CVE-2026-52908: RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

CVE-2026-52908: RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

[Greg Kroah-Hartman]

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

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

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

RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

If IB_MR_REREG_ACCESS changes from RO to RW then the umem has to be
re-evaluated to ensure it is properly pinned as RW. Since the umem is
hidden inside each driver's mr struct add a ib_umem_check_rereg() function
that each driver has to call before processing IB_MR_REREG_ACCESS.

mlx4 has to retain its duplicate ib_access_writable check because it
implements IB_MR_REREG_ACCESS | IB_MR_REREG_TRANS by changing both items
in place sequentially while the MR is live, so it will continue to not
support this combination.

The Linux kernel CVE team has assigned CVE-2026-52908 to this issue.


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

	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 6.6.143 with commit 09dc18894148381d3bfc550083b1236043870dce
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 6.12.94 with commit eba5df21eda0fe7418efbea2f799f8ea1b8ca94c
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 6.18.36 with commit 2904e985a2917b5dac65df82733065e78a65fc9d
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 7.0.13 with commit 50334a05a950840b39a1ce3d2a173b4183db9b3e
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 7.1 with commit badad6fad60def1b9805559dd81dbab3d97b82aa

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-2026-52908
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:
	drivers/infiniband/core/umem.c
	drivers/infiniband/hw/hns/hns_roce_mr.c
	drivers/infiniband/hw/irdma/verbs.c
	drivers/infiniband/hw/mlx4/mr.c
	drivers/infiniband/hw/mlx5/mr.c
	drivers/infiniband/sw/rxe/rxe_verbs.c
	include/rdma/ib_umem.h


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/09dc18894148381d3bfc550083b1236043870dce
	https://git.kernel.org/stable/c/eba5df21eda0fe7418efbea2f799f8ea1b8ca94c
	https://git.kernel.org/stable/c/2904e985a2917b5dac65df82733065e78a65fc9d
	https://git.kernel.org/stable/c/50334a05a950840b39a1ce3d2a173b4183db9b3e
	https://git.kernel.org/stable/c/badad6fad60def1b9805559dd81dbab3d97b82aa

CVE-2026-52908: RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

[Greg Kroah-Hartman]

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

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

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

RDMA: During rereg_mr ensure that REREG_ACCESS is compatible

If IB_MR_REREG_ACCESS changes from RO to RW then the umem has to be
re-evaluated to ensure it is properly pinned as RW. Since the umem is
hidden inside each driver's mr struct add a ib_umem_check_rereg() function
that each driver has to call before processing IB_MR_REREG_ACCESS.

mlx4 has to retain its duplicate ib_access_writable check because it
implements IB_MR_REREG_ACCESS | IB_MR_REREG_TRANS by changing both items
in place sequentially while the MR is live, so it will continue to not
support this combination.

The Linux kernel CVE team has assigned CVE-2026-52908 to this issue.


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

	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 6.6.143 with commit 09dc18894148381d3bfc550083b1236043870dce
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 6.12.94 with commit eba5df21eda0fe7418efbea2f799f8ea1b8ca94c
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 6.18.36 with commit 2904e985a2917b5dac65df82733065e78a65fc9d
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 7.0.13 with commit 50334a05a950840b39a1ce3d2a173b4183db9b3e
	Issue introduced in 6.2 with commit b40656aa7d559adc1fe689396dc58b92a9a27286 and fixed in 7.1 with commit badad6fad60def1b9805559dd81dbab3d97b82aa

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-2026-52908
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:
	drivers/infiniband/core/umem.c
	drivers/infiniband/hw/hns/hns_roce_mr.c
	drivers/infiniband/hw/irdma/verbs.c
	drivers/infiniband/hw/mlx4/mr.c
	drivers/infiniband/hw/mlx5/mr.c
	drivers/infiniband/sw/rxe/rxe_verbs.c
	include/rdma/ib_umem.h


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/09dc18894148381d3bfc550083b1236043870dce
	https://git.kernel.org/stable/c/eba5df21eda0fe7418efbea2f799f8ea1b8ca94c
	https://git.kernel.org/stable/c/2904e985a2917b5dac65df82733065e78a65fc9d
	https://git.kernel.org/stable/c/50334a05a950840b39a1ce3d2a173b4183db9b3e
	https://git.kernel.org/stable/c/badad6fad60def1b9805559dd81dbab3d97b82aa