svn commit: r363625 - stable/12/usr.sbin/mountd

[Rick Macklem]

Brooks Davis wrote:
>Author: brooks
>Date: Mon Jul 27 23:18:14 2020
>New Revision: 363625
>URL: https://svnweb.freebsd.org/changeset/base/363625
>
>Log:
>  MFC r363439:
>
>  Correct a type-mismatch between xdr_long and the variable "bad".
>
>  Way back in r28911 (August 1997, CVS rev 1.22) we imported a NetBSD
>  information leak fix via OpenBSD.  Unfortunatly we failed to track the
>  followup commit that fixed the type of the error code.  Apply the change
>  from int to long now.
I don't think this is correct.
RFC-1813 defines the error return for a MNT RPC as a 32bit quantity.

Way back when this stuff was written it was in K&R days and "long" was
always a 32bit integer.

If you look at head/lib/libc/xdr/xdr.c you'll see "long" used to refer to 32bit
numbers throughout it. Look near the end, where it does a "longlong" (64bits)
using 2 longs.

The good news w.r.t. this ancient code is that XDR_PUTLONG() assumes 32bits.

Also, note that xdr_int() and xdr_long() do exactly the same thing.

I support int32_t would be preferred to "int" to make sure "bad" is 32bits
and then you can use xdr_int32_t(), which does exactly the same thing as
xdr_int() and about the same thing as xdr_long(). { They all assume a "long"
is 32bits. Scary to look at now that "long" isn't always 32bits. }
--> I can't see how the xdr.c code would work for a machine that is BIG_ENDIAN
      and where "long" is 64bits, but we don't have any of those.

I don't think "int bad" was wrong and "long bad" definitely seems wrong for
64bit systems, although the xdr.c code simply ends up putting the low order
32bits on the wire, I think?

rick

  Reviewed by:  emaste
  Reported by:  CHERI
  Obtained from:        CheriBSD
  Sponsored by: DARPA
  Differential Revision:        https://reviews.freebsd.org/D25779

Modified:
  stable/12/usr.sbin/mountd/mountd.c
Directory Properties:
  stable/12/   (props changed)

Modified: stable/12/usr.sbin/mountd/mountd.c
==============================================================================
--- stable/12/usr.sbin/mountd/mountd.c  Mon Jul 27 21:19:41 2020        (r363624)
+++ stable/12/usr.sbin/mountd/mountd.c  Mon Jul 27 23:18:14 2020        (r363625)
@@ -1087,7 +1087,8 @@ mntsrv(struct svc_req *rqstp, SVCXPRT *transp)
        struct sockaddr *saddr;
        u_short sport;
        char rpcpath[MNTPATHLEN + 1], dirpath[MAXPATHLEN];
-       int bad = 0, defset, hostset;
+       int defset, hostset;
+       long bad = 0;
        sigset_t sighup_mask;
        int numsecflavors, *secflavorsp;