From: Andrey Konovalov <andreyknvl@google.com>
To: Eric Dumazet <edumazet@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Kees Cook <keescook@chromium.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Shuah Khan <shuah@kernel.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
"David S. Miller" <davem@davemloft.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
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Arnaldo Carvalho de Melo <acme@kernel.org>,
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"open list:KERNEL SELFTEST FRAMEWORK"
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Kostya Serebryany <kcc@google.com>,
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Lee Smith <Lee.Smith@arm.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Jacob Bramley <Jacob.Bramley@arm.com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Chintan Pandya <cpandya@codeaurora.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Dave Martin <Dave.Martin@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Szabolcs Nagy <Szabolcs.Nagy@arm.com>
Subject: Re: [PATCH v12 08/13] net, arm64: untag user pointers in tcp_zerocopy_receive
Date: Tue, 19 Mar 2019 17:14:47 +0100 [thread overview]
Message-ID: <CAAeHK+xi4-6pgDYG8ypM8NsbhgncpsxgJeEXL1-BpkARXONvEQ@mail.gmail.com> (raw)
In-Reply-To: <CANn89iJ4SeccE79gKiv5RFqaouFV8shFA+0dCS8+2D_1aRq_Kw@mail.gmail.com>
On Mon, Mar 18, 2019 at 6:35 PM Eric Dumazet <edumazet@google.com> wrote:
>
> On Mon, Mar 18, 2019 at 10:18 AM Andrey Konovalov <andreyknvl@google.com> 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.
> >
> > tcp_zerocopy_receive() uses provided user pointers for vma lookups, which
> > can only by done with untagged pointers.
> >
> > Untag user pointers in this function.
> >
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> > ---
> > net/ipv4/tcp.c | 9 +++++++--
> > 1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> > index 6baa6dc1b13b..e76beb5ff1ff 100644
> > --- a/net/ipv4/tcp.c
> > +++ b/net/ipv4/tcp.c
> > @@ -1749,7 +1749,7 @@ EXPORT_SYMBOL(tcp_mmap);
> > static int tcp_zerocopy_receive(struct sock *sk,
> > struct tcp_zerocopy_receive *zc)
> > {
> > - unsigned long address = (unsigned long)zc->address;
> > + unsigned long address;
> > const skb_frag_t *frags = NULL;
> > u32 length = 0, seq, offset;
> > struct vm_area_struct *vma;
> > @@ -1758,7 +1758,12 @@ static int tcp_zerocopy_receive(struct sock *sk,
> > int inq;
> > int ret;
> >
> > - if (address & (PAGE_SIZE - 1) || address != zc->address)
> > + address = (unsigned long)untagged_addr(zc->address);
> > +
> > + /* The second test in this if detects if the u64->unsigned long
> > + * conversion had any truncated bits.
> > + */
> > + if (address & (PAGE_SIZE - 1) || address != untagged_addr(zc->address))
> > return -EINVAL;
> >
> > if (sk->sk_state == TCP_LISTEN)
>
>
> This is quite ugly, the comment does not really help nor belong to this patch.
>
> What about using untagged_addr() only once ?
>
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index 6baa6dc1b13b0b94b1da238668b93e167cf444fe..855a1f68c1ea9b0d07a92bd7f5e7c24840a99d3d
> 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -1761,6 +1761,8 @@ static int tcp_zerocopy_receive(struct sock *sk,
> if (address & (PAGE_SIZE - 1) || address != zc->address)
> return -EINVAL;
>
> + address = untagged_addr(address);
> +
> if (sk->sk_state == TCP_LISTEN)
> return -ENOTCONN;
Looks good, will do it like this in the next version. Thanks!
next prev parent reply other threads:[~2019-03-19 16:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 17:17 [PATCH v12 00/13] arm64: untag user pointers passed to the kernel Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 01/13] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 02/13] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 03/13] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 04/13] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 05/13] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 06/13] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 07/13] fs, arm64: untag user pointers in fs/userfaultfd.c Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 08/13] net, arm64: untag user pointers in tcp_zerocopy_receive Andrey Konovalov
2019-03-18 17:35 ` Eric Dumazet
2019-03-19 16:14 ` Andrey Konovalov [this message]
2019-03-18 17:17 ` [PATCH v12 09/13] kernel, arm64: untag user pointers in prctl_set_mm* Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 10/13] tracing, arm64: untag user pointers in seq_print_user_ip Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 11/13] uprobes, arm64: untag user pointers in find_active_uprobe Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 12/13] bpf, arm64: untag user pointers in stack_map_get_build_id_offset Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 13/13] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2019-03-19 18:32 ` [PATCH v12 00/13] arm64: untag user pointers passed to the kernel Andrew Morton
2019-03-20 11:25 ` Catalin Marinas
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