Re: [tipc-discussion] [PATCH] tipc: check for null after calling kmemdup

[Jon M. <jm...@re...>]

On 11/11/21 15:59, Tadeusz Struk wrote:
> kmemdup can return a null pointer so need to check for it, otherwise
> the null key will be dereferenced later in tipc_crypto_key_xmit as
> can be seen in the trace [1].
>
> Cc: Jon Maloy <jm...@re...>
> Cc: Ying Xue <yin...@wi...>
> Cc: "David S. Miller" <da...@da...>
> Cc: Jakub Kicinski <ku...@ke...>
> Cc: ne...@vg...
> Cc: tip...@li...
> Cc: lin...@vg...
> Cc: st...@vg... # 5.15, 5.14, 5.10
>
> [1] https://syzkaller.appspot.com/bug?id=bca180abb29567b189efdbdb34cbf7ba851c2a58
>
> Reported-by: Dmitry Vyukov <dv...@go...>
> Signed-off-by: Tadeusz Struk <tad...@li...>
> ---
>   net/tipc/crypto.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
> index dc60c32bb70d..988a343f9fd5 100644
> --- a/net/tipc/crypto.c
> +++ b/net/tipc/crypto.c
> @@ -597,6 +597,11 @@ static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
>   	tmp->cloned = NULL;
>   	tmp->authsize = TIPC_AES_GCM_TAG_SIZE;
>   	tmp->key = kmemdup(ukey, tipc_aead_key_size(ukey), GFP_KERNEL);
> +	if (!tmp->key) {
> +		free_percpu(tmp->tfm_entry);
> +		kfree_sensitive(tmp);
> +		return -ENOMEM;
> +	}
>   	memcpy(&tmp->salt, ukey->key + keylen, TIPC_AES_GCM_SALT_SIZE);
>   	atomic_set(&tmp->users, 0);
>   	atomic64_set(&tmp->seqno, 0);
Acked-by: Jon Maloy <jm...@re...>