commit eedf406a48e8354f680df19abb0784d9cd3ac1c5
Author: Yazen Ghannam <yazen.ghannam@amd.com>
Date:   Mon Sep 17 11:57:04 2018 -0500

    Fail to read/write if register number is not parsed correctly
    
    It's possible that a user will provide a register number in a format
    that strtoul() can't parse. strtoul() will return 0 if it fails to parse
    a value. The msr-tools will then silently read/write to MSR 0x0 and
    succeed. At best this may confuse the user, or at worst this will
    unintentionally write bad data to the system.
    
    Check that the register number parsing has succeeded. If it fails, then
    inform the user, give a suggestion, and exit.
    
    Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>

--- a/rdmsr.c
+++ b/rdmsr.c
@@ -194,7 +194,11 @@ int main(int argc, char *argv[])
 		exit(127);
 	}
 
-	reg = strtoul(argv[optind], NULL, 0);
+	reg = strtoul(argv[optind], &endarg, 0);
+	if (*endarg) {
+		printf("Failed to parse register number.\n");
+		exit(127);
+	}
 
 	if (cpu == -1) {
 		doing_for_all = 1;
--- a/wrmsr.c
+++ b/wrmsr.c
@@ -121,7 +121,11 @@ int main(int argc, char *argv[])
 		exit(127);
 	}
 
-	reg = strtoul(argv[optind++], NULL, 0);
+	reg = strtoul(argv[optind++], &endarg, 0);
+	if (*endarg) {
+		printf("Failed to parse register number.\n");
+		exit(127);
+	}
 
 	if (cpu == -1) {
 		doing_for_all = 1;