What happened
In the Linux kernel, the following vulnerability has been resolved: s390/dasd: Propagate partial completion length across ERP recovery dasd_default_erp_postaction() copies the timing and device state from the finished ERP request back to the original request but drops proc_bytes. A request that was partially completed, an ESE read of a not-yet-allocated track returns fewer bytes than requested, and then recovered through the ERP chain loses its partial-completion length. __dasd_cleanup_cqr() then sees proc_bytes == 0 and completes the whole request instead of requeueing the remainder, silently returning zeroed data for the part that was never read. Carry proc_bytes over to the original request like the other per-request state.
Affected versions
Linux: 5e6bdd37c5526ef01326df5dabb93011ee89237e through before d6b8778b1b82aa3a8dbf8612080f635b834bd16b (git); 5e6bdd37c5526ef01326df5dabb93011ee89237e through before ceafb262475ac6cb3a7d07b1102608be2b216b99 (git); 5e6bdd37c5526ef01326df5dabb93011ee89237e through before 15ec03452c18e8d288e519837d21b308300d74b2 (git); 5e6bdd37c5526ef01326df5dabb93011ee89237e through before 6fb5ba2e7e43173a3761e46f091070a8185efa14 (git); fbbacd0dcbc3ae9398c569dbea96ae4b5ad97e04 (git); 5f7c9989f11305aaa43e0f4378f4f070022a9f2b (git); 5.4.26 through before 5.5 (semver); 5.5.10 through before 5.6 (semver); 5.6 Fixed: See vendor advisory.
Why it matters
Review the vendor advisory and exposure of the affected product to determine operational impact.
Detection & mitigation
- Apply vendor-provided updates or mitigations.
- Review affected product exposure and access logs.
Public PoC references
No public PoC reference has passed the current publication threshold.