Mitigation Strategies

To mitigate this vulnerability, ensure that your Linux kernel is updated to a version where the fix has been applied. The fix involves adding an In_sync flag check when reading bitmap pages from member disks in md/md-llbitmap, preventing reading from disks that are still rebuilding and may contain stale bitmap data.

Until the kernel is updated, avoid relying on RAID bitmap data from disks that are still rebuilding or marked as spare, as this can lead to data corruption.

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Executive Summary

This vulnerability exists in the Linux kernel's md/md-llbitmap component, where the code responsible for reading bitmap pages from member disks does not properly check if the disks are fully synchronized (In_sync flag). Instead, it only checks for raid_disk assignment and Faulty flag.

Because of this missing In_sync check, the system may read bitmap data from spare disks that are still being rebuilt and do not yet have valid bitmap information. This can cause the system to use stale or uninitialized bitmap data.

As a result, the incorrect bitmap data can lead to improper tracking of dirty bits, which may cause data corruption during recovery or normal operation.

The fix involves adding the In_sync flag check to ensure bitmap pages are only read from fully synchronized member disks with valid bitmap data.

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Impact Analysis

This vulnerability can impact you by causing data corruption in systems using Linux kernel RAID configurations that rely on bitmap tracking.

Because stale or uninitialized bitmap data might be read from disks still rebuilding, the system may incorrectly track which parts of the disk are dirty.

This incorrect tracking can lead to data corruption during recovery processes or even during normal operation, potentially resulting in loss or inconsistency of important data.

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