diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2020-11-26 15:17:53 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2020-11-27 11:05:31 -0800 |
| commit | d3ab78858f1451351221061a1c365495df196500 (patch) | |
| tree | 7c248f3c5fd8372dab6afa8a5f7c888a64dfd91e | |
| parent | 69929d4c49e182f8526d42c43b37b460d562d3a0 (diff) | |
| download | linux-d3ab78858f1451351221061a1c365495df196500.tar.bz2 | |
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.c | 5 |
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; } |