title: Possibility of deadlock in libbpf function sock_hash_delete_elem
description: A deadlock flaw was found in the Linux kernel’s BPF subsystem. This flaw allows a local user to potentially crash the system.
problem types: Deadlock
affected:
{
product: kernel
vendor: n/a
versions:
version: 6.4-rc1, status: unaffected
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 6
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:6
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 7
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:7
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 7
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:7
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:8
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 8
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:8
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:9
}
{
vendor: Red Hat
product: Red Hat Enterprise Linux 9
collectionURL: https://access.redhat.com/downloads/content/package-browser/
packageName: kernel-rt
defaultStatus: unaffected
cpes: cpe:/o:redhat:enterprise_linux:9
}
{
product: Fedora
vendor: Fedora
collectionURL: https://packages.fedoraproject.org/
packageName: kernel
defaultStatus: affected
}
metrics:
other: [
content: {'value': 'Low', 'namespace': 'https://access.redhat.com/security/updates/classification/'}
type: Red Hat severity rating
]
workarounds: The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl.
This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.
For the Red Hat Enterprise Linux 7 the eBPF for unprivileged users is always disabled.
For the Red Hat Enterprise Linux 8 or 9 to confirm the current state, inspect the sysctl with the command:
# cat /proc/sys/kernel/unprivileged_bpf_disabled
The setting of 1 would mean that unprivileged users cannot use eBPF, mitigating the flaw.
A kernel update will be required to mitigate the flaw for the root or users with CAP_SYS_ADMIN capabilities.
Note: A fix for this CVE may be backported as a part of one of the future BPF subsystem rebases.