From e6f497955fb6a072999db491a01dd3a203d5bcea Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 17 Apr 2025 17:03:45 -0700 Subject: [PATCH] ipv6: Check GATEWAY in rtm_to_fib6_multipath_config(). In ip6_route_multipath_add(), we call rt6_qualify_for_ecmp() for each entry. If it returns false, the request fails. rt6_qualify_for_ecmp() returns false if either of the conditions below is true: 1. f6i->fib6_flags has RTF_ADDRCONF 2. f6i->nh is not NULL 3. f6i->fib6_nh->fib_nh_gw_family is AF_UNSPEC 1 is unnecessary because rtm_to_fib6_config() never sets RTF_ADDRCONF to cfg->fc_flags. 2. is equivalent with cfg->fc_nh_id. 3. can be replaced by checking RTF_GATEWAY in the base and each multipath entry because AF_INET6 is set to f6i->fib6_nh->fib_nh_gw_family only when cfg.fc_is_fdb is true or RTF_GATEWAY is set, but the former is always false. These checks do not require RCU and can be done earlier. Let's perform the equivalent checks in rtm_to_fib6_multipath_config(). Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250418000443.43734-5-kuniyu@amazon.com Signed-off-by: Paolo Abeni --- net/ipv6/route.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index aa92e02a47f49..88d2f85ed69dc 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5031,6 +5031,7 @@ static int rtm_to_fib6_multipath_config(struct fib6_config *cfg, } do { + bool has_gateway = cfg->fc_flags & RTF_GATEWAY; int attrlen = rtnh_attrlen(rtnh); if (attrlen > 0) { @@ -5044,9 +5045,17 @@ static int rtm_to_fib6_multipath_config(struct fib6_config *cfg, "Invalid IPv6 address in RTA_GATEWAY"); return -EINVAL; } + + has_gateway = true; } } + if (newroute && (cfg->fc_nh_id || !has_gateway)) { + NL_SET_ERR_MSG(extack, + "Device only routes can not be added for IPv6 using the multipath API."); + return -EINVAL; + } + rtnh = rtnh_next(rtnh, &remaining); } while (rtnh_ok(rtnh, remaining)); @@ -5388,13 +5397,6 @@ static int ip6_route_multipath_add(struct fib6_config *cfg, rt = NULL; goto cleanup; } - if (!rt6_qualify_for_ecmp(rt)) { - err = -EINVAL; - NL_SET_ERR_MSG(extack, - "Device only routes can not be added for IPv6 using the multipath API."); - fib6_info_release(rt); - goto cleanup; - } rt->fib6_nh->fib_nh_weight = rtnh->rtnh_hops + 1; -- 2.39.5