s390/cio: fix out-of-bounds access on cio_ignore free
The channel-subsystem-driver scans for newly available devices whenever
device-IDs are removed from the cio_ignore list using a command such as:
echo free >/proc/cio_ignore
Since an I/O device scan might interfer with running I/Os, commit
172da89ed0ea ("s390/cio: avoid excessive path-verification requests")
introduced an optimization to exclude online devices from the scan.
The newly added check for online devices incorrectly assumes that
an I/O-subchannel's drvdata points to a struct io_subchannel_private.
For devices that are bound to a non-default I/O subchannel driver, such
as the vfio_ccw driver, this results in an out-of-bounds read access
during each scan.
Fix this by changing the scan logic to rely on a driver-independent
online indication. For this we can use struct subchannel->config.ena,
which is the driver's requested subchannel-enabled state. Since I/Os
can only be started on enabled subchannels, this matches the intent
of the original optimization of not scanning devices where I/O might
be running.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
EUVD |
EUVD-2022-55548 | In the Linux kernel, the following vulnerability has been resolved: s390/cio: fix out-of-bounds access on cio_ignore free The channel-subsystem-driver scans for newly available devices whenever device-IDs are removed from the cio_ignore list using a command such as: echo free >/proc/cio_ignore Since an I/O device scan might interfer with running I/Os, commit 172da89ed0ea ("s390/cio: avoid excessive path-verification requests") introduced an optimization to exclude online devices from the scan. The newly added check for online devices incorrectly assumes that an I/O-subchannel's drvdata points to a struct io_subchannel_private. For devices that are bound to a non-default I/O subchannel driver, such as the vfio_ccw driver, this results in an out-of-bounds read access during each scan. Fix this by changing the scan logic to rely on a driver-independent online indication. For this we can use struct subchannel->config.ena, which is the driver's requested subchannel-enabled state. Since I/Os can only be started on enabled subchannels, this matches the intent of the original optimization of not scanning devices where I/O might be running. |
Thu, 04 Dec 2025 15:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-125 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.15:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.15:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.15:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.1:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.1:rc2:*:*:*:*:*:* |
|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Wed, 17 Sep 2025 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Tue, 16 Sep 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Mon, 15 Sep 2025 15:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: s390/cio: fix out-of-bounds access on cio_ignore free The channel-subsystem-driver scans for newly available devices whenever device-IDs are removed from the cio_ignore list using a command such as: echo free >/proc/cio_ignore Since an I/O device scan might interfer with running I/Os, commit 172da89ed0ea ("s390/cio: avoid excessive path-verification requests") introduced an optimization to exclude online devices from the scan. The newly added check for online devices incorrectly assumes that an I/O-subchannel's drvdata points to a struct io_subchannel_private. For devices that are bound to a non-default I/O subchannel driver, such as the vfio_ccw driver, this results in an out-of-bounds read access during each scan. Fix this by changing the scan logic to rely on a driver-independent online indication. For this we can use struct subchannel->config.ena, which is the driver's requested subchannel-enabled state. Since I/Os can only be started on enabled subchannels, this matches the intent of the original optimization of not scanning devices where I/O might be running. | |
| Title | s390/cio: fix out-of-bounds access on cio_ignore free | |
| References |
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T19:16:46.881Z
Reserved: 2025-09-15T14:18:36.813Z
Link: CVE-2022-50307
No data.
Status : Analyzed
Published: 2025-09-15T15:15:42.377
Modified: 2025-12-04T15:30:58.510
Link: CVE-2022-50307
OpenCVE Enrichment
Updated: 2025-09-17T10:07:37Z
EUVD