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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id y12sm24064569pfm.158.2020.06.25.13.37.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Jun 2020 13:37:07 -0700 (PDT) From: Kees Cook To: Greg Kroah-Hartman Cc: Kees Cook , Prasad Sodagudi , Sami Tolvanen , Amit Daniel Kachhap , Randy Dunlap , Richard Weinberger , linux-kselftest@vger.kernel.org, clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org Subject: [PATCH drivers/misc v2 4/4] lkdtm: Make arch-specific tests always available Date: Thu, 25 Jun 2020 13:37:04 -0700 Message-Id: <20200625203704.317097-5-keescook@chromium.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200625203704.317097-1-keescook@chromium.org> References: <20200625203704.317097-1-keescook@chromium.org> MIME-Version: 1.0 Sender: linux-kselftest-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org I'd like arch-specific tests to XFAIL when on a mismatched architecture so that we can more easily compare test coverage across all systems. Lacking kernel configs or CPU features count as a FAIL, not an XFAIL. Additionally fixes a build failure under 32-bit UML. Fixes: b09511c253e5 ("lkdtm: Add a DOUBLE_FAULT crash type on x86") Fixes: cea23efb4de2 ("lkdtm/bugs: Make double-fault test always available") Fixes: 6cb6982f42cb ("lkdtm: arm64: test kernel pointer authentication") Signed-off-by: Kees Cook --- drivers/misc/lkdtm/bugs.c | 38 ++++++++++++++----------- drivers/misc/lkdtm/lkdtm.h | 2 -- tools/testing/selftests/lkdtm/tests.txt | 1 + 3 files changed, 22 insertions(+), 19 deletions(-) diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index 08c70281c380..10338800f6be 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -13,7 +13,7 @@ #include #include -#ifdef CONFIG_X86_32 +#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML) #include #endif @@ -418,7 +418,7 @@ void lkdtm_UNSET_SMEP(void) void lkdtm_DOUBLE_FAULT(void) { -#ifdef CONFIG_X86_32 +#if IS_ENABLED(CONFIG_X86_32) && !IS_ENABLED(CONFIG_UML) /* * Trigger #DF by setting the stack limit to zero. This clobbers * a GDT TLS slot, which is okay because the current task will die @@ -453,38 +453,42 @@ void lkdtm_DOUBLE_FAULT(void) #endif } -#ifdef CONFIG_ARM64_PTR_AUTH +#ifdef CONFIG_ARM64 static noinline void change_pac_parameters(void) { - /* Reset the keys of current task */ - ptrauth_thread_init_kernel(current); - ptrauth_thread_switch_kernel(current); + if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH)) { + /* Reset the keys of current task */ + ptrauth_thread_init_kernel(current); + ptrauth_thread_switch_kernel(current); + } } +#endif -#define CORRUPT_PAC_ITERATE 10 noinline void lkdtm_CORRUPT_PAC(void) { +#ifdef CONFIG_ARM64 +#define CORRUPT_PAC_ITERATE 10 int i; + if (!IS_ENABLED(CONFIG_ARM64_PTR_AUTH)) + pr_err("FAIL: kernel not built with CONFIG_ARM64_PTR_AUTH\n"); + if (!system_supports_address_auth()) { - pr_err("FAIL: arm64 pointer authentication feature not present\n"); + pr_err("FAIL: CPU lacks pointer authentication feature\n"); return; } - pr_info("Change the PAC parameters to force function return failure\n"); + pr_info("changing PAC parameters to force function return failure...\n"); /* - * Pac is a hash value computed from input keys, return address and + * PAC is a hash value computed from input keys, return address and * stack pointer. As pac has fewer bits so there is a chance of * collision, so iterate few times to reduce the collision probability. */ for (i = 0; i < CORRUPT_PAC_ITERATE; i++) change_pac_parameters(); - pr_err("FAIL: %s test failed. Kernel may be unstable from here\n", __func__); -} -#else /* !CONFIG_ARM64_PTR_AUTH */ -noinline void lkdtm_CORRUPT_PAC(void) -{ - pr_err("FAIL: arm64 pointer authentication config disabled\n"); -} + pr_err("FAIL: survived PAC changes! Kernel may be unstable from here\n"); +#else + pr_err("XFAIL: this test is arm64-only\n"); #endif +} diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 601a2156a0d4..8878538b2c13 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -31,9 +31,7 @@ void lkdtm_CORRUPT_USER_DS(void); void lkdtm_STACK_GUARD_PAGE_LEADING(void); void lkdtm_STACK_GUARD_PAGE_TRAILING(void); void lkdtm_UNSET_SMEP(void); -#ifdef CONFIG_X86_32 void lkdtm_DOUBLE_FAULT(void); -#endif void lkdtm_CORRUPT_PAC(void); /* lkdtm_heap.c */ diff --git a/tools/testing/selftests/lkdtm/tests.txt b/tools/testing/selftests/lkdtm/tests.txt index 92ca32143ae5..9d266e79c6a2 100644 --- a/tools/testing/selftests/lkdtm/tests.txt +++ b/tools/testing/selftests/lkdtm/tests.txt @@ -14,6 +14,7 @@ STACK_GUARD_PAGE_LEADING STACK_GUARD_PAGE_TRAILING UNSET_SMEP CR4 bits went missing DOUBLE_FAULT +CORRUPT_PAC UNALIGNED_LOAD_STORE_WRITE #OVERWRITE_ALLOCATION Corrupts memory on failure #WRITE_AFTER_FREE Corrupts memory on failure