From patchwork Mon Dec 11 19:10:00 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Stitt X-Patchwork-Id: 13488007 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="DXZXHnvW" Received: from mail-oa1-x49.google.com (mail-oa1-x49.google.com [IPv6:2001:4860:4864:20::49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1019DCD for ; Mon, 11 Dec 2023 11:10:04 -0800 (PST) Received: by mail-oa1-x49.google.com with SMTP id 586e51a60fabf-1fb1c742f0bso7396752fac.0 for ; Mon, 11 Dec 2023 11:10:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1702321803; x=1702926603; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=pLJuiH0afxkaD2YOLBf8rgHfrGxhKASBgMKSWQ9l3mE=; b=DXZXHnvWDv1GI9kRvrmRjIx3m4w0oTSRYgeKHGm4CwXW/tMsCg/+wi861aOf8Sgf7R EfwTiB/u9o3jZYKgDVsLxHNgoQlclQM8Q9oB2zjj5uP4WXafk+AAS5w+1+rZiHLy/VMd yGJ8WGJCdPYaYy8b+Q1fIKmxwoAXQO9go0xtIkcpYXffAdyTq+ClrG7If+nEbURcov3C YN2iqYt/ymSkBL3b4QVuHaqOGyIEq/g1vuaoytBAYcizwy1flPTYkStBjKadZ72tn58F igw70YImFR9E7k68vHr0d4oO9CRbDgPHldWj4Zqr9wj4cD4E9BAQGxFmfswK9wtX1Ng5 EZ8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702321803; x=1702926603; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=pLJuiH0afxkaD2YOLBf8rgHfrGxhKASBgMKSWQ9l3mE=; b=E4ngeDna3YrfwIc36g7Xeghx1V9kz2x8EfoZ4tsmKfGA85Cj1TZaXGxiAmDFN0iyZL 0dvT2caQg0ShB3wTL0NnCw2jEUGWbzuctjx8WlKIiz3+3FnnuxKJNxydXUST5PjM4azc LrJ3CqlZwiUSlBoUtYU4wjBDx5n6Jcfn7aagjZKx7+oyc8E2G0i8NeUZZeuzwSyyR3GI /1jmxxlcN75hxKuTUWXN6xPcHUl7dW7ECcTgW1st3A/veGYCXTdXsQtziSl4Ex/5S6wn h7JaZ284RqET/x92SKe2iNhigzoChQChkudezKxAB+4nNHmjU2cHcz4XSbPwHNu2eZGR jWZw== X-Gm-Message-State: AOJu0YwUtnhY8ztRQ06CCBfCveCc8qcXra7LAsSMuwc90+iDXQ32qNol Et4PpjoPN/d6kqJPjK2TinhAzhEZrmpumiyCgQ== X-Google-Smtp-Source: AGHT+IHvKqZP7f3jQfiI7xCBWbc5qtLEWaeWmYvrD28lL4j/tV/o+OHKvd7szRecAtwyGcYAOPdL5mAJDugJ7cETuQ== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a05:6870:e415:b0:1fb:1176:50ff with SMTP id n21-20020a056870e41500b001fb117650ffmr5427291oag.6.1702321803322; Mon, 11 Dec 2023 11:10:03 -0800 (PST) Date: Mon, 11 Dec 2023 19:10:00 +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=H4sIAIded2UC/5WNvQrCMBRGX0UyG8kPVuvke4hDc+9tGrBJSUqwl L67aR3ETZcPzjecM7NE0VFil93MImWXXPAF9H7HoGu8Je6wMFNCaSmk4mmMHoaJY3SZYuKeRt6 jC++xQxngBhFrQgGVFqyohkite26Z271w59IY4rRVs1zfPwNZcskbUxtRQQvYmKsNwT7oAKFna yGrj1WJ049WVaygznhUiBpb+rIuy/ICm7kPhi8BAAA= X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1702321802; l=2882; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=eLgUSsGRn6KvttCFjRNfTegIE4/MfMaKpVwBfZ9Mjyw=; b=4k3Sy8wCNWvA4Zo9ZylXCECbUz9MlMkk4n1/lpfkHH9mPOzfccsgiWsA7pNu7eVmRvk5OA8R3 ZGAN8m2trIxBVgmT/c0T+5IdaK9w5hrN5MwA5ExGe5c9OEfdps0SHAN X-Mailer: b4 0.12.3 Message-ID: <20231211-strncpy-drivers-net-mdio-mdio-gpio-c-v3-1-76dea53a1a52@google.com> Subject: [PATCH v3] net: mdio-gpio: replace deprecated strncpy with strscpy From: Justin Stitt To: Andrew Lunn , Heiner Kallweit , Russell King , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: netdev@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 new_bus->id to be NUL-terminated but not NUL-padded based on its prior assignment through snprintf: | snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id); Due to this, a suitable replacement is `strscpy` [2] due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. We can also use sizeof() instead of a length macro as this more closely ties the maximum buffer size to the destination buffer. Do this for two instances. 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 Signed-off-by: Justin Stitt Reviewed-by: Russell King (Oracle) Reviewed-by: Kees Cook --- Changes in v3: - swap another instance of MII_BUS_ID_SIZE to sizeof() (thanks Russell) - rebase onto mainline bee0e7762ad2c602 - Link to v2: https://lore.kernel.org/r/20231207-strncpy-drivers-net-mdio-mdio-gpio-c-v2-1-c28d52dd3dfe@google.com Changes in v2: - change subject line as it was causing problems in patchwork with "superseded" label being improperly applied. - update commit msg with rationale around sizeof() (thanks Kees) - Link to v1 (lore): https://lore.kernel.org/r/20231012-strncpy-drivers-net-mdio-mdio-gpio-c-v1-1-ab9b06cfcdab@google.com - Link to v1 (patchwork): https://patchwork.kernel.org/project/netdevbpf/patch/20231012-strncpy-drivers-net-mdio-mdio-gpio-c-v1-1-ab9b06cfcdab@google.com/ - Link to other patch with same subject message: https://patchwork.kernel.org/project/netdevbpf/patch/20231012-strncpy-drivers-net-phy-mdio_bus-c-v1-1-15242e6f9ec4@google.com/ --- Note: build-tested only. Found with: $ rg "strncpy\(" --- drivers/net/mdio/mdio-gpio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- base-commit: bee0e7762ad2c6025b9f5245c040fcc36ef2bde8 change-id: 20231012-strncpy-drivers-net-mdio-mdio-gpio-c-bddd9ed0c630 Best regards, -- Justin Stitt diff --git a/drivers/net/mdio/mdio-gpio.c b/drivers/net/mdio/mdio-gpio.c index 897b88c50bbb..778db310a28d 100644 --- a/drivers/net/mdio/mdio-gpio.c +++ b/drivers/net/mdio/mdio-gpio.c @@ -123,9 +123,9 @@ static struct mii_bus *mdio_gpio_bus_init(struct device *dev, new_bus->parent = dev; if (bus_id != -1) - snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id); + snprintf(new_bus->id, sizeof(new_bus->id), "gpio-%x", bus_id); else - strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE); + strscpy(new_bus->id, "gpio", sizeof(new_bus->id)); if (pdata) { new_bus->phy_mask = pdata->phy_mask;