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Tue, 9 Nov 2021 19:53:05 +0100 (CET) Date: Tue, 9 Nov 2021 19:53:05 +0100 From: Peter Zijlstra To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Josh Poimboeuf , Jason Baron , Steven Rostedt , Mark Rutland , Kees Cook Subject: Re: [RFC PATCH 3/7] static_call: use helper to access non-exported key Message-ID: References: <20211109164549.1724710-1-ardb@kernel.org> <20211109164549.1724710-4-ardb@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20211109164549.1724710-4-ardb@kernel.org> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel