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According to Eric Blake on 11/13/2009 11:35 AM:
> I also discovered that
> FreeBSD getgroups(-1,NULL) fails with EFAULT instead of EINVAL, which
> means that it mistakenly populates a valid pointer rather than rejecting a
> negative argument; should be easy to fix today.
Like so. And I feel silly for the buffer overrun in the test; I was
originally using xnmalloc, but didn't want drag in "xalloc.h" for the
test, but converted it wrong.
- --
Don't work too hard, make some time for fun as well!
Eric Blake e...@byu.net
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>From 1e642be936b3a09f6200d753f035ce045d9c5dac Mon Sep 17 00:00:00 2001
From: Eric Blake <e...@byu.net>
Date: Fri, 13 Nov 2009 12:53:17 -0700
Subject: [PATCH] getgroups: work around FreeBSD bug
FreeBSD 7.2 mistakenly succeeds on getgroups(-1,ptr) (POSIX
requires EINVAL failure since -1 is less than the proper result).
* lib/getgroups.c (rpl_getgroups): Work around the bug.
* m4/getgroups.m4 (gl_FUNC_GETGROUPS): Detect the bug.
* doc/posix-functions/getgroups.texi (getgroups): Document it.
* tests/test-getgroups.c (main): Fix buffer overrun.
Signed-off-by: Eric Blake <e...@byu.net>
---
ChangeLog | 6 ++++++
doc/posix-functions/getgroups.texi | 6 +++++-
lib/getgroups.c | 16 ++++++++++------
m4/getgroups.m4 | 19 ++++++++++++++++++-
tests/test-getgroups.c | 2 +-
5 files changed, 40 insertions(+), 9 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 44e2120..b0b3016 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
2009-11-13 Eric Blake <e...@byu.net>
+ getgroups: work around FreeBSD bug
+ * lib/getgroups.c (rpl_getgroups): Work around the bug.
+ * m4/getgroups.m4 (gl_FUNC_GETGROUPS): Detect the bug.
+ * doc/posix-functions/getgroups.texi (getgroups): Document it.
+ * tests/test-getgroups.c (main): Fix buffer overrun.
+
getgroups: avoid compilation failure
* lib/getgroups.c (includes): Include <stdint.h> for SIZE_MAX.
* modules/getgroups (Depends-on): Add stdint.
diff --git a/doc/posix-functions/getgroups.texi
b/doc/posix-functions/getgroups.texi
index 745210e..a8478eb 100644
--- a/doc/posix-functions/getgroups.texi
+++ b/doc/posix-functions/getgroups.texi
@@ -12,7 +12,11 @@ getgroups
This function is missing on some platforms:
mingw.
@item
-On Ultrix 4.3, @code{getgroups (0, 0)} always fails. See macro
+On some platforms, this function fails to reject a negative count,
+even though that is less than the size that would be returned:
+FreeBSD 7.2.
+...@item
+On Ultrix 4.3, @code{getgroups (0, NULL)} always fails. See macro
@samp{AC_FUNC_GETGROUPS}.
@item
On very old systems, this function operated on an array of @samp{int},
diff --git a/lib/getgroups.c b/lib/getgroups.c
index bb2b38d..c07f2de 100644
--- a/lib/getgroups.c
+++ b/lib/getgroups.c
@@ -40,6 +40,9 @@ getgroups (int n _UNUSED_PARAMETER_, GETGROUPS_T *groups
_UNUSED_PARAMETER_)
#else /* HAVE_GETGROUPS */
# undef getgroups
+# ifndef GETGROUPS_ZERO_BUG
+# define GETGROUPS_ZERO_BUG 0
+# endif
/* On at least Ultrix 4.3 and NextStep 3.2, getgroups (0, NULL) always
fails. On other systems, it returns the number of supplemental
@@ -55,18 +58,19 @@ rpl_getgroups (int n, gid_t *group)
GETGROUPS_T *gbuf;
int saved_errno;
- if (n != 0)
+ if (n < 0)
+ {
+ errno = EINVAL;
+ return -1;
+ }
+
+ if (n != 0 || !GETGROUPS_ZERO_BUG)
{
int result;
int saved_errno;
if (sizeof *group == sizeof *gbuf)
return getgroups (n, (GETGROUPS_T *) group);
- if (n < 0)
- {
- errno = EINVAL;
- return -1;
- }
if (SIZE_MAX / sizeof *gbuf <= n)
{
errno = ENOMEM;
diff --git a/m4/getgroups.m4 b/m4/getgroups.m4
index 4d96712..0f8e89e 100644
--- a/m4/getgroups.m4
+++ b/m4/getgroups.m4
@@ -1,4 +1,4 @@
-# serial 14
+# serial 15
dnl From Jim Meyering.
dnl A wrapper around AC_FUNC_GETGROUPS.
@@ -21,6 +21,23 @@ AC_DEFUN([gl_FUNC_GETGROUPS],
then
AC_LIBOBJ([getgroups])
REPLACE_GETGROUPS=1
+ AC_DEFINE([GETGROUPS_ZERO_BUG], [1], [Define this to 1 if
+ getgroups(0,NULL) does not return the number of groups.])
+ else
+ dnl Detect FreeBSD bug; POSIX requires getgroups(-1,ptr) to fail.
+ AC_CACHE_CHECK([whether getgroups handles negative values],
+ [gl_cv_func_getgroups_works],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
+ [[int size = getgroups (0, 0);
+ gid_t *list = malloc (size * sizeof *list);
+ return getgroups (-1, list) != -1;]])],
+ [gl_cv_func_getgroups_works=yes],
+ [gl_cv_func_getgroups_works=no],
+ [gl_cv_func_getgroups_works="guessing no"])])
+ if test "$gl_cv_func_getgroups_works" != yes; then
+ AC_LIBOBJ([getgroups])
+ REPLACE_GETGROUPS=1
+ fi
fi
test -n "$GETGROUPS_LIB" && LIBS="$GETGROUPS_LIB $LIBS"
])
diff --git a/tests/test-getgroups.c b/tests/test-getgroups.c
index b2e65a0..aed80f1 100644
--- a/tests/test-getgroups.c
+++ b/tests/test-getgroups.c
@@ -52,7 +52,7 @@ main (int argc, char **argv _UNUSED_PARAMETER_)
}
ASSERT (0 <= result);
ASSERT (result + 1 < SIZE_MAX / sizeof *groups);
- groups = malloc (result + 1 * sizeof *groups);
+ groups = malloc ((result + 1) * sizeof *groups);
ASSERT (groups);
groups[result] = -1;
/* Check for EINVAL handling. Not all processes have supplemental
--
1.6.5.rc1
