Re: pkg/49804

[Brett Lymn <blymn%internode.on.net@localhost>]

The following reply was made to PR pkg/49804; it has been noted by GNATS.

From: Brett Lymn <blymn%internode.on.net@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: pkg/49804
Date: Tue, 30 May 2023 07:53:23 +0930

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 The getpeercred compat routine is returning pointers to variables on
 function stack, this is dangerous....  The attached patch declares a
 couple of static variables to prevent stack storage addresses being
 returned.
 
 -- 
 Brett Lymn
 --
 Sent from my NetBSD device.
 
 "We are were wolves",
 "You mean werewolves?",
 "No we were wolves, now we are something else entirely",
 "Oh"
 
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 --- getpeercred.c	2022-10-11 07:54:45.000000000 +1030
 +++ ../../nss-pam-ldapd-master.modified/compat/getpeercred.c	2023-05-30 07:52:10.429723839 +0930
 @@ -37,6 +37,11 @@
  
  #include "getpeercred.h"
  
 +#if defined(HAVE_GETPEEREID)
 +static uid_t tuid;
 +static gid_t tgid;
 +#endif
 +
  /* Note: most of this code is untested, except for the first
           implementation (it may even fail to compile) */
  
 @@ -96,19 +101,12 @@
    ucred_free(cred);
    return 0;
  #elif defined(HAVE_GETPEEREID)
 -  uid_t tuid;
 -  gid_t tgid;
    if (uid == NULL)
      uid = &tuid;
    if (gid == NULL)
 -    gid = &tguid;
 +    gid = &tgid;
    if (getpeereid(sock, uid, gid))
      return -1;
 -  /* return the data */
 -  if (uid != NULL)
 -    *uid = cred.uid;
 -  if (gid != NULL)
 -    *gid = cred.gid;
    if (pid != NULL)
      *pid = -1; /* we return a -1 pid because we have no usable pid */
    return 0;
 
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