CVE-2024-43819

What the bug is

This change rejects the KVM_SET_USER_MEMORY_REGION and KVM_SET_USER_MEMORY_REGION2 ioctls when called on a ucontrol VM. This is necessary since ucontrol VMs have kvm->arch.gmap set to 0 and would thus result in a null pointer dereference further in. Memory management needs to be performed in userspace and using the ioctls KVM_S390_UCAS_MAP and KVM_S390_UCAS_UNMAP. Also improve s390 specific documentation for KVM_SET_USER_MEMORY_REGION and KVM_SET_USER_MEMORY_REGION2. [frankja@linux.ibm.com: commit message spelling fix, subject prefix fix]

Where it lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

Documentation/virt/kvm/api.rst
arch/s390/kvm/kvm-s390.c

What this is

KERNEL VIRTUAL MACHINE (KVM)MAINTAINERS section matched on Documentation/virt/kvm/ · kvm@vger.kernel.org · Supported

Kernel module

kvm

Check it on the machine

grep -w CONFIG_KVM /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

lsmod | grep -w kvm

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormBnot built on arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
• trixieBnot built on armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp
• forky, sidBnot built on armhf/armmp, armhf/armmp-lpae

B

built in on some, a module on others, absent on the rest

Build switch

CONFIG_KVM

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2024-08-17 (2 years ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.5% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

Documentation/virt

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
3.4	6.10.3	49c9945c054d
3.4	6.11	7816e58967d0