sysctl net: Keep tcp_syn_retries inside the boundary

Limit the min/max value passed to the
/proc/sys/net/ipv4/tcp_syn_retries.

Signed-off-by: Michal Tesar <mtesar@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 1 deletions

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index b2c123c44d69..610e324348d1 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -36,6 +36,8 @@ static int tcp_adv_win_scale_min = -31;
 static int tcp_adv_win_scale_max = 31;
 static int ip_ttl_min = 1;
 static int ip_ttl_max = 255;
+static int tcp_syn_retries_min = 1;
+static int tcp_syn_retries_max = MAX_TCP_SYNCNT;
 static int ip_ping_group_range_min[] = { 0, 0 };
 static int ip_ping_group_range_max[] = { GID_T_MAX, GID_T_MAX };
 
@@ -332,7 +334,9 @@ static struct ctl_table ipv4_table[] = {
                 .data           = &sysctl_tcp_syn_retries,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
-                .proc_handler   = proc_dointvec
+                .proc_handler   = proc_dointvec_minmax,
+                .extra1         = &tcp_syn_retries_min,
+                .extra2         = &tcp_syn_retries_max
         },
         {
                 .procname       = "tcp_synack_retries",