aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPaolo Abeni <pabeni@redhat.com>2020-11-26 15:17:53 +0100
committerJakub Kicinski <kuba@kernel.org>2020-11-27 11:05:31 -0800
commitd3ab78858f1451351221061a1c365495df196500 (patch)
tree7c248f3c5fd8372dab6afa8a5f7c888a64dfd91e
parent69929d4c49e182f8526d42c43b37b460d562d3a0 (diff)
downloadlinux-stericsson-d3ab78858f1451351221061a1c365495df196500.tar.gz
mptcp: fix NULL ptr dereference on bad MPJ
If an msk listener receives an MPJ carrying an invalid token, it will zero the request socket msk entry. That should later cause fallback and subflow reset - as per RFC - at subflow_syn_recv_sock() time due to failing hmac validation. Since commit 4cf8b7e48a09 ("subflow: introduce and use mptcp_can_accept_new_subflow()"), we unconditionally dereference - in mptcp_can_accept_new_subflow - the subflow request msk before performing hmac validation. In the above scenario we hit a NULL ptr dereference. Address the issue doing the hmac validation earlier. Fixes: 4cf8b7e48a09 ("subflow: introduce and use mptcp_can_accept_new_subflow()") Tested-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Link: https://lore.kernel.org/r/03b2cfa3ac80d8fc18272edc6442a9ddf0b1e34e.1606400227.git.pabeni@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--net/mptcp/subflow.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index ac4a1fe3550b..953906e40742 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -543,9 +543,8 @@ create_msk:
fallback = true;
} else if (subflow_req->mp_join) {
mptcp_get_options(skb, &mp_opt);
- if (!mp_opt.mp_join ||
- !mptcp_can_accept_new_subflow(subflow_req->msk) ||
- !subflow_hmac_valid(req, &mp_opt)) {
+ if (!mp_opt.mp_join || !subflow_hmac_valid(req, &mp_opt) ||
+ !mptcp_can_accept_new_subflow(subflow_req->msk)) {
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_JOINACKMAC);
fallback = true;
}