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

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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>
This commit is contained in:
Joel Granados 2024-05-01 11:29:32 +02:00 committed by David S. Miller
parent e00e35e217
commit 78a7b5dbc0
5 changed files with 7 additions and 3 deletions
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2
include/net/ax25.h
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@ -139,7 +139,9 @@ enum {
AX25_VALUES_N2, /* Default N2 value */ AX25_VALUES_N2, /* Default N2 value */
AX25_VALUES_PACLEN, /* AX.25 MTU */ AX25_VALUES_PACLEN, /* AX.25 MTU */
AX25_VALUES_PROTOCOL, /* Std AX.25, DAMA Slave, DAMA Master */ AX25_VALUES_PROTOCOL, /* Std AX.25, DAMA Slave, DAMA Master */
#ifdef CONFIG_AX25_DAMA_SLAVE
AX25_VALUES_DS_TIMEOUT, /* DAMA Slave timeout */ AX25_VALUES_DS_TIMEOUT, /* DAMA Slave timeout */
#endif
AX25_MAX_VALUES /* THIS MUST REMAIN THE LAST ENTRY OF THIS LIST */ AX25_MAX_VALUES /* THIS MUST REMAIN THE LAST ENTRY OF THIS LIST */
}; };

3
net/ax25/ax25_dev.c
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@ -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_N2] = AX25_DEF_N2;
ax25_dev->values[AX25_VALUES_PACLEN] = AX25_DEF_PACLEN; ax25_dev->values[AX25_VALUES_PACLEN] = AX25_DEF_PACLEN;
ax25_dev->values[AX25_VALUES_PROTOCOL] = AX25_DEF_PROTOCOL; 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; ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;
#endif
#if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER) #if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
ax25_ds_setup_timer(ax25_dev); ax25_ds_setup_timer(ax25_dev);

1
net/ax25/ax25_ds_timer.c
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@ -55,6 +55,7 @@ void ax25_ds_set_timer(ax25_dev *ax25_dev)
ax25_dev->dama.slave_timeout = ax25_dev->dama.slave_timeout =
msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10; msecs_to_jiffies(ax25_dev->values[AX25_VALUES_DS_TIMEOUT]) / 10;
mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ); mod_timer(&ax25_dev->dama.slave_timer, jiffies + HZ);
return;
} }
/* /*

3
net/ax25/sysctl_net_ax25.c
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@ -141,8 +141,6 @@ static const struct ctl_table ax25_param_table[] = {
.extra2 = &max_ds_timeout .extra2 = &max_ds_timeout
}, },
#endif #endif
{ } /* that's all, folks! */
}; };
int ax25_register_dev_sysctl(ax25_dev *ax25_dev) int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
@ -155,6 +153,7 @@ int ax25_register_dev_sysctl(ax25_dev *ax25_dev)
if (!table) if (!table)
return -ENOMEM; return -ENOMEM;
BUILD_BUG_ON(ARRAY_SIZE(ax25_param_table) != AX25_MAX_VALUES);
for (k = 0; k < AX25_MAX_VALUES; k++) for (k = 0; k < AX25_MAX_VALUES; k++)
table[k].data = &ax25_dev->values[k]; table[k].data = &ax25_dev->values[k];

1
net/x25/sysctl_net_x25.c
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@ -71,7 +71,6 @@ static struct ctl_table x25_table[] = {
.mode = 0644, .mode = 0644,
.proc_handler = proc_dointvec, .proc_handler = proc_dointvec,
}, },
{ },
}; };
int __init x25_register_sysctl(void) int __init x25_register_sysctl(void)