diff mbox series

[v5,11/15] x86, relocs: Ignore __typeid__ relocations

Message ID 20211013181658.1020262-12-samitolvanen@google.com (mailing list archive)
State Changes Requested
Headers show
Series x86: Add support for Clang CFI | expand

Commit Message

Sami Tolvanen Oct. 13, 2021, 6:16 p.m. UTC 
From: Kees Cook <keescook@chromium.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@chromium.org>
[ Sami: clarified the commit message ]
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
---
 arch/x86/tools/relocs.c | 7 +++++++
 1 file changed, 7 insertions(+)
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Patch

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: