[Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Zhou Qingyang]

In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
passed to memcpy(), which could lead to undefined behavior on failure
of kmalloc().

Fix this bug by using kmemdup() instead of kmalloc()+memcpy().

This bug was found by a static analyzer.

Builds with 'make allyesconfig' show no new warnings,
and our static analyzer no longer warns about this code.

Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace "secure boot"")
Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
---
The analysis employs differential checking to identify inconsistent 
security operations (e.g., checks or kfrees) between two code paths 
and confirms that the inconsistent operations are not recovered in the
current function or the callers, so they constitute bugs. 

Note that, as a bug found by static analysis, it can be a false
positive or hard to trigger. Multiple researchers have cross-reviewed
the bug.

 drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
index 667fa016496e..a6ea89a5d51a 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
@@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const char *name, int ver,
 
 	hsfw->imem_size = desc->code_size;
 	hsfw->imem_tag = desc->start_tag;
-	hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
-	memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
-
+	hsfw->imem = kmemdup(data + desc->code_off, desc->code_size, GFP_KERNEL);
 	nvkm_firmware_put(fw);
-	return 0;
+	if (!hsfw->imem)
+		return -ENOMEM;
+	else
+		return 0;
 }
 
 int
-- 
2.25.1

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Lyude Paul]

Reviewed-by: Lyude Paul <lyude@redhat.com>

On Tue, 2022-01-25 at 00:58 +0800, Zhou Qingyang wrote:
> In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> passed to memcpy(), which could lead to undefined behavior on failure
> of kmalloc().
> 
> Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> 
> This bug was found by a static analyzer.
> 
> Builds with 'make allyesconfig' show no new warnings,
> and our static analyzer no longer warns about this code.
> 
> Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace
> "secure boot"")
> Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> ---
> The analysis employs differential checking to identify inconsistent 
> security operations (e.g., checks or kfrees) between two code paths 
> and confirms that the inconsistent operations are not recovered in the
> current function or the callers, so they constitute bugs. 
> 
> Note that, as a bug found by static analysis, it can be a false
> positive or hard to trigger. Multiple researchers have cross-reviewed
> the bug.
> 
>  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> index 667fa016496e..a6ea89a5d51a 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const char
> *name, int ver,
>  
>         hsfw->imem_size = desc->code_size;
>         hsfw->imem_tag = desc->start_tag;
> -       hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> -       memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> -
> +       hsfw->imem = kmemdup(data + desc->code_off, desc->code_size,
> GFP_KERNEL);
>         nvkm_firmware_put(fw);
> -       return 0;
> +       if (!hsfw->imem)
> +               return -ENOMEM;
> +       else
> +               return 0;
>  }
>  
>  int

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Greg KH]

On Tue, Jan 25, 2022 at 12:58:55AM +0800, Zhou Qingyang wrote:
> In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> passed to memcpy(), which could lead to undefined behavior on failure
> of kmalloc().
> 
> Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> 
> This bug was found by a static analyzer.
> 
> Builds with 'make allyesconfig' show no new warnings,
> and our static analyzer no longer warns about this code.
> 
> Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace "secure boot"")
> Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> ---
> The analysis employs differential checking to identify inconsistent 
> security operations (e.g., checks or kfrees) between two code paths 
> and confirms that the inconsistent operations are not recovered in the
> current function or the callers, so they constitute bugs. 
> 
> Note that, as a bug found by static analysis, it can be a false
> positive or hard to trigger. Multiple researchers have cross-reviewed
> the bug.
> 
>  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> index 667fa016496e..a6ea89a5d51a 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const char *name, int ver,
>  
>  	hsfw->imem_size = desc->code_size;
>  	hsfw->imem_tag = desc->start_tag;
> -	hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> -	memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> -
> +	hsfw->imem = kmemdup(data + desc->code_off, desc->code_size, GFP_KERNEL);
>  	nvkm_firmware_put(fw);
> -	return 0;
> +	if (!hsfw->imem)
> +		return -ENOMEM;
> +	else
> +		return 0;
>  }
>  
>  int
> -- 
> 2.25.1
> 

As stated before, umn.edu is still not allowed to contribute to the
Linux kernel.  Please work with your administration to resolve this
issue.

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Lyude Paul]

Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
I pushed this already but I will go ahead and send a revert for this patch.
Will cc you on it as well.

