From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: x86@kernel.org, Kees Cook <keescook@chromium.org>,
Sami Tolvanen <samitolvanen@google.com>,
Joao Moreira <joao@overdrivepizza.com>,
linux-kernel@vger.kernel.org, Mark Rutland <mark.rutland@arm.com>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH] x86/ibt: Implement FineIBT
Date: Sat, 22 Oct 2022 17:03:45 +0200 [thread overview]
Message-ID: <Y1QGUXSc43rInacJ@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20221021230859.gysp5v3yzfqz4xgb@treble>
On Fri, Oct 21, 2022 at 04:08:59PM -0700, Josh Poimboeuf wrote:
> On Tue, Oct 18, 2022 at 03:35:50PM +0200, Peter Zijlstra wrote:
> > +#ifdef CONFIG_FINEIBT
> > +/*
> > + * kCFI FineIBT
> > + *
> > + * __cfi_\func: __cfi_\func:
> > + * movl $0x12345678,%eax endbr64 // 4
> > + * nop subl $0x12345678,%r10d // 7
> > + * nop jz 1f // 2
> > + * nop ud2 // 2
> > + * nop 1: nop // 1
> > + * nop
> > + * nop
> > + * nop
> > + * nop
> > + * nop
> > + * nop
> > + * nop
>
> All the "CFI" naming everywhere is very unfortunate. We already have
> "call frame information" in both the toolchain and objtool.
>
> The feature is called "kCFI" anyway, can Clang call the symbols
> '__kcfi_*'?
I think the compiler patch is already merged in clang, not sure that's
still an option, Sami?
> > +++ b/tools/objtool/builtin-check.c
> > @@ -79,6 +79,7 @@ const struct option check_options[] = {
> > OPT_BOOLEAN('s', "stackval", &opts.stackval, "validate frame pointer rules"),
> > OPT_BOOLEAN('t', "static-call", &opts.static_call, "annotate static calls"),
> > OPT_BOOLEAN('u', "uaccess", &opts.uaccess, "validate uaccess rules for SMAP"),
> > + OPT_BOOLEAN(0 , "cfi", &opts.cfi, "generate cfi_sites"),
>
> "annotate kernel control flow integrity (kCFI) function preambles" ?
Sure.
> > +++ b/tools/objtool/check.c
> > @@ -861,6 +861,62 @@ static int create_ibt_endbr_seal_section
> > return 0;
> > }
> >
> > +static int create_cfi_sections(struct objtool_file *file)
> > +{
> > + struct section *sec, *s;
> > + struct symbol *sym;
> > + unsigned int *loc;
> > + int idx;
> > +
> > + sec = find_section_by_name(file->elf, ".cfi_sites");
> > + if (sec) {
> > + INIT_LIST_HEAD(&file->call_list);
> > + WARN("file already has .cfi_sites section, skipping");
> > + return 0;
> > + }
> > +
> > + idx = 0;
> > + for_each_sec(file, s) {
> > + if (!s->text)
> > + continue;
> > +
> > + list_for_each_entry(sym, &s->symbol_list, list) {
> > + if (strncmp(sym->name, "__cfi_", 6))
> > + continue;
>
> Also make sure it's STT_FUNC.
OK.
next prev parent reply other threads:[~2022-10-22 15:04 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-18 13:35 [PATCH] x86/ibt: Implement FineIBT Peter Zijlstra
2022-10-18 14:43 ` David Laight
2022-10-18 15:58 ` Joao Moreira
2022-10-18 17:20 ` Kees Cook
2022-10-18 20:09 ` Joao Moreira
2022-10-19 5:33 ` Kees Cook
2022-10-18 21:27 ` David Laight
2022-10-18 14:47 ` Peter Zijlstra
2022-10-18 18:09 ` Kees Cook
2022-10-18 19:56 ` Peter Zijlstra
2022-10-18 23:31 ` Josh Poimboeuf
2022-10-19 5:22 ` Kees Cook
2022-10-19 11:38 ` Peter Zijlstra
2022-10-19 5:14 ` Kees Cook
2022-10-18 19:59 ` Peter Zijlstra
2022-10-18 21:09 ` Peter Zijlstra
2022-10-19 5:05 ` Kees Cook
2022-10-19 12:03 ` Peter Zijlstra
2022-10-19 15:22 ` Sami Tolvanen
2022-10-20 11:04 ` Peter Zijlstra
2022-10-18 19:59 ` Joao Moreira
2022-10-19 5:32 ` Kees Cook
2022-10-19 19:35 ` Joao Moreira
2022-10-18 20:05 ` Peter Zijlstra
2022-10-19 5:00 ` Kees Cook
2022-10-18 20:09 ` Peter Zijlstra
2022-10-18 20:17 ` Joao Moreira
2022-10-18 20:30 ` Peter Zijlstra
2022-10-19 4:48 ` Joao Moreira
2022-10-19 5:19 ` Kees Cook
2022-10-31 19:13 ` Joao Moreira
2022-11-01 21:39 ` Kees Cook
2022-11-01 21:50 ` Joao Moreira
2022-10-19 5:18 ` Kees Cook
2022-10-19 5:16 ` Kees Cook
2022-10-20 11:05 ` Peter Zijlstra
2022-10-18 23:38 ` Josh Poimboeuf
2022-10-19 7:29 ` Peter Zijlstra
2022-10-21 23:08 ` Josh Poimboeuf
2022-10-22 15:03 ` Peter Zijlstra [this message]
2022-10-24 17:15 ` Sami Tolvanen
2022-10-24 18:38 ` Joao Moreira
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