[PATCH v2] i40e: Add checking for null for nlmsg_find_attr()

[PATCH v2] i40e: Add checking for null for nlmsg_find_attr()

[Natalia Petrova]

The result of nlmsg_find_attr() 'br_spec' is dereferenced in
nla_for_each_nested(), but it can take null value in nla_find() function,
which will result in an error.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops")
Signed-off-by: Natalia Petrova <n.petrova@fintech.ru>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
---
v2: The remark about the error code by Simon Horman <simon.horman@corigine.com> 
was taken into account; return value -ENOENT was changed to -EINVAL.
 drivers/net/ethernet/intel/i40e/i40e_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 53d0083e35da..4626d2a1af91 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -13167,6 +13167,8 @@ static int i40e_ndo_bridge_setlink(struct net_device *dev,
 	}
 
 	br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC);
+	if (!br_spec)
+		return -EINVAL;
 
 	nla_for_each_nested(attr, br_spec, rem) {
 		__u16 mode;
-- 
2.34.1

Re: [PATCH v2] i40e: Add checking for null for nlmsg_find_attr()

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

Rule: 'Cc: stable@vger.kernel.org' or 'commit <sha1> upstream.'
Subject: [PATCH v2] i40e: Add checking for null for nlmsg_find_attr()
Link: https://lore.kernel.org/stable/20230130221106.19267-1-n.petrova%40fintech.ru

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Re: [PATCH v2] i40e: Add checking for null for nlmsg_find_attr()

[Greg Kroah-Hartman]

On Tue, Jan 31, 2023 at 01:11:06AM +0300, Natalia Petrova wrote:
> The result of nlmsg_find_attr() 'br_spec' is dereferenced in
> nla_for_each_nested(), but it can take null value in nla_find() function,
> which will result in an error.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops")
> Signed-off-by: Natalia Petrova <n.petrova@fintech.ru>
> Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
> ---
> v2: The remark about the error code by Simon Horman <simon.horman@corigine.com> 
> was taken into account; return value -ENOENT was changed to -EINVAL.
>  drivers/net/ethernet/intel/i40e/i40e_main.c | 2 ++
>  1 file changed, 2 insertions(+)
> 

<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree.  Please read:
    https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this properly.

</formletter>

Re: [PATCH v2] i40e: Add checking for null for nlmsg_find_attr()

[Simon Horman]

On Tue, Jan 31, 2023 at 06:17:49AM +0100, Greg Kroah-Hartman wrote:
> On Tue, Jan 31, 2023 at 01:11:06AM +0300, Natalia Petrova wrote:
> > The result of nlmsg_find_attr() 'br_spec' is dereferenced in
> > nla_for_each_nested(), but it can take null value in nla_find() function,
> > which will result in an error.
> > 
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> > 
> > Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops")
> > Signed-off-by: Natalia Petrova <n.petrova@fintech.ru>
> > Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
> > ---
> > v2: The remark about the error code by Simon Horman <simon.horman@corigine.com> 
> > was taken into account; return value -ENOENT was changed to -EINVAL.
> >  drivers/net/ethernet/intel/i40e/i40e_main.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> 
> <formletter>
> 
> This is not the correct way to submit patches for inclusion in the
> stable kernel tree.  Please read:
>     https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this properly.
> 
> </formletter>

Hi Natalia,

offering some friendly guidance here.

It seems to me that the problem you have highlighted is present
in current upstream code, and thus should be addressed there.

If it is considered a bug fix, then it should be targeted at the 'net'
tree. If the patch is accepted, into the release currently being
worked on (v6.2), backporting to older kernels can follow from there.
Otherwise it can be targeted at 'net-next', for inclusion
in the following release (v6.3).

As I think might have been mentioned, elsewhere, for networking
changes, you should indicate the target tree in the subject.
E.g. for net

Subject: [PATCH v3] i40e: Check if nlmsg_find_attr() returns null

The above also incorporates a suggested enhancement to the subject text.

I believe there was also a typo spotted in the patch description:
finction -> function

In all, my suggestion would be to address these problems as a v3.
I do not believe that you need to include stable@vger.kernel.org
or Greg on the recipient list, as the patch would be for 'net'
or 'net-next', not stable.