diff mbox series

selinux-testsuite: Add kernel module tests

Message ID 20191113161454.4370-1-richard_c_haines@btinternet.com (mailing list archive)
State Superseded
Headers show
Series selinux-testsuite: Add kernel module tests | expand

Commit Message

Richard Haines Nov. 13, 2019, 4:14 p.m. UTC
Test kernel module loading permissions.

Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
---
 policy/Makefile                        |   4 +
 policy/test_module_load.te             | 118 ++++++++++++++++++++++++
 tests/Makefile                         |   4 +
 tests/module_load/.gitignore           |  13 +++
 tests/module_load/Makefile             |  12 +++
 tests/module_load/finit_load.c         |  94 +++++++++++++++++++
 tests/module_load/init_load.c          | 121 +++++++++++++++++++++++++
 tests/module_load/setestsuite_module.c |  22 +++++
 tests/module_load/test                 |  62 +++++++++++++
 9 files changed, 450 insertions(+)
 create mode 100644 policy/test_module_load.te
 create mode 100644 tests/module_load/.gitignore
 create mode 100644 tests/module_load/Makefile
 create mode 100644 tests/module_load/finit_load.c
 create mode 100644 tests/module_load/init_load.c
 create mode 100644 tests/module_load/setestsuite_module.c
 create mode 100755 tests/module_load/test

Comments

Stephen Smalley Nov. 14, 2019, 3:31 p.m. UTC | #1
On 11/13/19 11:14 AM, Richard Haines wrote:
> Test kernel module loading permissions.
> 
> Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
> ---
<snip>
> diff --git a/tests/module_load/setestsuite_module.c b/tests/module_load/setestsuite_module.c
> new file mode 100644
> index 0000000..1f6be02
> --- /dev/null
> +++ b/tests/module_load/setestsuite_module.c
> @@ -0,0 +1,22 @@
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +
> +static int __init setestsuite_module_init(void)
> +{
> +	int result = 0;
> +
> +	pr_info("INIT - setestsuite_module\n");
> +	result = request_module_nowait("dummy-module");
> +	pr_info("request_module() returned: %d\n", result);
> +	return result;
> +}
> +
> +static void __exit setestsuite_module_exit(void)
> +{
> +	pr_info("EXIT - setestsuite_module\n");
> +}
> +
> +module_init(setestsuite_module_init);
> +module_exit(setestsuite_module_exit);
> +MODULE_LICENSE("GPL");

Hmm...with this approach, we can't distinguish a permission denial on 
the module_load versus one on the module_request, right?  Would it be 
better to have a separate no-op kernel module that always returns 0 for 
testing module_load and only use this one for testing module_request?
diff mbox series

Patch

diff --git a/policy/Makefile b/policy/Makefile
index ff65153..545f3b5 100644
--- a/policy/Makefile
+++ b/policy/Makefile
@@ -90,6 +90,10 @@  ifeq ($(shell grep -q all_file_perms.*watch $(POLDEV)/include/support/all_perms.
 TARGETS+=test_notify.te
 endif
 
