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[2620:137:e000::3:4]) by mx.google.com with ESMTPS id j7-20020a056a00234700b0068e26ca7f00si2766344pfj.39.2023.09.14.21.56.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Sep 2023 21:56:57 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) client-ip=2620:137:e000::3:4; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20230601 header.b=Bxn5R+b1; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by howler.vger.email (Postfix) with ESMTP id 855A788D517B; Thu, 14 Sep 2023 11:08:52 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at howler.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238295AbjINSIw (ORCPT + 33 others); Thu, 14 Sep 2023 14:08:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237421AbjINSIv (ORCPT ); Thu, 14 Sep 2023 14:08:51 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0E551FF9 for ; Thu, 14 Sep 2023 11:08:46 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5925fb6087bso16629467b3.2 for ; Thu, 14 Sep 2023 11:08:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1694714926; x=1695319726; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=643G47GETNhqNdCuDURH7WS6HlitohpBl/WopZi3siE=; b=Bxn5R+b1g8a0Kv4v/3SKs/7FFXxscduq0iIX7Dzlo0z4z7rBdjOjT4gbYnbmml8vTN w/V2CSL7dfvSYIk147DnulaRMg+rT9rL+isOFLTOSRhLYzKj/99zEpfGcjynpsoluoxD YiqDFQd6dICw1tIkm4rOLf5N2eLZ2LGQqOlKn/R+HuHuFkcywX43vATzf3TmCyynz5F6 17B4PCjMy3s737/YDdvP4J+3kHPOdn8+LMupU1RP7aIzYG8MfD+NG+dBVvKUQpoQbczM yasecrIqIBpIWGgV+MsCWVSbgYglFveSoRRFJexgbaRGqXty790O5Adflv2qJpL5Su9H j74g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694714926; x=1695319726; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=643G47GETNhqNdCuDURH7WS6HlitohpBl/WopZi3siE=; b=QTXRNaxzqHyInw/tvZmoPeCHsIJFg1btoS/LQjuHOB1kD9IrSUWmNJdHT2az4UNbxq FH5Oo5Tck+4Ch7rY7mJ5PDE2t9uJimOf57eTl0z+wA85Ura8ADIpRIxzF3JQMZJQGjIJ TbDRf38GmExKYXStJw4woswouJrqiekO36pDEmejRKS/QZvOmtxoQa2GUCNO4UWomjKo xntLKtLe8w5pTJA6kZIgdUd5bS8eHl9WqXBjBkm43nkwraZy0bDbP31q1z3C0mTU05yY 455gjdzTZPRGLTTOhFPZEk6XPeM7597cFhC8V3Ce033o3L5ZPi0hHV8PsDYBDY/Q0W2Q N7pA== X-Gm-Message-State: AOJu0YzyRMH4IIuBbqLijQTFqAG5ow3HP7rMlA8XngT43F6CLbPqNhif LR9fUX/xDZzMq8O2wqPX0OhO6rC7zxRue/DoNg== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a81:78d6:0:b0:59b:d33b:5ddc with SMTP id t205-20020a8178d6000000b0059bd33b5ddcmr133238ywc.4.1694714926173; Thu, 14 Sep 2023 11:08:46 -0700 (PDT) Date: Thu, 14 Sep 2023 18:08:44 +0000 Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIACtMA2UC/x2NSwrDMAwFrxK0rsB2Wvq5SinFWGqqRRwjpaYh5 O5xuxh4s3mzgrEKG9y6FZSrmEy5iT90kN4xD4xCzSG40LurP6LNmlNZkFQqq+FQPm2PP57jRGy YMPYnOl9CiuQ8tKei/JLvv3J/bNsOrmjEmXUAAAA= X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1694714925; l=2160; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=/VCD7DX1eCwVY46g4u81ZzjWo56f8DBPp1HX5L6qls8=; b=MSSj1xqOuKPodBgV3hCbCUvST05NmhGqT2NoNhh2CgiIOwHCP9o4MvQZLtDioILfwHV7oAWOC NasnjoSdir4BVmDVA/kDQPWT/uy8cxs5U1km0orFGKX5eaHoO0od7O3 X-Mailer: b4 0.12.3 Message-ID: <20230914-strncpy-drivers-gpu-drm-drm_modes-c-v1-1-079b532553a3@google.com> Subject: [PATCH] drm/modes: refactor deprecated strncpy From: Justin Stitt To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Xu Panda , Justin Stitt Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Thu, 14 Sep 2023 11:08:52 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1777078178716129434 X-GMAIL-MSGID: 1777078178716129434 `strncpy` is deprecated for use on NUL-terminated destination strings [1]. We should prefer more robust and less ambiguous string interfaces. A suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer and doesn't incur the performance loss of unnecessarily NUL-padding. Link: https://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 Cc: Xu Panda Signed-off-by: Justin Stitt --- This patch is basically a resend of [1] by Xu but rebased onto mainline. This patch is also similar to: commit 0f9aa074c92dd ("drm/modes: Use strscpy() to copy command-line mode name") [1]: https://lore.kernel.org/all/202212051935289159302@zte.com.cn/ --- drivers/gpu/drm/drm_modes.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- base-commit: 3669558bdf354cd352be955ef2764cde6a9bf5ec change-id: 20230914-strncpy-drivers-gpu-drm-drm_modes-c-a35d782cad01 Best regards, -- Justin Stitt diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c index ac9a406250c5..c702a8b866cf 100644 --- a/drivers/gpu/drm/drm_modes.c +++ b/drivers/gpu/drm/drm_modes.c @@ -2617,8 +2617,7 @@ void drm_mode_convert_to_umode(struct drm_mode_modeinfo *out, break; } - strncpy(out->name, in->name, DRM_DISPLAY_MODE_LEN); - out->name[DRM_DISPLAY_MODE_LEN-1] = 0; + strscpy(out->name, in->name, DRM_DISPLAY_MODE_LEN); } /** @@ -2659,8 +2658,7 @@ int drm_mode_convert_umode(struct drm_device *dev, * useful for the kernel->userspace direction anyway. */ out->type = in->type & DRM_MODE_TYPE_ALL; - strncpy(out->name, in->name, DRM_DISPLAY_MODE_LEN); - out->name[DRM_DISPLAY_MODE_LEN-1] = 0; + strscpy(out->name, in->name, DRM_DISPLAY_MODE_LEN); /* Clearing picture aspect ratio bits from out flags, * as the aspect-ratio information is not stored in