Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read
parse_dcc() treats data_end as an inclusive end pointer, but its only caller passes data_limit = ib_ptr + datalen, which points one past the last valid byte.
The newline search loop iterates while tmp <= data_end, so when no newline is present, *tmp is read at tmp == data_end, one byte beyond the region filled by skb_header_pointer().
irc_buffer is kmalloc’d as MAX_SEARCH_SIZE + 1 bytes and datalen is capped at MAX_SEARCH_SIZE, so the stray read does not fault. The byte is uninitialized or stale; if it contains an ASCII digit, simple_strtoul will consume it and produce a wrong DCC IP or port in the conntrack expectation. The extra allocation byte is also a fragile guard: if the cap or allocation size changes, this becomes a real out-of-bounds read.
Change the loop and its post-loop check to use strict less-than, consistent with the caller’s exclusive-end convention. Update the function comment accordingly.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.19.0 (+19 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Amazon Linux 2023 | Planned | — |
| Debian 12 | Released |
42 kernels
|
| Debian 13 | Released |
13 kernels
|
| Oracle Linux 8 UEK 7 | Released |
112 kernels
|
| Oracle Linux 9 UEK 7 | Released |
112 kernels
|
| Proxmox VE 7 5.15 | In Rollout |
47 kernels
|
| Ubuntu 20.04 HWE AWS | Released |
57 kernels
|
| Ubuntu 22.04 | Released |
102 kernels
|
| Ubuntu 22.04 AWS | Released |
93 kernels
|
| Ubuntu 22.04 Azure | Released |
83 kernels
|
| Ubuntu 24.04 | Planned | — |
| Ubuntu 24.04 AWS | Planned | — |
| Ubuntu 26.04 | In Rollout |
2 kernels
|