Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 23 Aug 2021 10:13:14 -0700
In-Reply-To: <20210823171318.2801096-1-samitolvanen@google.com>
Message-Id: <20210823171318.2801096-11-samitolvanen@google.com>
Mime-Version: 1.0
References: <20210823171318.2801096-1-samitolvanen@google.com>
Subject: [PATCH v2 10/14] x86, relocs: Ignore __typeid__ relocations
From:   Sami Tolvanen <samitolvanen@google.com>
To:     x86@kernel.org
Cc:     Kees Cook <keescook@chromium.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Sedat Dilek <sedat.dilek@gmail.com>,
        linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
        clang-built-linux@googlegroups.com,
        Sami Tolvanen <samitolvanen@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

From: Kees Cook <keescook@chromium.org>

The __typeid__* symbols aren't actually relocations, so they can be
ignored during relocation generation.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/x86/tools/relocs.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/x86/tools/relocs.c b/arch/x86/tools/relocs.c
index 9ba700dc47de..fbc57cc00914 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -48,6 +48,7 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"^(xen_irq_disable_direct_reloc$|"
 	"xen_save_fl_direct_reloc$|"
 	"VDSO|"
+	"__typeid__|"
 	"__crc_)",
 
 /*
@@ -808,6 +809,12 @@ static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
 			    symname);
 		break;
 
+	case R_X86_64_8:
+		if (!shn_abs || !is_reloc(S_ABS, symname))
+			die("Non-whitelisted %s relocation: %s\n",
+				rel_type(r_type), symname);
+		break;
+
 	case R_X86_64_32:
 	case R_X86_64_32S:
 	case R_X86_64_64:
-- 
2.33.0.rc2.250.ged5fa647cd-goog