linux-hardening - [RFC PATCH 15/17] objtool: arm64: Handle supported relocations in alternatives

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: <20210120173800.1660730-16-jthierry@redhat.com>
Date:   Wed, 20 Jan 2021 18:37:58 +0100
From:   Julien Thierry <jthierry@...hat.com>
To:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc:     catalin.marinas@....com, will@...nel.org, ardb@...nel.org,
        masahiroy@...nel.org, keescook@...omium.org,
        michal.lkml@...kovi.net, jpoimboe@...hat.com, peterz@...radead.org,
        mark.rutland@....com, broonie@...nel.org,
        linux-efi@...r.kernel.org, linux-hardening@...r.kernel.org,
        Julien Thierry <jthierry@...hat.com>
Subject: [RFC PATCH 15/17] objtool: arm64: Handle supported relocations in alternatives

Based on get_alt_insn() in arch/arm64/kernel/alternative.c, arm64
alternative code adapts offsets for static branches and adrp
instructions.

Signed-off-by: Julien Thierry <jthierry@...hat.com>
---
 tools/objtool/arch/arm64/special.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/objtool/arch/arm64/special.c b/tools/objtool/arch/arm64/special.c
index c9c3e0bfd581..d47e5590ed60 100644
--- a/tools/objtool/arch/arm64/special.c
+++ b/tools/objtool/arch/arm64/special.c
@@ -30,7 +30,11 @@ bool arch_support_alt_relocation(struct special_alt *special_alt,
 				 struct instruction *insn,
 				 struct reloc *reloc)
 {
-	return false;
+	u32 opcode = *(u32 *)(insn->sec->data->d_buf + insn->offset);
+
+	return aarch64_insn_is_branch_imm(opcode) ||
+	       aarch64_insn_is_adrp(opcode) ||
+	       !aarch64_insn_uses_literal(opcode);
 }
 
 static struct section *get_switch_table_info_section(struct objtool_file *file)
-- 
2.25.4