+ifeq ($(shell grep -q module_load $(POLDEV)/include/support/all_perms.spt && echo true),true)
+TARGETS+=test_module_load.te
+endif
+
 ifeq (x$(DISTRO),$(filter x$(DISTRO),xRHEL4 xRHEL5 xRHEL6))
 TARGETS:=$(filter-out test_overlayfs.te test_mqueue.te test_ibpkey.te, $(TARGETS))
 endif
diff --git a/policy/test_module_load.te b/policy/test_module_load.te
new file mode 100644
index 0000000..566ddf7
--- /dev/null
+++ b/policy/test_module_load.te
@@ -0,0 +1,118 @@ 
+#
+############################## Define Macro ################################
+#
+# Replace domain_type() macro as it hides some relevant denials in audit.log
+#
+gen_require(`
+	type setrans_var_run_t, syslogd_t;
+')
+
+define(`module_domain_type',`
+	allow $1 proc_t:dir { search };
+	allow $1 proc_t:lnk_file { read };
+	allow $1 self:dir { search };
+	allow $1 self:file { open read write };
+	dontaudit init_t syslogd_t:fd use;
+	dontaudit $1 security_t:filesystem getattr;
+	dontaudit $1 self:file getattr;
+	dontaudit $1 setrans_var_run_t:dir search;
+	dontaudit unconfined_t $1:process { noatsecure rlimitinh siginh };
+')
+
+#
+############# Test kernel modules with finitmod_module(2) ###################
+#
+attribute finitmoddomain;
+
+type test_finitmod_t;
+module_domain_type(test_finitmod_t)
+unconfined_runs_test(test_finitmod_t)
+typeattribute test_finitmod_t testdomain;
+typeattribute test_finitmod_t finitmoddomain;
+
+allow test_finitmod_t self:capability { sys_module };
+allow test_finitmod_t test_file_t:system { module_load };
+allow test_finitmod_t kernel_t:system { module_request };
+
+############### Deny cap sys_module ######################
+type test_finitmod_deny_sys_module_t;
+module_domain_type(test_finitmod_deny_sys_module_t)
+unconfined_runs_test(test_finitmod_deny_sys_module_t)
+typeattribute test_finitmod_deny_sys_module_t testdomain;
+typeattribute test_finitmod_deny_sys_module_t finitmoddomain;
+
+neverallow test_finitmod_deny_sys_module_t self:capability { sys_module };
+
+############### Deny sys module_load ######################
+type test_finitmod_deny_module_load_t;
+module_domain_type(test_finitmod_deny_module_load_t)
+unconfined_runs_test(test_finitmod_deny_module_load_t)
+typeattribute test_finitmod_deny_module_load_t testdomain;
+typeattribute test_finitmod_deny_module_load_t finitmoddomain;
+
+allow test_finitmod_deny_module_load_t self:capability { sys_module };
+neverallow test_finitmod_deny_module_load_t test_file_t:system { module_load };
+
+############### Deny sys module_request ######################
+type test_finitmod_deny_module_request_t;
+module_domain_type(test_finitmod_deny_module_request_t)
+unconfined_runs_test(test_finitmod_deny_module_request_t)
+typeattribute test_finitmod_deny_module_request_t testdomain;
+typeattribute test_finitmod_deny_module_request_t finitmoddomain;
+
+allow test_finitmod_deny_module_request_t self:capability { sys_module };
+allow test_finitmod_deny_module_request_t test_file_t:system { module_load };
+neverallow test_finitmod_deny_module_request_t kernel_t:system { module_request };
+
+#
+############# Test kernel modules with initmod_module(2) ###################
+#
+attribute initmoddomain;
+
+type test_initmod_t;
+module_domain_type(test_initmod_t)
+unconfined_runs_test(test_initmod_t)
+typeattribute test_initmod_t testdomain;
+typeattribute test_initmod_t initmoddomain;
+
+allow test_initmod_t self:capability { sys_module };
+allow test_initmod_t self:system { module_load };
+allow test_initmod_t kernel_t:system { module_request };
+
+############### Deny cap sys_module ######################
+type test_initmod_deny_sys_module_t;
+module_domain_type(test_initmod_deny_sys_module_t)
+unconfined_runs_test(test_initmod_deny_sys_module_t)
+typeattribute test_initmod_deny_sys_module_t testdomain;
+typeattribute test_initmod_deny_sys_module_t initmoddomain;
+
+neverallow test_initmod_deny_sys_module_t self:capability { sys_module };
+
+############### Deny sys module_load ######################
+type test_initmod_deny_module_load_t;
+module_domain_type(test_initmod_deny_module_load_t)
+unconfined_runs_test(test_initmod_deny_module_load_t)
+typeattribute test_initmod_deny_module_load_t testdomain;
+typeattribute test_initmod_deny_module_load_t initmoddomain;
+
+allow test_initmod_deny_module_load_t self:capability { sys_module };
+neverallow test_initmod_deny_module_load_t self:system { module_load };
+
+############### Deny sys module_request ######################
+type test_initmod_deny_module_request_t;
+module_domain_type(test_initmod_deny_module_request_t)
+unconfined_runs_test(test_initmod_deny_module_request_t)
+typeattribute test_initmod_deny_module_request_t testdomain;
+typeattribute test_initmod_deny_module_request_t initmoddomain;
+
+allow test_initmod_deny_module_request_t self:capability { sys_module };
+allow test_initmod_deny_module_request_t self:system { module_load };
+neverallow test_initmod_deny_module_request_t kernel_t:system { module_request };
+
+#
+########### Allow these domains to be entered from sysadm domain ############
+#
+miscfiles_domain_entry_test_files(finitmoddomain)
+userdom_sysadm_entry_spec_domtrans_to(finitmoddomain)
+miscfiles_domain_entry_test_files(initmoddomain)
+userdom_sysadm_entry_spec_domtrans_to(initmoddomain)
diff --git a/tests/Makefile b/tests/Makefile
index 0021590..4731d8c 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -68,6 +68,10 @@  ifeq ($(shell grep -q all_file_perms.*watch $(POLDEV)/include/support/all_perms.
 SUBDIRS+=notify
 endif
 