On Fri, 2022-01-28 at 11:18 +0100, Greg KH wrote:
> On Tue, Jan 25, 2022 at 12:58:55AM +0800, Zhou Qingyang wrote:
> > In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> > passed to memcpy(), which could lead to undefined behavior on failure
> > of kmalloc().
> > 
> > Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> > 
> > This bug was found by a static analyzer.
> > 
> > Builds with 'make allyesconfig' show no new warnings,
> > and our static analyzer no longer warns about this code.
> > 
> > Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace
> > "secure boot"")
> > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> > ---
> > The analysis employs differential checking to identify inconsistent 
> > security operations (e.g., checks or kfrees) between two code paths 
> > and confirms that the inconsistent operations are not recovered in the
> > current function or the callers, so they constitute bugs. 
> > 
> > Note that, as a bug found by static analysis, it can be a false
> > positive or hard to trigger. Multiple researchers have cross-reviewed
> > the bug.
> > 
> >  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
> >  1 file changed, 5 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > index 667fa016496e..a6ea89a5d51a 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const
> > char *name, int ver,
> >  
> >         hsfw->imem_size = desc->code_size;
> >         hsfw->imem_tag = desc->start_tag;
> > -       hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> > -       memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> > -
> > +       hsfw->imem = kmemdup(data + desc->code_off, desc->code_size,
> > GFP_KERNEL);
> >         nvkm_firmware_put(fw);
> > -       return 0;
> > +       if (!hsfw->imem)
> > +               return -ENOMEM;
> > +       else
> > +               return 0;
> >  }
> >  
> >  int
> > -- 
> > 2.25.1
> > 
> 
> As stated before, umn.edu is still not allowed to contribute to the
> Linux kernel.  Please work with your administration to resolve this
> issue.
> 

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Alex Deucher]

On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
>
> Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> I pushed this already but I will go ahead and send a revert for this patch.
> Will cc you on it as well.

This seems short-sighted.  If the patch is valid I see no reason to
not accept it.  I'm not trying to downplay the mess umn got into, but
as long as the patch is well scrutinized and fixes a valid issue, it
should be applied rather than leaving potential bugs in place.

Alex


>
> On Fri, 2022-01-28 at 11:18 +0100, Greg KH wrote:
> > On Tue, Jan 25, 2022 at 12:58:55AM +0800, Zhou Qingyang wrote:
> > > In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> > > passed to memcpy(), which could lead to undefined behavior on failure
> > > of kmalloc().
> > >
> > > Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> > >
> > > This bug was found by a static analyzer.
> > >
> > > Builds with 'make allyesconfig' show no new warnings,
> > > and our static analyzer no longer warns about this code.
> > >
> > > Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace
> > > "secure boot"")
> > > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> > > ---
> > > The analysis employs differential checking to identify inconsistent
> > > security operations (e.g., checks or kfrees) between two code paths
> > > and confirms that the inconsistent operations are not recovered in the
> > > current function or the callers, so they constitute bugs.
> > >
> > > Note that, as a bug found by static analysis, it can be a false
> > > positive or hard to trigger. Multiple researchers have cross-reviewed
> > > the bug.
> > >
> > >  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
> > >  1 file changed, 5 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > index 667fa016496e..a6ea89a5d51a 100644
> > > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const
> > > char *name, int ver,
> > >
> > >         hsfw->imem_size = desc->code_size;
> > >         hsfw->imem_tag = desc->start_tag;
> > > -       hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> > > -       memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> > > -
> > > +       hsfw->imem = kmemdup(data + desc->code_off, desc->code_size,
> > > GFP_KERNEL);
> > >         nvkm_firmware_put(fw);
> > > -       return 0;
> > > +       if (!hsfw->imem)
> > > +               return -ENOMEM;
> > > +       else
> > > +               return 0;
> > >  }
> > >
> > >  int
> > > --
> > > 2.25.1
> > >
> >
> > As stated before, umn.edu is still not allowed to contribute to the
> > Linux kernel.  Please work with your administration to resolve this
> > issue.
> >
>
> --
> Cheers,
>  Lyude Paul (she/her)
>  Software Engineer at Red Hat
>

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Lyude Paul]

On Fri, 2022-01-28 at 14:53 -0500, Alex Deucher wrote:
> On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> > 
> > Sigh-thank you for catching this - I had totally forgot about the umn.edu
> > ban.
> > I pushed this already but I will go ahead and send a revert for this
> > patch.
> > Will cc you on it as well.
> 
> This seems short-sighted.  If the patch is valid I see no reason to
> not accept it.  I'm not trying to downplay the mess umn got into, but
> as long as the patch is well scrutinized and fixes a valid issue, it
> should be applied rather than leaving potential bugs in place.
> 

Yeah - I sent a revert for this, but that was mainly just to make sure I
didn't cause problems with Linus or something like that. If it's all the same
I'd much rather just leave this patch in, as looking at the code the fix seems
completely valid.

