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dccp: don't duplicate ccid when cloning dccp sock

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Commit 2677d20677 ("dccp: don't free ccid2_hc_tx_sock ...") fixed
a UAF but reintroduced CVE-2017-6074.

When the sock is cloned, two dccps_hc_tx_ccid will reference to the
same ccid. So one can free the ccid object twice from two socks after
cloning.

This issue was found by "Hadar Manor" as well and assigned with
CVE-2020-16119, which was fixed in Ubuntu's kernel. So here I port
the patch from Ubuntu to fix it.

The patch prevents cloned socks from referencing the same ccid.

Fixes: 2677d20677 ("dccp: don't free ccid2_hc_tx_sock ...")
Signed-off-by: Zhenpeng Lin <zplin@psu.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Lin, Zhenpeng 2021-09-08 03:40:59 +00:00 committed by David S. Miller
parent 0f31ab217d
commit d9ea761fdd
1 changed files with 2 additions and 0 deletions
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2
net/dccp/minisocks.c
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@ -94,6 +94,8 @@ struct sock *dccp_create_openreq_child(const struct sock *sk,
newdp->dccps_role = DCCP_ROLE_SERVER;
newdp->dccps_hc_rx_ackvec = NULL;
newdp->dccps_service_list = NULL;
newdp->dccps_hc_rx_ccid = NULL;
newdp->dccps_hc_tx_ccid = NULL;
newdp->dccps_service = dreq->dreq_service;
newdp->dccps_timestamp_echo = dreq->dreq_timestamp_echo;
newdp->dccps_timestamp_time = dreq->dreq_timestamp_time;