coverity bugs found in v4l2loopback dkms source

[You-Sheng Yang]

[SRU Justification]

[Impact]

On a MIPI camera through Intel IPU6 platform that its raw V4L2 loopback interface is preserved for Intel Camera HAL libraries, a relay daemon + v4l2loopback is used to allow the usage of legacy V4L2 based apps.

v4l2loopback itself contains several potential issues that were identified by coverity tools. In order to prebuilt and sign this kernel module, these issues should be addressed first.

[Test Plan]

The changes here doesn't change the semantics of the implementation, and have no observable differences.

[Where problems could occur]

N/A.

[Other Info]

For Focal backports, 0.12.5-1 is equivalent to 0.12.3-1ubuntu0.3 plus micro version updates, so there should be little risk backport a new release, and we can drop additional patches carried. This implies bug 1905613.

This focal backport includes changes for bug 1921474, bug 1930208, and bug 1936250, so it will then become synced with Impish and newer again. The 0007-compliance-stop-declaring-V4L2_CAP_VIDEO_M2M-capabil.patch carried in bug 1930208 is deliberately skipped to avoid bug 1946660.

========= original bug report ==========

By running coverity scan tool[1], a few errors were found.

[1]: https://scan.coverity.com/
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu65.1
Architecture: amd64
CasperMD5CheckResult: unknown
DistroRelease: Ubuntu 21.04
InstallationDate: Installed on 2019-09-28 (610 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Alpha amd64 (20190923)
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair wl
Package: v4l2loopback-dkms 0.12.5-1ubuntu1
PackageArchitecture: all
ProcVersionSignature: Ubuntu 5.13.0-1002.2-oem 5.13.0-rc2
Tags: hirsute
Uname: Linux 5.13.0-1002-oem x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: N/A
_MarkForUpload: True

[You-Sheng Yang (vicamo)]

apport information

[You-Sheng Yang (vicamo)]

apport information

[You-Sheng Yang (vicamo)]

apport information

[You-Sheng Yang (vicamo)]

Attach proposed fix in debdiff. Prebuilt packages will be available in https://launchpad.net/~vicamo/+archive/ubuntu/ppa-1930208 .

[Ubuntu Foundations Team Bug Bot (crichton)]

The attachment "v4l2loopback_0.12.5-1ubuntu2.debdiff" seems to be a debdiff. The ubuntu-sponsors team has been subscribed to the bug report so that they can review and hopefully sponsor the debdiff. If the attachment isn't a patch, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are member of the ~ubuntu-sponsors, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issue please contact him.]

[Sebastien Bacher (seb128)]

Thank you for the work, the issue is an upstream one right? if so could you submit a PR on github and reference is in the patch information?

[You-Sheng Yang (vicamo)]

Changes from previous upload:
* Update cherry-pick information for those already merged in upstream. For those not, add prefix "UBUNTU: SAUCE: " in the subjects.
* Filed https://github.com/umlaeute/v4l2loopback/pull/438 for errors to worthy of fixing in upstream develop branch.

[Launchpad Janitor (janitor)]

This bug was fixed in the package v4l2loopback - 0.12.5-1ubuntu2

---------------
v4l2loopback (0.12.5-1ubuntu2) impish; urgency=low

  * Fix coverity errors. (LP: #1930208)

 -- You-Sheng Yang <email address hidden> Fri, 09 Jul 2021 18:08:29 +0800

[Erich Eickmeyer (eeickmeyer)]

After updating, there has been an error related to modprobe that I reported as a new bug (LP: #1936250), however, this may be a regression from the fixes presented in this bug.

[You-Sheng Yang (vicamo)]

Focal debdiff uploaded to https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1921474/+attachment/5551074/+files/v4l2loopback_0.12.3-1ubuntu0.4_0.12.3-1ubuntu0.5.debdiff

[Robie Basak (racb)]

An upload of v4l2loopback to focal-proposed has been rejected from the upload queue for the following reason: "Clearing this from the queue for now as it isn't ready for an SRU to Focal. See https://bugs.launchpad.net/ubuntu/+source/v4l2loopback/+bug/1921474/comments/12 and subsequent comments for details.".

[Julian Andres Klode (juliank)]

Unsubscribing Ubuntu sponsors, as the SRU was uploaded and rejected, please resubscribe when/if there's something ready to sponsor again.