netdev - [bpf PATCH v4 4/4] bpf: sockmap fix msg->sg.size account on ingress skb

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Message-ID: <155746432481.20677.8713455957718721777.stgit@john-XPS-13-9360>
Date:   Thu, 09 May 2019 21:58:44 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     jakub.kicinski@...ronome.com, ast@...nel.org, daniel@...earbox.net
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        john.fastabend@...il.com
Subject: [bpf PATCH v4 4/4] bpf: sockmap fix msg->sg.size account on ingress
 skb

When converting a skb to msg->sg we forget to set the size after the
latest ktls/tls code conversion. This patch can be reached by doing
a redir into ingress path from BPF skb sock recv hook. Then trying to
read the size fails.

Fix this by setting the size.

Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@...il.com>
---
 net/core/skmsg.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 49d1efa329d7..93bffaad2135 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -411,6 +411,7 @@ static int sk_psock_skb_ingress(struct sk_psock *psock, struct sk_buff *skb)
 	sk_mem_charge(sk, skb->len);
 	copied = skb->len;
 	msg->sg.start = 0;
+	msg->sg.size = copied;
 	msg->sg.end = num_sge == MAX_MSG_FRAGS ? 0 : num_sge;
 	msg->skb = skb;