CVE-2026-80756: selinux: do not cancel a policy conversion that never started

CVE-2026-80756: selinux: do not cancel a policy conversion that never started

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

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

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

selinux: do not cancel a policy conversion that never started

sel_write_load() calls selinux_policy_cancel() when sel_make_policy_nodes()
fails, and that helper dereferences the outgoing policy to cancel its
sidtab conversion. On the first policy load there is no outgoing policy:
security_load_policy() returns early for that case, before it converts
anything, and state->policy is still NULL. A first load that fails while
building the selinuxfs tree therefore takes a NULL dereference in
selinux_policy_cancel(), reached from a write(2) to /sys/fs/selinux/load.

Skip the cancel when there is no old policy, mirroring the check
security_load_policy() already makes before it converts.

The Linux kernel CVE team has assigned CVE-2026-80756 to this issue.


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

	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 5.10.266 with commit 2d29983104f06f5b0babcd5a25a0f0408272cd27
	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 5.15.217 with commit a4f182f8715cb0819445f0850cd5436828f4bafc
	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 6.1.184 with commit 1059789ae9f99cbbe3a78e361e9c0976beb5958b
	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 6.6.153 with commit 1acc317d67a755a45e32419a15d70e403fa43f0e
	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 6.12.105 with commit a42932c6aa33d0aac683cacdf1ec7009b955ba5d
	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 6.18.46 with commit 1b4ff94ae7c580c880291519fb0e3e2bd075beef
	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 7.1.10 with commit 219c96de5d9b6b4af7e8576ad897b774cc3ee9a7
	Issue introduced in 5.10 with commit 02a52c5c8c3b8cbad0f12009cde9f36dbefb6972 and fixed in 7.2 with commit e5c0235a3c4e9eb047a16cd02323fe4ecf2f570e

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-2026-80756
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:
	security/selinux/ss/services.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/2d29983104f06f5b0babcd5a25a0f0408272cd27
	https://git.kernel.org/stable/c/a4f182f8715cb0819445f0850cd5436828f4bafc
	https://git.kernel.org/stable/c/1059789ae9f99cbbe3a78e361e9c0976beb5958b
	https://git.kernel.org/stable/c/1acc317d67a755a45e32419a15d70e403fa43f0e
	https://git.kernel.org/stable/c/a42932c6aa33d0aac683cacdf1ec7009b955ba5d
	https://git.kernel.org/stable/c/1b4ff94ae7c580c880291519fb0e3e2bd075beef
	https://git.kernel.org/stable/c/219c96de5d9b6b4af7e8576ad897b774cc3ee9a7
	https://git.kernel.org/stable/c/e5c0235a3c4e9eb047a16cd02323fe4ecf2f570e