From: Peter Zijlstra <peterz@infradead.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jason Baron <jbaron@akamai.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mark Rutland <mark.rutland@arm.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [RFC PATCH 3/7] static_call: use helper to access non-exported key
Date: Tue, 9 Nov 2021 20:42:29 +0100 [thread overview]
Message-ID: <YYrPJXlyQV5pXPHt@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAMj1kXEW72y1p-qR+X6EBqM8Rf5+fZnEs2WSSz7b+eU=zvPt6w@mail.gmail.com>
On Tue, Nov 09, 2021 at 07:54:23PM +0100, Ard Biesheuvel wrote:
> On Tue, 9 Nov 2021 at 19:53, Peter Zijlstra <peterz@infradead.org> wrote:
> >
> > On Tue, Nov 09, 2021 at 05:45:45PM +0100, Ard Biesheuvel wrote:
> > > @@ -196,13 +190,21 @@ extern long __static_call_return0(void);
> > > EXPORT_SYMBOL_GPL(STATIC_CALL_KEY(name)); \
> > > EXPORT_SYMBOL_GPL(STATIC_CALL_TRAMP(name))
> > >
> > > +#define EXPORT_STATIC_CALL_GETKEY_HELPER(name) \
> > > + struct static_call_key *STATIC_CALL_GETKEY(name)(void) { \
> > > + BUG_ON(!core_kernel_text( \
> > > + (unsigned long)__builtin_return_address(0))); \
> > > + return &STATIC_CALL_KEY(name); \
> > > + } \
> > > + EXPORT_SYMBOL_GPL(STATIC_CALL_GETKEY(name))
> >
> > So if I were a nevarious module, I would look up the above symbol from
> > kallsyms (it is exported and easily obtainable) and then simply
> > read the text to discover the key address and we're in business.
> >
>
> Yeah I realised that. So would you prefer to have a
> .static_call_tramp_key section in each module and look up the keys in
> the module loader?
Think so... do you actually have a need for this?
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next prev parent reply other threads:[~2021-11-09 19:43 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-09 16:45 [RFC PATCH 0/7] static call updates Ard Biesheuvel
2021-11-09 16:45 ` [RFC PATCH 1/7] static_call: get rid of static_call_cond() Ard Biesheuvel
2021-11-09 18:38 ` Peter Zijlstra
2021-11-09 18:41 ` Ard Biesheuvel
2021-11-09 19:22 ` Peter Zijlstra
2021-11-09 19:32 ` Peter Zijlstra
2021-11-09 16:45 ` [RFC PATCH 2/7] static_call: deal with unexported keys without cluttering up the API Ard Biesheuvel
2021-11-09 18:49 ` Peter Zijlstra
2021-11-09 18:53 ` Ard Biesheuvel
2021-11-09 19:41 ` Peter Zijlstra
2021-11-09 16:45 ` [RFC PATCH 3/7] static_call: use helper to access non-exported key Ard Biesheuvel
2021-11-09 18:53 ` Peter Zijlstra
2021-11-09 18:54 ` Ard Biesheuvel
2021-11-09 19:42 ` Peter Zijlstra [this message]
2021-11-09 19:45 ` Ard Biesheuvel
2021-11-09 16:45 ` [RFC PATCH 4/7] static_call: fix broken static_call_query() for non-exported keys Ard Biesheuvel
2021-11-09 18:56 ` Peter Zijlstra
2021-11-09 16:45 ` [RFC PATCH 5/7] static_call: use non-function types to refer to the trampolines Ard Biesheuvel
2021-11-09 16:45 ` [RFC PATCH 6/7] static_call: rename EXPORT_ macros to be more self-explanatory Ard Biesheuvel
2021-11-09 19:00 ` Peter Zijlstra
2021-11-09 19:03 ` Ard Biesheuvel
2021-11-09 16:45 ` [RFC PATCH 7/7] static_call: add generic support for non-exported keys Ard Biesheuvel
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