CVE-2022-49569
📋 TL;DR
This CVE describes a NULL pointer dereference vulnerability in the Linux kernel's BCM2835 SPI driver. When an IRQ-based SPI transfer times out, the error handling function attempts to cancel DMA transfers without checking if DMA pointers are valid, causing a kernel panic. This affects systems using the BCM2835 SPI controller, particularly Raspberry Pi devices and other embedded systems with this hardware.
💻 Affected Systems
- Linux kernel with BCM2835 SPI driver
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially causing data loss or system instability.
Likely Case
System crash or reboot when SPI transfers timeout under specific conditions, resulting in temporary denial of service.
If Mitigated
Minimal impact if systems don't use BCM2835 SPI controller or have proper monitoring for system stability.
🎯 Exploit Status
Exploitation requires ability to trigger SPI transfer timeouts, typically requiring local access and hardware interaction. Not suitable for remote exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in Linux kernel stable releases via commits referenced in CVE
Vendor Advisory: https://git.kernel.org/stable/c/49ffa473218012e765682343de2052eb4c1f06a7
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from official repositories. 2. For Raspberry Pi: Update firmware and kernel via 'sudo apt update && sudo apt full-upgrade'. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable SPI controller
linuxPrevent use of vulnerable BCM2835 SPI driver if not needed
echo 'blacklist spi-bcm2835' | sudo tee /etc/modprobe.d/blacklist-spi-bcm2835.conf
sudo update-initramfs -u
sudo reboot
Use DMA transfers only
linuxConfigure SPI to use DMA transfers exclusively to avoid IRQ-based timeout path
Modify SPI device tree or configuration to force DMA mode
🧯 If You Can't Patch
- Monitor system logs for kernel panics and implement automatic recovery
- Restrict physical and local access to systems using BCM2835 SPI hardware
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if BCM2835 SPI driver is loaded: 'uname -r' and 'lsmod | grep spi_bcm2835'Check Version:
uname -rVerify Fix Applied:
Verify kernel version is patched and check for NULL pointer checks in driver error handling📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- NULL pointer dereference in kernel logs
- SPI timeout errors
Network Indicators:
- None - local hardware vulnerability
SIEM Query:
source="kernel" AND ("NULL pointer" OR "kernel panic" OR "spi_bcm2835")🔗 References
- https://git.kernel.org/stable/c/49ffa473218012e765682343de2052eb4c1f06a7
- https://git.kernel.org/stable/c/4ceaa684459d414992acbefb4e4c31f2dfc50641
- https://git.kernel.org/stable/c/58466e05390043d2805685c70f55f3f59711bdf2
- https://git.kernel.org/stable/c/684896e675edd8b669fd3e9f547c5038222d85bc
- https://git.kernel.org/stable/c/76668d2a2f367d25ff448e6d7087406af7d7bb2b
