Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
bpf: Skip unsettled links in link iterator
bpf_link_prime() inserts a link into link_idr before anon_inode_getfile() succeeds and before bpf_link_settle() publishes the ID in link->id. bpf_link_by_id() treats such an ID-zero link as unsettled, but the link iterator takes a reference without this check.
If anon_inode_getfile() then fails, the creator removes the ID and frees its still-private link directly. The iterator is left with a dangling reference and its next bpf_link_put() accesses freed memory.
Treat ID-zero entries as transient in bpf_link_get_curr_or_next(), just as bpf_link_by_id() does.
BUG: KASAN: slab-use-after-free in bpf_link_put Write of size 8 by task exp/384 Call Trace: bpf_link_put kernel/bpf/syscall.c:3372 bpf_link_seq_next kernel/bpf/link_iter.c:33 bpf_seq_read kernel/bpf/bpf_iter.c:158 vfs_read fs/read_write.c:572 ksys_read fs/read_write.c:716 do_syscall_64 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe arch/x86/entry/entry_64.S:121 Kernel panic - not syncing: KASAN: panic_on_warn set …
Details
- Affected product:
- AlmaLinux 9.2 ESU , TuxCare 9.6 ESU , TuxCare 9.8 ESU
- Affected packages:
- kernel @ 5.14.0 (+2 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 9.2 ESU | Planned | — |
| AlmaLinux 9.6 ESU | Planned | — |
| Debian 12 | In Rollout |
44 kernels
|
| Debian 13 | Planned | — |
| Ubuntu 26.04 | Planned | — |