Description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: bpf: must hold reference on net namespace

BUG: KASAN: slab-use-after-free in __nf_unregister_net_hook+0x640/0x6b0
Read of size 8 at addr ffff8880106fe400 by task repro/72=
bpf_nf_link_release+0xda/0x1e0
bpf_link_free+0x139/0x2d0
bpf_link_release+0x68/0x80
__fput+0x414/0xb60

Eric says:
It seems that bpf was able to defer the __nf_unregister_net_hook()
after exit()/close() time.
Perhaps a netns reference is missing, because the netns has been
dismantled/freed already.
bpf_nf_link_attach() does :
link->net = net;
But I do not see a reference being taken on net.

Add such a reference and release it after hook unreg.
Note that I was unable to get syzbot reproducer to work, so I
do not know if this resolves this splat.

Classification

CVE ID: CVE-2024-50130

CVSS Base Severity: HIGH

CVSS Base Score: 7.8

Affected Products

Vendor: Linux, Linux

Product: Linux, Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 9.92% (scored less or equal to compared to others)

EPSS Date: 2025-04-04 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: total

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2024-50130
https://git.kernel.org/stable/c/f41bd93b3e0508edc7ba820357f949071dcc0acc
https://git.kernel.org/stable/c/d0d7939543a1b3bb93af9a18d258a774daf8f162
https://git.kernel.org/stable/c/1230fe7ad3974f7bf6c78901473e039b34d4fb1f

Timeline