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 X-Spam-Level: X-Spam-Status: No, score=-19.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D7F0CC2B9F0 for ; Wed, 5 May 2021 16:54:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B41F261431 for ; Wed, 5 May 2021 16:54:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236975AbhEEQzT (ORCPT ); Wed, 5 May 2021 12:55:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:49544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235623AbhEEQqu (ORCPT ); Wed, 5 May 2021 12:46:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3F33F610FB; Wed, 5 May 2021 16:36:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1620232600; bh=4SUyrWMklPhz6u+2+ZQbOuVSYJvmj9deWcfZDult3CM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=owPyY2PKK7qkXDN5bARnSR4Zo0Y4QvnFqjkd5LSQA1b3KArPm+erZfByr/2+cZfOM wpN3h28QQsdCBmfmAN6FFJEUNFwkpdPuoAv38L3HN/zG+gfDoRJxoqNXFtb7kA2aVG XhZh/zd+CD4u1oyLTxnJoZEJpbZwQtOxoLfCovP5y59//Tl3ZTxJBMAiqbDbPakytp WDF3/vqOkM5IIjHpY/XLZgso7PEha/jJczMeA3c4/ztzjSt5XgPG8oxT9ZzQALCMj/ z4XiONvjndSFkGM3bzQbvVIsKftgj5i9n/QgXQXyBMGJm3mYcsBeA315wDHVsHkL3i L+Pf6PMAnBzsQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sergei Trofimovich , Andrew Morton , Linus Torvalds , Sasha Levin , linux-ia64@vger.kernel.org Subject: [PATCH AUTOSEL 5.11 100/104] ia64: module: fix symbolizer crash on fdescr Date: Wed, 5 May 2021 12:34:09 -0400 Message-Id: <20210505163413.3461611-100-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210505163413.3461611-1-sashal@kernel.org> References: <20210505163413.3461611-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sergei Trofimovich [ Upstream commit 99e729bd40fb3272fa4b0140839d5e957b58588a ] Noticed failure as a crash on ia64 when tried to symbolize all backtraces collected by page_owner=on: $ cat /sys/kernel/debug/page_owner CPU: 1 PID: 2074 Comm: cat Not tainted 5.12.0-rc4 #226 Hardware name: hp server rx3600, BIOS 04.03 04/08/2008 ip is at dereference_module_function_descriptor+0x41/0x100 Crash happens at dereference_module_function_descriptor() due to use-after-free when dereferencing ".opd" section header. All section headers are already freed after module is laoded successfully. To keep symbolizer working the change stores ".opd" address and size after module is relocated to a new place and before section headers are discarded. To make similar errors less obscure module_finalize() now zeroes out all variables relevant to module loading only. Link: https://lkml.kernel.org/r/20210403074803.3309096-1-slyfox@gentoo.org Signed-off-by: Sergei Trofimovich Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- arch/ia64/include/asm/module.h | 6 +++++- arch/ia64/kernel/module.c | 29 +++++++++++++++++++++++++---- 2 files changed, 30 insertions(+), 5 deletions(-) diff --git a/arch/ia64/include/asm/module.h b/arch/ia64/include/asm/module.h index 5a29652e6def..7271b9c5fc76 100644 --- a/arch/ia64/include/asm/module.h +++ b/arch/ia64/include/asm/module.h @@ -14,16 +14,20 @@ struct elf64_shdr; /* forward declration */ struct mod_arch_specific { + /* Used only at module load time. */ struct elf64_shdr *core_plt; /* core PLT section */ struct elf64_shdr *init_plt; /* init PLT section */ struct elf64_shdr *got; /* global offset table */ struct elf64_shdr *opd; /* official procedure descriptors */ struct elf64_shdr *unwind; /* unwind-table section */ unsigned long gp; /* global-pointer for module */ + unsigned int next_got_entry; /* index of next available got entry */ + /* Used at module run and cleanup time. */ void *core_unw_table; /* core unwind-table cookie returned by unwinder */ void *init_unw_table; /* init unwind-table cookie returned by unwinder */ - unsigned int next_got_entry; /* index of next available got entry */ + void *opd_addr; /* symbolize uses .opd to get to actual function */ + unsigned long opd_size; }; #define ARCH_SHF_SMALL SHF_IA_64_SHORT diff --git a/arch/ia64/kernel/module.c b/arch/ia64/kernel/module.c index 00a496cb346f..2cba53c1da82 100644 --- a/arch/ia64/kernel/module.c +++ b/arch/ia64/kernel/module.c @@ -905,9 +905,31 @@ register_unwind_table (struct module *mod) int module_finalize (const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *mod) { + struct mod_arch_specific *mas = &mod->arch; + DEBUGP("%s: init: entry=%p\n", __func__, mod->init); - if (mod->arch.unwind) + if (mas->unwind) register_unwind_table(mod); + + /* + * ".opd" was already relocated to the final destination. Store + * it's address for use in symbolizer. + */ + mas->opd_addr = (void *)mas->opd->sh_addr; + mas->opd_size = mas->opd->sh_size; + + /* + * Module relocation was already done at this point. Section + * headers are about to be deleted. Wipe out load-time context. + */ + mas->core_plt = NULL; + mas->init_plt = NULL; + mas->got = NULL; + mas->opd = NULL; + mas->unwind = NULL; + mas->gp = 0; + mas->next_got_entry = 0; + return 0; } @@ -926,10 +948,9 @@ module_arch_cleanup (struct module *mod) void *dereference_module_function_descriptor(struct module *mod, void *ptr) { - Elf64_Shdr *opd = mod->arch.opd; + struct mod_arch_specific *mas = &mod->arch; - if (ptr < (void *)opd->sh_addr || - ptr >= (void *)(opd->sh_addr + opd->sh_size)) + if (ptr < mas->opd_addr || ptr >= mas->opd_addr + mas->opd_size) return ptr; return dereference_function_descriptor(ptr); -- 2.30.2