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From 93ecea3488081a726bcd2ddb04d557decaa87f80 Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@collabora.com>
Date: Mon, 18 Jan 2021 17:52:13 +0000
Subject: [PATCH] build: Convert environment into a sequence of bwrap arguments

This means we can systematically pass the environment variables
through bwrap(1), even if it is setuid and thus is filtering out
security-sensitive environment variables. bwrap itself ends up being
run with an empty environment instead.

This fixes a regression when CVE-2021-21261 was fixed: before the
CVE fixes, LD_LIBRARY_PATH would have been passed through like this
and appeared in the `flatpak build` shell, but during the CVE fixes,
the special case that protected LD_LIBRARY_PATH was removed in favour
of the more general flatpak_bwrap_envp_to_args(). That reasoning only
works if we use flatpak_bwrap_envp_to_args(), consistently, everywhere
that we run the potentially-setuid bwrap.

Fixes: 6d1773d2 "run: Convert all environment variables into bwrap arguments"
Resolves: https://github.com/flatpak/flatpak/issues/4080
Bug-Debian: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=980323
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit 9a61d2c44f0a58cebcb9b2787ae88db07ca68bb0)
---
 app/flatpak-builtins-build.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/app/flatpak-builtins-build.c b/app/flatpak-builtins-build.c
index 8da0de814..07ef6fc07 100644
--- a/app/flatpak-builtins-build.c
+++ b/app/flatpak-builtins-build.c
@@ -569,6 +569,8 @@ flatpak_builtin_build (int argc, char **argv, GCancellable *cancellable, GError
                               NULL);
     }
 
+  flatpak_bwrap_envp_to_args (bwrap);
+
   if (!flatpak_bwrap_bundle_args (bwrap, 1, -1, FALSE, error))
     return FALSE;
 
From f91857c07ede7ef5150a38d6b8e49ee43d6b3d50 Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@collabora.com>
Date: Mon, 18 Jan 2021 18:07:38 +0000
Subject: [PATCH] dir: Pass environment via bwrap --setenv when running
 apply_extra

This means we can systematically pass the environment variables
through bwrap(1), even if it is setuid and thus is filtering out
security-sensitive environment variables. bwrap ends up being
run with an empty environment instead.

As with the previous commit, this regressed while fixing CVE-2021-21261.

Fixes: 6d1773d2 "run: Convert all environment variables into bwrap arguments"
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit fb473cad801c6b61706353256cab32330557374a)
---
 common/flatpak-dir.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/common/flatpak-dir.c b/common/flatpak-dir.c
index ed1248e74..40767fa77 100644
--- a/common/flatpak-dir.c
+++ b/common/flatpak-dir.c
@@ -7426,6 +7426,8 @@ apply_extra_data (FlatpakDir   *self,
                                          app_context, NULL, NULL, NULL, cancellable, error))
     return FALSE;
 
+  flatpak_bwrap_envp_to_args (bwrap);
+
   flatpak_bwrap_add_arg (bwrap, "/app/bin/apply_extra");
 
   flatpak_bwrap_finish (bwrap);