calls to cuserid() can result in buffer overruns and/or overflows

git-mirror · Mar 24, 2010 · fd8ccb0 · fd8ccb0
1 parent 54bf215
commit fd8ccb0
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diff --git a/ChangeLog b/ChangeLog
@@ -1,5 +1,10 @@
 2010-03-24  Ulrich Drepper  <drepper@redhat.com>
 
+	[BZ #11397]
+	* sysdeps/posix/cuserid.c (cuserid): Make sure the returned string
+	is NUL terminated.
+	Patch by Jonathan Geisler <jgeisler@cse.taylor.edu>.
+
 	* sysdeps/unix/sysv/linux/mmap64.c: Allow variable shift values.
 
 2010-03-24  H.J. Lu  <hongjiu.lu@intel.com>

diff --git a/sysdeps/posix/cuserid.c b/sysdeps/posix/cuserid.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1991, 1996, 1998, 1999, 2001 Free Software Foundation, Inc.
+/* Copyright (C) 1991, 1996, 1998, 1999, 2001, 2010 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -44,5 +44,6 @@ cuserid (s)
 
   if (s == NULL)
     s = name;
-  return strncpy (s, pwptr->pw_name, L_cuserid);
+  s[L_userid - 1] = '\0';
+  return strncpy (s, pwptr->pw_name, L_cuserid - 1);
 }