From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6DE28238174 for ; Wed, 21 May 2025 08:52:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747817561; cv=none; b=skV4d6wK6KCYTDr5ytZPQGvbbjlxoPiInh7K9M+yhJPvikS4upLf/UyETrYwX0ArEhCArHBum1oyds2y4bPl28CqoD4vAE6dpqOBIB8LLAvX4cKtktOUhrCes5yYKdfb71FeH3rBUe2OPSbz0e8opHq1PTqG8OnSR9gIEFe3OCM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747817561; c=relaxed/simple; bh=PD46+ourdXDcszKYFR2bVHsQctHZM0RLmWsbQVapegI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=D7k7ntas0jVs1mzl7QsSEAcEsdHlEh3XDOgRArLKmMkUpaqfq4cNyplR3pf6r2vnnlxxQEUsUtBhSC50D6PXbpcb3zbnVUJ3mIbyChvigz/Ro14bOx+LTnXU2PG3UYq4nEaFlULzSQ8SRgNqqAU0o00Pcc8ioHXddFT2Q5U81Mw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--dvyukov.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=w2JVM/O4; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--dvyukov.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="w2JVM/O4" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-43d5ca7c86aso40827885e9.0 for ; Wed, 21 May 2025 01:52:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1747817558; x=1748422358; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=WHj8OpGfndLIKKcorEWM8n6SM67qF6VgisoF/dxjdy4=; b=w2JVM/O4iqm+ROVS+0S8saBRPo8czB5haJSKpA1pTS/nZ+1A+Me/mwCkLlk/YX1oyw n0iJ7eKjrYn64fTbe79+o9lB1nTM9iVeTuT63THtLlwi9rNE4q+GX7wHNiC2WxuZeCe2 fAcq0b8DebGA9b88sHAh3bTi/pt5e0t5YEoEX0YDQCIPB0kOk0dED5+7V+BhwrMKuMu0 djbbleyinVChJSHqKuMM4KtRv8facIbE65TXKg1/hWSbvGQ/CLvqwTJJnTDk18uXkpYV gK3uQk4EYYC3itbItSV+0l2sS2W+vhdjWPbDMlU35IZXnSW87mwnmpJeuRfaGeLDY8li 4SWA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747817558; x=1748422358; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WHj8OpGfndLIKKcorEWM8n6SM67qF6VgisoF/dxjdy4=; b=wA2Chz3g1UgMx87urEmiMYoYsVWDSwAuNmzbd/zV+vE09Ln2i5qCcS4lwuZOQuY52v jI9XD8jr2CCCNHodUt1dM9JizAE8PmGi+2e881l+OTVZ66KDqlkFD3Qu+36mSvICKNvL tyUD1YUsvn0CLSidajYm5CGNT2MGf3DCv405X+NJ+fUoODdnsAg3UQtlYcRZbX8E5mD/ kmhcsJZyR0KyBqf6q2Zdj3H12eacSc/h7Vxy7kg+DpcicdzV76GfBZwgM+9gXktiHp59 yxQcgmk6oUfDdBBTzpcg88+DktEEhOa0sOao8B9w5ry51HenxEwfHahF7CWbKndD3FNy IdHA== X-Forwarded-Encrypted: i=1; AJvYcCV2kQdIPXzTQUSnNotuUim5N40Hpu2gL5NDtcLjdm5qXE9FpDMSnwJ6DleqLUExgWGxq7IxVyhOTpOELQM=@vger.kernel.org X-Gm-Message-State: AOJu0YxMJRAcFNb32YUPGqUx4QzGCclK0EaUUR/5wYtOfmga8Yd488Tk pqphpa/IwyN1EefU/DB1Xv+B4nvzUQSM7CA4yCQYfk3arACeZM8vycOsXxDu7yKsqX3BofXU89x O++xXduyCiw== X-Google-Smtp-Source: AGHT+IHDJtY/2c6fXiE2M6SJD4QN66toVQpvNWxET8tGnEUZy7qObhe8e+RKYr/Jiu/2SWeO2//H748sAcwK X-Received: from wmbdt15.prod.google.com ([2002:a05:600c:630f:b0:43c:f8ae:4d6c]) (user=dvyukov job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:4f42:b0:43b:cb12:ba6d with SMTP id 5b1f17b1804b1-442fd60b543mr196886765e9.3.1747817557800; Wed, 21 May 2025 01:52:37 -0700 (PDT) Date: Wed, 21 May 2025 10:47:49 +0200 In-Reply-To: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.49.0.1143.g0be31eac6b-goog Message-ID: <0dc8992f3fe4a76d7fdd73f553236a570dc5a5eb.1747817128.git.dvyukov@google.com> Subject: [PATCH v7 4/4] selftests/rseq: Add test for rseq+pkeys From: Dmitry Vyukov To: mathieu.desnoyers@efficios.com, peterz@infradead.org, boqun.feng@gmail.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, aruna.ramakrishna@oracle.com, elver@google.com Cc: Dmitry Vyukov , "Paul E. McKenney" , x86@kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Add a test that ensures that PKEY-protected struct rseq_cs works and does not lead to process kills. Signed-off-by: Dmitry Vyukov Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: "Paul E. McKenney" Cc: Boqun Feng Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: "H. Peter Anvin" Cc: Aruna Ramakrishna Cc: x86@kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Dave Hansen Fixes: d7822b1e24f2 ("rseq: Introduce restartable sequences system call") --- Changes in v7: - Add rseq_unregister_current_thread() call in the test Changes in v5: - Use static for variables/functions - Use RSEQ_READ/WRITE_ONCE instead