netdev - Re: [PATCH net-next] bpf: dev_map_alloc() shouldn't return NULL

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Message-ID: <5973A25D.8030903@gmail.com>
Date:   Sat, 22 Jul 2017 12:07:09 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     Dan Carpenter <dan.carpenter@...cle.com>,
        Alexei Starovoitov <ast@...nel.org>
CC:     Daniel Borkmann <daniel@...earbox.net>, netdev@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH net-next] bpf: dev_map_alloc() shouldn't return NULL

On 07/22/2017 12:40 AM, Dan Carpenter wrote:
> We forgot to set the error code on two error paths which means that we
> return ERR_PTR(0) which is NULL.  The caller, find_and_alloc_map(), is
> not expecting that and will have a NULL dereference.
> 
> Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references")
> Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> 
> diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
> index 899364d097f5..d439ee0eadb1 100644
> --- a/kernel/bpf/devmap.c
> +++ b/kernel/bpf/devmap.c
> @@ -114,6 +114,7 @@ static struct bpf_map *dev_map_alloc(union bpf_attr *attr)
>  	if (err)
>  		goto free_dtab;
>  
> +	err = -ENOMEM;
>  	/* A per cpu bitfield with a bit per possible net device */
>  	dtab->flush_needed = __alloc_percpu(
>  				BITS_TO_LONGS(attr->max_entries) *
> 

Thanks.

Acked-by: John Fastabend <john.fastabend@...il.com>