From 85ee970039f8f2a8911bf7efcd228cbc471fd38e Mon Sep 17 00:00:00 2001 From: Luka Gejak Date: Wed, 13 May 2026 20:26:57 +0200 Subject: [PATCH] net: hsr: reject unresolved interlink ifindex In hsr_newlink(), a provided but invalid IFLA_HSR_INTERLINK attribute was silently ignored if __dev_get_by_index() returned NULL. This leads to incorrect RedBox topology creation without notifying the user. Fix this by returning -EINVAL and an extack message when the interlink attribute is present but cannot be resolved. Reviewed-by: Felix Maurer Signed-off-by: Luka Gejak Reviewed-by: Fernando Fernandez Mancera Link: https://patch.msgid.link/20260513182657.20346-3-luka.gejak@linux.dev Signed-off-by: Jakub Kicinski --- net/hsr/hsr_netlink.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c index db0b0af7a692..f0ca23da3ab9 100644 --- a/net/hsr/hsr_netlink.c +++ b/net/hsr/hsr_netlink.c @@ -76,9 +76,14 @@ static int hsr_newlink(struct net_device *dev, return -EINVAL; } - if (data[IFLA_HSR_INTERLINK]) + if (data[IFLA_HSR_INTERLINK]) { interlink = __dev_get_by_index(link_net, nla_get_u32(data[IFLA_HSR_INTERLINK])); + if (!interlink) { + NL_SET_ERR_MSG_MOD(extack, "Interlink does not exist"); + return -EINVAL; + } + } if (interlink && interlink == link[0]) { NL_SET_ERR_MSG_MOD(extack, "Interlink and Slave1 are the same");