> Alex
> 
> 
> > 
> > On Fri, 2022-01-28 at 11:18 +0100, Greg KH wrote:
> > > On Tue, Jan 25, 2022 at 12:58:55AM +0800, Zhou Qingyang wrote:
> > > > In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> > > > passed to memcpy(), which could lead to undefined behavior on failure
> > > > of kmalloc().
> > > > 
> > > > Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> > > > 
> > > > This bug was found by a static analyzer.
> > > > 
> > > > Builds with 'make allyesconfig' show no new warnings,
> > > > and our static analyzer no longer warns about this code.
> > > > 
> > > > Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace
> > > > "secure boot"")
> > > > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> > > > ---
> > > > The analysis employs differential checking to identify inconsistent
> > > > security operations (e.g., checks or kfrees) between two code paths
> > > > and confirms that the inconsistent operations are not recovered in the
> > > > current function or the callers, so they constitute bugs.
> > > > 
> > > > Note that, as a bug found by static analysis, it can be a false
> > > > positive or hard to trigger. Multiple researchers have cross-reviewed
> > > > the bug.
> > > > 
> > > >  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
> > > >  1 file changed, 5 insertions(+), 4 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > index 667fa016496e..a6ea89a5d51a 100644
> > > > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr,
> > > > const
> > > > char *name, int ver,
> > > > 
> > > >         hsfw->imem_size = desc->code_size;
> > > >         hsfw->imem_tag = desc->start_tag;
> > > > -       hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> > > > -       memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> > > > -
> > > > +       hsfw->imem = kmemdup(data + desc->code_off, desc->code_size,
> > > > GFP_KERNEL);
> > > >         nvkm_firmware_put(fw);
> > > > -       return 0;
> > > > +       if (!hsfw->imem)
> > > > +               return -ENOMEM;
> > > > +       else
> > > > +               return 0;
> > > >  }
> > > > 
> > > >  int
> > > > --
> > > > 2.25.1
> > > > 
> > > 
> > > As stated before, umn.edu is still not allowed to contribute to the
> > > Linux kernel.  Please work with your administration to resolve this
> > > issue.
> > > 
> > 
> > --
> > Cheers,
> >  Lyude Paul (she/her)
> >  Software Engineer at Red Hat
> > 
> 

-- 
Cheers,
 Lyude Paul (she/her)
 Software Engineer at Red Hat

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Karol Herbst]

On Fri, Jan 28, 2022 at 8:54 PM Alex Deucher <alexdeucher@gmail.com> wrote:
>
> On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> >
> > Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> > I pushed this already but I will go ahead and send a revert for this patch.
> > Will cc you on it as well.
>
> This seems short-sighted.  If the patch is valid I see no reason to
> not accept it.  I'm not trying to downplay the mess umn got into, but
> as long as the patch is well scrutinized and fixes a valid issue, it
> should be applied rather than leaving potential bugs in place.
>
> Alex
>

Even though knowing that malicious code can be introduced via
perfectly fine looking patches, and sometimes one will never spot the
problem, this patch isn't all that bad tbh.

So should we reject patches out of "policies" or should we just be
extra careful? But not addressing the concerns as Greg pointed out is
also kind of a bad move, but also not knowing what the state of
resolving this mess is anyway.

