netdev - [PATCH bpf-next v4 1/3] bpf, net: validate struct

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Date: Sat, 24 Feb 2024 14:34:16 -0800
From: Kui-Feng Lee <thinker.li@...il.com>
To: bpf@...r.kernel.org,
	ast@...nel.org,
	martin.lau@...ux.dev,
	song@...nel.org,
	kernel-team@...a.com,
	andrii@...nel.org
Cc: sinquersw@...il.com,
	kuifeng@...a.com,
	Kui-Feng Lee <thinker.li@...il.com>,
	netdev@...r.kernel.org
Subject: [PATCH bpf-next v4 1/3] bpf, net: validate struct_ops when updating value.

Perform all validations when updating values of struct_ops maps. Doing
validation in st_ops->reg() and st_ops->update() is not necessary anymore.
However, tcp_register_congestion_control() has been called in various
places. It still needs to do validations.

Cc: netdev@...r.kernel.org
Signed-off-by: Kui-Feng Lee <thinker.li@...il.com>
---
 kernel/bpf/bpf_struct_ops.c | 11 ++++++-----
 net/ipv4/tcp_cong.c         |  6 +-----
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index a6019087b467..07e554c191d1 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -672,13 +672,14 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
 		*(unsigned long *)(udata + moff) = prog->aux->id;
 	}
 
+	if (st_ops->validate) {
+		err = st_ops->validate(kdata);
+		if (err)
+			goto reset_unlock;
+	}
+
 	if (st_map->map.map_flags & BPF_F_LINK) {
 		err = 0;
-		if (st_ops->validate) {
-			err = st_ops->validate(kdata);
-			if (err)
-				goto reset_unlock;
-		}
 		arch_protect_bpf_trampoline(st_map->image, PAGE_SIZE);
 		/* Let bpf_link handle registration & unregistration.
 		 *
diff --git a/net/ipv4/tcp_cong.c b/net/ipv4/tcp_cong.c
index 1b34050a7538..28ffcfbeef14 100644
--- a/net/ipv4/tcp_cong.c
+++ b/net/ipv4/tcp_cong.c
@@ -146,11 +146,7 @@ EXPORT_SYMBOL_GPL(tcp_unregister_congestion_control);
 int tcp_update_congestion_control(struct tcp_congestion_ops *ca, struct tcp_congestion_ops *old_ca)
 {
 	struct tcp_congestion_ops *existing;
-	int ret;
-
-	ret = tcp_validate_congestion_control(ca);
-	if (ret)
-		return ret;
+	int ret = 0;
 
 	ca->key = jhash(ca->name, sizeof(ca->name), strlen(ca->name));
 
-- 
2.34.1