Subject: Re: [PATCH v5 1/2] sctp: check the rto_min and rto_max

From: Wang Weidong <[email-masked]>
Date: Mon, 9 Dec 2013 09:53:39 +0800

On 2013/12/8 2:54, Vlad Yasevich wrote:
> On 12/07/2013 02:17 AM, Wang Weidong wrote:
>> rto_min should be smaller than rto_max while rto_max should be larger
>> than rto_min. Add two proc_handler for the checking. Add the check in
>> sctp_setsockopt_rtoinfo.
>>
>> Suggested-by: Vlad Yasevich <[email-masked]>
>> Signed-off-by: Wang Weidong <[email-masked]>
>> ---
>>  include/net/sctp/constants.h |  3 ++
>>  net/sctp/socket.c            |  5 +++
>>  net/sctp/sysctl.c            | 73 ++++++++++++++++++++++++++++++++++++++++----
>>  3 files changed, 75 insertions(+), 6 deletions(-)
>>
>> diff --git a/include/net/sctp/constants.h b/include/net/sctp/constants.h
>> index 2f0a565..d276978 100644
>> --- a/include/net/sctp/constants.h
>> +++ b/include/net/sctp/constants.h
>> @@ -279,6 +279,9 @@ enum { SCTP_MAX_GABS = 16 };
>>  #define SCTP_RTO_ALPHA          3   /* 1/8 when converted to right shifts. */
>>  #define SCTP_RTO_BETA           2   /* 1/4 when converted to right shifts. */
>>  
>> +#define SCTP_ONE                1        /* 1 ms */
>> +#define SCTP_TIMER_MAX          86400000 /* ms in one day */
>> +
>>  /* Maximum number of new data packets that can be sent in a burst.  */
>>  #define SCTP_DEFAULT_MAX_BURST		4
>>  
>> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
>> index 72046b9..13411ad 100644
>> --- a/net/sctp/socket.c
>> +++ b/net/sctp/socket.c
>> @@ -2818,6 +2818,11 @@ static int sctp_setsockopt_rtoinfo(struct sock *sk, char __user *optval, unsigne
>>  	if (copy_from_user(&rtoinfo, optval, optlen))
>>  		return -EFAULT;
>>  
>> +	if (rtoinfo.srto_min < SCTP_ONE ||
>> +	    rtoinfo.srto_max > SCTP_TIMER_MAX ||
>> +	    rtoinfo.srto_max < rtoinfo.srto_min)
>> +		return -EINVAL;
>> +
> 
> You can not do the check for srto_min < 1.  The following is the text
> from the spec:
>    All times are given in milliseconds.  A value of 0, when modifying
>    the parameters, indicates that the current value should not be
>    changed.
> 
Yes, Your are right, I found it in draft-ietf-tsvwg-sctpsocket-14.txt.
Thanks.

> So, it is valid for a user to pass in a value of 0.  Also, I am not sure
> if it makes sense to bind the upper limit here, as well.
> 
> -vlad
> 
Here, I am not sure as well. I think it should like what we do to the
init_net.sctp.rto_max when set larger than timer_max. Just not change the value.

