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(localhost [IPv6:::1]) by gnu-cfl-3.localdomain (Postfix) with ESMTP id 69C5174062C; Wed, 6 Dec 2023 09:20:10 -0800 (PST) From: "H.J. Lu" To: libc-alpha@sourceware.org Cc: rick.p.edgecombe@intel.com Subject: [PATCH 03/17] x86/cet: Don't assume that SHSTK implies IBT Date: Wed, 6 Dec 2023 09:19:56 -0800 Message-ID: <20231206172010.1023415-4-hjl.tools@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231206172010.1023415-1-hjl.tools@gmail.com> References: <20231206172010.1023415-1-hjl.tools@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-3024.9 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Since shadow stack (SHSTK) is enabled in the Linux kernel without enabling indirect branch tracking (IBT), don't assume that SHSTK implies IBT. Use "CPU_FEATURE_ACTIVE (IBT)" to check if IBT is active and "CPU_FEATURE_ACTIVE (SHSTK)" to check if SHSTK is active. --- sysdeps/x86/Makefile | 1 - sysdeps/x86/tst-cet-legacy-10.c | 6 +++--- sysdeps/x86/tst-cet-legacy-8.c | 15 ++++++++------- 3 files changed, 11 insertions(+), 11 deletions(-) diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile index 917c26f116..ea45aad34c 100644 --- a/sysdeps/x86/Makefile +++ b/sysdeps/x86/Makefile @@ -165,7 +165,6 @@ CFLAGS-tst-cet-legacy-mod-6a.c += -fcf-protection=branch CFLAGS-tst-cet-legacy-mod-6b.c += -fcf-protection CFLAGS-tst-cet-legacy-mod-6c.c += -fcf-protection CFLAGS-tst-cet-legacy-7.c += -fcf-protection=none -CFLAGS-tst-cet-legacy-8.c += -mshstk CFLAGS-tst-cet-legacy-10.c += -mshstk CFLAGS-tst-cet-legacy-10-static.c += -mshstk diff --git a/sysdeps/x86/tst-cet-legacy-10.c b/sysdeps/x86/tst-cet-legacy-10.c index a85cdc3171..ae2c34de3e 100644 --- a/sysdeps/x86/tst-cet-legacy-10.c +++ b/sysdeps/x86/tst-cet-legacy-10.c @@ -21,19 +21,19 @@ #include #include -/* Check that CPU_FEATURE_ACTIVE on IBT and SHSTK matches _get_ssp. */ +/* Check that CPU_FEATURE_ACTIVE on SHSTK matches _get_ssp. */ static int do_test (void) { if (_get_ssp () != 0) { - if (CPU_FEATURE_ACTIVE (IBT) && CPU_FEATURE_ACTIVE (SHSTK)) + if (CPU_FEATURE_ACTIVE (SHSTK)) return EXIT_SUCCESS; } else { - if (!CPU_FEATURE_ACTIVE (IBT) && !CPU_FEATURE_ACTIVE (SHSTK)) + if (!CPU_FEATURE_ACTIVE (SHSTK)) return EXIT_SUCCESS; } diff --git a/sysdeps/x86/tst-cet-legacy-8.c b/sysdeps/x86/tst-cet-legacy-8.c index 5d8d9ba7dc..77d77a5408 100644 --- a/sysdeps/x86/tst-cet-legacy-8.c +++ b/sysdeps/x86/tst-cet-legacy-8.c @@ -18,7 +18,7 @@ #include #include -#include +#include #include #include #include @@ -29,11 +29,6 @@ static int do_test (void) { - /* NB: This test should trigger SIGSEGV on CET platforms. If SHSTK - is disabled, assuming IBT is also disabled. */ - if (_get_ssp () == 0) - return EXIT_UNSUPPORTED; - void (*funcp) (void); funcp = xmmap (NULL, 0x1000, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, -1); @@ -41,8 +36,14 @@ do_test (void) /* Write RET instruction. */ *(char *) funcp = 0xc3; funcp (); + + /* NB: This test should trigger SIGSEGV when IBT is active. We should + reach here if IBT isn't active. */ + if (!CPU_FEATURE_ACTIVE (IBT)) + return EXIT_UNSUPPORTED; + return EXIT_FAILURE; } -#define EXPECTED_SIGNAL (_get_ssp () == 0 ? 0 : SIGSEGV) +#define EXPECTED_SIGNAL (CPU_FEATURE_ACTIVE (IBT) ? SIGSEGV : 0) #include