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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Kees Cook <keescook@chromium.org>,
        Marco Elver <elver@google.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Arnd Bergmann <arnd@arndb.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Tadeusz Struk <tadeusz.struk@linaro.org>
Subject: [PATCH 5.10 160/171] ubsan: remove CONFIG_UBSAN_OBJECT_SIZE
Date:   Tue, 12 Apr 2022 08:30:51 +0200
Message-Id: <20220412062932.528214929@linuxfoundation.org>
In-Reply-To: <20220412062927.870347203@linuxfoundation.org>
References: <20220412062927.870347203@linuxfoundation.org>
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From: Kees Cook <keescook@chromium.org>

commit 69d0db01e210e07fe915e5da91b54a867cda040f upstream.

The object-size sanitizer is redundant to -Warray-bounds, and
inappropriately performs its checks at run-time when all information
needed for the evaluation is available at compile-time, making it quite
difficult to use:

  https://bugzilla.kernel.org/show_bug.cgi?id=214861

With -Warray-bounds almost enabled globally, it doesn't make sense to
keep this around.

Link: https://lkml.kernel.org/r/20211203235346.110809-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 lib/test_ubsan.c       |   11 -----------
 scripts/Makefile.ubsan |    1 -
 2 files changed, 12 deletions(-)

--- a/lib/test_ubsan.c
+++ b/lib/test_ubsan.c
@@ -89,16 +89,6 @@ static void test_ubsan_misaligned_access
 	*ptr = val;
 }
 
-static void test_ubsan_object_size_mismatch(void)
-{
-	/* "((aligned(8)))" helps this not into be misaligned for ptr-access. */
-	volatile int val __aligned(8) = 4;
-	volatile long long *ptr, val2;
-
-	ptr = (long long *)&val;
-	val2 = *ptr;
-}
-
 static const test_ubsan_fp test_ubsan_array[] = {
 	test_ubsan_add_overflow,
 	test_ubsan_sub_overflow,
@@ -110,7 +100,6 @@ static const test_ubsan_fp test_ubsan_ar
 	test_ubsan_load_invalid_value,
 	//test_ubsan_null_ptr_deref, /* exclude it because there is a crash */
 	test_ubsan_misaligned_access,
-	test_ubsan_object_size_mismatch,
 };
 
 static int __init test_ubsan_init(void)
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -23,7 +23,6 @@ ifdef CONFIG_UBSAN_MISC
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=integer-divide-by-zero)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=unreachable)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=signed-integer-overflow)
-      CFLAGS_UBSAN += $(call cc-option, -fsanitize=object-size)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=bool)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=enum)
 endif