From b6b68db896f9963558334aff7fca61adde4ec10f Mon Sep 17 00:00:00 2001
From: Seebs <seebs@seebs.net>
Date: Thu, 13 Apr 2017 18:12:01 -0500
Subject: Prevent bash from segfaulting when unloading pseudo

bash's extremely fancy internal awareness of how the environment looks
means that, if you directly call the underlying libc "unsetenv" on
a variable, bash can end up trying to access a null pointer. Fixing
this generically is actually rather hard; you can't really avoid
writing to environ on fork() or popen(), even if you change all
execv*() functions to use the execv*e() variants. So for now, instead
of unsetting the variable, set it to an empty string.

Thanks to Saur in IRC for spotting this and helping debug it.

Signed-off-by: Seebs <seebs@seebs.net>

Upstream-Status: Backport

diff --git a/ChangeLog.txt b/ChangeLog.txt
index a2d30e9..8ba1ffa 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -1,3 +1,8 @@
+2017-04-13:
+	* (seebs) don't unset LD_PRELOAD or the like, because if you
+	  do that, bash can segfault because it "knows" how many
+	  fields are in environ.
+
 2017-02-24:
 	* (seebs) import posix_acl_default fix from Anton Gerasimov
 	  <anton@advancedtelematic.com>
diff --git a/pseudo_util.c b/pseudo_util.c
index 172990b..6a1fac2 100644
--- a/pseudo_util.c
+++ b/pseudo_util.c
@@ -844,7 +844,7 @@ void pseudo_dropenv() {
 		if (ld_preload && strlen(ld_preload)) {
 			SETENV(PRELINK_LIBRARIES, ld_preload, 1);
 		} else {
-			UNSETENV(PRELINK_LIBRARIES);
+			SETENV(PRELINK_LIBRARIES, "", 1);
 		}
 	}
 }
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