPF_PERF_EVENT) {
- ret = -EINVAL;
- goto out;
- }
- break;
- case BPF_PROG_TYPE_KPROBE:
- if (attr->link_create.attach_type != BPF_PERF_EVENT &&
- attr->link_create.attach_type != BPF_TRACE_KPROBE_MULTI) {
- ret = -EINVAL;
- goto out;
- }
- break;
- case BPF_PROG_TYPE_SCHED_CLS:
- if (attr->link_create.attach_type != BPF_TCX_INGRESS &&
- attr->link_create.attach_type != BPF_TCX_EGRESS) {
- ret = -EINVAL;
- goto out;
- }
- break;
- default:
- ptype = attach_type_to_prog_type(attr->link_create.attach_type);
- if (ptype == BPF_PROG_TYPE_UNSPEC || ptype != prog->type) {
- ret = -EINVAL;
- goto out;
- }
- break;
- }
-
switch (prog->type) {
case BPF_PROG_TYPE_CGROUP_SKB:
case BPF_PROG_TYPE_CGROUP_SOCK:
--
2.41.0