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Subject[PATCH v5 11/15] x86, relocs: Ignore __typeid__ relocations
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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(+)

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
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