[PATCH] net: check passed optlen before reading

[PATCH] net: check passed optlen before reading

[Tamir Duberstein]

From 52e464972f88ff5e9647d92b63c815e1f350f65e Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@gmail.com>
Date: Tue, 28 Dec 2021 15:09:11 -0500
Subject: [PATCH] net: check passed optlen before reading

Add a check that the user-provided option is at least as long as the
number of bytes we intend to read. Before this patch we would blindly
read sizeof(int) bytes even in cases where the user passed
optlen<sizeof(int), which would potentially read garbage or fault.

Discovered by new tests in https://github.com/google/gvisor/pull/6957.

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 net/ipv6/raw.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 60f1e4f5be5a..547613058182 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -1020,6 +1020,9 @@ static int do_rawv6_setsockopt(struct sock *sk,
int level, int optname,
        struct raw6_sock *rp = raw6_sk(sk);
        int val;

+       if (optlen < sizeof(val)) {
+               return -EINVAL;
+
        if (copy_from_sockptr(&val, optval, sizeof(val)))
                return -EFAULT;

-- 
2.34.1.448.ga2b2bfdf31-goog

Re: [PATCH] net: check passed optlen before reading

[Tamir Duberstein]

Errant brace in the earlier version.

From 8586be4d72c6c583b1085d2239076987e1b7c43a Mon Sep 17 00:00:00 2001
From: Tamir Duberstein <tamird@gmail.com>
Date: Tue, 28 Dec 2021 15:09:11 -0500
Subject: [PATCH v2] net: check passed optlen before reading

Add a check that the user-provided option is at least as long as the
number of bytes we intend to read. Before this patch we would blindly
read sizeof(int) bytes even in cases where the user passed
optlen<sizeof(int), which would potentially read garbage or fault.

Discovered by new tests in https://github.com/google/gvisor/pull/6957 .

Signed-off-by: Tamir Duberstein <tamird@gmail.com>
---
 net/ipv6/raw.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 60f1e4f5be5a..c51d5ce3711c 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -1020,6 +1020,9 @@ static int do_rawv6_setsockopt(struct sock *sk,
int level, int optname,
        struct raw6_sock *rp = raw6_sk(sk);
        int val;

+       if (optlen < sizeof(val))
+               return -EINVAL;
+
        if (copy_from_sockptr(&val, optval, sizeof(val)))
                return -EFAULT;

-- 
2.34.1.448.ga2b2bfdf31-goog

On Tue, Dec 28, 2021 at 3:18 PM Tamir Duberstein <tamird@gmail.com> wrote:
>
> From 52e464972f88ff5e9647d92b63c815e1f350f65e Mon Sep 17 00:00:00 2001
> From: Tamir Duberstein <tamird@gmail.com>
> Date: Tue, 28 Dec 2021 15:09:11 -0500
> Subject: [PATCH] net: check passed optlen before reading
>
> Add a check that the user-provided option is at least as long as the
> number of bytes we intend to read. Before this patch we would blindly
> read sizeof(int) bytes even in cases where the user passed
> optlen<sizeof(int), which would potentially read garbage or fault.
>
> Discovered by new tests in https://github.com/google/gvisor/pull/6957.
>
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>
> ---
>  net/ipv6/raw.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
> index 60f1e4f5be5a..547613058182 100644
> --- a/net/ipv6/raw.c
> +++ b/net/ipv6/raw.c
> @@ -1020,6 +1020,9 @@ static int do_rawv6_setsockopt(struct sock *sk,
> int level, int optname,
>         struct raw6_sock *rp = raw6_sk(sk);
>         int val;
>
> +       if (optlen < sizeof(val)) {
> +               return -EINVAL;
> +
>         if (copy_from_sockptr(&val, optval, sizeof(val)))
>                 return -EFAULT;
>
> --
> 2.34.1.448.ga2b2bfdf31-goog

Re: [PATCH] net: check passed optlen before reading

[Jakub Kicinski]

On Tue, 28 Dec 2021 16:02:29 -0500 Tamir Duberstein wrote:
> Errant brace in the earlier version.
> 
> From 8586be4d72c6c583b1085d2239076987e1b7c43a Mon Sep 17 00:00:00 2001
> From: Tamir Duberstein <tamird@gmail.com>
> Date: Tue, 28 Dec 2021 15:09:11 -0500
> Subject: [PATCH v2] net: check passed optlen before reading
> 
> Add a check that the user-provided option is at least as long as the
> number of bytes we intend to read. Before this patch we would blindly
> read sizeof(int) bytes even in cases where the user passed
> optlen<sizeof(int), which would potentially read garbage or fault.
> 
> Discovered by new tests in https://github.com/google/gvisor/pull/6957 .
> 
> Signed-off-by: Tamir Duberstein <tamird@gmail.com>

Your patches are corrupted by your email client.

Can you try sending the latest version with git send-email?

