Test kernel module loading permissions. Signed-off-by: Richard Haines <richard_c_haines@xxxxxxxxxxxxxx> --- V2 Change: Check permission denial module_load versus module_request by using a test kernel module for each. Note: Rawhide (with secnext kernel) adds built-in.a and built-in.a.cmd when building modules, therefore added to Makefile and .gitignore. V3 Changes: As requested in [1] except policy change, coalesced type attributes instead. V4 Change: Change attributes initmoddoman and finitmoddomain to a single attribute of kmoduledomain. [1] https://lore.kernel.org/selinux/CAFqZXNtm_X+YssnX_3_5ThkVZY+9SBeQC5Qo78s+geSsBok8=Q@xxxxxxxxxxxxxx/ policy/Makefile | 4 + policy/test_module_load.te | 108 +++++++++++++++++++ tests/Makefile | 4 + tests/module_load/.gitignore | 11 ++ tests/module_load/Makefile | 12 +++ tests/module_load/finit_load.c | 94 +++++++++++++++++ tests/module_load/init_load.c | 123 ++++++++++++++++++++++ tests/module_load/setest_module_load.c | 18 ++++ tests/module_load/setest_module_request.c | 22 ++++ tests/module_load/test | 62 +++++++++++ 10 files changed, 458 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/setest_module_load.c create mode 100644 tests/module_load/setest_module_request.c create mode 100755 tests/module_load/test diff --git a/policy/Makefile b/policy/Makefile index ad94c43..25dfb69 100644 --- a/policy/Makefile +++ b/policy/Makefile @@ -94,6 +94,10 @@ ifeq ($(shell grep -q key_socket $(POLDEV)/include/support/all_perms.spt && echo TARGETS += test_key_socket.te endif +ifeq ($(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..5496d86 --- /dev/null +++ b/policy/test_module_load.te @@ -0,0 +1,108 @@ +############# Test kernel modules ################### +# +attribute kmoduledomain; + +# +############################## 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) ################### +# +type test_finitmod_t; +module_domain_type(test_finitmod_t) +unconfined_runs_test(test_finitmod_t) +typeattribute test_finitmod_t testdomain, kmoduledomain; + +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, kmoduledomain; + +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, kmoduledomain; + +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, kmoduledomain; + +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) ################### +# +type test_initmod_t; +module_domain_type(test_initmod_t) +unconfined_runs_test(test_initmod_t) +typeattribute test_initmod_t testdomain, kmoduledomain; + +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, kmoduledomain; + +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, kmoduledomain; + +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, kmoduledomain; + +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(kmoduledomain) +userdom_sysadm_entry_spec_domtrans_to(kmoduledomain) diff --git a/tests/Makefile b/tests/Makefile index cca6648..0452887 100644 --- a/tests/Makefile +++ b/tests/Makefile @@ -72,6 +72,10 @@ 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, $(SUBDIRS)) endif diff --git a/tests/module_load/.gitignore b/tests/module_load/.gitignore new file mode 100644 index 0000000..7fa5772 --- /dev/null +++ b/tests/module_load/.gitignore @@ -0,0 +1,11 @@ +finit_load +init_load +modules.order +Module.symvers +*.a +*.o +*.ko +*.cmd +*.mod +*.mod.c +.*.cmd diff --git a/tests/module_load/Makefile b/tests/module_load/Makefile new file mode 100644 index 0000000..b6eba25 --- /dev/null +++ b/tests/module_load/Makefile @@ -0,0 +1,12 @@ +obj-m = setest_module_load.o setest_module_request.o + +TARGETS = finit_load init_load +LDLIBS += -lselinux +KDIR = /lib/modules/$(shell uname -r)/build + +all: $(TARGETS) + $(MAKE) -C $(KDIR) M=$(PWD) + +clean: + rm -f $(TARGETS) + rm -f *.a *.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..1c05d7b --- /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, s_errno; + 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); + } + + if (verbose) { + result = getcon(&context); + if (result < 0) { + fprintf(stderr, "Failed to obtain process context\n"); + close(fd); + exit(-1); + } + + printf("Process context:\n\t%s\n", context); + free(context); + } + + result = syscall(__NR_finit_module, fd, "", 0); + s_errno = errno; + close(fd); + if (result < 0) { + fprintf(stderr, "Failed to load '%s' module: %s\n", + file_name, strerror(s_errno)); + /* Denying: sys_module=EPERM, module_load=EACCES */ + exit(s_errno); + } + + 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..0422c19 --- /dev/null +++ b/tests/module_load/init_load.c @@ -0,0 +1,123 @@ +#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, s_errno; + 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); + } + + if (verbose) { + result = getcon(&context); + if (result < 0) { + fprintf(stderr, "Failed to obtain process context\n"); + close(fd); + exit(-1); + } + + 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); + free(elf_image); + exit(-1); + } + close(fd); + + result = syscall(__NR_init_module, elf_image, st.st_size, ""); + s_errno = errno; + free(elf_image); + if (result < 0) { + fprintf(stderr, "Failed to load '%s' module: %s\n", + file_name, strerror(s_errno)); + /* Denying: sys_module=EPERM, module_load & request=EACCES */ + exit(s_errno); + } + + 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/setest_module_load.c b/tests/module_load/setest_module_load.c new file mode 100644 index 0000000..0be7a26 --- /dev/null +++ b/tests/module_load/setest_module_load.c @@ -0,0 +1,18 @@ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> + +static int __init setest_module_load_init(void) +{ + pr_info("INIT - setest_module_load\n"); + return 0; +} + +static void __exit setest_module_load_exit(void) +{ + pr_info("EXIT - setest_module_load\n"); +} + +module_init(setest_module_load_init); +module_exit(setest_module_load_exit); +MODULE_LICENSE("GPL"); diff --git a/tests/module_load/setest_module_request.c b/tests/module_load/setest_module_request.c new file mode 100644 index 0000000..f79d4ef --- /dev/null +++ b/tests/module_load/setest_module_request.c @@ -0,0 +1,22 @@ +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> + +static int __init setest_module_request_init(void) +{ + int result; + + pr_info("INIT - setest_module_request\n"); + result = request_module_nowait("dummy-module"); + pr_info("request_module() returned: %d\n", result); + return result; +} + +static void __exit setest_module_request_exit(void) +{ + pr_info("EXIT - setest_module_request\n"); +} + +module_init(setest_module_request_init); +module_exit(setest_module_request_exit); +MODULE_LICENSE("GPL"); diff --git a/tests/module_load/test b/tests/module_load/test new file mode 100755 index 0000000..c3242fc --- /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 setest_module_request"; +ok( $result eq 0 ); + +# Deny capability { sys_module } - EPERM +$result = system +"runcon -t test_finitmod_deny_sys_module_t $basedir/finit_load $v $basedir setest_module_load 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 setest_module_load 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 setest_module_request 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 setest_module_request"; +ok( $result eq 0 ); + +# Deny capability { sys_module } - EPERM +$result = system +"runcon -t test_initmod_deny_sys_module_t $basedir/init_load $v $basedir setest_module_load 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 setest_module_load 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 setest_module_request 2>&1"; +ok( $result >> 8 eq 13 ); + +exit; -- 2.23.0
