ipv6: sr: validate HMAC algorithm ID in seg6_hmac_info_add

[ Upstream commit 84967deee9d9870b15bc4c3acb50f1d401807902 ]

The seg6_genl_sethmac() directly uses the algorithm ID provided by the
userspace without verifying whether it is an HMAC algorithm supported
by the system.
If an unsupported HMAC algorithm ID is configured, packets using SRv6 HMAC
will be dropped during encapsulation or decapsulation.

Fixes: 4f4853dc1c9c ("ipv6: sr: implement API to control SR HMAC structure")
Signed-off-by: Minhong He <heminhong@kylinos.cn>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250815063845.85426-1-heminhong@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c
index 2e2b94ae6355225aa8ddfb03ebb7417682c266cc..4a3f7bb027ed2708cb0953e93a24a56627570112 100644 (file)
--- a/net/ipv6/seg6_hmac.c
+++ b/net/ipv6/seg6_hmac.c
@@ -294,6 +294,9 @@ int seg6_hmac_info_add(struct net *net, u32 key, struct seg6_hmac_info *hinfo)
        struct seg6_pernet_data *sdata = seg6_pernet(net);
        int err;
 
+       if (!__hmac_get_algo(hinfo->alg_id))
+               return -EINVAL;
+
        err = rhashtable_lookup_insert_fast(&sdata->hmac_infos, &hinfo->node,
                                            rht_params);