linux-kernel - [tip: x86/core] objtool: Correctly handle retpoline thunk calls

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: <161728973821.29796.14241839144918537341.tip-bot2@tip-bot2>
Date:   Thu, 01 Apr 2021 15:08:58 -0000
From:   "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Borislav Petkov <bp@...e.de>, Miroslav Benes <mbenes@...e.cz>,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/core] objtool: Correctly handle retpoline thunk calls

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     db9d1dd670d7f3f146c654f289f20968af6a12de
Gitweb:        https://git.kernel.org/tip/db9d1dd670d7f3f146c654f289f20968af6a12de
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Fri, 26 Mar 2021 16:12:03 +01:00
Committer:     Borislav Petkov <bp@...e.de>
CommitterDate: Thu, 01 Apr 2021 11:34:01 +02:00

objtool: Correctly handle retpoline thunk calls

Just like JMP handling, convert a direct CALL to a retpoline thunk
into a retpoline safe indirect CALL.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Borislav Petkov <bp@...e.de>
Reviewed-by: Miroslav Benes <mbenes@...e.cz>
Link: https://lkml.kernel.org/r/20210326151259.567568238@infradead.org
---
 tools/objtool/check.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index d45f018..519af4b 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1025,6 +1025,18 @@ static int add_call_destinations(struct objtool_file *file)
 					  dest_off);
 				return -1;
 			}
+
+		} else if (!strncmp(reloc->sym->name, "__x86_indirect_thunk_", 21)) {
+			/*
+			 * Retpoline calls are really dynamic calls in
+			 * disguise, so convert them accordingly.
+			 */
+			insn->type = INSN_CALL_DYNAMIC;
+			insn->retpoline_safe = true;
+
+			remove_insn_ops(insn);
+			continue;
+
 		} else
 			insn->call_dest = reloc->sym;