linux-hardening - [PATCH v5 11/15] x86, relocs: Ignore __typeid_

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20211013181658.1020262-12-samitolvanen@google.com>
Date:   Wed, 13 Oct 2021 11:16:54 -0700
From:   Sami Tolvanen <samitolvanen@...gle.com>
To:     x86@...nel.org
Cc:     Kees Cook <keescook@...omium.org>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Sedat Dilek <sedat.dilek@...il.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-hardening@...r.kernel.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, Sami Tolvanen <samitolvanen@...gle.com>
Subject: [PATCH v5 11/15] x86, relocs: Ignore __typeid__ relocations

From: Kees Cook <keescook@...omium.org>

The R_X86_64_8 __typeid__* relocations are for constants the compiler
generates for indirect call type checking with CONFIG_CFI_CLANG. They
can be ignored during relocation generation.

Signed-off-by: Kees Cook <keescook@...omium.org>
[ Sami: clarified the commit message ]
Signed-off-by: Sami Tolvanen <samitolvanen@...gle.com>
Tested-by: Nick Desaulniers <ndesaulniers@...gle.com>
Tested-by: Sedat Dilek <sedat.dilek@...il.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 27c82207d387..5304a6037924 100644
--- a/arch/x86/tools/relocs.c
+++ b/arch/x86/tools/relocs.c
@@ -51,6 +51,7 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"^(xen_irq_disable_direct_reloc$|"
 	"xen_save_fl_direct_reloc$|"
 	"VDSO|"
+	"__typeid__|"
 	"__crc_)",
 
 /*
@@ -811,6 +812,12 @@ 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:
-- 
2.33.0.1079.g6e70778dc9-goog