>
> >
> > On Fri, 2022-01-28 at 11:18 +0100, Greg KH wrote:
> > > On Tue, Jan 25, 2022 at 12:58:55AM +0800, Zhou Qingyang wrote:
> > > > In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> > > > passed to memcpy(), which could lead to undefined behavior on failure
> > > > of kmalloc().
> > > >
> > > > Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> > > >
> > > > This bug was found by a static analyzer.
> > > >
> > > > Builds with 'make allyesconfig' show no new warnings,
> > > > and our static analyzer no longer warns about this code.
> > > >
> > > > Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace
> > > > "secure boot"")
> > > > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> > > > ---
> > > > The analysis employs differential checking to identify inconsistent
> > > > security operations (e.g., checks or kfrees) between two code paths
> > > > and confirms that the inconsistent operations are not recovered in the
> > > > current function or the callers, so they constitute bugs.
> > > >
> > > > Note that, as a bug found by static analysis, it can be a false
> > > > positive or hard to trigger. Multiple researchers have cross-reviewed
> > > > the bug.
> > > >
> > > >  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
> > > >  1 file changed, 5 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > index 667fa016496e..a6ea89a5d51a 100644
> > > > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const
> > > > char *name, int ver,
> > > >
> > > >         hsfw->imem_size = desc->code_size;
> > > >         hsfw->imem_tag = desc->start_tag;
> > > > -       hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> > > > -       memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> > > > -
> > > > +       hsfw->imem = kmemdup(data + desc->code_off, desc->code_size,
> > > > GFP_KERNEL);
> > > >         nvkm_firmware_put(fw);
> > > > -       return 0;
> > > > +       if (!hsfw->imem)
> > > > +               return -ENOMEM;
> > > > +       else
> > > > +               return 0;
> > > >  }
> > > >
> > > >  int
> > > > --
> > > > 2.25.1
> > > >
> > >
> > > As stated before, umn.edu is still not allowed to contribute to the
> > > Linux kernel.  Please work with your administration to resolve this
> > > issue.
> > >
> >
> > --
> > Cheers,
> >  Lyude Paul (she/her)
> >  Software Engineer at Red Hat
> >
>

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Alex Deucher]

On Fri, Jan 28, 2022 at 2:58 PM Karol Herbst <kherbst@redhat.com> wrote:
>
> On Fri, Jan 28, 2022 at 8:54 PM Alex Deucher <alexdeucher@gmail.com> wrote:
> >
> > On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> > >
> > > Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> > > I pushed this already but I will go ahead and send a revert for this patch.
> > > Will cc you on it as well.
> >
> > This seems short-sighted.  If the patch is valid I see no reason to
> > not accept it.  I'm not trying to downplay the mess umn got into, but
> > as long as the patch is well scrutinized and fixes a valid issue, it
> > should be applied rather than leaving potential bugs in place.
> >
> > Alex
> >
>
> Even though knowing that malicious code can be introduced via
> perfectly fine looking patches, and sometimes one will never spot the
> problem, this patch isn't all that bad tbh.
>
> So should we reject patches out of "policies" or should we just be
> extra careful? But not addressing the concerns as Greg pointed out is
> also kind of a bad move, but also not knowing what the state of
> resolving this mess is anyway.

I think if the umn mess taught us anything, it's the need for more
careful scrutiny.  But I certainly don't have the time to retype every
valid patch if it comes from a umn source.  There are also ethical
implications to that as well.  You didn't actually write the patch.

Alex

>
> >
> > >
> > > On Fri, 2022-01-28 at 11:18 +0100, Greg KH wrote:
> > > > On Tue, Jan 25, 2022 at 12:58:55AM +0800, Zhou Qingyang wrote:
> > > > > In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> > > > > passed to memcpy(), which could lead to undefined behavior on failure
> > > > > of kmalloc().
> > > > >
> > > > > Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> > > > >
> > > > > This bug was found by a static analyzer.
> > > > >
> > > > > Builds with 'make allyesconfig' show no new warnings,
> > > > > and our static analyzer no longer warns about this code.
> > > > >
> > > > > Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace
> > > > > "secure boot"")
> > > > > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> > > > > ---
> > > > > The analysis employs differential checking to identify inconsistent
> > > > > security operations (e.g., checks or kfrees) between two code paths
> > > > > and confirms that the inconsistent operations are not recovered in the
> > > > > current function or the callers, so they constitute bugs.
> > > > >
> > > > > Note that, as a bug found by static analysis, it can be a false
> > > > > positive or hard to trigger. Multiple researchers have cross-reviewed
> > > > > the bug.
> > > > >
> > > > >  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
> > > > >  1 file changed, 5 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > index 667fa016496e..a6ea89a5d51a 100644
> > > > > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const
> > > > > char *name, int ver,
> > > > >
> > > > >         hsfw->imem_size = desc->code_size;
> > > > >         hsfw->imem_tag = desc->start_tag;
> > > > > -       hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> > > > > -       memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> > > > > -
> > > > > +       hsfw->imem = kmemdup(data + desc->code_off, desc->code_size,
> > > > > GFP_KERNEL);
> > > > >         nvkm_firmware_put(fw);
> > > > > -       return 0;
> > > > > +       if (!hsfw->imem)
> > > > > +               return -ENOMEM;
> > > > > +       else
> > > > > +               return 0;
> > > > >  }
> > > > >
> > > > >  int
> > > > > --
> > > > > 2.25.1
> > > > >
> > > >
> > > > As stated before, umn.edu is still not allowed to contribute to the
> > > > Linux kernel.  Please work with your administration to resolve this
> > > > issue.
> > > >
> > >
> > > --
> > > Cheers,
> > >  Lyude Paul (she/her)
> > >  Software Engineer at Red Hat
> > >
> >
>

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Greg KH]

On Fri, Jan 28, 2022 at 02:20:24PM -0500, Lyude Paul wrote:
> Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> I pushed this already but I will go ahead and send a revert for this patch.

