From patchwork Fri Nov 18 17:28:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 626235 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56D31C433FE for ; Fri, 18 Nov 2022 17:32:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241961AbiKRRcP (ORCPT ); Fri, 18 Nov 2022 12:32:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242530AbiKRRcL (ORCPT ); Fri, 18 Nov 2022 12:32:11 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59A32186EC; Fri, 18 Nov 2022 09:32:10 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 6253FCE221A; Fri, 18 Nov 2022 17:32:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5560BC433C1; Fri, 18 Nov 2022 17:32:05 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="Ck10xJJF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1668792724; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=GyKOGkofkPCvMPD0/UwJzzsEw9ZOaxhI19IJoJsqMz4=; b=Ck10xJJFyJtJu2syfKbZVRObrnnQWQQl4uCW82Ixw9QTcO0pvDWSSDNrWQpF28KzVirC8E 94cCuokeZvQBA8UdWGqX3ec1roFifnyxFkjv+f9eQTeKIdo8EsDKQCId6MnKR5czXDdwCh O2e9onhFhYQMa1O39oHan0T3zGUDSvY= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 70c6e225 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Fri, 18 Nov 2022 17:32:04 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-kernel@vger.kernel.org, patches@lists.linux.dev Cc: "Jason A. Donenfeld" , linux-crypto@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell Subject: [PATCH v4 3/3] x86: vdso: Wire up getrandom() vDSO implementation Date: Fri, 18 Nov 2022 18:28:39 +0100 Message-Id: <20221118172839.2653829-4-Jason@zx2c4.com> In-Reply-To: <20221118172839.2653829-1-Jason@zx2c4.com> References: <20221118172839.2653829-1-Jason@zx2c4.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org Hook up the generic vDSO implementation to the x86 vDSO data page. Since the existing vDSO infrastructure is heavily based on the timekeeping functionality, which works over arrays of bases, a new macro is introduced for vvars that are not arrays. Signed-off-by: Jason A. Donenfeld --- arch/x86/Kconfig | 1 + arch/x86/entry/vdso/Makefile | 3 ++- arch/x86/entry/vdso/vdso.lds.S | 2 ++ arch/x86/entry/vdso/vgetrandom.c | 16 ++++++++++++ arch/x86/include/asm/vdso/getrandom.h | 37 +++++++++++++++++++++++++++ arch/x86/include/asm/vdso/vsyscall.h | 2 ++ arch/x86/include/asm/vvar.h | 16 ++++++++++++ 7 files changed, 76 insertions(+), 1 deletion(-) create mode 100644 arch/x86/entry/vdso/vgetrandom.c create mode 100644 arch/x86/include/asm/vdso/getrandom.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 67745ceab0db..210318da7505 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -269,6 +269,7 @@ config X86 select HAVE_UNSTABLE_SCHED_CLOCK select HAVE_USER_RETURN_NOTIFIER select HAVE_GENERIC_VDSO + select HAVE_VDSO_GETRANDOM select HOTPLUG_SMT if SMP select IRQ_FORCED_THREADING select NEED_PER_CPU_EMBED_FIRST_CHUNK diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 3e88b9df8c8f..adc3792dbbac 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -27,7 +27,7 @@ VDSO32-$(CONFIG_X86_32) := y VDSO32-$(CONFIG_IA32_EMULATION) := y # files to link into the vdso -vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o +vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vgetrandom.o vobjs32-y := vdso32/note.o vdso32/system_call.o vdso32/sigreturn.o vobjs32-y += vdso32/vclock_gettime.o vobjs-$(CONFIG_X86_SGX) += vsgx.o @@ -104,6 +104,7 @@ CFLAGS_REMOVE_vclock_gettime.o = -pg CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg CFLAGS_REMOVE_vgetcpu.o = -pg CFLAGS_REMOVE_vsgx.o = -pg +CFLAGS_REMOVE_vgetrandom.o = -pg # # X32 processes use x32 vDSO to access 64bit kernel data. diff --git