Re: [PATCH net v5 1/2] net/smc: order the CDC receive path against RMB publication

[sashiko-bot@kernel.org]

> From: Bryam Vargas <hexlabsecurity@proton.me>
> 
> smc_conn_create() adds an SMC-R connection to the token tree before
> smc_buf_create() sets conn->rmb_desc. Tokens come from one global
> counter, so a peer in the link group can predict the next one. A CDC
> with that token, arriving in the window, makes
> smc_cdc_msg_recv_action() dereference a NULL rmb_desc in softirq.
> 
> Set rmb_desc with a release store after the receive fields that go
> with it, and drop a CDC in smc_cdc_rx_handler() while rmb_desc is
> unset. A conforming peer learns the token only from the CLC accept or
> confirm, sent after smc_buf_create(), so nothing it sends is dropped.
> The SMC-D receive tasklet needs no check: smc_ism_set_conn() publishes
> the connection under smcd->lock, which smcd_handle_irq() also takes.
> 
> Fixes: 69cb7dc0218b ("net/smc: add common buffer size in send and receive buffer descriptors")
> Closes: https://sashiko.dev/#/patchset/20261008-b4-disp-f7cd3d96-v6-0-fba616c0920c@proton.me?part=1
> Cc: stable@vger.kernel.org
> Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261015-b4-disp-2a8d85ef-v5-0-6b795e8263c9@proton.me?part=1