No worries, thanks for doing this.

greg k-h

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Greg KH]

On Fri, Jan 28, 2022 at 08:57:56PM +0100, Karol Herbst wrote:
> On Fri, Jan 28, 2022 at 8:54 PM Alex Deucher <alexdeucher@gmail.com> wrote:
> >
> > On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> > >
> > > Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> > > I pushed this already but I will go ahead and send a revert for this patch.
> > > Will cc you on it as well.
> >
> > This seems short-sighted.  If the patch is valid I see no reason to
> > not accept it.  I'm not trying to downplay the mess umn got into, but
> > as long as the patch is well scrutinized and fixes a valid issue, it
> > should be applied rather than leaving potential bugs in place.
> >
> > Alex
> >
> 
> Even though knowing that malicious code can be introduced via
> perfectly fine looking patches, and sometimes one will never spot the
> problem, this patch isn't all that bad tbh.
> 
> So should we reject patches out of "policies" or should we just be
> extra careful? But not addressing the concerns as Greg pointed out is
> also kind of a bad move, but also not knowing what the state of
> resolving this mess is anyway.

If you think the change is correct, and are willing to sign off on it,
that's fine for now.

The big issue here is that the umn.edu "researchers" are not folling the
very basic and simple proceedures that we worked to set up with them,
and have resumed sending buggy patches to the kernel community.  If you
think this one is not a problem, then feel free to keep it.

As I just now told their administration, it is very difficult to tell
malice from incompetence.  If this is malice, then we need to defend our
community.  If this is just incompetence, then the university has to
handle that as the contributions are coming in their name, _and_ we also
need to defend from that.  What we have tried in the past for this group
is obviously not working, so we now will need to do something else.

{sigh}

greg k-h

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Greg KH]

On Fri, Jan 28, 2022 at 02:57:36PM -0500, Lyude Paul wrote:
> On Fri, 2022-01-28 at 14:53 -0500, Alex Deucher wrote:
> > On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> > > 
> > > Sigh-thank you for catching this - I had totally forgot about the umn.edu
> > > ban.
> > > I pushed this already but I will go ahead and send a revert for this
> > > patch.
> > > Will cc you on it as well.
> > 
> > This seems short-sighted.  If the patch is valid I see no reason to
> > not accept it.  I'm not trying to downplay the mess umn got into, but
> > as long as the patch is well scrutinized and fixes a valid issue, it
> > should be applied rather than leaving potential bugs in place.
> > 
> 
> Yeah - I sent a revert for this, but that was mainly just to make sure I
> didn't cause problems with Linus or something like that. If it's all the same
> I'd much rather just leave this patch in, as looking at the code the fix seems
> completely valid.

You will not cause any problem at all, don't worry about this, it's not
your fault or responsibility.  If you think the patch is fine, that's
great, no problems.  But be extra careful here, treat these developers
as you would with any other "they are known to send bad patches so are
safe to ignore if I don't want to deal with it" group that many of us
maintainers already have to defend against.

thanks,

greg k-h

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Kangjie Lu]

On Fri, Jan 28, 2022 at 1:58 PM Karol Herbst <kherbst@redhat.com> wrote:
>
> On Fri, Jan 28, 2022 at 8:54 PM Alex Deucher <alexdeucher@gmail.com> wrote:
> >
> > On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> > >
> > > Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> > > I pushed this already but I will go ahead and send a revert for this patch.
> > > Will cc you on it as well.
> >
> > This seems short-sighted.  If the patch is valid I see no reason to
> > not accept it.  I'm not trying to downplay the mess umn got into, but
> > as long as the patch is well scrutinized and fixes a valid issue, it
> > should be applied rather than leaving potential bugs in place.
> >
> > Alex
> >
>
> Even though knowing that malicious code can be introduced via
> perfectly fine looking patches, and sometimes one will never spot the
> problem, this patch isn't all that bad tbh.
>
> So should we reject patches out of "policies" or should we just be
> extra careful? But not addressing the concerns as Greg pointed out is
> also kind of a bad move, but also not knowing what the state of
> resolving this mess is anyway.