a/arch/x86/entry/vdso/vdso.lds.S b/arch/x86/entry/vdso/vdso.lds.S index 4bf48462fca7..1919cc39277e 100644 --- a/arch/x86/entry/vdso/vdso.lds.S +++ b/arch/x86/entry/vdso/vdso.lds.S @@ -28,6 +28,8 @@ VERSION { clock_getres; __vdso_clock_getres; __vdso_sgx_enter_enclave; + getrandom; + __vdso_getrandom; local: *; }; } diff --git a/arch/x86/entry/vdso/vgetrandom.c b/arch/x86/entry/vdso/vgetrandom.c new file mode 100644 index 000000000000..0a0c0ad93cd0 --- /dev/null +++ b/arch/x86/entry/vdso/vgetrandom.c @@ -0,0 +1,16 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2022 Jason A. Donenfeld . All Rights Reserved. + */ +#include +#include + +#include "../../../../lib/vdso/getrandom.c" + +ssize_t __vdso_getrandom(void *buffer, size_t len, unsigned int flags, void *state) +{ + return __cvdso_getrandom(buffer, len, flags, state); +} + +ssize_t getrandom(void *, size_t, unsigned int, void *) + __attribute__((weak, alias("__vdso_getrandom"))); diff --git a/arch/x86/include/asm/vdso/getrandom.h b/arch/x86/include/asm/vdso/getrandom.h new file mode 100644 index 000000000000..c414043e975d --- /dev/null +++ b/arch/x86/include/asm/vdso/getrandom.h @@ -0,0 +1,37 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2022 Jason A. Donenfeld . All Rights Reserved. + */ +#ifndef __ASM_VDSO_GETRANDOM_H +#define __ASM_VDSO_GETRANDOM_H + +#ifndef __ASSEMBLY__ + +#include +#include + +static __always_inline ssize_t +getrandom_syscall(void *buffer, size_t len, unsigned int flags) +{ + long ret; + + asm ("syscall" : "=a" (ret) : + "0" (__NR_getrandom), "D" (buffer), "S" (len), "d" (flags) : + "rcx", "r11", "memory"); + + return ret; +} + +#define __vdso_rng_data (VVAR(_vdso_rng_data)) + +static __always_inline const struct vdso_rng_data *__arch_get_vdso_rng_data(void) +{ + if (__vdso_data->clock_mode == VDSO_CLOCKMODE_TIMENS) + return (void *)&__vdso_rng_data + + ((void *)&__timens_vdso_data - (void *)&__vdso_data); + return &__vdso_rng_data; +} + +#endif /* !__ASSEMBLY__ */ + +#endif /* __ASM_VDSO_GETRANDOM_H */ diff --git a/arch/x86/include/asm/vdso/vsyscall.h b/arch/x86/include/asm/vdso/vsyscall.h index be199a9b2676..71c56586a22f 100644 --- a/arch/x86/include/asm/vdso/vsyscall.h +++ b/arch/x86/include/asm/vdso/vsyscall.h @@ -11,6 +11,8 @@ #include DEFINE_VVAR(struct vdso_data, _vdso_data); +DEFINE_VVAR_SINGLE(struct vdso_rng_data, _vdso_rng_data); + /* * Update the vDSO data page to keep in sync with kernel timekeeping. */ diff --git a/arch/x86/include/asm/vvar.h b/arch/x86/include/asm/vvar.h index 183e98e49ab9..9d9af37f7cab 100644 --- a/arch/x86/include/asm/vvar.h +++ b/arch/x86/include/asm/vvar.h @@ -26,6 +26,8 @@ */ #define DECLARE_VVAR(offset, type, name) \ EMIT_VVAR(name, offset) +#define DECLARE_VVAR_SINGLE(offset, type, name) \ + EMIT_VVAR(name, offset) #else @@ -37,6 +39,10 @@ extern char __vvar_page; extern type timens_ ## name[CS_BASES] \ __attribute__((visibility("hidden"))); \ +#define DECLARE_VVAR_SINGLE(offset, type, name) \ + extern type vvar_ ## name \ + __attribute__((visibility("hidden"))); \ + #define VVAR(name) (vvar_ ## name) #define TIMENS(name) (timens_ ## name) @@ -44,12 +50,22 @@ extern char __vvar_page; type name[CS_BASES] \ __attribute__((section(".vvar_" #name), aligned(16))) __visible +#define DEFINE_VVAR_SINGLE(type, name) \ + type name \ + __attribute__((section(".vvar_" #name), aligned(16))) __visible + #endif /* DECLARE_VVAR(offset, type, name) */ DECLARE_VVAR(128, struct vdso_data, _vdso_data) +#if !defined(_SINGLE_DATA) +#define _SINGLE_DATA +DECLARE_VVAR_SINGLE(640, struct vdso_rng_data, _vdso_rng_data) +#endif + #undef DECLARE_VVAR +#undef DECLARE_VVAR_SINGLE #endif