From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrey Konovalov Subject: Re: [PATCH v11 09/14] kernel, arm64: untag user pointers in prctl_set_mm* Date: Mon, 18 Mar 2019 17:53:56 +0100 Message-ID: References: <96675b72-d325-0682-4864-b6a96f63f8fd@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <96675b72-d325-0682-4864-b6a96f63f8fd@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Kevin Brodsky Cc: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Steven Rostedt , Ingo Molnar , Peter Zijlstra List-Id: linux-arch.vger.kernel.org On Mon, Mar 18, 2019 at 12:47 PM Kevin Brodsky wrote: > > On 15/03/2019 19:51, Andrey Konovalov wrote: > > This patch is a part of a series that extends arm64 kernel ABI to allow to > > pass tagged user pointers (with the top byte set to something else other > > than 0x00) as syscall arguments. > > > > prctl_set_mm() and prctl_set_mm_map() use provided user pointers for vma > > lookups, which can only by done with untagged pointers. > > > > Untag user pointers in these functions. > > > > Signed-off-by: Andrey Konovalov > > --- > > kernel/sys.c | 14 ++++++++++++++ > > 1 file changed, 14 insertions(+) > > > > diff --git a/kernel/sys.c b/kernel/sys.c > > index 12df0e5434b8..8e56d87cc6db 100644 > > --- a/kernel/sys.c > > +++ b/kernel/sys.c > > @@ -1993,6 +1993,18 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data > > if (copy_from_user(&prctl_map, addr, sizeof(prctl_map))) > > return -EFAULT; > > > > + prctl_map->start_code = untagged_addr(prctl_map.start_code); > > + prctl_map->end_code = untagged_addr(prctl_map.end_code); > > + prctl_map->start_data = untagged_addr(prctl_map.start_data); > > + prctl_map->end_data = untagged_addr(prctl_map.end_data); > > + prctl_map->start_brk = untagged_addr(prctl_map.start_brk); > > + prctl_map->brk = untagged_addr(prctl_map.brk); > > + prctl_map->start_stack = untagged_addr(prctl_map.start_stack); > > + prctl_map->arg_start = untagged_addr(prctl_map.arg_start); > > + prctl_map->arg_end = untagged_addr(prctl_map.arg_end); > > + prctl_map->env_start = untagged_addr(prctl_map.env_start); > > + prctl_map->env_end = untagged_addr(prctl_map.env_end); > > As the buildbot suggests, those -> should be . instead :) You might want to check > your local build with CONFIG_CHECKPOINT_RESTORE=y. Oops :) > > > + > > error = validate_prctl_map(&prctl_map); > > if (error) > > return error; > > @@ -2106,6 +2118,8 @@ static int prctl_set_mm(int opt, unsigned long addr, > > opt != PR_SET_MM_MAP_SIZE))) > > return -EINVAL; > > > > + addr = untagged_addr(addr); > > This is a bit too coarse, addr is indeed used for find_vma() later on, but it is also > used to access memory, by prctl_set_mm_mmap() and prctl_set_auxv(). Yes, I wrote this patch before our Friday discussion and forgot about it. I'll fix it in v12, thanks! > > Kevin > > > + > > #ifdef CONFIG_CHECKPOINT_RESTORE > > if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE) > > return prctl_set_mm_map(opt, (const void __user *)addr, arg4); > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f196.google.com ([209.85.210.196]:40039 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726983AbfCRQyI (ORCPT ); Mon, 18 Mar 2019 12:54:08 -0400 Received: by mail-pf1-f196.google.com with SMTP id c207so2666223pfc.7 for ; Mon, 18 Mar 2019 09:54:08 -0700 (PDT) MIME-Version: 1.0 References: <96675b72-d325-0682-4864-b6a96f63f8fd@arm.com> In-Reply-To: <96675b72-d325-0682-4864-b6a96f63f8fd@arm.com> From: Andrey Konovalov Date: Mon, 18 Mar 2019 17:53:56 +0100 Message-ID: Subject: Re: [PATCH v11 09/14] kernel, arm64: untag user pointers in prctl_set_mm* Content-Type: text/plain; charset="UTF-8" Sender: linux-arch-owner@vger.kernel.org List-ID: To: Kevin Brodsky Cc: Catalin Marinas , Will Deacon , Mark Rutland , Robin Murphy , Kees Cook , Kate Stewart , Greg Kroah-Hartman , Andrew Morton , Ingo Molnar , "Kirill A . Shutemov" , Shuah Khan , Vincenzo Frascino , Eric Dumazet , "David S. Miller" , Alexei Starovoitov , Daniel Borkmann , Steven Rostedt , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Linux ARM , "open list:DOCUMENTATION" , Linux Memory Management List , linux-arch , netdev , bpf , "open list:KERNEL SELFTEST FRAMEWORK" , LKML , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Chintan Pandya , Luc Van Oostenryck , Dave Martin , Szabolcs Nagy Message-ID: <20190318165356.cGw_72Uh6rO-hxBMpGd9R6oeJn-acSfbjXKNGgI-TKg@z> On Mon, Mar 18, 2019 at 12:47 PM Kevin Brodsky wrote: > > On 15/03/2019 19:51, Andrey Konovalov wrote: > > This patch is a part of a series that extends arm64 kernel ABI to allow to > > pass tagged user pointers (with the top byte set to something else other > > than 0x00) as syscall arguments. > > > > prctl_set_mm() and prctl_set_mm_map() use provided user pointers for vma > > lookups, which can only by done with untagged pointers. > > > > Untag user pointers in these functions. > > > > Signed-off-by: Andrey Konovalov > > --- > > kernel/sys.c | 14 ++++++++++++++ > > 1 file changed, 14 insertions(+) > > > > diff --git a/kernel/sys.c b/kernel/sys.c > > index 12df0e5434b8..8e56d87cc6db 100644 > > --- a/kernel/sys.c > > +++ b/kernel/sys.c > > @@ -1993,6 +1993,18 @@ static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data > > if (copy_from_user(&prctl_map, addr, sizeof(prctl_map))) > > return -EFAULT; > > > > + prctl_map->start_code = untagged_addr(prctl_map.start_code); > > + prctl_map->end_code = untagged_addr(prctl_map.end_code); > > + prctl_map->start_data = untagged_addr(prctl_map.start_data); > > + prctl_map->end_data = untagged_addr(prctl_map.end_data); > > + prctl_map->start_brk = untagged_addr(prctl_map.start_brk); > > + prctl_map->brk = untagged_addr(prctl_map.brk); > > + prctl_map->start_stack = untagged_addr(prctl_map.start_stack); > > + prctl_map->arg_start = untagged_addr(prctl_map.arg_start); > > + prctl_map->arg_end = untagged_addr(prctl_map.arg_end); > > + prctl_map->env_start = untagged_addr(prctl_map.env_start); > > + prctl_map->env_end = untagged_addr(prctl_map.env_end); > > As the buildbot suggests, those -> should be . instead :) You might want to check > your local build with CONFIG_CHECKPOINT_RESTORE=y. Oops :) > > > + > > error = validate_prctl_map(&prctl_map); > > if (error) > > return error; > > @@ -2106,6 +2118,8 @@ static int prctl_set_mm(int opt, unsigned long addr, > > opt != PR_SET_MM_MAP_SIZE))) > > return -EINVAL; > > > > + addr = untagged_addr(addr); > > This is a bit too coarse, addr is indeed used for find_vma() later on, but it is also > used to access memory, by prctl_set_mm_mmap() and prctl_set_auxv(). Yes, I wrote this patch before our Friday discussion and forgot about it. I'll fix it in v12, thanks! > > Kevin > > > + > > #ifdef CONFIG_CHECKPOINT_RESTORE > > if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE) > > return prctl_set_mm_map(opt, (const void __user *)addr, arg4); >