strtoul: check errno

src/lxc/caps.c

@@ -202,9 +202,9 @@ static int _real_caps_last_cap(void)
 
 		if ((n = read(fd, buf, 31)) >= 0) {
 			buf[n] = '\0';
+			errno = 0;
 			result = strtol(buf, &ptr, 10);
-			if (!ptr || (*ptr != '\0' && *ptr != '\n') ||
-			    result == INT_MIN || result == INT_MAX)
+			if (!ptr || (*ptr != '\0' && *ptr != '\n') || errno != 0)
 				result = -1;
 		}
 

src/lxc/conf.c

@@ -1946,9 +1946,9 @@ static int setup_caps(struct lxc_list *caps)
 			/* try to see if it's numeric, so the user may specify
 			* capabilities  that the running kernel knows about but
 			* we don't */
+			errno = 0;
 			capid = strtol(drop_entry, &ptr, 10);
-			if (!ptr || *ptr != '\0' ||
-			capid == INT_MIN || capid == INT_MAX)
+			if (!ptr || *ptr != '\0' || errno != 0)
 				/* not a valid number */
 				capid = -1;
 			else if (capid > lxc_caps_last_cap())

src/lxc/utils.c

@@ -179,8 +179,9 @@ extern int get_u16(unsigned short *val, const char *arg, int base)
 	if (!arg || !*arg)
 		return -1;
 
+	errno = 0;
 	res = strtoul(arg, &ptr, base);
-	if (!ptr || ptr == arg || *ptr || res > 0xFFFF)
+	if (!ptr || ptr == arg || *ptr || res > 0xFFFF || errno != 0)
 		return -1;
 
 	*val = res;