netdev - [PATCH v1 net-next 5/5] ipv6: exthdrs: Remove redundant skb_headlen() check in ip6_parse

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Message-ID: <20230614230107.22301-6-kuniyu@amazon.com>
Date: Wed, 14 Jun 2023 16:01:07 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
	<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>, David Ahern <dsahern@...nel.org>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
	<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net-next 5/5] ipv6: exthdrs: Remove redundant skb_headlen() check in ip6_parse_tlv().

ipv6_destopt_rcv() and ipv6_parse_hopopts() pulls these data

  - Hop-by-Hop/Destination Options Header : 8
  - Hdr Ext Len                           : skb_transport_header(skb)[1] << 3

and calls ip6_parse_tlv(), so it need not check if skb_headlen() is less
than skb_transport_offset(skb) + (skb_transport_header(skb)[1] << 3).

Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
 net/ipv6/exthdrs.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index dd23531387e3..202fc3aaa83c 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -126,9 +126,6 @@ static bool ip6_parse_tlv(bool hopbyhop,
 		max_count = -max_count;
 	}
 
-	if (skb_transport_offset(skb) + len > skb_headlen(skb))
-		goto bad;
-
 	off += 2;
 	len -= 2;
 
-- 
2.30.2