s390/dasd: Guard sysfs discipline callbacks against unallocated private data

Summary

In the Linux kernel, the following vulnerability has been resolved: s390/dasd: Guard sysfs discipline callbacks against unallocated private data Several sysfs show/store handlers call a discipline callback that dereferences device->private, either directly or through the DASD_DEFINE_ATTR() macro. During dasd_generic_set_online() the discipline is assigned before check_device() allocates device->private, so an unprivileged read of one of these world-readable attributes in that window dereferences a NULL pointer and panics. Guard the dereference inside each callback that actually touches device->private.

Timeline

1. Sep 11, 2026, 7:43 PM UTCCVE published
2. Oct 19, 2026, 8:47 AM UTCRecord last updated

Affected versions

• Linux Linux

  From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in 644b666c202cce12ccfcf9ded67089b18f4f7659; From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in 4a042d8e5f34282577ece50515cea8bb1246914d; From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in bd8b4572528f9604a13bf3c7c2a167f5cf222f72; From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in 57db27ccc162afe0726cffec0ae62e410ed2d0e9; From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in 536407b272402af679155910d7fdeeb4834eefb9; From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in 6452c13646af7c13d7f6668b6690cfb2427e7f7b; From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in 449f3bada7a9fad8b8cdf4bb20baf27ee9ca56c5; From c729696bcf8b23450043dd9c9972c15e53419ae4 · fixed in 2a1780f9fc2493bd34c418a0be6fc58943afcecf

• Linux Linux

  5.3

• KernelLinux

  From 5.3.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8