Subject: Re: [PATCH v2] IPv6: fix bug when specifying the non-exist outgoing interface

From: Shan Wei <[email-masked]>
Date: Tue, 03 Jun 2008 15:03:12 +0800

YOSHIFUJI Hideaki / 吉藤英明 写道:
> In article <[email-masked]> (at Mon, 02 Jun 2008 13:39:10 -0400), Brian Haley <[email-masked]> says:
> 
>> YOSHIFUJI Hideaki / 吉藤英明 wrote:
>>> -			if (addr_type == IPV6_ADDR_ANY)
>>> +			addr_type = ipv6_addr_type(&src_info->ipi6_addr);
>>> +			if (addr_type == IPV6_ADDR_ANY ||
>>> +			    addr_type & IPV6_ADDR_MULTICAST) {
>>> +				if (dev)
>>> +					dev_put(dev);
>>>  				break;
>> What about link-local multicast?  We should check ifindex there too.  I
>> think that check should just be for IPV6_ADDR_ANY.  I think making this
>> more like inet6_bind() and not doing the ipv6_chk_addr() call for
>> Multicast would be the best thing, right?
> 
> My brain was sleeping.  I intended to check if the source
> address is NOT an multicast, but I think we can let ipv6_chk_addr()
> check it.
> 
  RFC3542 6.2 says: the kernel must verify that the requested source address 
is indeed a unicast address. If a multicast address is specified, what should 
kernel do ? returns error or choose source address by itself.

> BTW we do not check if the address is valid unicast when we assign new
> address on interface.  That does not seem good to me...
> (but (some?) BSDs do not seem to check this, hmm...)
> 
> ---
> diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
> index 94fa6ae..f55269a 100644
> --- a/net/ipv6/datagram.c
> +++ b/net/ipv6/datagram.c
> @@ -509,7 +509,6 @@ int datagram_send_ctl(struct msghdr *msg, struct flowi *fl,
>  
>  	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
>  		int addr_type;
> -		struct net_device *dev = NULL;
>  
>  		if (!CMSG_OK(msg, cmsg)) {
>  			err = -EINVAL;
> @@ -522,6 +521,9 @@ int datagram_send_ctl(struct msghdr *msg, struct flowi *fl,
>  		switch (cmsg->cmsg_type) {
>  		case IPV6_PKTINFO:
>  		case IPV6_2292PKTINFO:
> +		    {
> +			struct net_device *dev = NULL;
> +
>  			if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
>  				err = -EINVAL;
>  				goto exit_f;
> @@ -535,32 +537,34 @@ int datagram_send_ctl(struct msghdr *msg, struct flowi *fl,
>  				fl->oif = src_info->ipi6_ifindex;
>  			}
>  
> -			addr_type = ipv6_addr_type(&src_info->ipi6_addr);
> +			if (fl->oif) {
> +				dev = dev_get_by_index(&init_net, fl->oif);
> +				if (!dev)
> +					return -ENODEV;
> +			}
>  
> -			if (addr_type == IPV6_ADDR_ANY)
> +			addr_type = ipv6_addr_type(&src_info->ipi6_addr);
> +			if (addr_type == IPV6_ADDR_ANY) {
> +				if (dev)
> +					dev_put(dev);
>  				break;
> -
> -			if (addr_type & IPV6_ADDR_LINKLOCAL) {
> -				if (!src_info->ipi6_ifindex)
> -					return -EINVAL;
> -				else {
> -					dev = dev_get_by_index(&init_net, src_info->ipi6_ifindex);
> -					if (!dev)
> -						return -ENODEV;
> -				}
>  			}
> +
>  			if (!ipv6_chk_addr(&init_net, &src_info->ipi6_addr,
> -					   dev, 0)) {
> +					   addr_type & IPV6_ADDR_LINKLOCAL ? dev : NULL,
if oif==0 and address is link-local.
now it does well,not returns EINVAL.

> +					   0)) {
>  				if (dev)
>  					dev_put(dev);
>  				err = -EINVAL;
>  				goto exit_f;
>  			}
> +
>  			if (dev)
>  				dev_put(dev);
>  
>  			ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
>  			break;
> +		    }
>  
>  		case IPV6_FLOWINFO:
>  			if (cmsg->cmsg_len < CMSG_LEN(4)) {
> 
> --yoshfuji
> 
> 
> 

-- 
Regards
単 衛
--------------------------------------------------
Shan Wei
Development Dept.I

Nanjing Fujitsu Nanda Software Tech. Co., Ltd.(FNST)
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