CVE-2026-68313: tipc: fix infinite loop in __tipc_nl_compat_dumpit

From: Greg Kroah-Hartman <[email protected]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

tipc: fix infinite loop in __tipc_nl_compat_dumpit

cmd->dumpit callback can return a negative errno, causing an infinite
loop due to the while(len) condition. As the loop never terminates,
genl_mutex is never released, and other tasks waiting on it starve in D
state.

Check dumpit's return value, propagate it and jump to err_out on error.

The Linux kernel CVE team has assigned CVE-2026-68313 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 4.0 with commit d0796d1ef63deb38147729664691ba3090930b26 and fixed in 6.6.148 with commit f9c669d9f4cac832fe31193cdbc24c6a9d99398b
	Issue introduced in 4.0 with commit d0796d1ef63deb38147729664691ba3090930b26 and fixed in 6.12.101 with commit 1ab78af2140189b735b8d3b889b0284128cb2013
	Issue introduced in 4.0 with commit d0796d1ef63deb38147729664691ba3090930b26 and fixed in 6.18.42 with commit e740e90ca8e7f70d9eac1aa31a8b3e0e4d32b2ef
	Issue introduced in 4.0 with commit d0796d1ef63deb38147729664691ba3090930b26 and fixed in 7.1.6 with commit b8f3b8efa5f99081b14de1a7ffa68a81bf01bd48
	Issue introduced in 4.0 with commit d0796d1ef63deb38147729664691ba3090930b26 and fixed in 7.2-rc5 with commit 22f8aa35964e8f2ab026578f45befc9605fd1b28

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-68313
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/tipc/netlink_compat.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/f9c669d9f4cac832fe31193cdbc24c6a9d99398b
	https://git.kernel.org/stable/c/1ab78af2140189b735b8d3b889b0284128cb2013
	https://git.kernel.org/stable/c/e740e90ca8e7f70d9eac1aa31a8b3e0e4d32b2ef
	https://git.kernel.org/stable/c/b8f3b8efa5f99081b14de1a7ffa68a81bf01bd48
	https://git.kernel.org/stable/c/22f8aa35964e8f2ab026578f45befc9605fd1b28