From: Peter Zijlstra <peterz@infradead.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-kernel@vger.kernel.org,
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 19:53:05 +0100 [thread overview]
Message-ID: <YYrDkUsJVcOzxMPL@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20211109164549.1724710-4-ardb@kernel.org>
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.
next prev parent reply other threads:[~2021-11-09 18:53 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 [this message]
2021-11-09 18:54 ` Ard Biesheuvel
2021-11-09 19:42 ` Peter Zijlstra
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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