net: sctp: fix permissions for rto_alpha and rto_beta knobs

[firefly-linux-kernel-4.4.55.git] / net / sctp / sysctl.c

diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index c82fdc1eab7c359dbee3812db3f3707fa5c65560..dcb19592761e3b80b92057ba5b834e568a338ab9 100644 (file)
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -34,6 +34,8 @@
  *    Sridhar Samudrala     <sri@us.ibm.com>
  */
 
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
 #include <net/sctp/structs.h>
 #include <net/sctp/sctp.h>
 #include <linux/sysctl.h>
@@ -46,6 +48,11 @@ static int sack_timer_min = 1;
 static int sack_timer_max = 500;
 static int addr_scope_max = 3; /* check sctp_scope_policy_t in include/net/sctp/constants.h for max entries */
 static int rwnd_scale_max = 16;
+static int rto_alpha_min = 0;
+static int rto_beta_min = 0;
+static int rto_alpha_max = 1000;
+static int rto_beta_max = 1000;
+
 static unsigned long max_autoclose_min = 0;
 static unsigned long max_autoclose_max =
        (MAX_SCHEDULE_TIMEOUT / HZ > UINT_MAX)
@@ -64,6 +71,9 @@ static int proc_sctp_do_rto_min(struct ctl_table *ctl, int write,
 static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
                                void __user *buffer, size_t *lenp,
                                loff_t *ppos);
+static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
+                                  void __user *buffer, size_t *lenp,
+                                  loff_t *ppos);
 static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
                             void __user *buffer, size_t *lenp,
                             loff_t *ppos);
@@ -126,15 +136,19 @@ static struct ctl_table sctp_net_table[] = {
                .procname       = "rto_alpha_exp_divisor",
                .data           = &init_net.sctp.rto_alpha,
                .maxlen         = sizeof(int),
-               .mode           = 0444,
-               .proc_handler   = proc_dointvec,
+               .mode           = 0644,
+               .proc_handler   = proc_sctp_do_alpha_beta,
+               .extra1         = &rto_alpha_min,
+               .extra2         = &rto_alpha_max,
        },
        {
                .procname       = "rto_beta_exp_divisor",
                .data           = &init_net.sctp.rto_beta,
                .maxlen         = sizeof(int),
-               .mode           = 0444,
-               .proc_handler   = proc_dointvec,
+               .mode           = 0644,
+               .proc_handler   = proc_sctp_do_alpha_beta,
+               .extra1         = &rto_beta_min,
+               .extra2         = &rto_beta_max,
        },
        {
                .procname       = "max_burst",
@@ -403,6 +417,16 @@ static int proc_sctp_do_rto_max(struct ctl_table *ctl, int write,
        return ret;
 }
 
+static int proc_sctp_do_alpha_beta(struct ctl_table *ctl, int write,
+                                  void __user *buffer, size_t *lenp,
+                                  loff_t *ppos)
+{
+       pr_warn_once("Changing rto_alpha or rto_beta may lead to "
+                    "suboptimal rtt/srtt estimations!\n");
+
+       return proc_dointvec_minmax(ctl, write, buffer, lenp, ppos);
+}
+
 static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
                             void __user *buffer, size_t *lenp,
                             loff_t *ppos)
@@ -436,20 +460,21 @@ static int proc_sctp_do_auth(struct ctl_table *ctl, int write,
 
 int sctp_sysctl_net_register(struct net *net)
 {
-       struct ctl_table *table = sctp_net_table;
-
-       if (!net_eq(net, &init_net)) {
-               int i;
+       struct ctl_table *table;
+       int i;
 
-               table = kmemdup(sctp_net_table, sizeof(sctp_net_table), GFP_KERNEL);
-               if (!table)
-                       return -ENOMEM;
+       table = kmemdup(sctp_net_table, sizeof(sctp_net_table), GFP_KERNEL);
+       if (!table)
+               return -ENOMEM;
 
-               for (i = 0; table[i].data; i++)
-                       table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;
-       }
+       for (i = 0; table[i].data; i++)
+               table[i].data += (char *)(&net->sctp) - (char *)&init_net.sctp;
 
        net->sctp.sysctl_header = register_net_sysctl(net, "net/sctp", table);
+       if (net->sctp.sysctl_header == NULL) {
+               kfree(table);
+               return -ENOMEM;
+       }
        return 0;
 }