[PATCH 5.4 26/85] sctp: move the active_key update after sh_keys is added

Greg Kroah-Hartman
2021-08-10T17:35:40Z

From: Xin Long <lucien.xin@gmail.com>

[ Upstream commit ae954bbc451d267f7d60d7b49db811d5a68ebd7b ]

In commit 58acd1009226 ("sctp: update active_key for asoc when old key is
being replaced"), sctp_auth_asoc_init_active_key() is called to update
the active_key right after the old key is deleted and before the new key
is added, and it caused that the active_key could be found with the key_id.

In Ying Xu's testing, the BUG_ON in sctp_auth_asoc_init_active_key() was
triggered:

[ ] kernel BUG at net/sctp/auth.c:416!
[ ] RIP: 0010:sctp_auth_asoc_init_active_key.part.8+0xe7/0xf0 [sctp]
[ ] Call Trace:
[ ] sctp_auth_set_key+0x16d/0x1b0 [sctp]
[ ] sctp_setsockopt.part.33+0x1ba9/0x2bd0 [sctp]
[ ] __sys_setsockopt+0xd6/0x1d0
[ ] __x64_sys_setsockopt+0x20/0x30
[ ] do_syscall_64+0x5b/0x1a0

So fix it by moving the active_key update after sh_keys is added.

Fixes: 58acd1009226 ("sctp: update active_key for asoc when old key is being replaced")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/sctp/auth.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/net/sctp/auth.c b/net/sctp/auth.c
index 7eced1e523a5..3b2d0bd616dd 100644
--- a/net/sctp/auth.c
+++ b/net/sctp/auth.c
@@ -863,14 +863,18 @@ int sctp_auth_set_key(struct sctp_endpoint *ep,
memcpy(key->data, &auth_key->sca_key[0], auth_key->sca_keylength);
cur_key->key = key;

- if (replace) {
- list_del_init(&shkey->key_list);
- sctp_auth_shkey_release(shkey);
- if (asoc && asoc->active_key_id == auth_key->sca_keynumber)
- sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
+ if (!replace) {
+ list_add(&cur_key->key_list, sh_keys);
+ return 0;
}
+
+ list_del_init(&shkey->key_list);
+ sctp_auth_shkey_release(shkey);
list_add(&cur_key->key_list, sh_keys);

+ if (asoc && asoc->active_key_id == auth_key->sca_keynumber)
+ sctp_auth_asoc_init_active_key(asoc, GFP_KERNEL);
+
return 0;
}

--
2.30.2