From owner-svn-src-head@freebsd.org Mon Oct 26 16:42:54 2020 Return-Path: Delivered-To: svn-src-head@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 5F08244968C; Mon, 26 Oct 2020 16:42:54 +0000 (UTC) (envelope-from vangyzen@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) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 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 4CKgcZ1rJRz4SgQ; Mon, 26 Oct 2020 16:42:54 +0000 (UTC) (envelope-from vangyzen@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 22C6F1D351; Mon, 26 Oct 2020 16:42:54 +0000 (UTC) (envelope-from vangyzen@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 09QGgraj087490; Mon, 26 Oct 2020 16:42:53 GMT (envelope-from vangyzen@FreeBSD.org) Received: (from vangyzen@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 09QGgr2R087489; Mon, 26 Oct 2020 16:42:53 GMT (envelope-from vangyzen@FreeBSD.org) Message-Id: <202010261642.09QGgr2R087489@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: vangyzen set sender to vangyzen@FreeBSD.org using -f From: Eric van Gyzen Date: Mon, 26 Oct 2020 16:42:53 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r367059 - head/sys/ddb X-SVN-Group: head X-SVN-Commit-Author: vangyzen X-SVN-Commit-Paths: head/sys/ddb X-SVN-Commit-Revision: 367059 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 26 Oct 2020 16:42:54 -0000 Author: vangyzen Date: Mon Oct 26 16:42:53 2020 New Revision: 367059 URL: https://svnweb.freebsd.org/changeset/base/367059 Log: db_search_symbol: prevent pollution from bogus symbols The kernel will never map the first page, so any symbols in that range cannot refer to addresses. Some third-party assembly files define internal constants which appear in their symbol table. Avoiding the lookup for those symbols avoids replacing small offsets with those symbols during disassembly. Reported by: Anton Rang Reviewed by: Anton Rang , markj MFC after: 2 weeks Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D26895 Modified: head/sys/ddb/db_sym.c Modified: head/sys/ddb/db_sym.c ============================================================================== --- head/sys/ddb/db_sym.c Mon Oct 26 13:24:20 2020 (r367058) +++ head/sys/ddb/db_sym.c Mon Oct 26 16:42:53 2020 (r367059) @@ -371,8 +371,21 @@ db_search_symbol(db_addr_t val, db_strategy_t strategy unsigned int diff; size_t newdiff; int i; - c_db_sym_t ret = C_DB_SYM_NULL, sym; + c_db_sym_t ret, sym; + /* + * The kernel will never map the first page, so any symbols in that + * range cannot refer to addresses. Some third-party assembly files + * define internal constants which appear in their symbol table. + * Avoiding the lookup for those symbols avoids replacing small offsets + * with those symbols during disassembly. + */ + if (val < PAGE_SIZE) { + *offp = 0; + return (C_DB_SYM_NULL); + } + + ret = C_DB_SYM_NULL; newdiff = diff = val; for (i = 0; i < db_nsymtab; i++) { sym = X_db_search_symbol(&db_symtabs[i], val, strategy, &newdiff);