[src/trunk]: src/lib/libc/stdlib Restore binary compatibility with applicatio...

[tron <tron%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/bfb81b918b46
branches:  trunk
changeset: 757901:bfb81b918b46
user:      tron <tron%NetBSD.org@localhost>
date:      Sat Oct 02 16:56:03 2010 +0000

description:
Restore binary compatibility with applications which use putenv(3)
on constant strings (e.g. postdrop(1)):
- Don't write to the environment string passed to putenv(3).
- Don't overwrite the value of an existing environment string
  unless the memory was actually allocated by setenv(3).

diffstat:

 lib/libc/stdlib/putenv.c |  22 +++++++++++++++-------
 lib/libc/stdlib/setenv.c |  13 ++++++++++---
 2 files changed, 25 insertions(+), 10 deletions(-)

diffs (87 lines):

diff -r 6b19921dd3b2 -r bfb81b918b46 lib/libc/stdlib/putenv.c
--- a/lib/libc/stdlib/putenv.c  Sat Oct 02 12:22:20 2010 +0000
+++ b/lib/libc/stdlib/putenv.c  Sat Oct 02 16:56:03 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: putenv.c,v 1.14 2010/10/02 10:05:55 tron Exp $ */
+/*     $NetBSD: putenv.c,v 1.15 2010/10/02 16:56:03 tron Exp $ */
 
 /*-
  * Copyright (c) 1988, 1993
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "@(#)putenv.c   8.2 (Berkeley) 3/27/94";
 #else
-__RCSID("$NetBSD: putenv.c,v 1.14 2010/10/02 10:05:55 tron Exp $");
+__RCSID("$NetBSD: putenv.c,v 1.15 2010/10/02 16:56:03 tron Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -54,7 +54,8 @@
 int
 putenv(char *str)
 {
-       char *p, *equal;
+       char *name, *equal, *p;
+       size_t namelen;
        int offset;
 
        _DIAGASSERT(str != NULL);
@@ -62,12 +63,19 @@
        if ((equal = strchr(str, '=')) == NULL)
                return -1;
 
-       if (rwlock_wrlock(&__environ_lock) != 0)
+       namelen = equal - str;
+       if ((name = malloc(namelen + 1)) == NULL)
                return -1;
+       (void)memcpy(name, str, namelen);
+       name[namelen] = '\0';
 
-       *equal = '\0';
-       p = __findenv(str, &offset);
-       *equal = '=';
+       if (rwlock_wrlock(&__environ_lock) != 0) {
+               free(name);
+               return -1;
+       }
+
+       p = __findenv(name, &offset);
+       free(name);
 
        if (__allocenv(offset) == -1)
                goto bad;
diff -r 6b19921dd3b2 -r bfb81b918b46 lib/libc/stdlib/setenv.c
--- a/lib/libc/stdlib/setenv.c  Sat Oct 02 12:22:20 2010 +0000
+++ b/lib/libc/stdlib/setenv.c  Sat Oct 02 16:56:03 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: setenv.c,v 1.39 2010/10/01 20:11:32 christos Exp $     */
+/*     $NetBSD: setenv.c,v 1.40 2010/10/02 16:56:03 tron Exp $ */
 
 /*
  * Copyright (c) 1987, 1993
@@ -34,7 +34,7 @@
 #if 0
 static char sccsid[] = "@(#)setenv.c   8.1 (Berkeley) 6/4/93";
 #else
-__RCSID("$NetBSD: setenv.c,v 1.39 2010/10/01 20:11:32 christos Exp $");
+__RCSID("$NetBSD: setenv.c,v 1.40 2010/10/02 16:56:03 tron Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -83,8 +83,15 @@
        if (c != NULL) {
                if (!rewrite)
                        goto good;
-               if (strlen(c) >= l_value)       /* old is enough; copy over */
+               /*
+                * Check whether the buffer was allocated via setenv(3) and
+                * whether there is enough space. If so simply overwrite the
+                * existing value.
+                */
+               if (environ[offset] == __environ_malloced[offset] &&
+                   strlen(c) >= l_value) {
                        goto copy;
+               }
        }
        for (cc = name; *cc && *cc != '='; ++cc)        /* no `=' in name */
                continue;