of volatile Changes in v4: - Added Fixes tag Changes in v3: - added Acked-by: Dave Hansen - rework the test to work when only pkey 0 is supported for rseq Changes in v2: - change test to install protected rseq_cs instead of rseq --- tools/testing/selftests/rseq/Makefile | 2 +- tools/testing/selftests/rseq/pkey_test.c | 101 +++++++++++++++++++++++ tools/testing/selftests/rseq/rseq.h | 1 + 3 files changed, 103 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/rseq/Makefile b/tools/testing/selftests/rseq/Makefile index 0d0a5fae59547..e5fd819011582 100644 --- a/tools/testing/selftests/rseq/Makefile +++ b/tools/testing/selftests/rseq/Makefile @@ -17,7 +17,7 @@ OVERRIDE_TARGETS = 1 TEST_GEN_PROGS = basic_test basic_percpu_ops_test basic_percpu_ops_mm_cid_test param_test \ param_test_benchmark param_test_compare_twice param_test_mm_cid \ param_test_mm_cid_benchmark param_test_mm_cid_compare_twice \ - syscall_errors_test + syscall_errors_test pkey_test TEST_GEN_PROGS_EXTENDED = librseq.so diff --git a/tools/testing/selftests/rseq/pkey_test.c b/tools/testing/selftests/rseq/pkey_test.c new file mode 100644 index 0000000000000..5dc214cd7a1e6 --- /dev/null +++ b/tools/testing/selftests/rseq/pkey_test.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * Ensure that rseq works when rseq data is inaccessible due to PKEYs. + */ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "rseq.h" +#include "rseq-abi.h" + +static int pkey; +static ucontext_t ucp0, ucp1; + +static void coroutine(void) +{ + int i, orig_pk0, old_pk0, old_pk1, pk0, pk1; + /* + * When we disable access to pkey 0, globals and TLS become + * inaccessible too, so we need to tread carefully. + * Pkey is global so we need to copy it onto the stack. + */ + int pk = RSEQ_READ_ONCE(pkey); + struct timespec ts; + + orig_pk0 = pkey_get(0); + if (pkey_set(0, PKEY_DISABLE_ACCESS)) + err(1, "pkey_set failed"); + old_pk0 = pkey_get(0); + old_pk1 = pkey_get(pk); + + /* + * Prevent compiler from initializing it by loading a 16-global. + */ + RSEQ_WRITE_ONCE(ts.tv_sec, 0); + RSEQ_WRITE_ONCE(ts.tv_nsec, 10 * 1000); + /* + * If the kernel misbehaves, context switches in the following loop + * will terminate the process with SIGSEGV. + * Trigger preemption w/o accessing TLS. + * Note that glibc's usleep touches errno always. + */ + for (i = 0; i < 10; i++) + syscall(SYS_clock_nanosleep, CLOCK_MONOTONIC, 0, &ts, NULL); + + pk0 = pkey_get(0); + pk1 = pkey_get(pk); + if (pkey_set(0, orig_pk0)) + err(1, "pkey_set failed"); + + /* + * Ensure that the kernel has restored the previous value of pkeys + * register after changing them. + */ + if (old_pk0 != pk0) + errx(1, "pkey 0 changed %d->%d", old_pk0, pk0); + if (old_pk1 != pk1) + errx(1, "pkey 1 changed %d->%d", old_pk1, pk1); + + swapcontext(&ucp1, &ucp0); + abort(); +} + +int main(int argc, char **argv) +{ + pkey = pkey_alloc(0, 0); + if (pkey == -1) { + printf("[SKIP]\tKernel does not support PKEYs: %s\n", + strerror(errno)); + return 0; + } + + if (rseq_register_current_thread()) + err(1, "rseq_register_current_thread failed"); + + if (getcontext(&ucp1)) + err(1, "getcontext failed"); + ucp1.uc_stack.ss_size = getpagesize() * 4; + ucp1.uc_stack.ss_sp = mmap(NULL, ucp1.uc_stack.ss_size, + PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0); + if (ucp1.uc_stack.ss_sp == MAP_FAILED) + err(1, "mmap failed"); + if (pkey_mprotect(ucp1.uc_stack.ss_sp, ucp1.uc_stack.ss_size, + PROT_READ | PROT_WRITE, pkey)) + err(1, "pkey_mprotect failed"); + makecontext(&ucp1, coroutine, 0); + if (swapcontext(&ucp0, &ucp1)) + err(1, "swapcontext failed"); + + if (rseq_unregister_current_thread()) + err(1, "rseq_unregister_current_thread failed"); + return 0; +} diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h index f51a5fdb04443..cdb34cbad1adb 100644 --- a/tools/testing/selftests/rseq/rseq.h +++ b/tools/testing/selftests/rseq/rseq.h @@ -8,6 +8,7 @@ #ifndef RSEQ_H #define RSEQ_H +#include #include #include #include -- 2.49.0.1143.g0be31eac6b-goog