CVE-2026-64052: block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()

CVE-2026-64052: block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()

[Greg Kroah-Hartman]

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

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

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

block: bio-integrity: Fix null-ptr-deref in bio_integrity_map_user()

pin_user_pages_fast() can partially succeed and return the number of
pages that were actually pinned. However, the bio_integrity_map_user()
does not handle this partial pinning. This leads to a general protection
fault since bvec_from_pages() dereferences an unpinned page address,
which is 0.

To fix this, add a check to verify that all requested memory is pinned.
If partial pinning occurs, unpin the memory and return -EFAULT.

Kernel Oops:

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 UID: 0 PID: 1061 Comm: nvme-passthroug Not tainted 7.0.0-11783-g90957f9314e8-dirty #16 PREEMPT(lazy)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
RIP: 0010:bio_integrity_map_user.cold+0x1b0/0x9d6

The Linux kernel CVE team has assigned CVE-2026-64052 to this issue.


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

	Issue introduced in 6.8 with commit 492c5d455969fc2e829f26ed4c83487b068f0dd7 and fixed in 6.12.92 with commit 77c059f41e9395793917d067476f549a911d77d3
	Issue introduced in 6.8 with commit 492c5d455969fc2e829f26ed4c83487b068f0dd7 and fixed in 6.18.34 with commit 76410790f1491c8e06a451045ae223a61c652455
	Issue introduced in 6.8 with commit 492c5d455969fc2e829f26ed4c83487b068f0dd7 and fixed in 7.0.11 with commit 8fa244738641d95ea4d70e6f9a62778bba42a5b7
	Issue introduced in 6.8 with commit 492c5d455969fc2e829f26ed4c83487b068f0dd7 and fixed in 7.1 with commit 8582792cf23b3d94674d4d838f7cde9a28d0fcaf

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-2026-64052
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:
	block/bio-integrity.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/77c059f41e9395793917d067476f549a911d77d3
	https://git.kernel.org/stable/c/76410790f1491c8e06a451045ae223a61c652455
	https://git.kernel.org/stable/c/8fa244738641d95ea4d70e6f9a62778bba42a5b7
	https://git.kernel.org/stable/c/8582792cf23b3d94674d4d838f7cde9a28d0fcaf