From patchwork Thu Oct 19 18:21:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Stitt X-Patchwork-Id: 13429639 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 9B3D332C90 for ; Thu, 19 Oct 2023 18:21:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="UlxO7jfJ" Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3397911D for ; Thu, 19 Oct 2023 11:21:24 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-d86dac81f8fso12038746276.1 for ; Thu, 19 Oct 2023 11:21:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1697739683; x=1698344483; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=d4Js1cGoVd6Is4II9UaSATIKgACWkFcGE+hiHb+zhb4=; b=UlxO7jfJT7LrfqoagBtOhuJDKklt5UatDzxoL19uExnG3cHnbhVlAteA8K+lq02Oak dWEfb5nmtOerLFmeSsKEkQag+GAyLAycW9koeRTLFwOEbvIQRHLcY4wAly7fJoAmBk1L Y7C3fOlOdIXERSKauJTLIvPRvu0hKm7itahJNkLNu39jtxbL1yEunOBXMJbZBCm99yPK +JZmI6xScf3C7E4CXYZBnWj7fUBGNSyaHk0sN5uk2I5WmAJwxfrQfSoGmt+C/MNtNHZs cl1adaMhd5QgbswD6DIPUXRI2DaHdgPX370WE7OhwZf9uDvCX/Ctb4puB+id2KI07K76 Y1TA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697739683; x=1698344483; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=d4Js1cGoVd6Is4II9UaSATIKgACWkFcGE+hiHb+zhb4=; b=cLbj/6uF2LHBdJJN7k6JcXDZ9fTHkTpfGdVj9uBhnQhlkJc0lJ1H3nB9308pUmBpqC k/og+2RlXPtw9QctY+DN1hrdZmY9FnHg0fmzm37TmuOfZp7+RovG7mmZaT3HYujNcEJs cNJZUV9rqmIE0h9ERAXOLkpZF1OHL6nsa0ZZZxVy0I7uzkq/3N67fbugw5HTPAfr4WIb YbUHlyCQUAqyv4b+a9XG1wmm1Lfh4Ti3IPaucP5SBKhuLZI3qt8jrHfy8oeHjIIiWtPl ZZKlwzzQJGgpOTeh675ROjEYbmziW16gMxNHg1GCRmR9huxElScslGCxq6mJF0lH3xEw QEHA== X-Gm-Message-State: AOJu0Yzbe6WudV66BBtZfDHl+SjDGtv+c6wb61GWmmtykp9R8G1CMO+a cyUhB8z+Svq5ojbIJwEw9rtEmCV02wP9moGisA== X-Google-Smtp-Source: AGHT+IFlXICmJcfbDSmoO7A7EUA6iVEF74betNl2k852/gxnaf3TEuSWEbGfjZQ7BNIH7NpUBEkFg+ungfm4ArnZtQ== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a25:ec02:0:b0:d9a:3dac:6c1a with SMTP id j2-20020a25ec02000000b00d9a3dac6c1amr73575ybh.11.1697739683357; Thu, 19 Oct 2023 11:21:23 -0700 (PDT) Date: Thu, 19 Oct 2023 18:21:22 +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=H4sIAKFzMWUC/52NSwqDMBRFt1Iy7iv5iJaOuo8iEuIzBjSRlxAr4 t4bXUJn99zBOTuLSA4je912RphddMEXkPcbM6P2FsH1hZnkUgkunhATebNs0JPLSBE8JlhX7YG WOdrunJ1JNIEBNdSSaz30StasCBfCwX2v2KctPLqYAm1XO4vz/SuTBQioUFVKNlw1Sr9tCHbCh wkza4/j+AHiV2SL5QAAAA== X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1697739682; l=2821; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=fmlQfhWbiCM67LS2nuJX0KI/1NzFMdegLgKJe+cta+Q=; b=wDUtP3Ror/d2KFXBRlN9RT2CDGzEW5TDMAgY6ZpEV6DYbx7hZuns1er9Wb2wR7lXEPmqCtncN RTkxhUuMmpTDTdSDV0A6ncnIw87LXyDFbMHjm6T7oMQfm5T/3jQHUTh X-Mailer: b4 0.12.3 Message-ID: <20231019-strncpy-drivers-net-wwan-rpmsg_wwan_ctrl-c-v2-1-ecf9b5a39430@google.com> Subject: [PATCH v2] net: wwan: replace deprecated strncpy with strscpy From: Justin Stitt To: Stephan Gerhold , Loic Poulain , Sergey Ryazanov , Johannes Berg , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt , Kees Cook 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 chinfo.name to be NUL-terminated based on its use with format strings and sprintf: rpmsg/rpmsg_char.c 165: dev_err(dev, "failed to open %s\n", eptdev->chinfo.name); 368: return sprintf(buf, "%s\n", eptdev->chinfo.name); ... and with strcmp(): | static struct rpmsg_endpoint *qcom_glink_create_ept(struct rpmsg_device *rpdev, | rpmsg_rx_cb_t cb, | void *priv, | struct rpmsg_channel_info | chinfo) | ... | const char *name = chinfo.name; | ... | if (!strcmp(channel->name, name)) Since chinfo is initialized as such (just above the strscpy()): | struct rpmsg_channel_info chinfo = { | .src = rpwwan->rpdev->src, | .dst = RPMSG_ADDR_ANY, | }; ... we know other members are zero-initialized. This means no NUL-padding is required (as any NUL-byte assignments are redundant). Considering the above, a suitable replacement is `strscpy` due to the fact that it guarantees NUL-termination on the destination buffer without unnecessarily NUL-padding. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt Reviewed-by: Kees Cook --- Changes in v2: - clarify chinfo _is_ zero-init'd in commit msg (thanks Stephan) - use strscpy instead (thanks Kees, Stephan) - Link to v1: https://lore.kernel.org/r/20231018-strncpy-drivers-net-wwan-rpmsg_wwan_ctrl-c-v1-1-4e343270373a@google.com --- Note: found with grep Note: build-tested only I've rolled Kees' RB into this patch from v1 as it matches his previous review. --- drivers/net/wwan/rpmsg_wwan_ctrl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- base-commit: 58720809f52779dc0f08e53e54b014209d13eebb change-id: 20231018-strncpy-drivers-net-wwan-rpmsg_wwan_ctrl-c-3f620aafd326 Best regards, -- Justin Stitt diff --git a/drivers/net/wwan/rpmsg_wwan_ctrl.c b/drivers/net/wwan/rpmsg_wwan_ctrl.c index 86b60aadfa11..26756ff0e44d 100644 --- a/drivers/net/wwan/rpmsg_wwan_ctrl.c +++ b/drivers/net/wwan/rpmsg_wwan_ctrl.c @@ -37,7 +37,7 @@ static int rpmsg_wwan_ctrl_start(struct wwan_port *port) .dst = RPMSG_ADDR_ANY, }; - strncpy(chinfo.name, rpwwan->rpdev->id.name, RPMSG_NAME_SIZE); + strscpy(chinfo.name, rpwwan->rpdev->id.name, sizeof(chinfo.name)); rpwwan->ept = rpmsg_create_ept(rpwwan->rpdev, rpmsg_wwan_ctrl_callback, rpwwan, chinfo); if (!rpwwan->ept)