Linux Kernel up to 4.19.324/6.11.10/6.12.1 initramfs buffer-format.rst do_name uninitialized pointer

Summaryinfo

A vulnerability was found in Linux Kernel up to 4.19.324/6.11.10/6.12.1. It has been rated as critical. This affects the function do_name of the file Documentation/driver-api/early-userspace/buffer-format.rst of the component initramfs. This manipulation causes uninitialized pointer. The identification of this vulnerability is CVE-2024-53142. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 4.19.324/6.11.10/6.12.1. Affected by this vulnerability is the function do_name of the file Documentation/driver-api/early-userspace/buffer-format.rst of the component initramfs. The manipulation with an unknown input leads to a uninitialized pointer vulnerability. The CWE definition for the vulnerability is CWE-824. The product accesses or uses a pointer that has not been initialized. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: initramfs: avoid filename buffer overrun The initramfs filename field is defined in Documentation/driver-api/early-userspace/buffer-format.rst as: 37 cpio_file := ALGN(4) + cpio_header + filename + "\0" + ALGN(4) + data ... 55 ============= ================== ========================= 56 Field name Field size Meaning 57 ============= ================== ========================= ... 70 c_namesize 8 bytes Length of filename, including final \0 When extracting an initramfs cpio archive, the kernel's do_name() path handler assumes a zero-terminated path at @collected, passing it directly to filp_open() / init_mkdir() / init_mknod(). If a specially crafted cpio entry carries a non-zero-terminated filename and is followed by uninitialized memory, then a file may be created with trailing characters that represent the uninitialized memory. The ability to create an initramfs entry would imply already having full control of the system, so the buffer overrun shouldn't be considered a security vulnerability. Append the output of the following bash script to an existing initramfs and observe any created /initramfs_test_fname_overrunAA* path. E.g. ./reproducer.sh | gzip >> /myinitramfs It's easiest to observe non-zero uninitialized memory when the output is gzipped, as it'll overflow the heap allocated @out_buf in __gunzip(), rather than the initrd_start+initrd_size block. ---- reproducer.sh ---- nilchar="A" # change to "\0" to properly zero terminate / pad magic="070701" ino=1 mode=$(( 0100777 )) uid=0 gid=0 nlink=1 mtime=1 filesize=0 devmajor=0 devminor=1 rdevmajor=0 rdevminor=0 csum=0 fname="initramfs_test_fname_overrun" namelen=$(( ${#fname} + 1 )) # plus one to account for terminator printf "%s%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%08x%s" \ $magic $ino $mode $uid $gid $nlink $mtime $filesize \ $devmajor $devminor $rdevmajor $rdevminor $namelen $csum $fname termpadlen=$(( 1 + ((4 - ((110 + $namelen) & 3)) % 4) )) printf "%.s${nilchar}" $(seq 1 $termpadlen) ---- reproducer.sh ---- Symlink filename fields handled in do_symlink() won't overrun past the data segment, due to the explicit zero-termination of the symlink target. Fix filename buffer overrun by aborting the initramfs FSM if any cpio entry doesn't carry a zero-terminator at the expected (name_len - 1) offset.

It is possible to read the advisory at git.kernel.org. This vulnerability is known as CVE-2024-53142 since 11/19/2024. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 216020 (EulerOS 2.0 SP11 : kernel (EulerOS-SA-2025-1140)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.19.325, 6.11.11 or 6.12.2 eliminates this vulnerability. Applying the patch bb7ac96670ab/49d01e736c30/fb83b093f758/e017671f534d is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (216020) and CERT Bund (WID-SEC-2024-3619). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Google Container-Optimized OS
• Debian Linux
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• Kyocera Printer
• Dell NetWorker
• Dell Avamar
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.19.324
• 6.11.0
• 6.11.1
• 6.11.2
• 6.11.3
• 6.11.4
• 6.11.5
• 6.11.6
• 6.11.7
• 6.11.8
• 6.11.9
• 6.11.10
• 6.12.0
• 6.12.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

Discussion