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[209.85.220.65]) by mx.google.com with SMTPS id o70sor21693711pje.2.2019.07.15.09.00.46 for (Google Transport Security); Mon, 15 Jul 2019 09:00:46 -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=awILUWqn; 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=7Q0q/IfCRadymayHol/UUF72+yJ91bYAnFv+xLR30xQ=; b=awILUWqnOhL8QrLhWTtK3zyGeYzsbGaDmlapw+TJPtpLmDPRw1GP6vt2k8M63kLr39 ZOpRC9dNiFsjXCuRW9tvX+XJ4TMinqKEg4V9d0/Cohi7g+H0FLJqsymSlujZFTSwFgq+ HGvo45b5poteQElVP2ylrss//l0SvENb9w0NdEWBIgvpqnNLsaE/1Oq03NG9YiPmMbZi 8k5Fou1N/CEVlyaSlbvq+wKBgrOUzCIo1B2qg8bQ1mlF2+F/VYvQbx6QNpAS+GS8VYMS 4d6tYcKUYuIyyU24AI3+kh3w0LS9e+N+YdRnIzCnanxcL1YdF0dX0SOZIdMQqtDbfKe6 /xuQ== X-Google-Smtp-Source: APXvYqw+s/Xsm1Inj9c3bcQDg7/b3DVU+zlhxUxxhLhtcMSC55W2OaWJF9iNwAodQ+4dHaGR8RmRVxTzfqDyBCor0Ro= X-Received: by 2002:a17:90a:25c8:: with SMTP id k66mr30231713pje.129.1563206445986; Mon, 15 Jul 2019 09:00:45 -0700 (PDT) MIME-Version: 1.0 References: <20190624175120.GN29120@arrakis.emea.arm.com> In-Reply-To: <20190624175120.GN29120@arrakis.emea.arm.com> From: Andrey Konovalov Date: Mon, 15 Jul 2019 18:00:34 +0200 Message-ID: Subject: Re: [PATCH v18 08/15] userfaultfd: untag user pointers To: Catalin Marinas Cc: Linux ARM , Linux Memory Management List , LKML , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK" , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Kees Cook , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Leon Romanovsky , Luc Van Oostenryck , Dave Martin , Khalid Aziz , enh , Jason Gunthorpe , Christoph Hellwig , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Robin Murphy , Kevin Brodsky , Szabolcs Nagy , Al Viro 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, Jun 24, 2019 at 7:51 PM Catalin Marinas wrote: > > On Mon, Jun 24, 2019 at 04:32:53PM +0200, Andrey Konovalov wrote: > > This patch is a part of a series that extends kernel ABI to allow to pass > > tagged user pointers (with the top byte set to something else other than > > 0x00) as syscall arguments. > > > > userfaultfd code use provided user pointers for vma lookups, which can > > only by done with untagged pointers. > > > > Untag user pointers in validate_range(). > > > > Reviewed-by: Vincenzo Frascino > > Reviewed-by: Catalin Marinas > > Reviewed-by: Kees Cook > > Signed-off-by: Andrey Konovalov > > --- > > fs/userfaultfd.c | 22 ++++++++++++---------- > > 1 file changed, 12 insertions(+), 10 deletions(-) > > Same here, it needs an ack from Al Viro. Hi Al, Could you take a look at this one as well and give your acked-by? Thanks! > > > diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c > > index ae0b8b5f69e6..c2be36a168ca 100644 > > --- a/fs/userfaultfd.c > > +++ b/fs/userfaultfd.c > > @@ -1261,21 +1261,23 @@ static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx, > > } > > > > static __always_inline int validate_range(struct mm_struct *mm, > > - __u64 start, __u64 len) > > + __u64 *start, __u64 len) > > { > > __u64 task_size = mm->task_size; > > > > - if (start & ~PAGE_MASK) > > + *start = untagged_addr(*start); > > + > > + if (*start & ~PAGE_MASK) > > return -EINVAL; > > if (len & ~PAGE_MASK) > > return -EINVAL; > > if (!len) > > return -EINVAL; > > - if (start < mmap_min_addr) > > + if (*start < mmap_min_addr) > > return -EINVAL; > > - if (start >= task_size) > > + if (*start >= task_size) > > return -EINVAL; > > - if (len > task_size - start) > > + if (len > task_size - *start) > > return -EINVAL; > > return 0; > > } > > @@ -1325,7 +1327,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, > > goto out; > > } > > > > - ret = validate_range(mm, uffdio_register.range.start, > > + ret = validate_range(mm, &uffdio_register.range.start, > > uffdio_register.range.len); > > if (ret) > > goto out; > > @@ -1514,7 +1516,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx, > > if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister))) > > goto out; > > > > - ret = validate_range(mm, uffdio_unregister.start, > > + ret = validate_range(mm, &uffdio_unregister.start, > > uffdio_unregister.len); > > if (ret) > > goto out; > > @@ -1665,7 +1667,7 @@ static int userfaultfd_wake(struct userfaultfd_ctx *ctx, > > if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake))) > > goto out; > > > > - ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len); > > + ret = validate_range(ctx->mm, &uffdio_wake.start, uffdio_wake.len); > > if (ret) > > goto out; > > > > @@ -1705,7 +1707,7 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx, > > sizeof(uffdio_copy)-sizeof(__s64))) > > goto out; > > > > - ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len); > > + ret = validate_range(ctx->mm, &uffdio_copy.dst, uffdio_copy.len); > > if (ret) > > goto out; > > /* > > @@ -1761,7 +1763,7 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, > > sizeof(uffdio_zeropage)-sizeof(__s64))) > > goto out; > > > > - ret = validate_range(ctx->mm, uffdio_zeropage.range.start, > > + ret = validate_range(ctx->mm, &uffdio_zeropage.range.start, > > uffdio_zeropage.range.len); > > if (ret) > > goto out; > > -- > > 2.22.0.410.gd8fdbe21b5-goog