ipv6: Continue processing multipath route even if gateway attribute is invalid

stable inclusion
from stable-v5.10.91
commit 72b0d14a0a882262d1c38a12be5f9042f53aa10e
bugzilla: 186187 https://gitee.com/openeuler/kernel/issues/I4SI2C

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72b0d14a0a882262d1c38a12be5f9042f53aa10e

--------------------------------

[ Upstream commit e30a845b ]

ip6_route_multipath_del loop continues processing the multipath
attribute even if delete of a nexthop path fails. For consistency,
do the same if the gateway attribute is invalid.

Fixes: 1ff15a71 ("ipv6: Check attribute length for RTA_GATEWAY when deleting multipath route")
Signed-off-by: NDavid Ahern <dsahern@kernel.org>
Acked-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://lore.kernel.org/r/20220103171911.94739-1-dsahern@kernel.orgSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/ipv6/route.c

@@ -5348,8 +5348,10 @@ static int ip6_route_multipath_del(struct fib6_config *cfg,
 			if (nla) {
 				err = fib6_gw_from_attr(&r_cfg.fc_gateway, nla,
 							extack);
-				if (err)
-					return err;
+				if (err) {
+					last_err = err;
+					goto next_rtnh;
+				}
 
 				r_cfg.fc_flags |= RTF_GATEWAY;
 			}
@@ -5358,6 +5360,7 @@ static int ip6_route_multipath_del(struct fib6_config *cfg,
 		if (err)
 			last_err = err;
 
+next_rtnh:
 		rtnh = rtnh_next(rtnh, &remaining);
 	}