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Date:   Tue, 5 Mar 2019 14:49:20 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Su Yanjun <suyj.fnst@cn.fujitsu.com>
Cc:     steffen.klassert@secunet.com, davem@davemloft.net,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: xfrm: Fix potential oops in xfrm_user_rcv_msg and
 array out of bounds
Message-ID: <20190305064920.gcpwvkp7yikq33cy@gondor.apana.org.au>
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On Sun, Mar 03, 2019 at 10:47:39PM -0500, Su Yanjun wrote:
> When i review xfrm_user.c code, i found some potentical bug in it.
> 
> In xfrm_user_rcvmsg if type parameter from user space is set to
> XFRM_MSG_MAX or  XFRM_MSG_NEWSADINFO or XFRM_MSG_NEWSPDINFO. It will cause
> xfrm_user_rcv_msg  referring to null entry in xfrm_dispatch array.
> 
> Signed-off-by: Su Yanjun <suyj.fnst@cn.fujitsu.com>
> ---
>  net/xfrm/xfrm_user.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
> index a131f9f..d832783 100644
> --- a/net/xfrm/xfrm_user.c
> +++ b/net/xfrm/xfrm_user.c
> @@ -2630,11 +2630,13 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
>  		return -EOPNOTSUPP;
>  
>  	type = nlh->nlmsg_type;
> -	if (type > XFRM_MSG_MAX)
> +	if (type >= XFRM_MSG_MAX)
>  		return -EINVAL;

Your patch is wrong.  Please check the definition of XFRM_MSG_MAX.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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