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[209.85.220.65]) by mx.google.com with SMTPS id 38sor15908114pln.23.2019.03.18.09.54.07 for (Google Transport Security); Mon, 18 Mar 2019 09:54:07 -0700 (PDT) Received-SPF: pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=qL2sbyGF; spf=pass (google.com: domain of andreyknvl@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=andreyknvl@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oTTTDsmzZRxE0P4UD+1ikNPbtlS4Dyc6/3yBg27ixDQ=; b=qL2sbyGFEclrtQPUA6LVmMhwOgE9ZrDgMW6Yf0szQXcjCN8uVFclD6Agav2oG/HaIH tt+Y2mHDCoddFKSu8Zy4+3UpfZZ7SmbEpgE0cwANONzfIFjpTwwIM+e92N9XMSRRWHoH PxF+RlzsqmGVQHybjhaImaimN17+872PGPB3vCwmBpKws2yHzSmXHY74ILhBEtFUAPZC ZvI5cWjIE/Xp9Y+h7052jpM79vanjEebGQOinpddGY5fyw7tCnhdUPSnrMHlG9O0r3NS 7j+QGp+4xtUxFT/lBj7jefQ9mZPAHUuw6v1QjZFT5Vjqdwgm4b+IedSWlUu5f+FbiQK2 9n2w== X-Google-Smtp-Source: APXvYqwtoSENSqe0flkUh8DZSgYEqtIQ0XKdJGpbQGPZjtv967mBGLrNb/wGEHW2f3Co8+OtTDYgx1PZKLh949N1HIQ= X-Received: by 2002:a17:902:d24:: with SMTP id 33mr13090976plu.246.1552928047514; Mon, 18 Mar 2019 09:54:07 -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* 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 Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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); >