From patchwork Tue Aug 8 22:48:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Justin Stitt X-Patchwork-Id: 13347140 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 8FF7FC04FDF for ; Tue, 8 Aug 2023 22:48:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231544AbjHHWsm (ORCPT ); Tue, 8 Aug 2023 18:48:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36854 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231511AbjHHWsl (ORCPT ); Tue, 8 Aug 2023 18:48:41 -0400 Received: from mail-oo1-xc4a.google.com (mail-oo1-xc4a.google.com [IPv6:2607:f8b0:4864:20::c4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8AEFF106 for ; Tue, 8 Aug 2023 15:48:40 -0700 (PDT) Received: by mail-oo1-xc4a.google.com with SMTP id 006d021491bc7-56d46f0ac4bso8549665eaf.1 for ; Tue, 08 Aug 2023 15:48:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1691534920; x=1692139720; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Pvwje1x+fgK9E9IR7qsfn31Dc5XiXldAZ1Fo1xHQpAo=; b=ZowPnFVAEOQu1o/+XzT8fcaX6DHlVccwrE7gGNHkAx3YDdV+D3o7fUpYyj/vi1Ct5Q +QYJDWnAhftWiK8EgTciXmjxfJNfL1DHfcE3o+XOVVHbUUBr2oc33L84fXDKdg0spibe GZ5bqdG9qrHx/UtSzbaBTMqp6lQxfoXnPa2UM0vLrI7Zb2YiefFjL0pSu/+rNaKy1wlN XhfOQJjCKLo/y7i/PPyKhKK6HKjXtVSpBWc22UEpkQAx89z/FVCmSvgnGCxbk5FjWRbD QKj317GKJBKiDYTXPzGM5v1TxwYmVWI7QXAAaldoX9Tx9r5cTrpz+UfvZC+saxnSr//L 67Hg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691534920; x=1692139720; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Pvwje1x+fgK9E9IR7qsfn31Dc5XiXldAZ1Fo1xHQpAo=; b=SfL4aENpvq7nBEUZD+JfH/2ysCp/hmvxt5frw6XktBVpFEkOUbw2dfJOE+pfHXukS+ liYeCvzIdtYDghtmfC3EjqPkWodSuSbGcg+q357upEUGs0k/qUeOT6PEuAsO4moX2cIK TmXsO3T4bgtdIZj15pOb2EKGiEEFp+pua0lgGqNe+Cob3izJ099GwsskdzD19k0as7k0 NmCuws2y5IgaXHThpgWOOyPURzLVt7UzTrWyQ4+4qGbh+CwzDrp/49+I6+inZ33gBqNF 0mSXmb4+9YwkUKyw58nGRfoX7osYf4dJUQJ3Gm8JDCYz3QdEiVETL1R15y4oJKbfgfOY 9dKA== X-Gm-Message-State: AOJu0YxYHN+aVjVBrc+ORw4qJ6C7VLrw+2Ce/lmEoR0bdrgmQCnTXciq 1FqEGuolJSlqh+clSB3mhpJauqq/jgJTBS8lRg== X-Google-Smtp-Source: AGHT+IFfTapulzyD7mF8uId+U6qhT9W1jzh/xLHutjoQ+baESmwt1nASohgDjGgqfc8DbSFYevzOUew1G7Fcn9bwfg== X-Received: from jstitt-linux1.c.googlers.com ([fda3:e722:ac3:cc00:2b:ff92:c0a8:23b5]) (user=justinstitt job=sendgmr) by 2002:a05:6870:5b03:b0:1bf:a06f:ce6f with SMTP id ds3-20020a0568705b0300b001bfa06fce6fmr315997oab.9.1691534919982; Tue, 08 Aug 2023 15:48:39 -0700 (PDT) Date: Tue, 08 Aug 2023 22:48:11 +0000 In-Reply-To: <20230808-net-netfilter-v1-0-efbbe4ec60af@google.com> Mime-Version: 1.0 References: <20230808-net-netfilter-v1-0-efbbe4ec60af@google.com> X-Developer-Key: i=justinstitt@google.com; a=ed25519; pk=tC3hNkJQTpNX/gLKxTNQKDmiQl6QjBNCGKJINqAdJsE= X-Developer-Signature: v=1; a=ed25519-sha256; t=1691534912; l=1616; i=justinstitt@google.com; s=20230717; h=from:subject:message-id; bh=epcsNlzjLL3K9DAOvrsRp37/1eZVu8TeiuJpMs34l/Q=; b=L1P2cQc3z99LSWR/qio44oxncmlWLIBSvxY6HOu5W2BRo4B41BhDGwuAbcow63n2hPhRjceUI 9E5bGIoGP2nDYAORkqUToKLoCEdCN/nRopReeZhHhL/7pSX4tiOQrrn X-Mailer: b4 0.12.3 Message-ID: <20230808-net-netfilter-v1-6-efbbe4ec60af@google.com> Subject: [PATCH 6/7] netfilter: x_tables: refactor deprecated strncpy From: Justin Stitt To: Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: linux-hardening@vger.kernel.org, Kees Cook , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Justin Stitt Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org Prefer `strscpy` to `strncpy` for use on NUL-terminated destination buffers. This fixes a potential bug due to the fact that both `t->u.user.name` and `name` share the same size. Signed-off-by: Justin Stitt --- Here's an example of what happens when dest and src share same size: | #define MAXLEN 5 | char dest[MAXLEN]; | const char *src = "hello"; | strncpy(dest, src, MAXLEN); // -> should use strscpy() | // dest is now not NUL-terminated --- net/netfilter/x_tables.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/netfilter/x_tables.c b/net/netfilter/x_tables.c index 470282cf3fae..714a38ec9055 100644 --- a/net/netfilter/x_tables.c +++ b/net/netfilter/x_tables.c @@ -768,7 +768,7 @@ void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, m->u.user.match_size = msize; strscpy(name, match->name, sizeof(name)); module_put(match->me); - strncpy(m->u.user.name, name, sizeof(m->u.user.name)); + strscpy(m->u.user.name, name, sizeof(m->u.user.name)); *size += off; *dstptr += msize; @@ -1148,7 +1148,7 @@ void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, t->u.user.target_size = tsize; strscpy(name, target->name, sizeof(name)); module_put(target->me); - strncpy(t->u.user.name, name, sizeof(t->u.user.name)); + strscpy(t->u.user.name, name, sizeof(t->u.user.name)); *size += off; *dstptr += tsize; @@ -2014,4 +2014,3 @@ static void __exit xt_fini(void) module_init(xt_init); module_exit(xt_fini); -