From patchwork Mon Nov 2 18:55:03 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Elijah Newren X-Patchwork-Id: 11874973 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD9B6C2D0A3 for ; Mon, 2 Nov 2020 18:55:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63DAE22268 for ; Mon, 2 Nov 2020 18:55:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MmVpuPlt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726433AbgKBSzX (ORCPT ); Mon, 2 Nov 2020 13:55:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726162AbgKBSzV (ORCPT ); Mon, 2 Nov 2020 13:55:21 -0500 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B29E4C061A47 for ; Mon, 2 Nov 2020 10:55:19 -0800 (PST) Received: by mail-wr1-x443.google.com with SMTP id b3so9926937wrx.11 for ; Mon, 02 Nov 2020 10:55:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:in-reply-to:references:from:date:subject:fcc :content-transfer-encoding:mime-version:to:cc; bh=IEPGTilWFeb/gYnUiQHEDPP0R8dCTuzsEUTPxGrkZm8=; b=MmVpuPltKb7eA6tjoT/JFGHI30J3q6pQzrOvYQyU1alDdeD0r5Egsla351n7/Zv8kl mhshrusduW/DAkf1hmKb+zel5q5xD0aBsuBl5h20pKyVbdrGoIR54h/SctqX2OucBiIC Dc1yygq+EldB7j9FeL9kBGE13IXaSeUhvJ32TSEcOSNtlhG2gDhBEq1G8TT2glPIf8Jh AlbEoN6bI5+i9mEuqnrXMbONj+6VCLwG6hrtiH9NX2iCcmqFtgfbRFZ9wIYWNrRAijvK IPS5fpGkK4MMEnV8+Zhk2vIkLQvFAt0l/aDZuOCPDUtuJzCNS0wlbih3hAb0WDrpQJZV SbGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:in-reply-to:references:from:date :subject:fcc:content-transfer-encoding:mime-version:to:cc; bh=IEPGTilWFeb/gYnUiQHEDPP0R8dCTuzsEUTPxGrkZm8=; b=X6bghLz/DFfpZ5/tTcqR/jxzHW+a7FT/PhqQ3zHnY0SCH27feGVgoWTnqHjQ0Ptg0c +B7/lbIev/RVV6/Ul6sAfSBp5N8KyStwSkluX1fMBhFQOqN5OOhXBH0Gq0DV2rBHoAMM ceYcQJ/JPKwn2d0bjcD3dfUf4XHpAdm6aAUuE8D8YqyVwvzXHYCXpEYRTK07pakDwdE+ blOVF7+CU2YqGYo65K1nuxVnMhBIAHZP+kdA26BykA+jA463zvres7qq6t4U9gY83lk+ 4CHrzzpvcdL10o7V+hpZBHS8k9/o8viHPIBL9uFjwXOxYEzjt28OvXYo+h+7jlx1SS5t 0Hag== X-Gm-Message-State: AOAM533MRP+570pEBqPuLE7G7UY31oJtXGFjI6APxkhGwNHceEmRjVSv RrufcobUc+npIVQDazcbrQ/ogaCWP4c= X-Google-Smtp-Source: ABdhPJw7xCAmEQXjQJJmOSQa9FZK8C6deNx1wGda0zAcxcIN4Qy6fAAup/Qvi+J2st9RkbhFlV23xA== X-Received: by 2002:adf:fc07:: with SMTP id i7mr16712331wrr.223.1604343318334; Mon, 02 Nov 2020 10:55:18 -0800 (PST) Received: from [127.0.0.1] ([13.74.141.28]) by smtp.gmail.com with ESMTPSA id f13sm23930021wrp.12.2020.11.02.10.55.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Nov 2020 10:55:17 -0800 (PST) Message-Id: In-Reply-To: References: Date: Mon, 02 Nov 2020 18:55:03 +0000 Subject: [PATCH v3 03/13] hashmap: allow re-use after hashmap_free() Fcc: Sent MIME-Version: 1.0 To: git@vger.kernel.org Cc: Jeff King , Elijah Newren , Elijah Newren , Elijah Newren Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Elijah Newren From: Elijah Newren Previously, once map->table had been freed, any calls to hashmap_put(), hashmap_get(), or hashmap_remove() would cause a NULL pointer dereference (since hashmap_free_() also zeros the memory; without that zeroing, calling these functions would cause a use-after-free problem). Modify these functions to check for a NULL table and automatically allocate as needed. Also add a HASHMAP_INIT(fn, data) macro for initializing hashmaps on the stack without calling hashmap_init(). Signed-off-by: Elijah Newren --- hashmap.c | 16 ++++++++++++++-- hashmap.h | 3 +++ 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/hashmap.c b/hashmap.c index e44d8a3e85..bb7c9979b8 100644 --- a/hashmap.c +++ b/hashmap.c @@ -114,6 +114,7 @@ int hashmap_bucket(const struct hashmap *map, unsigned int hash) static void rehash(struct hashmap *map, unsigned int newsize) { + /* map->table MUST NOT be NULL when this function is called */ unsigned int i, oldsize = map->tablesize; struct hashmap_entry **oldtable = map->table; @@ -134,6 +135,7 @@ static void rehash(struct hashmap *map, unsigned int newsize) static inline struct hashmap_entry **find_entry_ptr(const struct hashmap *map, const struct hashmap_entry *key, const void *keydata) { + /* map->table MUST NOT be NULL when this function is called */ struct hashmap_entry **e = &map->table[bucket(map, key)]; while (*e && !entry_equals(map, *e, key, keydata)) e = &(*e)->next; @@ -196,6 +198,8 @@ struct hashmap_entry *hashmap_get(const struct hashmap *map, const struct hashmap_entry *key, const void *keydata) { + if (!map->table) + return NULL; return *find_entry_ptr(map, key, keydata); } @@ -211,8 +215,12 @@ struct hashmap_entry *hashmap_get_next(const struct hashmap *map, void hashmap_add(struct hashmap *map, struct hashmap_entry *entry) { - unsigned int b = bucket(map, entry); + unsigned int b; + + if (!map->table) + alloc_table(map, HASHMAP_INITIAL_SIZE); + b = bucket(map, entry); /* add entry */ entry->next = map->table[b]; map->table[b] = entry; @@ -230,7 +238,11 @@ struct hashmap_entry *hashmap_remove(struct hashmap *map, const void *keydata) { struct hashmap_entry *old; - struct hashmap_entry **e = find_entry_ptr(map, key, keydata); + struct hashmap_entry **e; + + if (!map->table) + return NULL; + e = find_entry_ptr(map, key, keydata); if (!*e) return NULL; diff --git a/hashmap.h b/hashmap.h index 904f61d6e1..3b0f2bcade 100644 --- a/hashmap.h +++ b/hashmap.h @@ -210,6 +210,9 @@ struct hashmap { /* hashmap functions */ +#define HASHMAP_INIT(fn, data) { .cmpfn = fn, .cmpfn_data = data, \ + .do_count_items = 1 } + /* * Initializes a hashmap structure. *