From: Peter Zijlstra <peterz@infradead.org>
To: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com,
julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net,
mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
valentin.schneider@arm.com, brgerst@gmail.com,
jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de,
dvlasenk@redhat.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org
Subject: [PATCH 8/8] objtool: Add Direction Flag validation
Date: Thu, 28 Feb 2019 15:54:58 +0100 [thread overview]
Message-ID: <20190228150152.721954047@infradead.org> (raw)
In-Reply-To: 20190228145450.289603901@infradead.org
Having DF escape is BAD(tm).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
tools/objtool/arch.h | 4 +++-
tools/objtool/arch/x86/decode.c | 8 ++++++++
tools/objtool/check.c | 21 +++++++++++++++++++++
tools/objtool/check.h | 2 +-
4 files changed, 33 insertions(+), 2 deletions(-)
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -35,7 +35,9 @@
#define INSN_NOP 10
#define INSN_STAC 11
#define INSN_CLAC 12
-#define INSN_OTHER 13
+#define INSN_STD 13
+#define INSN_CLD 14
+#define INSN_OTHER 15
#define INSN_LAST INSN_OTHER
enum op_dest_type {
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -456,6 +456,14 @@ int arch_decode_instruction(struct elf *
*type = INSN_CALL;
break;
+ case 0xfc:
+ *type = INSN_CLD;
+ break;
+
+ case 0xfd:
+ *type = INSN_STD;
+ break;
+
case 0xff:
if (modrm_reg == 2 || modrm_reg == 3)
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1930,6 +1930,9 @@ static int validate_branch(struct objtoo
if (state.uaccess)
WARN_FUNC("return with UACCESS enabled", sec, insn->offset);
+ if (state.df)
+ WARN_FUNC("return with DF set", sec, insn->offset);
+
if (func && has_modified_stack_frame(&state)) {
WARN_FUNC("return with modified stack frame",
sec, insn->offset);
@@ -1951,6 +1954,10 @@ static int validate_branch(struct objtoo
WARN_FUNC("call to %s() with UACCESS enabled",
sec, insn->offset, insn_dest_name(insn));
}
+ if (state.df) {
+ WARN_FUNC("call to %s() with DF set",
+ sec, insn->offset, insn_dest_name(insn));
+ }
if (insn->type == INSN_CALL) {
if (is_fentry_call(insn))
@@ -2034,6 +2041,20 @@ static int validate_branch(struct objtoo
state.uaccess = false;
break;
+ case INSN_STD:
+ if (state.df)
+ WARN_FUNC("recursive STD", sec, insn->offset);
+
+ state.df = true;
+ break;
+
+ case INSN_CLD:
+ if (!state.df && insn->func)
+ WARN_FUNC("redundant CLD", sec, insn->offset);
+
+ state.df = false;
+ break;
+
default:
break;
}
--- a/tools/objtool/check.h
+++ b/tools/objtool/check.h
@@ -31,7 +31,7 @@ struct insn_state {
int stack_size;
unsigned char type;
bool bp_scratch;
- bool drap, end, uaccess, uaccess_safe;
+ bool drap, end, uaccess, uaccess_safe, df;
int drap_reg, drap_offset;
struct cfi_reg vals[CFI_NUM_REGS];
};
prev parent reply other threads:[~2019-02-28 15:05 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-28 14:54 [PATCH 0/8] objtool: UACCESS validation v2 Peter Zijlstra
2019-02-28 14:54 ` [PATCH 1/8] kasan,x86: Frob kasan_report() in an exception Peter Zijlstra
2019-02-28 15:22 ` Dmitry Vyukov
2019-02-28 15:45 ` Peter Zijlstra
2019-02-28 15:52 ` Dmitry Vyukov
2019-02-28 16:01 ` Andrey Ryabinin
2019-02-28 16:03 ` Dmitry Vyukov
2019-02-28 17:46 ` Peter Zijlstra
2019-02-28 18:18 ` Dmitry Vyukov
2019-03-01 14:45 ` Peter Zijlstra
2019-03-01 15:06 ` Dmitry Vyukov
2019-03-01 15:23 ` Peter Zijlstra
2019-03-06 13:13 ` Peter Zijlstra
2019-03-06 13:39 ` Dmitry Vyukov
2019-03-06 13:57 ` Peter Zijlstra
2019-03-06 14:01 ` Dmitry Vyukov
2019-03-06 14:12 ` Peter Zijlstra
2019-03-06 14:34 ` Peter Zijlstra
2019-03-06 14:40 ` Dmitry Vyukov
2019-03-06 14:41 ` Dmitry Vyukov
2019-03-06 14:55 ` Peter Zijlstra
2019-03-06 15:01 ` Dmitry Vyukov
2019-03-06 17:14 ` Peter Zijlstra
2019-03-06 17:27 ` Linus Torvalds
2019-03-06 17:37 ` Peter Zijlstra
2019-03-06 17:59 ` Linus Torvalds
2019-03-07 13:49 ` Peter Zijlstra
2019-02-28 14:54 ` [PATCH 2/8] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-02-28 14:54 ` [PATCH 3/8] objtool: Set insn->func for alternatives Peter Zijlstra
2019-02-28 14:54 ` [PATCH 4/8] objtool: Hande function aliases Peter Zijlstra
2019-02-28 14:54 ` [PATCH 5/8] objtool: Rewrite add_ignores() Peter Zijlstra
2019-02-28 14:54 ` [PATCH 6/8] i915,uaccess: Fix redundant CLAC Peter Zijlstra
2019-02-28 15:10 ` Chris Wilson
2019-02-28 15:24 ` Peter Zijlstra
2019-02-28 16:49 ` Linus Torvalds
2019-02-28 17:51 ` Peter Zijlstra
2019-02-28 18:01 ` Peter Zijlstra
2019-02-28 18:29 ` Linus Torvalds
2019-02-28 19:01 ` Peter Zijlstra
2019-03-01 10:34 ` Peter Zijlstra
2019-03-01 12:27 ` Peter Zijlstra
2019-03-01 12:57 ` Peter Zijlstra
2019-03-01 14:38 ` Peter Zijlstra
2019-03-01 15:27 ` Andy Lutomirski
2019-03-01 16:15 ` Linus Torvalds
2019-03-01 16:17 ` Linus Torvalds
2019-02-28 14:54 ` [PATCH 7/8] objtool: Add UACCESS validation Peter Zijlstra
2019-02-28 14:54 ` Peter Zijlstra [this message]
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