CVE-2024-36950

high

Published 2024-08-08 · Modified 2024-08-08

💬 Discuss on Community ✚ Propose mitigation

CVSS v3

—

CVSS v4 NEW

—

not yet in upstream

VIR risk

8.0

Description

In the Linux kernel, the following vulnerability has been resolved: firewire: ohci: mask bus reset interrupts between ISR and bottom half In the FireWire OHCI interrupt handler, if a bus reset interrupt has occurred, mask bus reset interrupts until bus_reset_work has serviced and cleared the interrupt. Normally, we always leave bus reset interrupts masked. We infer the bus reset from the self-ID interrupt that happens shortly thereafter. A scenario where we unmask bus reset interrupts was introduced in 2008 in a007bb857e0b26f5d8b73c2ff90782d9c0972620: If OHCI_PARAM_DEBUG_BUSRESETS (8) is set in the debug parameter bitmask, we will unmask bus reset interrupts so we can log them. irq_handler logs the bus reset interrupt. However, we can't clear the bus reset event flag in irq_handler, because we won't service the event until later. irq_handler exits with the event flag still set. If the corresponding interrupt is still unmasked, the first bus reset will usually freeze the system due to irq_handler being called again each time it exits. This freeze can be reproduced by loading firewire_ohci with "modprobe firewire_ohci debug=-1" (to enable all debugging output). Apparently there are also some cases where bus_reset_work will get called soon enough to clear the event, and operation will continue normally. This freeze was first reported a few months after a007bb85 was committed, but until now it was never fixed. The debug level could safely be set to -1 through sysfs after the module was loaded, but this would be ineffectual in logging bus reset interrupts since they were only unmasked during initialization. irq_handler will now leave the event flag set but mask bus reset interrupts, so irq_handler won't be called again and there will be no freeze. If OHCI_PARAM_DEBUG_BUSRESETS is enabled, bus_reset_work will unmask the interrupt after servicing the event, so future interrupts will be caught as desired. As a side effect to this change, OHCI_PARAM_DEBUG_BUSRESETS can now be enabled through sysfs in addition to during initial module loading. However, when enabled through sysfs, logging of bus reset interrupts will be effective only starting with the second bus reset, after bus_reset_work has executed.

Predictions

Exploit likelihood

20%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

Mitigation details

Source: Red Hat Errata — Red Hat Inc. · View original ↗ · Open-Errata-API

Description kernel: firewire: ohci: mask bus reset interrupts between ISR and bottom half CVSS v3: 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H) Errata / fixed releases ProductPackageAdvisoryReleased Red Hat Enterprise Linux 8kernel-rt-0:4.18.0-553.16.1.rt7.357.el8_10RHSA-2024:51022024-08-08T00:00:00Z Red Hat Enterprise Linux 8kernel-0:4.18.0-553.16.1.el8_10RHSA-2024:51012024-08-08T00:00:00Z…

Description

kernel: firewire: ohci: mask bus reset interrupts between ISR and bottom half

CVSS v3: 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H)

Errata / fixed releases

Product	Package	Advisory	Released
Red Hat Enterprise Linux 8	`kernel-rt-0:4.18.0-553.16.1.rt7.357.el8_10`	RHSA-2024:5102	2024-08-08T00:00:00Z
Red Hat Enterprise Linux 8	`kernel-0:4.18.0-553.16.1.el8_10`	RHSA-2024:5101	2024-08-08T00:00:00Z

Package state

Product	Package	State
Red Hat Enterprise Linux 6	`kernel`	Out of support scope
Red Hat Enterprise Linux 7	`kernel`	Out of support scope
Red Hat Enterprise Linux 7	`kernel-rt`	Out of support scope
Red Hat Enterprise Linux 9	`kernel`	Not affected
Red Hat Enterprise Linux 9	`kernel-rt`	Not affected

Apply commands

bash fix

Apply RHSA-2024:5102 for Red Hat Enterprise Linux 8

yum update -y kernel-rt
# or:
dnf upgrade -y kernel-rt

Affected

Vendor	Product	Version
redhat	Red Hat Enterprise Linux 9	`Not affected`
redhat	Red Hat Enterprise Linux 9	`Not affected`

OS impact

SUSE Affected 1 release

Version	Status	Fixed in
—	Affected	—

AlmaLinux Fixed 1 release

Version	Status	Fixed in
8	Fixed	`kernel-doc-4.18.0-553.16.1.el8_10.noarch.rpm`

Debian Fixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`6.8.11-1`
sid	Fixed	`6.8.11-1`
forky	Fixed	`6.8.11-1`
bullseye	Fixed	`5.10.218-1`
bookworm	Fixed	`6.1.94-1`

Red Hat Fixed 1 release

Version	Status	Fixed in
8	Fixed	—

Rocky Linux Fixed 1 release

Version	Status	Fixed in
8	Fixed	—

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.