Bug 1225046 (CVE-2021-47327)

Summary: VUL-0: CVE-2021-47327: kernel: iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails
Product: [Novell Products] SUSE Security Incidents Reporter: SMASH SMASH <smash_bz>
Component: IncidentsAssignee: Karasulli <vasant.karasulli>
Status: NEW --- QA Contact: Security Team bot <security-team>
Severity: Minor    
Priority: P3 - Medium CC: andrea.mattiazzo, jlee
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: Other   
URL: https://smash.suse.de/issue/406963/
Whiteboard: CVSSv3.1:SUSE:CVE-2021-47327:3.3:(AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L)
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---

Description SMASH SMASH 2024-05-22 15:57:35 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iommu/arm-smmu: Fix arm_smmu_device refcount leak when arm_smmu_rpm_get fails

arm_smmu_rpm_get() invokes pm_runtime_get_sync(), which increases the
refcount of the "smmu" even though the return value is less than 0.

The reference counting issue happens in some error handling paths of
arm_smmu_rpm_get() in its caller functions. When arm_smmu_rpm_get()
fails, the caller functions forget to decrease the refcount of "smmu"
increased by arm_smmu_rpm_get(), causing a refcount leak.

Fix this issue by calling pm_runtime_resume_and_get() instead of
pm_runtime_get_sync() in arm_smmu_rpm_get(), which can keep the refcount
balanced in case of failure.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47327
https://www.cve.org/CVERecord?id=CVE-2021-47327
https://git.kernel.org/stable/c/1adf30f198c26539a62d761e45af72cde570413d
https://git.kernel.org/stable/c/3761ae0d0e549f2acdaf11f49df4ed06d256b20f
https://git.kernel.org/stable/c/c4007596fbdabc29f858dc2e1990858a146b60b2
https://git.kernel.org/stable/c/fbf4daa6f4105e01fbd3868006f65c163365c1e3
https://git.kernel.org/stable/c/fe92c058199067ae90cf2a901ddf3c271893557a
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2021/CVE-2021-47327.mbox