Regards.
Wang

>>  	asoc = sctp_id2assoc(sk, rtoinfo.srto_assoc_id);
>>  
>>  	/* Set the values to the specific association */
>> diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
>> index 6b36561..33c56c6 100644
>> --- a/net/sctp/sysctl.c
>> +++ b/net/sctp/sysctl.c
>> @@ -40,8 +40,8 @@
>>  #include <linux/sysctl.h>
>>  
>>  static int zero = 0;
>> -static int one = 1;
>> -static int timer_max = 86400000; /* ms in one day */
>> +static int one = SCTP_ONE;
>> +static int timer_max = SCTP_TIMER_MAX;
>>  static int int_max = INT_MAX;
>>  static int sack_timer_min = 1;
>>  static int sack_timer_max = 500;
>> @@ -61,6 +61,13 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl,
>>  				void __user *buffer, size_t *lenp,
>>  
>>  				loff_t *ppos);
>> +static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
>> +				void __user *buffer, size_t *lenp,
>> +				loff_t *ppos);
>> +static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
>> +				void __user *buffer, size_t *lenp,
>> +				loff_t *ppos);
>> +
>>  static struct ctl_table sctp_table[] = {
>>  	{
>>  		.procname	= "sctp_mem",
>> @@ -102,17 +109,17 @@ static struct ctl_table sctp_net_table[] = {
>>  		.data		= &init_net.sctp.rto_min,
>>  		.maxlen		= sizeof(unsigned int),
>>  		.mode		= 0644,
>> -		.proc_handler	= proc_dointvec_minmax,
>> +		.proc_handler	= proc_sctp_do_rto_min,
>>  		.extra1         = &one,
>> -		.extra2         = &timer_max
>> +		.extra2         = &init_net.sctp.rto_max
>>  	},
>>  	{
>>  		.procname	= "rto_max",
>>  		.data		= &init_net.sctp.rto_max,
>>  		.maxlen		= sizeof(unsigned int),
>>  		.mode		= 0644,
>> -		.proc_handler	= proc_dointvec_minmax,
>> -		.extra1         = &one,
>> +		.proc_handler	= proc_sctp_do_rto_max,
>> +		.extra1         = &init_net.sctp.rto_min,
>>  		.extra2         = &timer_max
>>  	},
>>  	{
>> @@ -342,6 +349,60 @@ static int proc_sctp_do_hmac_alg(struct ctl_table *ctl,
>>  	return ret;
>>  }
>>  
>> +static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
>> +				void __user*buffer, size_t *lenp,
>> +				loff_t *ppos)
>> +{
>> +	struct net *net = current->nsproxy->net_ns;
>> +	int new_value;
>> +	struct ctl_table tbl;
>> +	unsigned int min = *(unsigned int *) ctl->extra1;
>> +	unsigned int max = *(unsigned int *) ctl->extra2;
>> +	int ret;
>> +
>> +	memset(&tbl, 0, sizeof(struct ctl_table));
>> +	tbl.maxlen = sizeof(unsigned int);
>> +
>> +	if (write)
>> +		tbl.data = &new_value;
>> +	else
>> +		tbl.data = &net->sctp.rto_min;
>> +	ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
>> +	if (write) {
>> +		if (ret || new_value > max || new_value < min)
>> +			return -EINVAL;
>> +		net->sctp.rto_min = new_value;
>> +	}
>> +	return ret;
>> +}
>> +
>> +static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
>> +				void __user*buffer, size_t *lenp,
>> +				loff_t *ppos)
>> +{
>> +	struct net *net = current->nsproxy->net_ns;
>> +	int new_value;
>> +	struct ctl_table tbl;
>> +	unsigned int min = *(unsigned int *) ctl->extra1;
>> +	unsigned int max = *(unsigned int *) ctl->extra2;
>> +	int ret;
>> +
>> +	memset(&tbl, 0, sizeof(struct ctl_table));
>> +	tbl.maxlen = sizeof(unsigned int);
>> +
>> +	if (write)
>> +		tbl.data = &new_value;
>> +	else
>> +		tbl.data = &net->sctp.rto_max;
>> +	ret = proc_dointvec(&tbl, write, buffer, lenp, ppos);
>> +	if (write) {
>> +                if (ret || new_value > max || new_value < min)
>> +			return -EINVAL;
>> +		net->sctp.rto_max = new_value;
>> +	}
>> +	return ret;
>> +}
>> +
>>  int sctp_sysctl_net_register(struct net *net)
>>  {
>>  	struct ctl_table *table;
>>
> 
> --
> To unsubscribe from this list: send the line "unsubscribe netdev" in
> the body of a message to [email-masked]
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> .
>