+ifeq ($(shell grep -q module_load $(POLDEV)/include/support/all_perms.spt && echo true),true)
+SUBDIRS+=module_load
+endif
+
 ifeq ($(DISTRO),RHEL4)
     SUBDIRS:=$(filter-out bounds dyntrace dyntrans inet_socket mmap nnp_nosuid overlay unix_socket, $(SUBDIRS))
 endif
diff --git a/tests/module_load/.gitignore b/tests/module_load/.gitignore
new file mode 100644
index 0000000..77fe4bd
--- /dev/null
+++ b/tests/module_load/.gitignore
@@ -0,0 +1,13 @@ 
+finit_load
+init_load
+modules.order
+Module.symvers
+setestsuite_module.ko
+.setestsuite_module.ko.cmd
+setestsuite_module.mod
+setestsuite_module.mod.c
+.setestsuite_module.mod.cmd
+setestsuite_module.mod.o
+.setestsuite_module.mod.o.cmd
+setestsuite_module.o
+.setestsuite_module.o.cmd
diff --git a/tests/module_load/Makefile b/tests/module_load/Makefile
new file mode 100644
index 0000000..cb8f28d
--- /dev/null
+++ b/tests/module_load/Makefile
@@ -0,0 +1,12 @@ 
+obj-m = setestsuite_module.o
+
+TARGETS = finit_load init_load
+LDLIBS += -lselinux
+KDIR = /usr/src/kernels/$(shell uname -r)
+
+all: $(TARGETS)
+	$(MAKE) -C $(KDIR) M=$(PWD)
+
+clean:
+	rm -f $(TARGETS)
+	rm -f *.o *.ko *.cmd *.mod *.mod.c .*.cmd Module.symvers modules.order
diff --git a/tests/module_load/finit_load.c b/tests/module_load/finit_load.c
new file mode 100644
index 0000000..029c698
--- /dev/null
+++ b/tests/module_load/finit_load.c
@@ -0,0 +1,94 @@ 
+#define _GNU_SOURCE 1
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sys/syscall.h>
+#include <selinux/selinux.h>
+
+static void print_usage(char *progfile_name)
+{
+	fprintf(stderr,
+		"usage:  %s [-v] path name\n"
+		"Where:\n\t"
+		"-v    Print information.\n\t"
+		"path  Kernel module build path.\n\t"
+		"name  Name of kernel module to load.\n", progfile_name);
+	exit(-1);
+}
+
+int main(int argc, char *argv[])
+{
+	char *context, file_name[PATH_MAX];
+	int opt, result, fd;
+	bool verbose = false;
+
+	while ((opt = getopt(argc, argv, "v")) != -1) {
+		switch (opt) {
+		case 'v':
+			verbose = true;
+			break;
+		default:
+			print_usage(argv[0]);
+		}
+	}
+
+	if (optind >= argc)
+		print_usage(argv[0]);
+
+	result = sprintf(file_name, "%s/%s.ko", argv[optind],
+			 argv[optind + 1]);
+	if (result < 0) {
+		fprintf(stderr, "Failed sprintf\n");
+		exit(-1);
+	}
+
+	fd = open(file_name, O_RDONLY);
+	if (!fd) {
+		fprintf(stderr, "Failed to open %s: %s\n",
+			file_name, strerror(errno));
+		exit(-1);
+	}
+
+	result = getcon(&context);
+	if (result < 0) {
+		fprintf(stderr, "Failed to obtain process context\n");
+		close(fd);
+		exit(-1);
+	}
+
+	if (verbose)
+		printf("Process context:\n\t%s\n", context);
+
+	free(context);
+
+	result = syscall(__NR_finit_module, fd, "", 0);
+	if (result < 0) {
+		fprintf(stderr, "Failed to load '%s' module: %s\n",
+			file_name, strerror(errno));
+		close(fd);
+		/* Denying: sys_module=EPERM, module_load=EACCES */
