// SPDX-License-Identifier: GPL-2.0-or-later /* * KUnit tests for commoncap.c security functions * * Tests for security-critical functions in the capability subsystem, * particularly namespace-related capability checks. */ #include <kunit/test.h> #include <linux/user_namespace.h> #include <linux/uidgid.h> #include <linux/cred.h> #include <linux/mnt_idmapping.h> #include <linux/module.h> #include <linux/slab.h> #include <linux/refcount.h> #ifdef CONFIG_SECURITY_COMMONCAP_KUNIT_TEST /* Functions are static in commoncap.c, but we can call them since we're * included in the same compilation unit when tests are enabled. */ /** * test_vfsuid_root_in_currentns_init_ns - Test vfsuid_root_in_currentns with init ns * * Verifies that UID 0 in the init namespace correctly owns the current * namespace when running in init_user_ns. * * @test: KUnit test context */ static void test_vfsuid_root_in_currentns_init_ns(struct kunit *test) { vfsuid_t vfsuid; kuid_t kuid; /* Create UID 0 in init namespace */ kuid = KUIDT_INIT(0); vfsuid = VFSUIDT_INIT(kuid); /* In init namespace, UID 0 should own current namespace */ KUNIT_EXPECT_TRUE(test, vfsuid_root_in_currentns(vfsuid)); } /** * test_vfsuid_root_in_currentns_invalid - Test vfsuid_root_in_currentns with invalid vfsuid * * Verifies that an invalid vfsuid correctly returns false. * * @test: KUnit test context */ static void test_vfsuid_root_in_currentns_invalid(struct kunit *test) { vfsuid_t invalid_vfsuid; /* Use the predefined invalid vfsuid */ invalid_vfsuid = INVALID_VFSUID; /* Invalid vfsuid should return false */ KUNIT_EXPECT_FALSE(test, vfsuid_root_in_currentns(invalid_vfsuid)); } /** * test_vfsuid_root_in_currentns_nonzero - Test vfsuid_root_in_currentns with non-zero UID * * Verifies that a non-zero UID correctly returns false. * * @test: KUnit test context */ static void test_vfsuid_root_in_currentns_nonzero(struct kunit *test) { vfsuid_t vfsuid; kuid_t kuid; /* Create a non-zero UID */ kuid = KUIDT_INIT(1000); vfsuid = VFSUIDT_INIT(kuid); /* Non-zero UID should return false */ KUNIT_EXPECT_FALSE(test, vfsuid_root_in_currentns(vfsuid)); } /** * test_kuid_root_in_ns_init_ns_uid0 - Test kuid_root_in_ns with init namespace and UID 0 * * Verifies that kuid_root_in_ns correctly identifies UID 0 in init namespace. * This tests the core namespace traversal logic. In init namespace, UID 0 * maps to itself, so it should own the namespace. * * @test: KUnit test context */ static void test_kuid_root_in_ns_init_ns_uid0(struct kunit *test) { kuid_t kuid; struct user_namespace *init_ns; kuid = KUIDT_INIT(0); init_ns = &init_user_ns; /* UID 0 should own init namespace */ KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(kuid, init_ns)); } /** * test_kuid_root_in_ns_init_ns_nonzero - Test kuid_root_in_ns with init namespace and non-zero UID * * Verifies that kuid_root_in_ns correctly rejects non-zero UIDs in init namespace. * Only UID 0 should own a namespace. * * @test: KUnit test context */ static void test_kuid_root_in_ns_init_ns_nonzero(struct kunit *test) { kuid_t kuid; struct user_namespace *init_ns; kuid = KUIDT_INIT(1000); init_ns = &init_user_ns; /* Non-zero UID should not own namespace */ KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(kuid, init_ns)); } /** * create_test_user_ns_with_mapping - Create a mock user namespace with UID mapping * * Creates a minimal user namespace structure for testing where uid 0 in the * namespace maps to a specific kuid in the parent namespace. * * @test: KUnit test context * @parent_ns: Parent namespace (typically init_user_ns) * @mapped_kuid: The kuid that uid 0 in this namespace maps to in parent * * Returns: Pointer to allocated namespace, or NULL on failure */ static struct user_namespace *create_test_user_ns_with_mapping(struct kunit *test, struct user_namespace *parent_ns, kuid_t mapped_kuid) { struct user_namespace *ns; struct uid_gid_extent extent; /* Allocate a test namespace - use kzalloc to zero all fields */ ns = kunit_kzalloc(test, sizeof(*ns), GFP_KERNEL); if (!ns) return NULL; /* Initialize basic namespace structure fields */ ns->parent = parent_ns; ns->level = parent_ns ? parent_ns->level + 1 : 0; ns->owner = mapped_kuid; ns->group = KGIDT_INIT(0); /* Initialize ns_common structure */ refcount_set(&ns->ns.