| Summary: |
VUL-0: CVE-2021-47125: kernel: sch_htb: fix refcount leak in htb_parent_to_leaf_offload |
| Product: |
[Novell Products] SUSE Security Incidents
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Reporter: |
SMASH SMASH <smash_bz> |
| Component: |
Incidents | Assignee: |
Security Team bot <security-team> |
| Status: |
RESOLVED
FIXED
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QA Contact: |
Security Team bot <security-team> |
| Severity: |
Normal
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| Priority: |
P3 - Medium
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CC: |
gabriele.sonnu, osalvador
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| Version: |
unspecified | |
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| Target Milestone: |
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| Hardware: |
Other | |
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| OS: |
Other | |
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| URL: |
https://smash.suse.de/issue/397859/
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| Whiteboard: |
CVSSv3.1:SUSE:CVE-2021-47125:5.5:(AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) |
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Found By:
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Security Response Team
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Services Priority:
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Business Priority:
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Blocker:
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Marketing QA Status:
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IT Deployment:
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In the Linux kernel, the following vulnerability has been resolved: sch_htb: fix refcount leak in htb_parent_to_leaf_offload The commit ae81feb7338c ("sch_htb: fix null pointer dereference on a null new_q") fixes a NULL pointer dereference bug, but it is not correct. Because htb_graft_helper properly handles the case when new_q is NULL, and after the previous patch by skipping this call which creates an inconsistency : dev_queue->qdisc will still point to the old qdisc, but cl->parent->leaf.q will point to the new one (which will be noop_qdisc, because new_q was NULL). The code is based on an assumption that these two pointers are the same, so it can lead to refcount leaks. The correct fix is to add a NULL pointer check to protect qdisc_refcount_inc inside htb_parent_to_leaf_offload. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47125 https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893 https://www.cve.org/CVERecord?id=CVE-2021-47125 https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416 https://bugzilla.redhat.com/show_bug.cgi?id=2269839