Seeing some discussion here, I feel I owe you some quick updates on
the state. We sent three testing patches in August 2020, which is a
serious mistake. We never did that again and will never do that again.
All other patches including recent ones were sent to fix real bugs,
not to introduce problems. Clearly, although most of the patches are
valid, some patches are still not good enough, but it is not about
malice. Fixing bugs in Linux isn't an easy task and takes so much
effort.

We did not ignore the concerns pointed out by Greg, and have seriously
taken some actions. For example, we explained how our static-analysis
tool found the bugs, and members in my research group have internally
cross-reviewed the found bugs. We sent these patches after contacting
Greg---I thought Greg allowed us to send patches, but also requested
us to work on the last process with our administration. Unfortunately,
the process has been slow during the pandemic, but I hope this can be
resolved soon. Of course, before this is resolved, we will not send
any more patches.




>
> >
> > >
> > > On Fri, 2022-01-28 at 11:18 +0100, Greg KH wrote:
> > > > On Tue, Jan 25, 2022 at 12:58:55AM +0800, Zhou Qingyang wrote:
> > > > > In nvkm_acr_hsfw_load_bl(), the return value of kmalloc() is directly
> > > > > passed to memcpy(), which could lead to undefined behavior on failure
> > > > > of kmalloc().
> > > > >
> > > > > Fix this bug by using kmemdup() instead of kmalloc()+memcpy().
> > > > >
> > > > > This bug was found by a static analyzer.
> > > > >
> > > > > Builds with 'make allyesconfig' show no new warnings,
> > > > > and our static analyzer no longer warns about this code.
> > > > >
> > > > > Fixes: 22dcda45a3d1 ("drm/nouveau/acr: implement new subdev to replace
> > > > > "secure boot"")
> > > > > Signed-off-by: Zhou Qingyang <zhou1615@umn.edu>
> > > > > ---
> > > > > The analysis employs differential checking to identify inconsistent
> > > > > security operations (e.g., checks or kfrees) between two code paths
> > > > > and confirms that the inconsistent operations are not recovered in the
> > > > > current function or the callers, so they constitute bugs.
> > > > >
> > > > > Note that, as a bug found by static analysis, it can be a false
> > > > > positive or hard to trigger. Multiple researchers have cross-reviewed
> > > > > the bug.
> > > > >
> > > > >  drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c | 9 +++++----
> > > > >  1 file changed, 5 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > index 667fa016496e..a6ea89a5d51a 100644
> > > > > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/acr/hsfw.c
> > > > > @@ -142,11 +142,12 @@ nvkm_acr_hsfw_load_bl(struct nvkm_acr *acr, const
> > > > > char *name, int ver,
> > > > >
> > > > >         hsfw->imem_size = desc->code_size;
> > > > >         hsfw->imem_tag = desc->start_tag;
> > > > > -       hsfw->imem = kmalloc(desc->code_size, GFP_KERNEL);
> > > > > -       memcpy(hsfw->imem, data + desc->code_off, desc->code_size);
> > > > > -
> > > > > +       hsfw->imem = kmemdup(data + desc->code_off, desc->code_size,
> > > > > GFP_KERNEL);
> > > > >         nvkm_firmware_put(fw);
> > > > > -       return 0;
> > > > > +       if (!hsfw->imem)
> > > > > +               return -ENOMEM;
> > > > > +       else
> > > > > +               return 0;
> > > > >  }
> > > > >
> > > > >  int
> > > > > --
> > > > > 2.25.1
> > > > >
> > > >
> > > > As stated before, umn.edu is still not allowed to contribute to the
> > > > Linux kernel.  Please work with your administration to resolve this
> > > > issue.
> > > >
> > >
> > > --
> > > Cheers,
> > >  Lyude Paul (she/her)
> > >  Software Engineer at Red Hat
> > >
> >
>


--
Kangjie Lu
Assistant Professor
Department of Computer Science and Engineering
University of Minnesota
https://www-users.cs.umn.edu/~kjlu

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Greg KH]

