bpf: Cancel special fields on map value recycle
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
| Vendor | Product | Versions | ||||||||||||||||||||
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| Linux | Linux Kernel |
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| Linux | Linux Kernel |
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| Source | ID | Title |
|---|---|---|
Ubuntu USN |
USN-8887-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8888-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8889-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-8887-2 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8888-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8887-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-9003-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-9043-1 | Linux kernel (NVIDIA) vulnerabilities |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.177% probability within 30 days)
| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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| Type | Values Removed | Values Added |
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| Weaknesses | CWE-416 |
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-763 | |
| References |
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| Metrics |
threat_severity
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threat_severity
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| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-416 |
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-362 CWE-416 |
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
cvssV3_1
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| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-362 CWE-416 |
| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: bpf: Cancel special fields on map value recycle Map update and delete paths currently call bpf_obj_free_fields() when a value is being replaced or recycled. That makes field destruction depend on the context of the update/delete operation. For tracing programs this can include NMI context, where referenced kptr destructors, uptr unpinning, and graph root destruction are not generally safe. Introduce bpf_obj_cancel_fields() for the reusable-value path. It only performs NMI-safe cleanup for timer, workqueue, and task_work fields. Fields that need full destruction are left attached to the recycled value and are destroyed by the final cleanup path instead. Switch array and hashtab update/delete/recycle paths to this cancel helper. Keep bpf_obj_free_fields() for final map destruction and for bpf_mem_alloc destructors. Preallocated hashtabs do not have allocator destructors, so teardown continues to walk the normal and extra elements and fully destroy their fields. This deliberately relaxes the eager-free semantics of map update/delete for special fields. Programs that relied on a recycled map slot becoming empty immediately after update/delete were relying on behavior that cannot be implemented safely from every BPF execution context without offloading arbitrary destructors. There is a chance this change breaks programs making assumptions regarding the eager freeing of fields. If so, we can relax semantics to cancellation only when irqs_disabled() is true in the future. However, theoretically, map values that get reused eagerly already have weaker guarantees as parallel users can recreate freed fields before the new element becomes visible again. | |
| Title | bpf: Cancel special fields on map value recycle | |
| First Time appeared |
Linux
Linux linux Kernel |
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| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
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| References |
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