From patchwork Fri Oct 20 19:05:25 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Stitt X-Patchwork-Id: 13431040 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 565CA208C2 for ; Fri, 20 Oct 2023 19:05:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="EFIK5Xpz" 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 9B6BB1A8 for ; Fri, 20 Oct 2023 12:05:26 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d9cfec5e73dso663098276.2 for ; Fri, 20 Oct 2023 12:05:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1697828726; x=1698433526; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=kK3RwRQ2hFONySy7vb2rlodkP+v8D8sjNHk/2UXCQCw=; b=EFIK5Xpz+34ho6bGbNYhtTTAOKRNZBChdY961KgaC3rQm/R9jtB1AvVD9VbDC579IH v5hPaBylm71IcYiqZ0IsNY81y1JL5sr8p8XJ2sBt67yQpNdM00Y8ufjUOk0SCqskkQlo or63JBl69lQ/jjoADt39FhCSIV4QLoxVCURrUNrM+1E3+G3n0g5AKOaCD4MVEzkHYfx6 7LhFSQeCc3WnZuAa0KmUIknkrXA4ftNsDH9zJFLAeTcTIsRKYmqm2vE4vo0VPLbqYRdH Xmm61BhkknQDCIdqX1MbUafc537intIJnbpYjGejoo6VJSuQhwpkCj+fZKW2lZc4TS8i C/7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697828726; x=1698433526; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=kK3RwRQ2hFONySy7vb2rlodkP+v8D8sjNHk/2UXCQCw=; b=XgTWcxz1EyC4lH81GiXU6cHkZ/bPltUvXqGHtpWVrzqzC6j43cO5O9yF6kujAmHdzf Ct2vmKnY3W19nN5HOx8TiTDcw/WqkwAO51SKpLDugurBXk1b4nfkVo0AYdlnGn1zO2O+ o3EyJSvLHPQzqQHrm9XmrXQukWyKc/HNbAgrsKt8L5fGh9OuHPNd96hrEwTmvqy9u8Ms 7F5cMk88gRboDZuBiV6rHseMgz5XTvdVuNAjjSivM7AFkcuBrbLC6bZZU0vboP+w+/9u sv28vlpVS16qOQIIckjnP4S4uayl3ppP1fE8Hboncs3ERcahE7AutC6ltZEaYt0NwNeG 2bsw== X-Gm-Message-State: AOJu0YzH2c0QAbwhSmosqCe4H3QQ9w9YjGwocZk0lVhi9OxOKsgA14kF BvpjctzteKD/cXmyrQGKk1Q6mshYuM/5mQznBw== X-Google-Smtp-Source: AGHT+IFIgFCUI8HjqfIf+Tklc39JbTp6ZaF/+XXlfiROC7bIg7hcKRNqFinXZ9QpU3wT9cqFbgb/bHQiEOBuCbThNA== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a25:d34e:0:b0:d9a:e3d9:99bd with SMTP id e75-20020a25d34e000000b00d9ae3d999bdmr52155ybf.5.1697828725873; Fri, 20 Oct 2023 12:05:25 -0700 (PDT) Date: Fri, 20 Oct 2023 19:05:25 +0000 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAHTPMmUC/x2NUQrCQAwFr1LybWC70kW9iojYbawB2cZE65bSu xv8nAfzZgUjZTI4NSsozWw8FYd210B+3MpIyIMzxBD3bYgB7a0ly4KD8kxqKNOXFO0j8lywf8U u1Xp1VUefM/aUjrk7pBApgZ+K0p3rP3i+bNsPsPSlOYAAAAA= X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1697828724; l=2863; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=T9L+60rFiC2C22tjDxmZadYML+C8IPdvUbMCCZ+8ZV8=; b=g+KZD1lwFHNJ1xFiRWb7uqcL0Z5bEAbJH48+DOSAsG+RzN1Fpq+/0v1gC/I3Gh+CXpoyvlGbm 8FNycQ/9sVEB7z1Ag9/AEX/GrjaQo1VSyvG8K+T824uWpGW7D3fSaty X-Mailer: b4 0.12.3 Message-ID: <20231020-strncpy-drivers-power-supply-bq256xx_charger-c-v1-1-2fad856124f9@google.com> Subject: [PATCH] power: supply: bq256xx: replace deprecated strncpy with strscpy From: Justin Stitt To: Sebastian Reichel Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt strncpy() is deprecated for use on NUL-terminated destination strings [1] and as such we should prefer more robust and less ambiguous string interfaces. We expect bq->model_name to be NUL-terminated based on its usage with sysfs_emit and format strings: val->strval is assigned to bq->model_name in bq256xx_get_charger_property(): | val->strval = bq->model_name; ... then in power_supply_sysfs.c we use value.strval with a format string: | ret = sysfs_emit(buf, "%s\n", value.strval); we assigned value.strval via: | ret = power_supply_get_property(psy, psp, &value); ... which invokes psy->desc->get_property(): | return psy->desc->get_property(psy, psp, val); with bq256xx_get_charger_property(): | static const struct power_supply_desc bq256xx_power_supply_desc = { ... | .get_property = bq256xx_get_charger_property, Moreover, no NUL-padding is required as bq is zero-allocated in bq256xx_charger.c: | bq = devm_kzalloc(dev, sizeof(*bq), GFP_KERNEL); Considering the above, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. Let's also opt to use the more idiomatic strscpy() usage of (dest, src, sizeof(dest)) as this more closely ties the destination buffer and the length. 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 Similar-to: https://lore.kernel.org/all/20231020-strncpy-drivers-power-supply-bq24190_charger-c-v1-1-e896223cb795@google.com/ Similar-to: https://lore.kernel.org/all/20231020-strncpy-drivers-power-supply-bq2515x_charger-c-v1-1-46664c6edf78@google.com/ Signed-off-by: Justin Stitt Reviewed-by: Kees Cook --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/power/supply/bq256xx_charger.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: bb55d7f7f7445abcc8db50e6a65d4315e79f75c7 change-id: 20231020-strncpy-drivers-power-supply-bq256xx_charger-c-be69c58602e6 Best regards, -- Justin Stitt diff --git a/drivers/power/supply/bq256xx_charger.c b/drivers/power/supply/bq256xx_charger.c index 82d3cd5ee2f9..85e1185275b9 100644 --- a/drivers/power/supply/bq256xx_charger.c +++ b/drivers/power/supply/bq256xx_charger.c @@ -1706,7 +1706,7 @@ static int bq256xx_probe(struct i2c_client *client) mutex_init(&bq->lock); - strncpy(bq->model_name, id->name, I2C_NAME_SIZE); + strscpy(bq->model_name, id->name, sizeof(bq->model_name)); bq->regmap = devm_regmap_init_i2c(client, bq->chip_info->bq256xx_regmap_config);