+		exit(errno);
+	}
+	close(fd);
+
+	if (verbose)
+		printf("Loaded kernel module:  %s\n", file_name);
+
+	result = syscall(__NR_delete_module, argv[optind + 1], 0);
+	if (result < 0) {
+		fprintf(stderr, "Failed to delete '%s' module: %s\n",
+			argv[optind + 1], strerror(errno));
+		exit(-1);
+	}
+
+	if (verbose)
+		printf("Deleted kernel module: %s\n", argv[optind + 1]);
+
+	return 0;
+}
diff --git a/tests/module_load/init_load.c b/tests/module_load/init_load.c
new file mode 100644
index 0000000..5f9997b
--- /dev/null
+++ b/tests/module_load/init_load.c
@@ -0,0 +1,121 @@ 
+#define _GNU_SOURCE 1
+
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+#include <selinux/selinux.h>
+
+static void print_usage(char *progfile_name)
+{
+	fprintf(stderr,
+		"usage:  %s [-v] path name\n"
+		"Where:\n\t"
+		"-v    Print information.\n\t"
+		"path  Kernel module build path.\n\t"
+		"name  Name of kernel module to load.\n", progfile_name);
+	exit(-1);
+}
+
+int main(int argc, char *argv[])
+{
+	char *context, file_name[PATH_MAX];
+	int opt, result, fd;
+	bool verbose = false;
+	void *elf_image;
+	struct stat st;
+
+	while ((opt = getopt(argc, argv, "v")) != -1) {
+		switch (opt) {
+		case 'v':
+			verbose = true;
+			break;
+		default:
+			print_usage(argv[0]);
+		}
+	}
+
+	if (optind >= argc)
+		print_usage(argv[0]);
+
+	result = sprintf(file_name, "%s/%s.ko", argv[optind],
+			 argv[optind + 1]);
+	if (result < 0) {
+		fprintf(stderr, "Failed sprintf\n");
+		exit(-1);
+	}
+
+	fd = open(file_name, O_RDONLY);
+	if (!fd) {
+		fprintf(stderr, "Failed to open %s: %s\n",
+			file_name, strerror(errno));
+		exit(-1);
+	}
+
+	result = getcon(&context);
+	if (result < 0) {
+		fprintf(stderr, "Failed to obtain process context\n");
+		close(fd);
+		exit(-1);
+	}
+
+	if (verbose)
+		printf("Process context:\n\t%s\n", context);
+
+	free(context);
+
+	result = fstat(fd, &st);
+	if (result < 0) {
+		fprintf(stderr, "Failed fstat on %s: %s\n",
+			file_name, strerror(errno));
+		close(fd);
+		exit(-1);
+	}
+
+	elf_image = malloc(st.st_size);
+	if (!elf_image) {
+		fprintf(stderr, "Failed malloc on %s: %s\n",
+			file_name, strerror(errno));
+		close(fd);
+		exit(-1);
+	}
+
+	result = read(fd, elf_image, st.st_size);
+	if (result < 0) {
+		fprintf(stderr, "Failed read on %s: %s\n",
+			file_name, strerror(errno));
+		close(fd);
+		exit(-1);
+	}
+	close(fd);
+
+	result = syscall(__NR_init_module, elf_image, st.st_size, "");
+	if (result < 0) {
+		fprintf(stderr, "Failed to load '%s' module: %s\n",
+			file_name, strerror(errno));
+		/* Denying: sys_module=EPERM, module_load & request=EACCES */
+		exit(errno);
+	}
+	free(elf_image);
+
+	if (verbose)
+		printf("Loaded kernel module:  %s\n", file_name);
+
+	result = syscall(__NR_delete_module, argv[optind + 1], 0);
+	if (result < 0) {
+		fprintf(stderr, "Failed to delete '%s' module: %s\n",
