From owner-svn-src-all@freebsd.org Thu Sep 12 13:51:44 2019 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 75500F6DDD; Thu, 12 Sep 2019 13:51:44 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46TgDJ2ZKNz4Hjl; Thu, 12 Sep 2019 13:51:44 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 3B76C1F99E; Thu, 12 Sep 2019 13:51:44 +0000 (UTC) (envelope-from kevans@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id x8CDpi07038289; Thu, 12 Sep 2019 13:51:44 GMT (envelope-from kevans@FreeBSD.org) Received: (from kevans@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id x8CDpi9r038288; Thu, 12 Sep 2019 13:51:44 GMT (envelope-from kevans@FreeBSD.org) Message-Id: <201909121351.x8CDpi9r038288@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kevans set sender to kevans@FreeBSD.org using -f From: Kyle Evans Date: Thu, 12 Sep 2019 13:51:44 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r352244 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: kevans X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 352244 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 12 Sep 2019 13:51:44 -0000 Author: kevans Date: Thu Sep 12 13:51:43 2019 New Revision: 352244 URL: https://svnweb.freebsd.org/changeset/base/352244 Log: kenv: assert that an empty static buffer passed in is "empty" Garbage in the passed-in buffer can cause problems if any attempts to read the kenv are inadvertently made between init_static_kenv and the first kern_setenv -- assuming there is one. This is cheap and easy, so do it. This also helps rule out some class of bugs as one tries to debug; tunables fetch from the static environment up until SI_SUB_KMEM + 1, and many of these buffers are global ~4k buffers that rely on BSS clearing while others just grab a page of free memory and use it (e.g. xen). Modified: head/sys/kern/kern_environment.c Modified: head/sys/kern/kern_environment.c ============================================================================== --- head/sys/kern/kern_environment.c Thu Sep 12 12:33:09 2019 (r352243) +++ head/sys/kern/kern_environment.c Thu Sep 12 13:51:43 2019 (r352244) @@ -250,6 +250,8 @@ init_static_kenv(char *buf, size_t len) char *eval; KASSERT(!dynamic_kenv, ("kenv: dynamic_kenv already initialized")); + KASSERT(len == 0 || *buf == '\0', + ("kenv: sized buffer must be initially empty")); /* * We may be called twice, with the second call needed to relocate