Re: [BUG] Potential Null Pointer Dereference in nexthop_create_group Function

On 2/14/26 1:08 PM, 冯嘉仪 wrote:

Dear Maintainer,

Our team recently developed a null-pointer-dereference (NPD)
vulnerability detection tool, and we used it to scan the Linux Kernel
(version 6.9.6). After manual review, we identified a potentially
vulnerable code snippet that could lead to a null-pointer dereference
bug. We would appreciate your expert insight to confirm whether this
vulnerability could indeed pose a risk to the system.

Vulnerability Description:
File:  net/ipv4/nexthop.c
In the function nexthop_create_group, we found the following line of code:

if (!nexthop_get(nhe)) {

The issue arises because the nhe pointer may be passed as NULL in
certain situations. The statement passes the nhe pointer to nexthop_get
without any check, but nexthop_get might contain a dereference operation
on the nhe pointer, which could result in a null-pointer dereference.

Indeed even this one looks like a false positive: the id existence is
previously validated by nh_check_attr_group_rtnl().

The false positive rate in your reports strongly discourages any other
feedback; you should revisited your tool, do much better human review
and provide much more and better context information before any other post.

Thanks,

Paolo