From patchwork Sat Mar 13 09:47:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Vivier X-Patchwork-Id: 1452480 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4DyHv56K6zz9sWC for ; Sat, 13 Mar 2021 20:48:49 +1100 (AEDT) Received: from localhost ([::1]:40870 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lL0t5-0007L3-Rf for incoming@patchwork.ozlabs.org; Sat, 13 Mar 2021 04:48:47 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34016) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lL0sS-0007Ak-5h for qemu-devel@nongnu.org; Sat, 13 Mar 2021 04:48:09 -0500 Received: from mout.kundenserver.de ([217.72.192.73]:39879) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lL0sG-00075v-Ct for qemu-devel@nongnu.org; Sat, 13 Mar 2021 04:48:07 -0500 Received: from localhost.localdomain ([82.142.6.26]) by mrelayeu.kundenserver.de (mreue106 [212.227.15.183]) with ESMTPSA (Nemesis) id 1MadC8-1lsPgJ0oBO-00c5bI; Sat, 13 Mar 2021 10:47:53 +0100 From: Laurent Vivier To: qemu-devel@nongnu.org Subject: [PULL 5/5] linux-user/elfload: fix address calculation in fallback scenario Date: Sat, 13 Mar 2021 10:47:47 +0100 Message-Id: <20210313094747.2966948-6-laurent@vivier.eu> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210313094747.2966948-1-laurent@vivier.eu> References: <20210313094747.2966948-1-laurent@vivier.eu> MIME-Version: 1.0 X-Provags-ID: V03:K1:Ypx7//kkwQSt+PxxQ9JhdJGaZSLCEiDiUl2WnxSxR+hLLc33gA+ 0RLQam29jJrx5LLlSjoRaTBYpcb4Xdf+spy7KbIqFlGH6ZbttBo2le2duDrwG9c6/BtriDx cp6VwlpnNDKR9525BQffmBh90+uZ1ajyUa5T6b7aVa9J1+bfamyK1b/v1ynh22HGe0J46aW ZmhpACJKA2QRzHtxlaadg== X-UI-Out-Filterresults: notjunk:1;V03:K0:l5AvciM7xMA=:/kvJsT7CY/2u4c0Apr5L7a wmgfwXKXkGEzcIZe4Nh9/vAv3Ffyg7Q4i2al5RlPqehai3CSNy/Enhv9phxrtf+hIe9HuAKXk +rKVlH9TPjHGJ637BzPf6ODRVeJxFWoiChvNmt91xljtvMZw5SOUJFSkSmkqGX5M105xUTLnQ Hx/ptlPj80eKiraewcfbBw5p5XjC7TYQrw6y9fVSRfUQAAnYMZz0Tsqi7CsmzsAUuvaCEtNbR wMqX/bza6V0RASCcN0iWg+rAoooxwmDIRoNdL64VjvxjmT/LgHAx+2OMpMHFcQVSyNrGcQYHA VpcAbQEyavA+MsfWhmzp3kAl3GeMFlH6BQ85q/FAlsaT3mcoIJJkWdBGTNj92GOo8cfT0y1Uw t66h7CqVUnpWVw6Q8M5ulC6mqxV4VxRZxhaSjVSUlqPcixKgDfx/RN2GHBRsV0fgDjxWWDV0m CUgbFDJQWA== Received-SPF: none client-ip=217.72.192.73; envelope-from=laurent@vivier.eu; helo=mout.kundenserver.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Vincent Fazio Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Vincent Fazio Previously, guest_loaddr was not taken into account when returning an address from pgb_find_hole when /proc/self/maps was unavailable which caused an improper guest_base address to be calculated. This could cause a SIGSEGV later in load_elf_image -> target_mmap for ET_EXEC type images since the mmap MAP_FIXED flag is specified which could clobber existing mappings at the address returnd by g2h(). mmap(0xd87000, 16846912, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS|MAP_NORESERVE|0x100000, -1, 0) = 0xd87000 munmap(0xd87000, 16846912) = 0 write(2, "Locating guest address space @ 0"..., 40Locating guest address space @ 0xd87000) = 40 mmap(0x1187000, 16850944, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS|MAP_NORESERVE, -1, 0) = 0x1187000 --- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_ACCERR, si_addr=0x2188310} --- +++ killed by SIGSEGV +++ Now, pgd_find_hole accounts for guest_loaddr in this scenario. Fixes: ad592e37dfcc ("linux-user: provide fallback pgd_find_hole for bare chroots") Signed-off-by: Vincent Fazio Reviewed-by: Laurent Vivier Message-Id: <20210131061948.15990-1-vfazio@xes-inc.com> [lv: updated it to check if ret == -1] Signed-off-by: Laurent Vivier --- linux-user/elfload.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index e525901659d4..c6731013fde2 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2235,7 +2235,8 @@ static uintptr_t pgb_find_hole(uintptr_t guest_loaddr, uintptr_t guest_size, brk = (uintptr_t)sbrk(0); if (!maps) { - return pgd_find_hole_fallback(guest_size, brk, align, offset); + ret = pgd_find_hole_fallback(guest_size, brk, align, offset); + return ret == -1 ? -1 : ret - guest_loaddr; } /* The first hole is before the first map entry. */