On Sat, Jan 29, 2022 at 08:18:55AM -0600, Kangjie Lu wrote:
> On Fri, Jan 28, 2022 at 1:58 PM Karol Herbst <kherbst@redhat.com> wrote:
> >
> > On Fri, Jan 28, 2022 at 8:54 PM Alex Deucher <alexdeucher@gmail.com> wrote:
> > >
> > > On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> > > >
> > > > Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> > > > I pushed this already but I will go ahead and send a revert for this patch.
> > > > Will cc you on it as well.
> > >
> > > This seems short-sighted.  If the patch is valid I see no reason to
> > > not accept it.  I'm not trying to downplay the mess umn got into, but
> > > as long as the patch is well scrutinized and fixes a valid issue, it
> > > should be applied rather than leaving potential bugs in place.
> > >
> > > Alex
> > >
> >
> > Even though knowing that malicious code can be introduced via
> > perfectly fine looking patches, and sometimes one will never spot the
> > problem, this patch isn't all that bad tbh.
> >
> > So should we reject patches out of "policies" or should we just be
> > extra careful? But not addressing the concerns as Greg pointed out is
> > also kind of a bad move, but also not knowing what the state of
> > resolving this mess is anyway.
> 
> 
> Seeing some discussion here, I feel I owe you some quick updates on
> the state. We sent three testing patches in August 2020, which is a
> serious mistake. We never did that again and will never do that again.
> All other patches including recent ones were sent to fix real bugs,
> not to introduce problems. Clearly, although most of the patches are
> valid, some patches are still not good enough, but it is not about
> malice. Fixing bugs in Linux isn't an easy task and takes so much
> effort.
> 
> We did not ignore the concerns pointed out by Greg, and have seriously
> taken some actions. For example, we explained how our static-analysis
> tool found the bugs, and members in my research group have internally
> cross-reviewed the found bugs. We sent these patches after contacting
> Greg---I thought Greg allowed us to send patches, but also requested
> us to work on the last process with our administration.

I do not recall saying anything like this at all.

On January 4, I wrote to you and your coworkers on the mailing list
message https://lore.kernel.org/r/YdQfCGf8qr5zZJef@kroah.com by saying:

	Note that your university is still in many kernel maintainer's
	ignore-list (myself included, I dug this up as I saw Fei's response.)
	Please work with your administration and the process that is currently
	happening in order to give you all the needed training so you will not
	keep causing these types of basic errors that keep your patches from
	being accepted.

	*plonk*

And then later in a private email to you on January 5 where you emailed
Kees and me to try to see if you were allowed to start sending patches
again, I said:

	A kernel developer with lots of experience has already offered to work
	with your university.  Hopefully that process has already started, if
	not, I suggest contacting your administration as they should know who
	this is.

and then I closed with:

	Right now you all are still on my "ignore email" lists for patches.

The patches recently submitted have been shown to be incomplete and in
some places, completely wrong.  I have contacted your administration
about this issue because they asked to know if there were any problems
in the future at our last discussion.  In that response today, I wrote:

	I know that incompetence can often times be hard to distinguish from
	malice, but given the track-record here, we are now going to have to
	treat this as malice.  If it is just incompetence, well, that's
	something that your organization needs to overcome.

	Either way, this is not something that the Linux kernel community should
	be forced to endure.

So to be explicit, so you do not misunderstand me somehow:

	No more patches from umn.edu should be accepted into the Linux
	kernel until further public notice.  They should be considered a
	"bad actor" given their prior history of submissions and lack of
	complying with the kernel community's prior requirements to
	them.

Is this understood?

greg k-h

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Kangjie Lu]

Hi,Greg,

On Sat, Jan 29, 2022 at 8:47 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Sat, Jan 29, 2022 at 08:18:55AM -0600, Kangjie Lu wrote:
> > On Fri, Jan 28, 2022 at 1:58 PM Karol Herbst <kherbst@redhat.com> wrote:
> > >
> > > On Fri, Jan 28, 2022 at 8:54 PM Alex Deucher <alexdeucher@gmail.com> wrote:
> > > >
> > > > On Fri, Jan 28, 2022 at 2:20 PM Lyude Paul <lyude@redhat.com> wrote:
> > > > >
> > > > > Sigh-thank you for catching this - I had totally forgot about the umn.edu ban.
> > > > > I pushed this already but I will go ahead and send a revert for this patch.
> > > > > Will cc you on it as well.
> > > >
> > > > This seems short-sighted.  If the patch is valid I see no reason to
> > > > not accept it.  I'm not trying to downplay the mess umn got into, but
> > > > as long as the patch is well scrutinized and fixes a valid issue, it
> > > > should be applied rather than leaving potential bugs in place.
> > > >
> > > > Alex
> > > >
> > >
> > > Even though knowing that malicious code can be introduced via
> > > perfectly fine looking patches, and sometimes one will never spot the
> > > problem, this patch isn't all that bad tbh.
> > >
> > > So should we reject patches out of "policies" or should we just be
> > > extra careful? But not addressing the concerns as Greg pointed out is
> > > also kind of a bad move, but also not knowing what the state of
> > > resolving this mess is anyway.
> >
> >
> > Seeing some discussion here, I feel I owe you some quick updates on
> > the state. We sent three testing patches in August 2020, which is a
> > serious mistake. We never did that again and will never do that again.
> > All other patches including recent ones were sent to fix real bugs,
> > not to introduce problems. Clearly, although most of the patches are
> > valid, some patches are still not good enough, but it is not about
> > malice. Fixing bugs in Linux isn't an easy task and takes so much
> > effort.
> >
> > We did not ignore the concerns pointed out by Greg, and have seriously
> > taken some actions. For example, we explained how our static-analysis
> > tool found the bugs, and members in my research group have internally
> > cross-reviewed the found bugs. We sent these patches after contacting
> > Greg---I thought Greg allowed us to send patches, but also requested
> > us to work on the last process with our administration.
>
> I do not recall saying anything like this at all.

