In the Linux kernel, the following vulnerability has been resolved:
mm: resolve faulty mmap_region() error path behaviour
The mmap_region() function is somewhat terrifying, with spaghetti-like control flow and numerous means by which issues can arise and incomplete state, memory leaks and other unpleasantness can occur.
A large amount of the complexity arises from trying to handle errors late in the process of mapping a VMA, which forms the basis of recently observed issues with resource leaks and observable inconsistent state.
Taking advantage of previous patches in this series we move a number of checks earlier in the code, simplifying things by moving the core of the logic into a static internal function __mmap_region().
Doing this allows us to perform a number of checks up front before we do any real work, and allows us to unwind the writable unmap check unconditionally as required and to perform a CONFIG_DEBUG_VM_MAPLE_TREE validation unconditionally also.
We move a number of things here:
1. We preallocate memory for the iterator before we call the file-backed memory hook, allowing us to exit early and avoid having to perform complicated and error-prone close/free logic. We carefully free iterator state on both success and error paths.
2. The enclosing mmap_region() function handles the mapping_map_writable() logic early. Previously the logic had the mapping_map_writable() at the point of mapping a newly allocated file-backed VMA, and a matching mapping_unmap_writable() on success and error paths.
We now do this unconditionally if this is a file-backed, shared writable mapping. If a driver changes the flags to eliminate VM_MAYWRITE, however doing so does not invalidate the seal check we just performed, and we in any case always decrement the counter in the wrapper.
We perform a debug assert to ensure a driver does not attempt to do the opposite.
3. We also move arch_validate_flags() up into the mmap_region() function. This is only relevant on arm64 and sparc64, and the check is only meaningful for SPARC with ADI enabled. We explicitly add a warning for this arch if a driver invalidates this check, though the code ought eventually to be fixed to eliminate the need for this.
With all of these measures in place, we no longer need to explicitly close the VMA on error paths, as we place all checks which might fail prior to a call to any driver mmap hook.
This eliminates an entire class of errors, makes the code easier to reason about and more robust.
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade python-perfUpgrade kernel-livepatch-5.10.233-223.887Upgrade perfUpgrade bpftoolUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-aarch64Upgrade kernel-toolsUpgrade kernelUpgrade kernel-tools-debuginfoUpgrade kernel-headersUpgrade python-perf-debuginfoUpgrade kernel-debuginfoUpgrade kernel-develUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-tools-develUpgrade kernel-livepatch-5.15.176-118.170Upgrade perf-debuginfo | Mar 4, 2025 | Nov 25, 2024 |
