Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: proc: size address buffers for %pISpc output
The AF_RXRPC procfs helpers format local and remote socket addresses into fixed 50-byte stack buffers with “%pISpc”.
That is too small for the longest current-tree IPv6-with-port form the formatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a dotted-quad tail not only for v4mapped addresses, but also for ISATAP addresses via ipv6_addr_is_isatap().
As a result, a case such as
is possible with the current formatter. That is 50 visible characters, so 51 bytes including the trailing NUL, which does not fit in the existing char[50] buffers used by net/rxrpc/proc.c.
Size the buffers from the formatter’s maximum textual form and switch the call sites to scnprintf().
Changes since v1:
- correct the changelog to cite the actual maximum current-tree case explicitly
- frame the proof around the ISATAP formatting path instead of the earlier mapped-v4 example
Details
- Affected product:
- Ubuntu 20.04 ELS
- Affected packages:
- linux-meta @ 5.4.0
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 11 | Planned | — |
| Debian 11 cloud | Planned | — |
| Debian 12 | Planned | — |
| Ubuntu 22.04 | Planned | — |