common: Use secure_getenv() implementation when setuid

In anything security sensitive, use secure_getenv() implementation
for retrieving environment variables.

7 files changed, 112 insertions, 3 deletions

diff --git a/common/Makefile.am b/common/Makefile.am
index 47162dd..b053ec0 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -99,7 +99,13 @@ test_tests_LDADD = $(common_LIBS)
 test_url_SOURCES = common/test-url.c
 test_url_LDADD = $(common_LIBS)
 
-noinst_PROGRAMS += frob-getauxval
+noinst_PROGRAMS += \
+	frob-getauxval \
+	frob-getenv \
+	$(NULL)
 
 frob_getauxval_SOURCES = common/frob-getauxval.c
 frob_getauxval_LDADD = $(common_LIBS)
+
+frob_getenv_SOURCES = common/frob-getenv.c
+frob_getenv_LDADD = $(common_LIBS)
diff --git a/common/compat.c b/common/compat.c
index ce0ccab..768bb7d 100644
--- a/common/compat.c
+++ b/common/compat.c
@@ -845,6 +845,14 @@ getauxval (unsigned long type)
 
 #endif /* HAVE_GETAUXVAL */
 
+char *
+secure_getenv (const char *name)
+{
+	if (getauxval (AT_SECURE))
+		return NULL;
+	return getenv (name);
+}
+
 #ifndef HAVE_STRERROR_R
 
 int
diff --git a/common/compat.h b/common/compat.h
index 4771370..6483d4f 100644
--- a/common/compat.h
+++ b/common/compat.h
@@ -317,6 +317,8 @@ unsigned long     getauxval (unsigned long type);
 
 #endif /* !HAVE_GETAUXVAL */
 
+char *            secure_getenv (const char *name);
+
 #ifndef HAVE_STRERROR_R
 
 int         strerror_r      (int errnum,
diff --git a/common/debug.c b/common/debug.c
index 1fbdc7f..47933fa 100644
--- a/common/debug.c
+++ b/common/debug.c
@@ -36,6 +36,7 @@
 
 #include "config.h"
 
+#include "compat.h"
 #include "debug.h"
 
 #include <assert.h>
@@ -76,7 +77,7 @@ parse_environ_flags (void)
 	const char *q;
 	int i;
 
-	env = getenv ("P11_KIT_STRICT");
+	env = secure_getenv ("P11_KIT_STRICT");
 	if (env && env[0] != '\0')
 		debug_strict = true;
 
diff --git a/common/frob-getenv.c b/common/frob-getenv.c
new file mode 100644
index 0000000..a36594a
--- /dev/null
+++ b/common/frob-getenv.c
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2014 Red Hat Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *     * Redistributions of source code must retain the above
+ *       copyright notice, this list of conditions and the
+ *       following disclaimer.
+ *     * Redistributions in binary form must reproduce the
+ *       above copyright notice, this list of conditions and
+ *       the following disclaimer in the documentation and/or
+ *       other materials provided with the distribution.
+ *     * The names of contributors to this software may not be
+ *       used to endorse or promote products derived from this
+ *       software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+ * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * Author: Stef Walter <stefw@gnome.org>
+ */
+
+#include "config.h"
+#include "compat.h"
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+main (int argc,
+      char *argv[])
+{
+	int ret;
+	const char *val;
+
+fprintf (stderr, "calling secure_getenv(%s) getenv(%s) = %s\n", argv[1], argv[1], getenv(argv[1]));
+	val = secure_getenv (argv[1]);
+	if (val == NULL) {
+		printf ("%s=NULL\n", argv[1]);
+		return 0;
+	}
+
+	ret = atoi (val);
+	if (ret == 0) {
+		fprintf (stderr, "usage: frob-getenv VAR");
+		abort ();
+	}
+
+	printf ("%s=%d\n", argv[1], ret);
+	return ret;
+}
diff --git a/common/test-compat.c b/common/test-compat.c
index 42471ae..3af33ac 100644
--- a/common/test-compat.c
+++ b/common/test-compat.c
@@ -84,6 +84,32 @@ test_getauxval (void)
 }
 
 static void
+test_secure_getenv (void)
+{
+	const char *args[] = { BUILDDIR "/frob-getenv", "BLAH", NULL };
+	char *path;
+	int ret;
+
+	setenv ("BLAH", "5", 1);
+
+	ret = p11_test_run_child (args, true);
+	assert_num_eq (ret, 5);
+
+	path = p11_test_copy_setgid (args[0]);
+	if (path == NULL)
+		return;
+
+	args[0] = path;
+	ret = p11_test_run_child (args, true);
+	assert_num_cmp (ret, ==, 0);
+
+/*	if (unlink (path) < 0)
+		assert_fail ("unlink failed", strerror (errno));
+		*/
+	free (path);
+}
+
+static void
 test_mmap (void)
 {
 	p11_mmap *map;
@@ -110,6 +136,7 @@ main (int argc,
 	/* Don't run this test when under fakeroot */
 	if (!getenv ("FAKED_MODE")) {
 		p11_test (test_getauxval, "/compat/getauxval");
+		p11_test (test_secure_getenv, "/compat/secure_getenv");
 	}
 	p11_test (test_mmap, "/compat/mmap");
 #endif
diff --git a/common/test.c b/common/test.c
index 5a1cf72..9605d03 100644
--- a/common/test.c
+++ b/common/test.c
@@ -322,7 +322,7 @@ expand_tempdir (const char *name)
 {
 	const char *env;
 
-	env = getenv ("TMPDIR");
+	env = secure_getenv ("TMPDIR");
 	if (env && env[0]) {
 		return p11_path_build (env, name, NULL);