[PATCHv6 bpf-next 02/28] bpf: Add attach_type checks under bpf_prog_attach_check_attach_type

[Jiri Olsa <jolsa@xxxxxxxxxx>]

Add extra attach_type checks from link_create under
bpf_prog_attach_check_attach_type.

Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Acked-by: Yafang Shao <laoar.shao@xxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
 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