From mboxrd@z Thu Jan 1 00:00:00 1970 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 CB5EDC4167D for ; Mon, 30 Oct 2023 17:20:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233557AbjJ3RUy (ORCPT ); Mon, 30 Oct 2023 13:20:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229587AbjJ3RUw (ORCPT ); Mon, 30 Oct 2023 13:20:52 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A63FF8E; Mon, 30 Oct 2023 10:20:48 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3464BC433C8; Mon, 30 Oct 2023 17:20:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698686448; bh=J/BDKDmt4ytWYut9+XphDd+OA2xYRaH3LWnmAbLoFQE=; h=Subject:From:In-Reply-To:References:To:Cc:Date:From; b=Rde9Dv9j3N672wNfHkJUA0SIvXLKmsAIx2651HHsMohDpXIk6yRPthyTABuWJqL7w f5Ap7RlKuHXOqxPJmFFyk+TfPHMGPnmRezQAwe6eWsZR0WZ2rOW7e+Hmn2Gr2YRDad Q/DAoBJ6qX62/83GIuNVYlNHJx3OpOm5E2PRmI/wd5w1ZSeOd96daq/Drl1bLvIuT5 VbVMISEFqX6DH1gdc70xHkV4OHXJZgEQknZ/IbYQhemtpNBXaQNvwjqxTyGzrtjn3u 1KJvTE8ELQVZJDfDOK8NiBz4C/ngUgWlVV0tvfOTRI7Rj7RSMcWMFuvoTr0vNlIyzY ro/6w+2ZpJemA== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [PATCH v3 1/2] wifi: brcm80211: replace deprecated strncpy with strscpy From: Kalle Valo In-Reply-To: <20231017-strncpy-drivers-net-wireless-broadcom-brcm80211-brcmfmac-cfg80211-c-v3-1-af780d74ae38@google.com> References: <20231017-strncpy-drivers-net-wireless-broadcom-brcm80211-brcmfmac-cfg80211-c-v3-1-af780d74ae38@google.com> To: Justin Stitt Cc: Arend van Spriel , Franky Lin , Hante Meuleman , linux-wireless@vger.kernel.org, brcm80211-dev-list.pdl@broadcom.com, SHA-cyfmac-dev-list@infineon.com, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, Justin Stitt User-Agent: pwcli/0.1.1-git (https://github.com/kvalo/pwcli/) Python/3.11.2 Message-ID: <169868644429.1993746.5520695482478737730.kvalo@kernel.org> Date: Mon, 30 Oct 2023 17:20:45 +0000 (UTC) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Justin Stitt wrote: > Let's move away from using strncpy and instead favor a less ambiguous > and more robust interface. > > For ifp->ndev->name, we expect ifp->ndev->name to be NUL-terminated based > on its use in format strings within core.c: > 67 | char *brcmf_ifname(struct brcmf_if *ifp) > 68 | { > 69 | if (!ifp) > 70 | return ""; > 71 | > 72 | if (ifp->ndev) > 73 | return ifp->ndev->name; > 74 | > 75 | return ""; > 76 | } > ... > 288 | static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb, > 289 | struct net_device *ndev) { > ... > 330 | brcmf_dbg(INFO, "%s: insufficient headroom (%d)\n", > 331 | brcmf_ifname(ifp), head_delta); > ... > 336 | bphy_err(drvr, "%s: failed to expand headroom\n", > 337 | brcmf_ifname(ifp)); > > For di->name, we expect di->name to be NUL-terminated based on its usage > with format strings: > | brcms_dbg_dma(di->core, > | "%s: DMA64 tx doesn't have AE set\n", > | di->name); > > Looking at its allocation we can see that it is already zero-allocated > which means NUL-padding is not required: > | di = kzalloc(sizeof(struct dma_info), GFP_ATOMIC); > > For wlc->modulecb[i].name, we expect each name in wlc->modulecb to be > NUL-terminated based on their usage with strcmp(): > | if (!strcmp(wlc->modulecb[i].name, name) && > > NUL-padding is not required as wlc is zero-allocated in: > brcms_c_attach_malloc() -> > | wlc = kzalloc(sizeof(struct brcms_c_info), GFP_ATOMIC); > > For all these cases, a suitable replacement is `strscpy` due to the fact > that it guarantees NUL-termination on the destination buffer without > unnecessarily NUL-padding. > > Signed-off-by: Justin Stitt > Reviewed-by: Kees Cook 2 patches applied to wireless-next.git, thanks. 9d0d0a207040 wifi: brcm80211: replace deprecated strncpy with strscpy a614f9579705 wifi: brcmsmac: replace deprecated strncpy with memcpy -- https://patchwork.kernel.org/project/linux-wireless/patch/20231017-strncpy-drivers-net-wireless-broadcom-brcm80211-brcmfmac-cfg80211-c-v3-1-af780d74ae38@google.com/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches