ax.25: x.25: Remove the now superfluous sentinel elements from ctl_table array

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which will
reduce the overall build time size of the kernel and run time memory
bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@bombadil.infradead.org/)

Avoid a buffer overflow when traversing the ctl_table by ensuring that
AX25_MAX_VALUES is the same as the size of ax25_param_table. This is
done with a BUILD_BUG_ON where ax25_param_table is defined and a
CONFIG_AX25_DAMA_SLAVE guard in the unnamed enum definition as well as
in the ax25_dev_device_up and ax25_ds_set_timer functions.

The overflow happened when the sentinel was removed from
ax25_param_table. The sentinel's data element was changed when
CONFIG_AX25_DAMA_SLAVE was undefined. This had no adverse effects as it
still stopped on the sentinel's null procname but needed to be addressed
once the sentinel was removed.

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ax25.h b/include/net/ax25.h
index 0d939e5aee4eca38d2b1bd86f87fe3cd990af67b..eb9cee8252c855e6b5547020e724b016e4692e67 100644 (file)
--- a/include/net/ax25.h
+++ b/include/net/ax25.h
@@ -139,7 +139,9 @@ enum {
        AX25_VALUES_N2,         /* Default N2 value */
        AX25_VALUES_PACLEN,     /* AX.25 MTU */
        AX25_VALUES_PROTOCOL,   /* Std AX.25, DAMA Slave, DAMA Master */
+#ifdef CONFIG_AX25_DAMA_SLAVE
        AX25_VALUES_DS_TIMEOUT, /* DAMA Slave timeout */
+#endif
        AX25_MAX_VALUES         /* THIS MUST REMAIN THE LAST ENTRY OF THIS LIST */
 };
 

diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c
index 282ec581c0720105b0411d9596c7ac12ff3bf115..0bc682ffae9c5c481266b737f0156fd3acd8fac2 100644 (file)
--- a/net/ax25/ax25_dev.c
+++ b/net/ax25/ax25_dev.c
@@ -78,7 +78,10 @@ void ax25_dev_device_up(struct net_device *dev)
        ax25_dev->values[AX25_VALUES_N2]        = AX25_DEF_N2;
        ax25_dev->values[AX25_VALUES_PACLEN]    = AX25_DEF_PACLEN;
        ax25_dev->values[AX25_VALUES_PROTOCOL]  = AX25_DEF_PROTOCOL;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
        ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;
+#endif
 
 #if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
        ax25_ds_setup_timer(ax25_dev);

diff --git a/net/ax25/ax25_ds_timer.c b/net/ax25/ax25_ds_timer.c
index c4f8adbf81441b2bcfa34a5777bc88d3562baf8a..c50a58d9e368b9bc9b44acc2890d7e004d774bfe 100644 (file)
--- a/net/ax25/ax25_ds_timer.c
+++ b/net/ax25/ax25_ds_timer.c
@@ -55,6 +55,7 @@ void ax25_ds_set_timer(ax25_dev *ax25_dev)
        ax25_dev->dama.slave_timeout =
                msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
        mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
+       return;
 }
 
 /*

diff --git a/net/ax25/sysctl_net_ax25.c b/net/ax25/sysctl_net_ax25.c
index e0128dc9def33237f15fd02cbccaf6e5126cc483..68753aa303341a542ec9f319ec4bc836aeb6aba5 100644 (file)
--- a/net/ax25/sysctl_net_ax25.c
+++ b/net/ax25/sysctl_net_ax25.c
@@ -141,8 +141,6 @@ static const struct ctl_table ax25_param_table[] = {
                .extra2         = &max_ds_timeout
        },
 #endif
-
-       { }     /* that's all, folks! */
 };
 
 int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
@@ -155,6 +153,7 @@ int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
        if (!table)
                return -ENOMEM;
 
+       BUILD_BUG_ON(ARRAY_SIZE(ax25_param_table) != AX25_MAX_VALUES);
        for (k = 0; k < AX25_MAX_VALUES; k++)
                table[k].data = &ax25_dev->values[k];
 

diff --git a/net/x25/sysctl_net_x25.c b/net/x25/sysctl_net_x25.c
index e9802afa43d0d850b27d0d74afd8e1de077e63bc..643f50874dfe6b972a1161af70f486d948608b7c 100644 (file)
--- a/net/x25/sysctl_net_x25.c
+++ b/net/x25/sysctl_net_x25.c
@@ -71,7 +71,6 @@ static struct ctl_table x25_table[] = {
                .mode =         0644,
                .proc_handler = proc_dointvec,
        },
-       { },
 };
 
 int __init x25_register_sysctl(void)