CVE-2022-49989

Summary

In the Linux kernel, the following vulnerability has been resolved:

xen/privcmd: fix error exit of privcmd_ioctl_dm_op()

The error exit of privcmd_ioctl_dm_op() is calling unlock_pages() potentially with pages being NULL, leading to a NULL dereference.

Additionally lock_pages() doesn't check for pin_user_pages_fast() having been completely successful, resulting in potentially not locking all pages into memory. This could result in sporadic failures when using the related memory in user mode.

Fix all of that by calling unlock_pages() always with the real number of pinned pages, which will be zero in case pages being NULL, and by checking the number of pages pinned by pin_user_pages_fast() matching the expected number of pages.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxab520be8cd5d56867fc95cfbc34b90880faf1f9d < 6de50db104af0dc921f593fd95c55db86a52ceefaffected
LinuxLinuxab520be8cd5d56867fc95cfbc34b90880faf1f9d < c2b7bae7c90051fd6a679d5dee00400d67ebbf4aaffected
LinuxLinuxab520be8cd5d56867fc95cfbc34b90880faf1f9d < 45d47bd9b96e7874b98dbcc7602fe2826c5d62a6affected
LinuxLinuxab520be8cd5d56867fc95cfbc34b90880faf1f9d < c5deb27895e017a0267de0a20d140ad5fcc55a54affected
LinuxLinux4.11affected
LinuxLinux0 < 4.11unaffected
LinuxLinux5.10.140 <= 5.10.*unaffected
LinuxLinux5.15.64 <= 5.15.*unaffected
LinuxLinux5.19.6 <= 5.19.*unaffected
LinuxLinux6.0 <= *unaffected

Weaknesses

References