Re: [PATCH net,v6,1/2] net/smc: modify smc_sock structure

Eric Dumazet
2024-08-20T12:49:11Z

On Tue, Aug 20, 2024 at 2:15 PM Jeongjun Park <aha310510@gmail.com> wrote:
>
> Since inet_sk(sk)->pinet6 and smc_sk(sk)->clcsock practically
> point to the same address, when smc_create_clcsk() stores the newly
> created clcsock in smc_sk(sk)->clcsock, inet_sk(sk)->pinet6 is corrupted
> into clcsock. This causes NULL pointer dereference and various other
> memory corruptions.
>
> To solve this, we need to modify the smc_sock structure.
>
> Reported-by: syzkaller <syzkaller@googlegroups.com>
> Fixes: ac7138746e14 ("smc: establish new socket family")

Are you sure this Fixes: tag is correct ?

Hint : This commit is from 2017, but IPPROTO_SMC was added in 2024.

> Signed-off-by: Jeongjun Park <aha310510@gmail.com>
> ---
> net/smc/smc.h | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/net/smc/smc.h b/net/smc/smc.h
> index 34b781e463c4..f23f76e94a66 100644
> --- a/net/smc/smc.h
> +++ b/net/smc/smc.h
> @@ -283,7 +283,10 @@ struct smc_connection {
> };
>
> struct smc_sock { /* smc sock container */
> - struct sock sk;
> + union {
> + struct sock sk; /* for AF_SMC */
> + struct inet_sock inet; /* for IPPROTO_SMC */
> + };
> struct socket *clcsock; /* internal tcp socket */
> void (*clcsk_state_change)(struct sock *sk);
> /* original stat_change fct. */
> --