[bpf-next,3/8] bpf: skmsg, replace comments with BUILD bug

Message ID	1545334536-766-4-git-send-email-john.fastabend@gmail.com
State	Accepted, archived
Delegated to:	BPF Maintainers
Headers	show Return-Path: <netdev-owner@vger.kernel.org> From: John Fastabend <john.fastabend@gmail.com> To: ast@kernel.org, daniel@iogearbox.net Cc: netdev@vger.kernel.org, john.fastabend@gmail.com Subject: [PATCH bpf-next 3/8] bpf: skmsg, replace comments with BUILD bug Date: Thu, 20 Dec 2018 11:35:31 -0800 Message-Id: <1545334536-766-4-git-send-email-john.fastabend@gmail.com> In-Reply-To: <1545334536-766-1-git-send-email-john.fastabend@gmail.com> References: <1545334536-766-1-git-send-email-john.fastabend@gmail.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk
Series	sockmap fixes/improvments for bpf-next \| expand [bpf-next,0/8] sockmap fixes/improvments for bpf-next [bpf-next,1/8] bpf: sk_msg, fix sk_msg_md access past end test [bpf-next,2/8] bpf: sk_msg, improve offset chk in _is_valid_access [bpf-next,3/8] bpf: skmsg, replace comments with BUILD bug [bpf-next,4/8] bpf: skb_verdict, support SK_PASS on RX BPF path [bpf-next,5/8] bpf: sk_msg, fix socket data_ready events [bpf-next,6/8] bpf: sk_msg, zap ingress queue on psock down [bpf-next,7/8] bpf: sk_msg, sock{map\|hash} redirect through ULP [bpf-next,8/8] bpf: tls_sw, init TLS ULP removes BPF proto hooks

Message ID

1545334536-766-4-git-send-email-john.fastabend@gmail.com

State

Accepted, archived

Delegated to:

BPF Maintainers

Headers

From: John Fastabend <john.fastabend@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net
Cc: netdev@vger.kernel.org, john.fastabend@gmail.com
Subject: [PATCH bpf-next 3/8] bpf: skmsg, replace comments with BUILD bug
Date: Thu, 20 Dec 2018 11:35:31 -0800
Message-Id: <1545334536-766-4-git-send-email-john.fastabend@gmail.com>
In-Reply-To: <1545334536-766-1-git-send-email-john.fastabend@gmail.com>
References: <1545334536-766-1-git-send-email-john.fastabend@gmail.com>
Sender: netdev-owner@vger.kernel.org
Precedence: bulk

Series

sockmap fixes/improvments for bpf-next | expand

Commit Message

John Fastabend Dec. 20, 2018, 7:35 p.m. UTC

Enforce comment on structure layout dependency with a BUILD_BUG_ON
to ensure the condition is maintained.

Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
---
 include/linux/skmsg.h | 4 +---
 net/core/filter.c     | 3 +++
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index eb8f6cb..dd57e6f4 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -36,9 +36,7 @@  struct sk_msg_sg {
 	struct scatterlist		data[MAX_MSG_FRAGS + 1];
 };
 
-/* UAPI in filter.c depends on struct sk_msg_sg being first element. If
- * this is moved filter.c also must be updated.
- */
+/* UAPI in filter.c depends on struct sk_msg_sg being first element. */
 struct sk_msg {
 	struct sk_msg_sg		sg;
 	void				*data;
diff --git a/net/core/filter.c b/net/core/filter.c
index 6bd9f08..447dd1b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7425,6 +7425,9 @@  static u32 sk_msg_convert_ctx_access(enum bpf_access_type type,
 	int off;
 #endif
 
+	/* convert ctx uses the fact sg element is first in struct */
+	BUILD_BUG_ON(offsetof(struct sk_msg, sg) != 0);
+
 	switch (si->off) {
 	case offsetof(struct sk_msg_md, data):
 		*insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_msg, data),

[bpf-next,3/8] bpf: skmsg, replace comments with BUILD bug

Commit Message

Patch