From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3308147-1523479616-2-2754083859826771188 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1523479616; b=gyCWomegEMLz6RH/R0KksCZWFxwS7pRczTX7KcqEa0h5pDbPJc zpXdY45jbWqSCunmkLoI+p2AoGATuittkvYFUTmkWjjFhNREr194pI4BbMKpJsKT O7qdfDZ4AABEu6fr6qS5wk4rY2Ur1PMlm4ZZG4zunrLA70NjqdoBpgwToA/b/a4q PVHqh3XWWUI7Ow+gotSnrKhBx7wXRpdBTd+mv6wXe7DVNoOGUtaWsdXRrAdS4ZEB E46CkNi/TghQf0HEeLwZXGds9snRGMO2KWyh1YBDa6lPTRTusMXNjkZi5qvClnEX 9n4wLR39HEX8O8k1AyPG9y22pIv7orQ46+Ug== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1523479616; bh=1mxykoT3mhQoUR0abI+LGV+ZeUJrjZ JkkmqH88UWWMs=; b=PKtD8HVHk9AXdxMrZ7sGoay33TRfIMsfqPErQFrhOmuQmh 0m0rtTpZ6gKmOB3IW7LRe8788CuVOYtHaiQCTauOjWs89Wich2kteNHKBmbNtMPo s2aPK/5h3BQkMEoFGSNzOHqbC63+8yEqpBufTBPQj6pNOar9onlxv7N634gF8CpA nYDS7VupUM6tQJA+KCkaJe6bjtzBJwsilPOp31uMT4JoKFWIH4TucuoMi3Q4Fimb f2Peubm1x0jzpuMqVAZ2o3nSOzUombDoyEhdaNVae6tDHVPVU0wXf3YGzhUoESg8 6Z30MVSYcev/H9G6HvXX4Pk33Jl9MWBm5UBQl5QA== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfAeWQN5LMLcjNB717j/jBLUbF/DXUSvEuwUKmjggAp0d3p7Qm+Ly8UDUuHWgcSbo2fPFcjMu3ruivIpsfkohsKcQ42hD+qVG7bkFN7DwVPKgmxYcevjJ eCPNl8GLkKhXYMfcNtuADTO3a/TaSPuUl/rFnt2zHGbpjA/d6/YqN6ZC2qjwiJEZQ0OSEMo7qH17VQ6UYse9OlGkEtp2faweLYL77qeDftAfS+a4+C1yfjty X-CM-Analysis: v=2.3 cv=FKU1Odgs c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=Kd1tUaAdevIA:10 a=pGLkceISAAAA:8 a=yMhMjlubAAAA:8 a=ag1SF4gXAAAA:8 a=YmcqAzuuD1zigcaGsQ0A:9 a=QEXdDO2ut3YA:10 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755745AbeDKSqi (ORCPT ); Wed, 11 Apr 2018 14:46:38 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58992 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755738AbeDKSqg (ORCPT ); Wed, 11 Apr 2018 14:46:36 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Michael Schmitz , Theodore Tso , Sasha Levin Subject: [PATCH 4.4 073/190] fix race in drivers/char/random.c:get_reg() Date: Wed, 11 Apr 2018 20:35:19 +0200 Message-Id: <20180411183554.555102025@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180411183550.114495991@linuxfoundation.org> References: <20180411183550.114495991@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Schmitz [ Upstream commit 9dfa7bba35ac08a63565d58c454dccb7e1bb0a08 ] get_reg() can be reentered on architectures with prioritized interrupts (m68k in this case), causing f->reg_index to be incremented after the range check. Out of bounds memory access past the pt_regs struct results. This will go mostly undetected unless access is beyond end of memory. Prevent the race by disabling interrupts in get_reg(). Tested on m68k (Atari Falcon, and ARAnyM emulator). Kudos to Geert Uytterhoeven for helping to trace this race. Signed-off-by: Michael Schmitz Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -886,12 +886,16 @@ static void add_interrupt_bench(cycles_t static __u32 get_reg(struct fast_pool *f, struct pt_regs *regs) { __u32 *ptr = (__u32 *) regs; + unsigned long flags; if (regs == NULL) return 0; + local_irq_save(flags); if (f->reg_idx >= sizeof(struct pt_regs) / sizeof(__u32)) f->reg_idx = 0; - return *(ptr + f->reg_idx++); + ptr += f->reg_idx++; + local_irq_restore(flags); + return *ptr; } void add_interrupt_randomness(int irq, int irq_flags)