net/iucv: take a reference on the socket found in afiucv_hs_rcv()

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[ Upstream commit 4fa3491560 ]

afiucv_hs_rcv() looks up the destination socket under iucv_sk_list.lock,
drops the lock, and then passes the socket to the afiucv_hs_callback_*()
handlers without holding a reference. AF_IUCV sockets are not
RCU-protected and are freed synchronously by iucv_sock_kill() ->
sock_put(), so a concurrent close can free the socket in the window
between read_unlock() and the handler, which then dereferences freed
memory (for example sk->sk_data_ready() in afiucv_hs_callback_syn()).

Take a reference with sock_hold() while the socket is still on the list
and release it with sock_put() once the handler has run.

Fixes: 3881ac441f ("af_iucv: add HiperSockets transport")
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Reviewed-by: Hidayath Khan <hidayath@linux.ibm.com>
Link: https://patch.msgid.link/20260705-b4-disp-fc79c0dc-v1-1-d2cdcb57afa9@proton.me
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Bryam Vargas 2026-07-05 22:24:36 -05:00 • committed by Greg Kroah-Hartman

parent bb03350f97

commit bc6c6e546f

1 changed files with 4 additions and 0 deletions

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net/iucv/af_iucv.c

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