sctp: add check rto_min and rto_max in sysctl

rto_min should be smaller than rto_max while rto_max should be larger
than rto_min. Add two proc_handler for the checking.

Suggested-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Wang Weidong <wangweidong1@huawei.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 6b36561a1b3b7cceab5f5a4a9dce7aa2bc362266..43b5e3243871b463a319e2ff3fca0c984d127afb 100644 (file)
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -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;