CVE-2023-1076
A flaw was found in the Linux Kernel. The tun/tap sockets have their socket UID hardcoded to 0 due to a type confusion in their initialization function. While it will be often correct, as tuntap devices require CAP_NET_ADMIN, it may not always be the case, e.g., a non-root user only having that capability. This would make tun/tap sockets being incorrectly treated in filtering/routing decisions, possibly bypassing network filters.
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
A flaw was found in the Linux Kernel. The tun/tap sockets have their socket UID hardcoded to 0 due to a type confusion in their initialization function. While it will be often correct, as tuntap devices require CAP_NET_ADMIN, it may not always be the case, e.g., a non-root user only having that capability. This would make tun/tap sockets being incorrectly treated in filtering/routing decisions, possibly bypassing network filters.
05 / REFERENCES
Further evidence
- https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=66b2c338adce580dfce2199591e65e2bab889cff
- https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=a096ccca6e503a5c575717ff8a36ace27510ab0a
- https://lists.debian.org/debian-lts-announce/2023/05/msg00005.html