Re: [PATCH] net: check passed optlen before reading

[Willem de Bruijn]

On Tue, Dec 28, 2021 at 6:54 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Tue, 28 Dec 2021 16:02:29 -0500 Tamir Duberstein wrote:
> > Errant brace in the earlier version.
> >
> > From 8586be4d72c6c583b1085d2239076987e1b7c43a Mon Sep 17 00:00:00 2001
> > From: Tamir Duberstein <tamird@gmail.com>
> > Date: Tue, 28 Dec 2021 15:09:11 -0500
> > Subject: [PATCH v2] net: check passed optlen before reading
> >
> > Add a check that the user-provided option is at least as long as the
> > number of bytes we intend to read. Before this patch we would blindly
> > read sizeof(int) bytes even in cases where the user passed
> > optlen<sizeof(int), which would potentially read garbage or fault.
> >
> > Discovered by new tests in https://github.com/google/gvisor/pull/6957 .
> >
> > Signed-off-by: Tamir Duberstein <tamird@gmail.com>
>
> Your patches are corrupted by your email client.
>
> Can you try sending the latest version with git send-email?

Then perhaps also update the subject line to make it more clear where
this applies: "ipv6: raw: check passed optlen before reading".

Re: [PATCH] net: check passed optlen before reading

[Tamir Duberstein]

I'm having some trouble sending this using git send-email because of
the firewall I'm behind.

Please pull from
  git://github.com/tamird/linux raw-check-optlen
to get these changes:
  280c5742aab2 ipv6: raw: check passed optlen before reading

If this is not acceptable, I'll send the patch again when I'm outside
the firewall. Apologies.

On Wed, Dec 29, 2021 at 10:09 AM Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
>
> On Tue, Dec 28, 2021 at 6:54 PM Jakub Kicinski <kuba@kernel.org> wrote:
> >
> > On Tue, 28 Dec 2021 16:02:29 -0500 Tamir Duberstein wrote:
> > > Errant brace in the earlier version.
> > >
> > > From 8586be4d72c6c583b1085d2239076987e1b7c43a Mon Sep 17 00:00:00 2001
> > > From: Tamir Duberstein <tamird@gmail.com>
> > > Date: Tue, 28 Dec 2021 15:09:11 -0500
> > > Subject: [PATCH v2] net: check passed optlen before reading
> > >
> > > Add a check that the user-provided option is at least as long as the
> > > number of bytes we intend to read. Before this patch we would blindly
> > > read sizeof(int) bytes even in cases where the user passed
> > > optlen<sizeof(int), which would potentially read garbage or fault.
> > >
> > > Discovered by new tests in https://github.com/google/gvisor/pull/6957 .
> > >
> > > Signed-off-by: Tamir Duberstein <tamird@gmail.com>
> >
> > Your patches are corrupted by your email client.
> >
> > Can you try sending the latest version with git send-email?
>
> Then perhaps also update the subject line to make it more clear where
> this applies: "ipv6: raw: check passed optlen before reading".

Re: [PATCH] net: check passed optlen before reading

[Willem de Bruijn]

On Wed, Dec 29, 2021 at 2:50 PM Tamir Duberstein <tamird@gmail.com> wrote:
>
> I'm having some trouble sending this using git send-email because of
> the firewall I'm behind.
>
> Please pull from
>   git://github.com/tamird/linux raw-check-optlen
> to get these changes:
>   280c5742aab2 ipv6: raw: check passed optlen before reading
>
> If this is not acceptable, I'll send the patch again when I'm outside
> the firewall. Apologies.

I can send it on your behalf, Tamir.

Re: [PATCH] net: check passed optlen before reading

[Jakub Kicinski]

On Wed, 29 Dec 2021 14:53:10 -0500 Willem de Bruijn wrote:
> On Wed, Dec 29, 2021 at 2:50 PM Tamir Duberstein <tamird@gmail.com> wrote:
> >
> > I'm having some trouble sending this using git send-email because of
> > the firewall I'm behind.
> >
> > Please pull from
> >   git://github.com/tamird/linux raw-check-optlen
> > to get these changes:
> >   280c5742aab2 ipv6: raw: check passed optlen before reading
> >
> > If this is not acceptable, I'll send the patch again when I'm outside
> > the firewall. Apologies.  
> 
> I can send it on your behalf, Tamir.

Or we can use this opportunity to try out the infra Konstantin had been
working on:

https://lore.kernel.org/all/20211217183942.npvkb3ajnx6p5cbp@meerkat.local/

b4 submit --send seems to support sending via some web thing?

Dunno if anyone tried it, yet.

Re: [PATCH] net: check passed optlen before reading

[Willem de Bruijn]

On Wed, Dec 29, 2021 at 2:58 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Wed, 29 Dec 2021 14:53:10 -0500 Willem de Bruijn wrote:
> > On Wed, Dec 29, 2021 at 2:50 PM Tamir Duberstein <tamird@gmail.com> wrote:
> > >
> > > I'm having some trouble sending this using git send-email because of
> > > the firewall I'm behind.
> > >
> > > Please pull from
> > >   git://github.com/tamird/linux raw-check-optlen
> > > to get these changes:
> > >   280c5742aab2 ipv6: raw: check passed optlen before reading
> > >
> > > If this is not acceptable, I'll send the patch again when I'm outside
> > > the firewall. Apologies.
> >
> > I can send it on your behalf, Tamir.
>
> Or we can use this opportunity to try out the infra Konstantin had been
> working on:
>
> https://lore.kernel.org/all/20211217183942.npvkb3ajnx6p5cbp@meerkat.local/
>
> b4 submit --send seems to support sending via some web thing?
>
> Dunno if anyone tried it, yet.

I haven't tried b4 at all. Just sent it the traditional way for now.
Will take a look and maybe give it a spin next time.