Re: likely invalid CVE assignment for commit 95baa60a0da80a0143e3ddd4d3725758b4513825

Re: likely invalid CVE assignment for commit 95baa60a0da80a0143e3ddd4d3725758b4513825

[Marcus Meissner]

Hi,

Dave does not like private-only emails, so again for netdev list:

On Wed, Jun 05, 2019 at 11:20:29AM +0200, Marcus Meissner wrote:
> Hi Gen Zhang,
> 
> looking at https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=95baa60a0da80a0143e3ddd4d3725758b4513825
> 
> 	ipv6_sockglue: Fix a missing-check bug in ip6_ra_control()
> 	In function ip6_ra_control(), the pointer new_ra is allocated a memory
> 	space via kmalloc(). And it is used in the following codes. However,
> 	when there is a memory allocation error, kmalloc() fails. Thus null
> 	pointer dereference may happen. And it will cause the kernel to crash.
> 	Therefore, we should check the return value and handle the error.
> 
> There seems to be no case in current GIT where new_ra is being dereferenced even if it
> is NULL (kfree(NULL) will work fine).
> 
> Was this just an assumption based on insufficient code review, or was there a real
> crash observed and how?

The reporter had replied privately that he was only doing a code audit.

We (Redhat and SUSE) wonder if this fix is needed at all.

Ciao, Marcus

Re: likely invalid CVE assignment for commit 95baa60a0da80a0143e3ddd4d3725758b4513825

[Gen Zhang]

On Thu, Jun 06, 2019 at 09:55:07AM +0200, Marcus Meissner wrote:
> Hi,
> 
> Dave does not like private-only emails, so again for netdev list:
> 
> On Wed, Jun 05, 2019 at 11:20:29AM +0200, Marcus Meissner wrote:
> > Hi Gen Zhang,
> > 
> > looking at https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=95baa60a0da80a0143e3ddd4d3725758b4513825
> > 
> > 	ipv6_sockglue: Fix a missing-check bug in ip6_ra_control()
> > 	In function ip6_ra_control(), the pointer new_ra is allocated a memory
> > 	space via kmalloc(). And it is used in the following codes. However,
> > 	when there is a memory allocation error, kmalloc() fails. Thus null
> > 	pointer dereference may happen. And it will cause the kernel to crash.
> > 	Therefore, we should check the return value and handle the error.
> > 
> > There seems to be no case in current GIT where new_ra is being dereferenced even if it
> > is NULL (kfree(NULL) will work fine).
> > 
> > Was this just an assumption based on insufficient code review, or was there a real
> > crash observed and how?
> 
> The reporter had replied privately that he was only doing a code audit.
Thanks again for your concerns of this patch.

It is not exactly that. This comes from a static analysis research 
prototype. And I think it is different from 'only doing code audit'.

Thanks
Gen
> 
> We (Redhat and SUSE) wonder if this fix is needed at all.
> 
> Ciao, Marcus