First published: Tue Nov 05 2024(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Software | Affected Version | How to fix |
---|---|---|
Linux Linux kernel | >=6.4<6.6.59 | |
Linux Linux kernel | >=6.7<6.11.6 | |
Linux Linux kernel | =6.12-rc1 | |
Linux Linux kernel | =6.12-rc2 | |
Linux Linux kernel | =6.12-rc3 | |
Linux Linux kernel | =6.12-rc4 |
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