From a190b730ac327d25b23f12c78362e1deefe9b1a5 Mon Sep 17 00:00:00 2001
From: PA4WDH
Date: Sun, 21 May 2023 10:46:35 +0200
Subject: Add input validation

---
 cputemp2maxfreq.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/cputemp2maxfreq.c b/cputemp2maxfreq.c
index 163917c..6ea71bf 100644
--- a/cputemp2maxfreq.c
+++ b/cputemp2maxfreq.c
@@ -10,6 +10,14 @@
 #include "failsafe.h"
 #include "version.h"
 
+// Valid frequencies are between 100MHz and 10GHz
+#define VALID_FREQ_MIN 100000
+#define VALID_FREQ_MAX 10000000
+
+// Valid temperatures are between 10 and 150 degrees
+#define VALID_TEMP_MIN 10000
+#define VALID_TEMP_MAX 150000
+
 struct s_cpudata cpudata;
 struct s_config config={"conservative",70000,"/sys/devices/virtual/thermal/thermal_zone0/temp",100000,2000000,10};
 
@@ -39,9 +47,9 @@ int main()
  printf("Maximum frequency: %ld\n",cpudata.max_freq);
  printf("Scaling maximum frequency: %ld\n",cpudata.scale_max);
 
- if ((cpudata.min_freq<100000) || (cpudata.min_freq>10000000) ||
-     (cpudata.max_freq<100000) || (cpudata.max_freq>10000000) ||
-     (cpudata.scale_max<100000) || (cpudata.scale_max>10000000))
+ if ((cpudata.min_freq<VALID_FREQ_MIN) || (cpudata.min_freq>VALID_FREQ_MAX) ||
+     (cpudata.max_freq<VALID_FREQ_MIN) || (cpudata.max_freq>VALID_FREQ_MAX) ||
+     (cpudata.scale_max<VALID_FREQ_MIN) || (cpudata.scale_max>VALID_FREQ_MAX))
  {
 // If we have to fail now, there's not much we can do because we have no data
   printf("Invalid CPU data, exiting.\n");
@@ -59,9 +67,20 @@ int main()
 
  while(1)
  {
+// Get new measurements
   cpudata.cur_freq=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq");
-  cpudata.cur_temp=sysfs_read_long_int(config.temp_input);
+  if ((cpudata.cur_freq<VALID_FREQ_MIN) || (cpudata.cur_freq>VALID_FREQ_MAX))
+  {
+   printf("Invalid current frequency reported by CPU, exiting.\n");
+   failsafe(1);
+  }
 
+  cpudata.cur_temp=sysfs_read_long_int(config.temp_input);
+  if ((cpudata.cur_temp<VALID_TEMP_MIN) || (cpudata.cur_temp>VALID_TEMP_MAX))
+  {
+   printf("Invalid current tempature reported by CPU, exiting.\n");
+   failsafe(1);
+  }
 
   DEBUG1_MAIN("Data: %ld %ld %ld %ld %ld\n",cpudata.cur_temp,config.max_temp,cpudata.max_freq,cpudata.scale_max,cpudata.cur_freq);
 
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