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

[Eric Dumazet]

On Tue, Aug 20, 2024 at 2:15 PM Jeongjun Park <aha310510@xxxxxxxxx> 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@xxxxxxxxxxxxxxxx>
> 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@xxxxxxxxx>
> ---
>  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. */
> --