__ns_ref, 1); ns->ns.inum = 0; /* Mock inum */ /* Set up uid mapping: uid 0 in this namespace maps to mapped_kuid in parent * Format: first (uid in ns) : lower_first (kuid in parent) : count * So: uid 0 in ns -> kuid mapped_kuid in parent * This means from_kuid(ns, mapped_kuid) returns 0 */ extent.first = 0; /* uid 0 in this namespace */ extent.lower_first = __kuid_val(mapped_kuid); /* maps to this kuid in parent */ extent.count = 1; ns->uid_map.extent[0] = extent; ns->uid_map.nr_extents = 1; /* Set up gid mapping: gid 0 maps to gid 0 in parent (simplified) */ extent.first = 0; extent.lower_first = 0; extent.count = 1; ns->gid_map.extent[0] = extent; ns->gid_map.nr_extents = 1; return ns; } /** * test_kuid_root_in_ns_with_mapping - Test kuid_root_in_ns with namespace where uid 0 * maps to different kuid * * Creates a user namespace where uid 0 maps to kuid 1000 in the parent namespace. * Verifies that kuid_root_in_ns correctly identifies kuid 1000 as owning the namespace. * * Note: kuid_root_in_ns walks up the namespace hierarchy, so it checks the current * namespace first, then parent, then parent's parent, etc. So: * - kuid 1000 owns test_ns because from_kuid(test_ns, 1000) == 0 * - kuid 0 also owns test_ns because from_kuid(init_user_ns, 0) == 0 * (checked in parent) * * This tests the actual functionality as requested: creating namespaces with * different values for the namespace's uid 0. * * @test: KUnit test context */ static void test_kuid_root_in_ns_with_mapping(struct kunit *test) { struct user_namespace *test_ns; struct user_namespace *parent_ns; kuid_t mapped_kuid, other_kuid; parent_ns = &init_user_ns; mapped_kuid = KUIDT_INIT(1000); other_kuid = KUIDT_INIT(2000); test_ns = create_test_user_ns_with_mapping(test, parent_ns, mapped_kuid); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, test_ns); /* kuid 1000 should own test_ns because it maps to uid 0 in test_ns */ KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(mapped_kuid, test_ns)); /* kuid 0 should also own test_ns (checked via parent init_user_ns) */ KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), test_ns)); /* Other kuids should not own test_ns */ KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(other_kuid, test_ns)); KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(500), test_ns)); } /** * test_kuid_root_in_ns_with_different_mappings - Test with multiple namespaces * * Creates multiple user namespaces with different UID mappings to verify * that kuid_root_in_ns correctly distinguishes between namespaces. * * Each namespace maps uid 0 to a different kuid, and we verify that each * kuid only owns its corresponding namespace (plus kuid 0 owns all via * init_user_ns parent). * * @test: KUnit test context */ static void test_kuid_root_in_ns_with_different_mappings(struct kunit *test) { struct user_namespace *ns1, *ns2, *ns3; /* Create three independent namespaces, each mapping uid 0 to different kuids */ ns1 = create_test_user_ns_with_mapping(test, &init_user_ns, KUIDT_INIT(1000)); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ns1); ns2 = create_test_user_ns_with_mapping(test, &init_user_ns, KUIDT_INIT(2000)); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ns2); ns3 = create_test_user_ns_with_mapping(test, &init_user_ns, KUIDT_INIT(3000)); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ns3); /* Test ns1: kuid 1000 owns it, kuid 0 owns it (via parent), others do not */ KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(1000), ns1)); KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), ns1)); KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(2000), ns1)); KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(3000), ns1)); /* Test ns2: kuid 2000 owns it, kuid 0 owns it (via parent), others do not */ KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(2000), ns2)); KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), ns2)); KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(1000), ns2)); KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(3000), ns2)); /* Test ns3: kuid 3000 owns it, kuid 0 owns it (via parent), others do not */ KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(3000), ns3)); KUNIT_EXPECT_TRUE(test, kuid_root_in_ns(KUIDT_INIT(0), ns3)); KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(1000), ns3)); KUNIT_EXPECT_FALSE(test, kuid_root_in_ns(KUIDT_INIT(2000), ns3)); } static struct kunit_case commoncap_test_cases[] = { KUNIT_CASE(test_vfsuid_root_in_currentns_init_ns), KUNIT_CASE(test_vfsuid_root_in_currentns_invalid), KUNIT_CASE(test_vfsuid_root_in_currentns_nonzero), KUNIT_CASE(test_kuid_root_in_ns_init_ns_uid0), KUNIT_CASE(test_kuid_root_in_ns_init_ns_nonzero), KUNIT_CASE(test_kuid_root_in_ns_with_mapping), KUNIT_CASE(test_kuid_root_in_ns_with_different_mappings), {} }; static struct kunit_suite commoncap_test_suite = { .name = "commoncap", .test_cases = commoncap_test_cases, }; kunit_test_suite(commoncap_test_suite); MODULE_LICENSE("GPL"); #endif /* CONFIG_SECURITY_COMMONCAP_KUNIT_TEST */
