linux-kernel - [PATCH 5.15 290/917] gre/sit: Dont generate link-local addr if addr_gen_mode is IN6_ADDR_GEN_MODE

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Date:   Mon, 15 Nov 2021 17:56:25 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Stephen Suryaputra <ssuryaextr@...il.com>,
        Antonio Quartulli <a@...table.cc>,
        Jakub Kicinski <kuba@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 290/917] gre/sit: Dont generate link-local addr if addr_gen_mode is IN6_ADDR_GEN_MODE_NONE

From: Stephen Suryaputra <ssuryaextr@...il.com>

[ Upstream commit 61e18ce7348bfefb5688a8bcd4b4d6b37c0f9b2a ]

When addr_gen_mode is set to IN6_ADDR_GEN_MODE_NONE, the link-local addr
should not be generated. But it isn't the case for GRE (as well as GRE6)
and SIT tunnels. Make it so that tunnels consider the addr_gen_mode,
especially for IN6_ADDR_GEN_MODE_NONE.

Do this in add_v4_addrs() to cover both GRE and SIT only if the addr
scope is link.

Signed-off-by: Stephen Suryaputra <ssuryaextr@...il.com>
Acked-by: Antonio Quartulli <a@...table.cc>
Link: https://lore.kernel.org/r/20211020200618.467342-1-ssuryaextr@gmail.com
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/ipv6/addrconf.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index c6a90b7bbb70e..846037e73723f 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3110,6 +3110,9 @@ static void add_v4_addrs(struct inet6_dev *idev)
 	memcpy(&addr.s6_addr32[3], idev->dev->dev_addr + offset, 4);
 
 	if (idev->dev->flags&IFF_POINTOPOINT) {
+		if (idev->cnf.addr_gen_mode == IN6_ADDR_GEN_MODE_NONE)
+			return;
+
 		addr.s6_addr32[0] = htonl(0xfe800000);
 		scope = IFA_LINK;
 		plen = 64;
-- 
2.33.0