[PATCH] udev - safer string handling - part two

As promised, here is the next round. We provide in addition to the
already used macros:

  strfieldcpy(to, from)
  strfieldcat(to, from)

the corresponding friends, if the size of the target is not known and
must be provided by the caller:

  strnfieldcpy(to, from, maxsize)
  strnfieldcat(to, from, maxsize)

and switch nearly all possibly unsafe users of strcat(), strncat(),
strcpy() and strncpy() to these safer macros.

The last known remaining issue seems the use of sprintf() and
snprintf(). I will take on it later today or tomorrow.

1 files changed, 13 insertions, 1 deletions

diff --git a/udev.h b/udev.h
index fc44a9847c..0ce010f3c4 100644
--- a/udev.h
+++ b/udev.h
@@ -64,7 +64,19 @@ do { \
 #define strfieldcat(to, from) \
 do { \
 	to[sizeof(to)-1] = '\0'; \
-	strncat(to, from, sizeof(to) - strlen(to) -1); \
+	strncat(to, from, sizeof(to) - strlen(to)-1); \
+} while (0)
+
+#define strnfieldcpy(to, from, maxsize) \
+do { \
+	to[maxsize-1] = '\0'; \
+	strncpy(to, from, maxsize-1); \
+} while (0)
+
+#define strnfieldcat(to, from, maxsize) \
+do { \
+	to[maxsize-1] = '\0'; \
+	strncat(to, from, maxsize - strlen(to)-1); \
 } while (0)
 
 extern int udev_add_device(char *path, char *subsystem, int fake);