msm-4.14/drivers/rtc/rtc-proc.c
Dan Carpenter 8f256b32b5 rtc: fix snprintf() checking in is_rtc_hctosys()
[ Upstream commit 54b909436ede47e0ee07f1765da27ec2efa41e84 ]

The scnprintf() function silently truncates the printf() and returns
the number bytes that it was able to copy (not counting the NUL
terminator).  Thus, the highest value it can return here is
"NAME_SIZE - 1" and the overflow check is dead code.  Fix this by
using the snprintf() function which returns the number of bytes that
would have been copied if there was enough space and changing the
condition from "> NAME_SIZE" to ">= NAME_SIZE".

Fixes: 92589c986b33 ("rtc-proc: permit the /proc/driver/rtc device to use other devices")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/YJov/pcGmhLi2pEl@mwanda
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:17:54 +02:00

151 lines
3.6 KiB
C

/*
* RTC subsystem, proc interface
*
* Copyright (C) 2005-06 Tower Technologies
* Author: Alessandro Zummo <a.zummo@towertech.it>
*
* based on arch/arm/common/rtctime.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/rtc.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include "rtc-core.h"
#define NAME_SIZE 10
#if defined(CONFIG_RTC_HCTOSYS_DEVICE)
static bool is_rtc_hctosys(struct rtc_device *rtc)
{
int size;
char name[NAME_SIZE];
size = snprintf(name, NAME_SIZE, "rtc%d", rtc->id);
if (size >= NAME_SIZE)
return false;
return !strncmp(name, CONFIG_RTC_HCTOSYS_DEVICE, NAME_SIZE);
}
#else
static bool is_rtc_hctosys(struct rtc_device *rtc)
{
return (rtc->id == 0);
}
#endif
static int rtc_proc_show(struct seq_file *seq, void *offset)
{
int err;
struct rtc_device *rtc = seq->private;
const struct rtc_class_ops *ops = rtc->ops;
struct rtc_wkalrm alrm;
struct rtc_time tm;
err = rtc_read_time(rtc, &tm);
if (err == 0) {
seq_printf(seq,
"rtc_time\t: %02d:%02d:%02d\n"
"rtc_date\t: %04d-%02d-%02d\n",
tm.tm_hour, tm.tm_min, tm.tm_sec,
tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
}
err = rtc_read_alarm(rtc, &alrm);
if (err == 0) {
seq_printf(seq, "alrm_time\t: ");
if ((unsigned int)alrm.time.tm_hour <= 24)
seq_printf(seq, "%02d:", alrm.time.tm_hour);
else
seq_printf(seq, "**:");
if ((unsigned int)alrm.time.tm_min <= 59)
seq_printf(seq, "%02d:", alrm.time.tm_min);
else
seq_printf(seq, "**:");
if ((unsigned int)alrm.time.tm_sec <= 59)
seq_printf(seq, "%02d\n", alrm.time.tm_sec);
else
seq_printf(seq, "**\n");
seq_printf(seq, "alrm_date\t: ");
if ((unsigned int)alrm.time.tm_year <= 200)
seq_printf(seq, "%04d-", alrm.time.tm_year + 1900);
else
seq_printf(seq, "****-");
if ((unsigned int)alrm.time.tm_mon <= 11)
seq_printf(seq, "%02d-", alrm.time.tm_mon + 1);
else
seq_printf(seq, "**-");
if (alrm.time.tm_mday && (unsigned int)alrm.time.tm_mday <= 31)
seq_printf(seq, "%02d\n", alrm.time.tm_mday);
else
seq_printf(seq, "**\n");
seq_printf(seq, "alarm_IRQ\t: %s\n",
alrm.enabled ? "yes" : "no");
seq_printf(seq, "alrm_pending\t: %s\n",
alrm.pending ? "yes" : "no");
seq_printf(seq, "update IRQ enabled\t: %s\n",
(rtc->uie_rtctimer.enabled) ? "yes" : "no");
seq_printf(seq, "periodic IRQ enabled\t: %s\n",
(rtc->pie_enabled) ? "yes" : "no");
seq_printf(seq, "periodic IRQ frequency\t: %d\n",
rtc->irq_freq);
seq_printf(seq, "max user IRQ frequency\t: %d\n",
rtc->max_user_freq);
}
seq_printf(seq, "24hr\t\t: yes\n");
if (ops->proc)
ops->proc(rtc->dev.parent, seq);
return 0;
}
static int rtc_proc_open(struct inode *inode, struct file *file)
{
int ret;
struct rtc_device *rtc = PDE_DATA(inode);
if (!try_module_get(rtc->owner))
return -ENODEV;
ret = single_open(file, rtc_proc_show, rtc);
if (ret)
module_put(rtc->owner);
return ret;
}
static int rtc_proc_release(struct inode *inode, struct file *file)
{
int res = single_release(inode, file);
struct rtc_device *rtc = PDE_DATA(inode);
module_put(rtc->owner);
return res;
}
static const struct file_operations rtc_proc_fops = {
.open = rtc_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = rtc_proc_release,
};
void rtc_proc_add_device(struct rtc_device *rtc)
{
if (is_rtc_hctosys(rtc))
proc_create_data("driver/rtc", 0, NULL, &rtc_proc_fops, rtc);
}
void rtc_proc_del_device(struct rtc_device *rtc)
{
if (is_rtc_hctosys(rtc))
remove_proc_entry("driver/rtc", NULL);
}