rsync - Apr 2004 - Bug in 2.6.1

I'm not sure what the code is trying to do, but the SGI Irix 
compiler spotted  this usage of an undefined variable.

    In uidlist.c:

======static int map_uid(int id, char *name)
{
	uid_t uid;
	if (uid != 0 && name_to_uid(name, &uid))
		return uid;
	return id;
}

static int map_gid(int id, char *name)
{
	gid_t gid;
	if (gid != 0 && name_to_gid(name, &gid))
		return gid;
	return id;
}
======
    Both uid (in map_uid) and gid (in map_gid) are used (tested against 
0) without being defined.

    If these are dynamic variables they should be initilaized first, but 
then that makes the check superfluous, as you will just have set it so 
*know* the value.

    Are these supposed to be static variables?  That would mean that 
these functions are always expecting to be called with the same value of 
name.  Not sure this is likely, giving that the calling context refers 
to "list of uids".

On Wed, Apr 28, 2004 at 03:36:20PM +0100, Gordon Lack
wrote:
>    Both uid (in map_uid) and gid (in map_gid) are used (tested against 
> 0) without being defined.
Those tests were supposed to be for the "id" input variable so that
the code doesn't try to remap a zero ID.  The tests are, however,
superfluous since no ID with a value of 0 has an associated name
(rsync doesn't send them), so the check is merely an optimization.

The bad thing that might happen is that the garbage on the stack might
be 0, in which case we would leave the uid/gid unmapped (I don't know if
that's actually possible or not -- some calling sequences can never
result in a zero uninitialized value).  To fix this bug, apply the
appended patch.

Thanks for the report!

..wayne..
-------------- next part --------------
--- uidlist.c	20 Feb 2004 17:09:30 -0000	1.23
+++ uidlist.c	28 Apr 2004 17:04:55 -0000
@@ -81,7 +81,7 @@ static char *gid_to_name(gid_t gid)
 static int map_uid(int id, char *name)
 {
 	uid_t uid;
-	if (uid != 0 && name_to_uid(name, &uid))
+	if (id != 0 && name_to_uid(name, &uid))
 		return uid;
 	return id;
 }
@@ -89,7 +89,7 @@ static int map_uid(int id, char *name)
 static int map_gid(int id, char *name)
 {
 	gid_t gid;
-	if (gid != 0 && name_to_gid(name, &gid))
+	if (id != 0 && name_to_gid(name, &gid))
 		return gid;
 	return id;
 }