From patchwork Tue Sep 5 21:54:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Stitt X-Patchwork-Id: 13375136 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 0C030CA1019 for ; Tue, 5 Sep 2023 21:55:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244791AbjIEVzE (ORCPT ); Tue, 5 Sep 2023 17:55:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244678AbjIEVzB (ORCPT ); Tue, 5 Sep 2023 17:55:01 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1F1819A for ; Tue, 5 Sep 2023 14:54:46 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d7ea08906b3so2647690276.1 for ; Tue, 05 Sep 2023 14:54:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1693950886; x=1694555686; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=mYSSYqyZSAKIfvzMRnscK0LuxZzE2hQmiaI7r8kw+io=; b=JyJk91Z+QZRTbtKgeOK+Nk934z+HbCX09Ydgq9HHngyKBl70aBv7Rf2twBg9hzmzTt zfzpoq49lcoW2YyU3UgP1jpTMEteaB7Ig6Er6LCRSfjl6cu9uFwNBDlJDNw9MzPBS7cD cwG0b7IP9X1QqwomSD4xPJJo5tqAHMwBz/24zmJIMPtcHADklz6M1aF8lBROfeK3Ou/z PYlLA0CvCCY2q9iY3H/NhSXeQu5kt7mXdBesBuGt00om7K1dMtt4K/HL9fw+ROybWgV9 vxTxisuE0bsczIrZmkVKEFLUiStgtA7pmsqmWXO8uGOoacbufOPjcGO/WYpKPJo7j8SJ dfpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693950886; x=1694555686; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=mYSSYqyZSAKIfvzMRnscK0LuxZzE2hQmiaI7r8kw+io=; b=DgjV3qeae487dvOvND1B0lsknQKUvjgTM3wsKjpUmKRCoaYxyUhBggFxII9WqHuieO wTj0hW+PjWOcXGXLINu2aNcAOm+lU3N1GC5YLxiJqxd81v7l8m3qdUs7Ej9opSI7/FrZ T51/AyIa9ch2VD1uSzIKBBV5vaQlLsfKM8MqqRvI3cE9iBdUDYkRZfZoLhzH66sIy6gI zXre9QawR+Zt8o7vYE/TB8ZLoZbUXvaWgqueg4R+Y9NtmhUzvcmyV8/q8rfMKXbH7MR4 d+Ckui3k8desMs10EZAfw9LQFjv95eixGLz0L58X+f4gMLZ9qGoyRzEIHPpEVB5Bi2gn cWYQ== X-Gm-Message-State: AOJu0YwdWto9SQHO3Ay25dyuQBQPcgDlu9yw6nYqRdWZq42E/xDmqOD3 LyGpRvduIq9YRFAaUm1aVD4A41uy7D4RszIDnQ== X-Google-Smtp-Source: AGHT+IEthNzV8ZE+tRL4eK9ihsAlyb2EPkYYpRYCKGSbFbV8n6cZni6u1SkJNkJThkTG6zrJpu4FeNqiuTv3OYY/+g== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a25:b082:0:b0:d01:60ec:d0e with SMTP id f2-20020a25b082000000b00d0160ec0d0emr340324ybj.9.1693950886135; Tue, 05 Sep 2023 14:54:46 -0700 (PDT) Date: Tue, 05 Sep 2023 21:54:40 +0000 Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAJ+j92QC/5XNQQ6CMBCF4auQrh1DpwXElfcwxjRlgCZASYsNh HB3CyvdaTKbfxbfW5knZ8iza7IyR8F4Y4cY4pQw3aqhITBVbIYpivSCCH5ygx4XUE63MF9yGDs 11db18ArxnkNvQBaSMiwzjZqzKI2OajMfK/dH7Nb4ybrlGA18//7nBw4cSsFrLKWoKK1ujbVNR 2dte7YPBPxE5W8oRpR4XpVKkM6K9Avdtu0NRuNskCwBAAA= X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1693950885; l=2964; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=gDNLo7BwDTNW1pc/8WsCxyt7x3/IodsVK/vgZb9S0ms=; b=IXGF5h8HALV0QqVdSV0NY5o+3DcKJUjKJaxugsEIOU5l5nkn5MICgLmVSJpktWLpi5DXLER2m +QzOs8fM8cADr7PK33mrLHiIBTTAif+aH/Gsy4Qv8sV8thWQW0bekKZ X-Mailer: b4 0.12.3 Message-ID: <20230905-strncpy-arch-x86-platform-uv-uv_nmi-v3-1-3efd6798b569@google.com> Subject: [PATCH v3] x86/platform/uv: refactor deprecated strcpy and strncpy From: Justin Stitt To: Steve Wahl , Mike Travis , Dimitri Sivanich , Russ Anderson , Darren Hart , Andy Shevchenko , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Hans de Goede , Dimitri Sivanich , linux-hardening@vger.kernel.org, Justin Stitt Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org Both `strncpy` and `strcpy` are deprecated for use on NUL-terminated destination strings [1]. We can see that `arg` and `uv_nmi_action` are expected to be NUL-terminated strings due to their use within `strcmp()` and format strings respectively. With this in mind, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on its destination buffer argument which is _not_ the case for `strncpy` or `strcpy`! In this case, we can drop both the forced NUL-termination and the `... -1` from: | strncpy(arg, val, ACTION_LEN - 1); as `strscpy` implicitly has this behavior. Link: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings[1] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt Reviewed-by: Hans de Goede --- Changes in v3: - Use sizeof instead of strlen (thanks Andy and Dimitri) - Drop unrelated changes regarding strnchrnul (thanks Hans) - Link to v2: https://lore.kernel.org/r/20230824-strncpy-arch-x86-platform-uv-uv_nmi-v2-1-e16d9a3ec570@google.com Changes in v2: - use `sizeof` on destination string instead of `strlen` (thanks Andy, Kees and Dimitri) - refactor code to remove potential new-line chars (thanks Yang Yang and Andy) - Link to v1: https://lore.kernel.org/r/20230822-strncpy-arch-x86-platform-uv-uv_nmi-v1-1-931f2943de0d@google.com --- Note: build-tested only --- arch/x86/platform/uv/uv_nmi.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c change-id: 20230822-strncpy-arch-x86-platform-uv-uv_nmi-474e5295c2c1 Best regards, -- Justin Stitt diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c index a60af0230e27..dd30fb2baf6c 100644 --- a/arch/x86/platform/uv/uv_nmi.c +++ b/arch/x86/platform/uv/uv_nmi.c @@ -205,8 +205,7 @@ static int param_set_action(const char *val, const struct kernel_param *kp) char arg[ACTION_LEN], *p; /* (remove possible '\n') */ - strncpy(arg, val, ACTION_LEN - 1); - arg[ACTION_LEN - 1] = '\0'; + strscpy(arg, val, sizeof(arg)); p = strchr(arg, '\n'); if (p) *p = '\0'; @@ -216,7 +215,7 @@ static int param_set_action(const char *val, const struct kernel_param *kp) break; if (i < n) { - strcpy(uv_nmi_action, arg); + strscpy(uv_nmi_action, arg, sizeof(uv_nmi_action)); pr_info("UV: New NMI action:%s\n", uv_nmi_action); return 0; } @@ -959,7 +958,7 @@ static int uv_handle_nmi(unsigned int reason, struct pt_regs *regs) /* Unexpected return, revert action to "dump" */ if (master) - strncpy(uv_nmi_action, "dump", strlen(uv_nmi_action)); + strscpy(uv_nmi_action, "dump", sizeof(uv_nmi_action)); } /* Pause as all CPU's enter the NMI handler */