| Amazon_linux_2023 | — | Upgrade kernel-libbpf-staticUpgrade kernel-livepatch-6.1.119-129.201Upgrade kernel-libbpf-develUpgrade kernel-modules-extra-commonUpgrade bpftool-debuginfoUpgrade kernelUpgrade bpftoolUpgrade kernel-headersUpgrade kernel-modules-extraUpgrade python3-perf-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-toolsUpgrade kernel-debuginfo-common-aarch64Upgrade perf-debuginfoUpgrade perfUpgrade kernel-debuginfoUpgrade kernel-develUpgrade kernel-libbpfUpgrade kernel-tools-develUpgrade kernel-tools-debuginfoUpgrade python3-perf | Mar 10, 2025 | Nov 25, 2024 |
| Debian | — | Upgrade linux-6.1Upgrade linux | Dec 2, 2024 | Nov 25, 2024 |
| Huawei Euleros 2_0_sp11 | — | Upgrade python3-perfUpgrade kernel-abi-stablelistsUpgrade kernel-toolsUpgrade bpftoolUpgrade kernelUpgrade kernel-tools-libs | Feb 11, 2025 | Nov 25, 2024 |
| Huawei Euleros 2_0_sp12 | — | Upgrade kernel-abi-stablelistsUpgrade kernelUpgrade kernel-tools-libsUpgrade bpftoolUpgrade kernel-toolsUpgrade python3-perf | Feb 11, 2025 | Nov 25, 2024 |
| Oracle_linux | — | Upgrade kernel-uek | Feb 10, 2025 | Nov 25, 2024 |
| Redhat_linux | — | Upgrade kernel-rtNo solution existsUpgrade kernel | May 15, 2025 | Nov 25, 2024 |
| Ubuntu | — | Upgrade linux-image-oem-24.04Upgrade linux-image-nvidiaUpgrade linux-image-intel-iotgUpgrade linux-image-5.15.0-1077-intel-iotgUpgrade linux-image-5.15.0-136-genericUpgrade linux-image-6.8.0-1026-nvidia-lowlatency-64kUpgrade linux-image-oem-22.04cUpgrade linux-image-5.15.0-1079-gcpUpgrade linux-image-generic-64k-hwe-22.04Upgrade linux-image-6.8.0-1026-oemUpgrade linux-image-azure-lts-22.04Upgrade linux-image-6.8.0-58-lowlatencyUpgrade linux-image-5.15.0-1083-azure-fipsUpgrade linux-image-oem-22.04Upgrade linux-image-5.15.0-1080-awsUpgrade linux-image-6.8.0-58-lowlatency-64kUpgrade linux-image-generic-hwe-22.04Upgrade linux-image-5.15.0-1076-kvmUpgrade linux-image-oem-20.04cUpgrade linux-image-gkeop-5.15Upgrade linux-image-intelUpgrade linux-image-6.8.0-1026-nvidia-64kUpgrade linux-image-generic-64k-hwe-20.04Upgrade linux-image-6.8.0-1027-awsUpgrade linux-image-oracle-64kUpgrade linux-image-5.15.0-1086-azure-fdeUpgrade linux-image-nvidia-64kUpgrade linux-image-raspi-realtimeUpgrade linux-image-virtualUpgrade linux-image-5.15.0-1074-raspiUpgrade linux-image-gkeopUpgrade linux-image-gcpUpgrade linux-image-generic-lpae-hwe-20.04Upgrade linux-image-5.15.0-1033-nvidia-tegra-rtUpgrade linux-image-nvidia-tegraUpgrade linux-image-aws-lts-24.04Upgrade linux-image-oracle-lts-22.04Upgrade linux-image-6.8.0-1028-gcpUpgrade linux-image-oem-20.04dUpgrade linux-image-xilinx-zynqmpUpgrade linux-image-nvidia-tegra-igx-rtUpgrade linux-image-virtual-hwe-22.04Upgrade linux-image-6.8.0-1023-gkeUpgrade linux-image-5.15.0-135-lowlatency-64kUpgrade linux-image-realtimeUpgrade linux-image-5.15.0-1021-nvidia-tegra-igxUpgrade linux-image-5.15.0-135-genericUpgrade linux-image-intel-iot-realtimeUpgrade linux-image-oem-24.04aUpgrade linux-image-6.8.0-1026-nvidiaUpgrade linux-image-generic-64kUpgrade linux-image-5.15.0-1072-ibmUpgrade linux-image-6.8.0-1024-oracleUpgrade linux-image-5.15.0-1077-oracleUpgrade linux-image-5.15.0-135-generic-lpaeUpgrade linux-image-6.8.0-1010-gkeopUpgrade linux-image-5.15.0-1074-nvidiaUpgrade