I was referring to an email back to 11/13/2021 where you said
"some memory allocation checks are not ever going to be "resolved" as they are
not "real world" issues. So be aware of that when proposing patches
for these issues."

I optimistically interpreted this as, "you can still submit patches,
but I will personally ignore them". This turns out to be a
misunderstanding. I am sorry for that.

>
> On January 4, I wrote to you and your coworkers on the mailing list
> message https://lore.kernel.org/r/YdQfCGf8qr5zZJef@kroah.com by saying:
>
>         Note that your university is still in many kernel maintainer's
>         ignore-list (myself included, I dug this up as I saw Fei's response.)
>         Please work with your administration and the process that is currently
>         happening in order to give you all the needed training so you will not
>         keep causing these types of basic errors that keep your patches from
>         being accepted.
>
>         *plonk*
>
> And then later in a private email to you on January 5 where you emailed
> Kees and me to try to see if you were allowed to start sending patches
> again, I said:
>
>         A kernel developer with lots of experience has already offered to work
>         with your university.  Hopefully that process has already started, if
>         not, I suggest contacting your administration as they should know who
>         this is.
>
> and then I closed with:
>
>         Right now you all are still on my "ignore email" lists for patches.
>
> The patches recently submitted have been shown to be incomplete and in
> some places, completely wrong.  I have contacted your administration
> about this issue because they asked to know if there were any problems
> in the future at our last discussion.  In that response today, I wrote:
>
>         I know that incompetence can often times be hard to distinguish from
>         malice, but given the track-record here, we are now going to have to
>         treat this as malice.  If it is just incompetence, well, that's
>         something that your organization needs to overcome.
>
>         Either way, this is not something that the Linux kernel community should
>         be forced to endure.
>
> So to be explicit, so you do not misunderstand me somehow:
>
>         No more patches from umn.edu should be accepted into the Linux
>         kernel until further public notice.

This is clear to me.

> They should be considered a
>         "bad actor" given their prior history of submissions and lack of
>         complying with the kernel community's prior requirements to
>         them.

I am sorry for the delay of the last process which is unfortunately
not under the control of the researchers. According to our
administration, the process has started and is moving forward. I hope
that can be done soon.

Thanks.

>
> Is this understood?
>
> greg k-h



-- 
Kangjie Lu
Assistant Professor
Department of Computer Science and Engineering
University of Minnesota
https://www-users.cs.umn.edu/~kjlu

Re: [Nouveau] [PATCH] drm/nouveau/acr: Fix undefined behavior in nvkm_acr_hsfw_load_bl()

[Greg KH]

On Sat, Jan 29, 2022 at 09:19:18AM -0600, Kangjie Lu wrote:
> > So to be explicit, so you do not misunderstand me somehow:
> >
> >         No more patches from umn.edu should be accepted into the Linux
> >         kernel until further public notice.
> 
> This is clear to me.
> 
> > They should be considered a
> >         "bad actor" given their prior history of submissions and lack of
> >         complying with the kernel community's prior requirements to
> >         them.
> 
> I am sorry for the delay of the last process which is unfortunately
> not under the control of the researchers. According to our
> administration, the process has started and is moving forward. I hope
> that can be done soon.

Given that our previously agreed-upon requirements were not met, I do
not think that finally meeting these requirements when caught that you
were not following them is going to be acceptable to allow your
organization to return to the kernel community.

Your people have shown bad-faith toward us too many times, and we have
wasted too much of our own time and energy on this for absolutely no
benefit at all, except as an example to point others at and say "do not
be like them."

greg k-h