UBUNTU-CVE-2024-49881: Null Pointer Dereference
In the Linux kernel, the following vulnerability has been resolved: ext4: update origpath in ext4findextent() In ext4findextent(), if the path is not big enough, we free it and set origpath to NULL. But after reallocating and successfully initializing the path, we don't update origpath, in which case the caller gets a valid path but a NULL ppath, and this may cause a NULL pointer dereference or a path memory leak. For example: ext4splitextent path = ppath = 2000 ext4findextent if (depth > path[0].pmaxdepth) kfree(path = 2000); origpath = path = NULL; path = kcalloc() = 3000 ext4splitextentat(ppath = NULL) path = ppath; ex = path[depth].pext; // NULL pointer dereference! ================================================================== BUG: kernel NULL pointer dereference, address: 0000000000000010 CPU: 6 UID: 0 PID: 576 Comm: fsstress Not tainted 6.11.0-rc2-dirty #847 RIP: 0010:ext4splitextentat+0x6d/0x560 Call Trace: <TASK> ext4splitextent.isra.0+0xcb/0x1b0 ext4extconverttoinitialized+0x168/0x6c0 ext4exthandleunwrittenextents+0x325/0x4d0 ext4extmapblocks+0x520/0xdb0 ext4mapblocks+0x2b0/0x690 ext4iomapbegin+0x20e/0x2c0 [...] ================================================================== Therefore, origpath is updated when the extent lookup succeeds, so that the caller can safely use path or ppath.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-aws-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1073.79~20.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1078.87~20.04.1 - Upgrade
Upgrade
ubuntu/linux-gcp-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1072.80~20.04.1 - Upgrade
Upgrade
ubuntu/linux-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-127.137~20.04.1 - Upgrade
Upgrade
ubuntu/linux-ibm-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1066.69~20.04.1 - Upgrade
Upgrade
ubuntu/linux-intel-iotg-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1071.77~20.04.1 - Upgrade
Upgrade
ubuntu/linux-lowlatency-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-127.137~20.04.1 - Upgrade
Upgrade
ubuntu/linux-nvidia-tegra-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1032.32~20.04.1 - Upgrade
Upgrade
ubuntu/linux-oracle-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1071.77~20.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1069.73~20.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 5.15.0-127.137 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 5.15.0-1073.79 - Upgrade
Upgrade
ubuntu/linux-aws-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1023.25~22.04.1 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 5.15.0-1078.87 - Upgrade
Upgrade
ubuntu/linux-azure-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1025.30~22.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 5.15.0-1078.87.1 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 5.15.0-1072.80 - Upgrade
Upgrade
ubuntu/linux-gcp-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1024.26~22.04.1 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 5.15.0-1070.76 - Upgrade
Upgrade
ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 5.15.0-1056.63 - Upgrade
Upgrade
ubuntu/linux-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-57.59~22.04.1 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 5.15.0-1066.69 - Upgrade
Upgrade
ubuntu/linux-ibm-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1023.23~22.04.1 - Upgrade
Upgrade
ubuntu/linux-intel-iotgto a version that resolves this vulnerability.Fixed in 5.15.0-1071.77 - Upgrade
Upgrade
ubuntu/linux-kvmto a version that resolves this vulnerability.Fixed in 5.15.0-1070.75 - Upgrade
Upgrade
ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 5.15.0-127.137 - Upgrade
Upgrade
ubuntu/linux-lowlatency-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-54.56.1~22.04.1 - Upgrade
Upgrade
ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 5.15.0-1068.69 - Upgrade
Upgrade
ubuntu/linux-nvidia-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1022.25~22.04.2 - Upgrade
Upgrade
ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 5.15.0-1032.32 - Upgrade
Upgrade
ubuntu/linux-nvidia-tegra-igxto a version that resolves this vulnerability.Fixed in 5.15.0-1020.20 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 5.15.0-1071.77 - Upgrade
Upgrade
ubuntu/linux-oracle-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1020.21~22.04.1 - Upgrade
Upgrade
ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 5.15.0-1066.69 - Upgrade
Upgrade
ubuntu/linux-riscv-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-53.55.1~22.04.1 - Upgrade
Upgrade
ubuntu/linux-xilinx-zynqmpto a version that resolves this vulnerability.Fixed in 5.15.0-1039.43 - Upgrade
Upgrade
ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 5.15.0-1057.59 - Upgrade
Upgrade
ubuntu/linux-intel-iot-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1066.68 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1074.82 - Upgrade
Upgrade
ubuntu/linux-realtime-6.8to a version that resolves this vulnerability.Fixed in 6.8.1-1016.17~22.04.1 - Upgrade
Upgrade
ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1073.79+fips1 - Upgrade
Upgrade
ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1078.87+fips1 - Upgrade
Upgrade
ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-127.137+fips1 - Upgrade
Upgrade
ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1072.80+fips1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-54.56 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1023.25 - Upgrade
Upgrade
ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1025.30 - Upgrade
Upgrade
ubuntu/linux-azure-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1012.12~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1014.15 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1024.26 - Upgrade
Upgrade
ubuntu/linux-gcp-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1011.11~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 6.8.0-1019.23 - Upgrade
Upgrade
ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 6.8.0-1006.8 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1022.22 - Upgrade
Upgrade
ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-54.56.1 - Upgrade
Upgrade
ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1022.25 - Upgrade
Upgrade
ubuntu/linux-nvidia-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1007.7 - Upgrade
Upgrade
ubuntu/linux-nvidia-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-1022.25.2 - Upgrade
Upgrade
ubuntu/linux-oem-6.11to a version that resolves this vulnerability.Fixed in 6.11.0-1015.15 - Upgrade
Upgrade
ubuntu/linux-oem-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1024.24 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1020.21 - Upgrade
Upgrade
ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 6.8.0-1019.23 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 6.8.0-53.55.1 - Upgrade
Upgrade
ubuntu/linux-xilinxto a version that resolves this vulnerability.Fixed in 6.8.0-1017.18 - Upgrade
Upgrade
ubuntu/linux-raspi-realtimeto a version that resolves this vulnerability.Fixed in 6.8.0-2018.19 - Upgrade
Upgrade
ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1016.17 - Upgrade
Upgrade
ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-78.78+fips1
Event History
Frequently Asked Questions
Which systems are in scope?
The affected software list includes Ubuntu linux, linux-aws, linux-azure, linux-gcp, and their listed FIPS variants. The flaw is in the ext4 filesystem code path, so systems using ext4 are the relevant deployment context.
What access does an attacker need?
The severity vector indicates local access and low privileges are required, with no user interaction required. It also indicates that additional attack requirements are present.
What is the likely security impact?
The stated impact is availability only, rated High in the severity vector; confidentiality and integrity impacts are listed as None. The described failure can cause a kernel NULL-pointer dereference, which may crash or disrupt the affected system.
What evidence could indicate this issue has occurred?
A kernel NULL-pointer-dereference report whose call trace includes ext4_split_extent_at, ext4_split_extent, ext4_ext_convert_to_initialized, or ext4_ext_map_blocks is consistent with the described failure. The example report occurred during fsstress.