linux-image-5.15.0-1075-intel-iotgUpgrade linux-image-oem-20.04Upgrade linux-image-lowlatency-64k-hwe-22.04Upgrade linux-image-nvidia-hwe-22.04Upgrade linux-image-oem-22.04bUpgrade linux-image-5.15.0-1084-azureUpgrade linux-image-oracleUpgrade linux-image-lowlatency-64kUpgrade linux-image-gkeUpgrade linux-image-6.8.0-1027-azureUpgrade linux-image-genericUpgrade linux-image-5.15.0-136-generic-lpaeUpgrade linux-image-oracle-lts-24.04Upgrade linux-image-5.15.0-1044-xilinx-zynqmpUpgrade linux-image-5.15.0-1081-gcpUpgrade linux-image-5.15.0-1077-gkeUpgrade linux-image-5.15.0-1021-nvidia-tegra-igx-rtUpgrade linux-image-5.15.0-1079-gcp-fipsUpgrade linux-image-6.8.0-58-generic-64kUpgrade linux-image-5.15.0-1062-gkeopUpgrade linux-image-6.8.0-1028-gcp-64kUpgrade linux-image-5.15.0-1080-realtimeUpgrade linux-image-azure-fipsUpgrade linux-image-6.8.0-1026-nvidia-lowlatencyUpgrade linux-image-nvidia-tegra-rtUpgrade linux-image-lowlatencyUpgrade linux-image-kvmUpgrade linux-image-6.8.0-58-genericUpgrade linux-image-6.8.0-1028-raspiUpgrade linux-image-6.8.0-1024-oracle-64kUpgrade linux-image-gcp-fipsUpgrade linux-image-realtime-hwe-24.04Upgrade linux-image-5.15.0-1074-ibmUpgrade linux-image-5.15.0-1033-nvidia-tegraUpgrade linux-image-aws-lts-22.04Upgrade linux-image-5.15.0-135-lowlatencyUpgrade linux-image-5.15.0-1080-aws-fipsUpgrade linux-image-5.15.0-135-fipsUpgrade linux-image-oem-20.04bUpgrade linux-image-gcp-lts-22.04Upgrade linux-image-raspiUpgrade linux-image-gcp-lts-24.04Upgrade linux-image-5.15.0-1086-azureUpgrade linux-image-nvidia-64k-6.8Upgrade linux-image-virtual-hwe-20.04Upgrade linux-image-awsUpgrade linux-image-gcp-64k-lts-24.04Upgrade linux-image-oem-22.04dUpgrade linux-image-oracle-64k-lts-24.04Upgrade linux-image-6.8.1-1020-realtimeUpgrade linux-image-nvidia-6.8Upgrade linux-image-ibm-classicUpgrade linux-image-nvidia-64k-hwe-22.04Upgrade linux-image-fipsUpgrade linux-image-lowlatency-64k-hwe-20.04Upgrade linux-image-azureUpgrade linux-image-lowlatency-hwe-20.04Upgrade linux-image-ibm-lts-24.04Upgrade linux-image-nvidia-tegra-igxUpgrade linux-image-gkeop-6.8Upgrade linux-image-aws-fipsUpgrade linux-image-5.15.0-1073-intel-iot-realtimeUpgrade linux-image-generic-lpaeUpgrade linux-image-6.8.0-1027-azure-fdeUpgrade linux-image-5.15.0-1074-nvidia-lowlatencyUpgrade linux-image-gcp-64kUpgrade linux-image-azure-lts-24.04Upgrade linux-image-6.8.0-1014-azure-nvidiaUpgrade linux-image-5.15.0-135-generic-64kUpgrade linux-image-oem-22.04aUpgrade linux-image-6.8.0-1024-ibmUpgrade linux-image-ibmUpgrade linux-image-azure-cvmUpgrade linux-image-generic-hwe-20.04Upgrade linux-image-azure-fde-lts-24.04Upgrade linux-image-5.15.0-136-generic-64kUpgrade linux-image-lowlatency-hwe-22.04Upgrade linux-image-nvidia-lowlatency-64kUpgrade linux-image-gke-5.15Upgrade linux-image-raspi-nolpaeUpgrade linux-image-nvidia-lowlatencyUpgrade linux-image-6.8.0-2023-raspi-realtimeUpgrade linux-image-azure-fdeUpgrade linux-image-azure-nvidia | Mar 28, 2025 | Nov 25, 2024 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jan 20, 2025 | Nov 25, 2024 |
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