From: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
To: mricon@kernel.org
Subject: [PATCH v5 07/21] lkdtm: Emit an indirect call for CFI tests
Date: Thu, 01 Sep 2022 15:28:52 -0400 [thread overview]
Message-ID: <20220901-kcfi_support-v5-7-be2007d8da63@linuxfoundation.org> (raw)
In-Reply-To: <20220901-kcfi_support-v5-0-be2007d8da63@linuxfoundation.org>
From: Sami Tolvanen <samitolvanen@google.com>
Clang can convert the indirect calls in lkdtm_CFI_FORWARD_PROTO into
direct calls. Move the call into a noinline function that accepts the
target address as an argument to ensure the compiler actually emits an
indirect call instead.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
diff --git a/drivers/misc/lkdtm/cfi.c b/drivers/misc/lkdtm/cfi.c
index 71483cb1e422..5245cf6013c9 100644
--- a/drivers/misc/lkdtm/cfi.c
+++ b/drivers/misc/lkdtm/cfi.c
@@ -20,6 +20,13 @@ static noinline int lkdtm_increment_int(int *counter)
return *counter;
}
+
+/* Don't allow the compiler to inline the calls. */
+static noinline void lkdtm_indirect_call(void (*func)(int *))
+{
+ func(&called_count);
+}
+
/*
* This tries to call an indirect function with a mismatched prototype.
*/
@@ -29,15 +36,11 @@ static void lkdtm_CFI_FORWARD_PROTO(void)
* Matches lkdtm_increment_void()'s prototype, but not
* lkdtm_increment_int()'s prototype.
*/
- void (*func)(int *);
-
pr_info("Calling matched prototype ...\n");
- func = lkdtm_increment_void;
- func(&called_count);
+ lkdtm_indirect_call(lkdtm_increment_void);
pr_info("Calling mismatched prototype ...\n");
- func = (void *)lkdtm_increment_int;
- func(&called_count);
+ lkdtm_indirect_call((void *)lkdtm_increment_int);
pr_err("FAIL: survived mismatched prototype function call!\n");
pr_expected_config(CONFIG_CFI_CLANG);
--
b4 0.10.0-dev-03aea
next prev parent reply other threads:[~2022-09-01 19:28 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 19:28 [PATCH v5 00/21] KCFI support Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 01/21] treewide: Filter out CC_FLAGS_CFI Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 02/21] scripts/kallsyms: Ignore __kcfi_typeid_ Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 03/21] cfi: Remove CONFIG_CFI_CLANG_SHADOW Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 04/21] cfi: Drop __CFI_ADDRESSABLE Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 05/21] cfi: Switch to -fsanitize=kcfi Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 06/21] cfi: Add type helper macros Konstantin Ryabitsev
2022-09-01 19:28 ` Konstantin Ryabitsev [this message]
2022-09-01 19:28 ` [PATCH v5 08/21] psci: Fix the function type for psci_initcall_t Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 09/21] arm64: Add types to indirect called assembly functions Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 10/21] arm64: Add CFI error handling Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 11/21] arm64: Drop unneeded __nocfi attributes Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 12/21] init: Drop __nocfi from __init Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 13/21] treewide: Drop function_nocfi Konstantin Ryabitsev
2022-09-01 19:28 ` [PATCH v5 14/21] treewide: Drop WARN_ON_FUNCTION_MISMATCH Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 15/21] treewide: Drop __cficanonical Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 16/21] objtool: Disable CFI warnings Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 17/21] kallsyms: Drop CONFIG_CFI_CLANG workarounds Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 18/21] x86/tools/relocs: Ignore __kcfi_typeid_ relocations Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 19/21] x86: Add types to indirectly called assembly functions Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 20/21] x86/purgatory: Disable CFI Konstantin Ryabitsev
2022-09-01 19:29 ` [PATCH v5 21/21] x86: Add support for CONFIG_CFI_CLANG Konstantin Ryabitsev
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