env: considerably beef up environment cleaning logic

Now, actually check if the environment variable names and values used
are valid, before accepting them. With this in place are at some places
more rigid than POSIX, and less rigid at others. For example, this code
allows lower-case environment variables (which POSIX suggests not to
use), but it will not allow non-UTF8 variable values.

All in all this should be a good middle ground of what to allow and what
not to allow as environment variables.

(This also splits out all environment related calls into env-util.[ch])

1 files changed, 41 insertions, 0 deletions

diff --git a/src/shared/env-util.h b/src/shared/env-util.h
new file mode 100644
index 0000000000..93bf596ca8
--- /dev/null
+++ b/src/shared/env-util.h
@@ -0,0 +1,41 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2013 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <stdbool.h>
+#include <sys/types.h>
+
+bool env_name_is_valid(const char *e);
+bool env_value_is_valid(const char *e);
+bool env_assignment_is_valid(const char *e);
+
+bool strv_env_is_valid(char **e);
+char **strv_env_clean(char **l);
+
+char **strv_env_merge(unsigned n_lists, ...);
+char **strv_env_delete(char **x, unsigned n_lists, ...); /* New copy */
+
+char **strv_env_set(char **x, const char *p); /* New copy ... */
+char **strv_env_unset(char **l, const char *p); /* In place ... */
+
+char *strv_env_get_n(char **l, const char *name, size_t k);
+char *strv_env_get(char **x, const char *n);