[CVE-2026-46127][MODERATE REGULAR] RDMA/ocrdma: Don't NULL deref uctx on errors in ocrdma_copy_pd_uresp()

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-46127
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: RDMA/ocrdma: Don't NULL deref uctx on errors in ocrdma_copy_pd_uresp()
Commit: e01a957561f663d3b68d2fd233a4502e3367efcd
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e01a957561f663d3b68d2fd233a4502e3367efcd
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46127
Analysis date: Thu, 28 May 2026 13:48:49 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
A local process with access to the `ocrdma` RDMA uverbs interface can trigger an error path that dereferences an uninitialized `pd->uctx`, causing a kernel NULL pointer dereference and DoS.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-46127 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46127

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: MODERATE REGULAR
Manual review required: YES

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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AL-KERNEL CLASSIFICATION RESULT
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CVE-2026-46127	MODERATE	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';**CWE-476;CWE-703;CWE-754;BEST CVSS score: '5.5';DESCR 'RDMA ocrdma error handling in ocrdma_copy_pd_uresp can dereference pd uctx before it is initialized when an error path is taken after mmap setup or user response handling. A local process with access to the ocrdma RDMA uverbs interface may be able to trigger the error path and crash the kernel through a NULL pointer dereference. For the CVSS the PR:L is used because triggering requires local code execution and access to the RDMA userspace device, but it does not require full host administrator privileges when RDMA devices are delegated. The issue is not network reachable as packet processing and no information disclosure, write primitive, or privilege escalation path is shown. Impact is denial of service only.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 3) 	MAYBE	READ DANGER SIMPLEFIX NETWORK KERNEL_PANIC_PLUS_UAF MEMORY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: **2**
* Paranoid score: **3**
* Final recommended bucket: **Borderline, manual review recommended**::

## 2. Signal breakdown

* Local unprivileged trigger: **+1**. A local process with access to the `ocrdma` RDMA uverbs device may trigger the vulnerable error path.
* Reliable kernel crash / strong DoS: **+1**. The bug is a NULL pointer dereference on `pd->uctx` before it is initialized, which can crash the kernel.
* Availability impact realistic: **+1**. The realistic impact is local denial of service.
* Local high-control kernel device API, paranoid only: **+1**. RDMA uverbs is a rich userspace kernel interface, but this specific bug is only a NULL dereference, not a strong corruption primitive.
* Rare / hardware-specific exposure: **-1**. The issue requires the `ocrdma` driver and suitable Emulex OneConnect RDMA hardware or exposed uverbs device.
* No memory corruption: **+0**. The patch shows a NULL dereference, not UAF, OOB write, double-free, heap overwrite, or controlled corruption.
* No confidentiality or integrity signal: **+0**. No leak, write primitive, privilege escalation, or policy bypass is shown.

## 3. Reachability analysis

The bug is local and requires access to the `ocrdma` RDMA userspace interface. It is not remotely reachable through RDMA packets or normal network traffic. Containers may matter if the RDMA uverbs device is passed through or delegated to a workload. The path is not default on most systems because it depends on specific RDMA hardware and driver availability. Realistic exploitation is a local kernel crash if an attacker can force the relevant error cleanup path.

## 4. Severity interpretation

This behaves like a **borderline Moderate** issue. The realistic impact is DoS only. The patch does not support memory corruption or privilege escalation. It deserves some manual attention because RDMA uverbs devices are sometimes delegated to non-root workloads, but it is not an Important candidate without stronger primitives.

## 5. One-sentence report phrase

A local process with access to the `ocrdma` RDMA uverbs interface can trigger an error path that dereferences an uninitialized `pd->uctx`, causing a kernel NULL pointer dereference and DoS.

## 6. Manual review recommendation

**MANUAL CHECK RECOMMENDED**

Manual review is recommended mainly to confirm whether untrusted users can access the affected RDMA device. If not, this can be treated as low-priority DoS.

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UPSTREAM PATCH SUMMARY
======================================================================

Patch: RDMA/ocrdma: Don't NULL deref uctx on errors in ocrdma_copy_pd_uresp()
Commit: e01a957561f663d3b68d2fd233a4502e3367efcd
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e01a957561f663d3b68d2fd233a4502e3367efcd

Commit description:

Sashiko points out that pd->uctx isn't initialized until late in the
function so all these error flow references are NULL and will crash. Use
the uctx that isn't NULL.

Cc: stable@vger.kernel.org
Fixes: fe2caef ("RDMA/ocrdma: Add driver for Emulex OneConnect IBoE RDMA adapter")
Link: https://sashiko.dev/#/patchset/0-v1-e911b76a94d1%2B65d95-rdma_udata_rep_jgg%40nvidia.com?part=4
Link: https://patch.msgid.link/r/9-v1-41f3135e5565+9d2-rdma_ai_fixes1_jgg@nvidia.com
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/infiniband/hw/ocrdma/ocrdma_verbs.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e01a957561f663d3b68d2fd233a4502e3367efcd

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-46127 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46127

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: Not available
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 2
  Paranoid ActionableScore: 3

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).