+			argv[optind + 1], strerror(errno));
+		exit(-1);
+	}
+
+	if (verbose)
+		printf("Deleted kernel module: %s\n", argv[optind + 1]);
+
+	return 0;
+}
diff --git a/tests/module_load/setestsuite_module.c b/tests/module_load/setestsuite_module.c
new file mode 100644
index 0000000..1f6be02
--- /dev/null
+++ b/tests/module_load/setestsuite_module.c
@@ -0,0 +1,22 @@ 
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+static int __init setestsuite_module_init(void)
+{
+	int result = 0;
+
+	pr_info("INIT - setestsuite_module\n");
+	result = request_module_nowait("dummy-module");
+	pr_info("request_module() returned: %d\n", result);
+	return result;
+}
+
+static void __exit setestsuite_module_exit(void)
+{
+	pr_info("EXIT - setestsuite_module\n");
+}
+
+module_init(setestsuite_module_init);
+module_exit(setestsuite_module_exit);
+MODULE_LICENSE("GPL");
diff --git a/tests/module_load/test b/tests/module_load/test
new file mode 100755
index 0000000..1cfc219
--- /dev/null
+++ b/tests/module_load/test
@@ -0,0 +1,62 @@ 
+#!/usr/bin/perl
+use Test::More;
+
+BEGIN {
+    $basedir = $0;
+    $basedir =~ s|(.*)/[^/]*|$1|;
+
+    # allow info to be shown during tests
+    $v = $ARGV[0];
+    if ($v) {
+        if ( $v ne "-v" ) {
+            plan skip_all => "Invalid option (use -v)";
+        }
+    }
+    else {
+        $v = " ";
+    }
+
+    plan tests => 8;
+}
+
+print "Test finit_module(2)\n";
+$result = system
+"runcon -t test_finitmod_t $basedir/finit_load $v $basedir setestsuite_module";
+ok( $result eq 0 );
+
+# Deny capability { sys_module } - EPERM
+$result = system
+"runcon -t test_finitmod_deny_sys_module_t $basedir/finit_load $v $basedir setestsuite_module 2>&1";
+ok( $result >> 8 eq 1 );
+
+# Deny system { module_load } - EACCES
+$result = system
+"runcon -t test_finitmod_deny_module_load_t $basedir/finit_load $v $basedir setestsuite_module 2>&1";
+ok( $result >> 8 eq 13 );
+
+# Deny system { module_request } - EACCES
+$result = system
+"runcon -t test_finitmod_deny_module_request_t $basedir/finit_load $v $basedir setestsuite_module 2>&1";
+ok( $result >> 8 eq 13 );
+
+print "Test init_module(2)\n";
+$result = system
+  "runcon -t test_initmod_t $basedir/init_load $v $basedir setestsuite_module";
+ok( $result eq 0 );
+
+# Deny capability { sys_module } - EPERM
+$result = system
+"runcon -t test_initmod_deny_sys_module_t $basedir/init_load $v $basedir setestsuite_module 2>&1";
+ok( $result >> 8 eq 1 );
+
+# Deny system { module_load } - EACCES
+$result = system
+"runcon -t test_initmod_deny_module_load_t $basedir/init_load $v $basedir setestsuite_module 2>&1";
+ok( $result >> 8 eq 13 );
+
+# Deny system { module_request } - EACCES
+$result = system
+"runcon -t test_initmod_deny_module_request_t $basedir/init_load $v $basedir setestsuite_module 2>&1";
+ok( $result >> 8 eq 13 );
+
+exit;