CVE-2025-38222

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ext4: inline: fix len overflow in ext4_prepare_inline_data

When running the following code on an ext4 filesystem with inline_data

feature enabled, it will lead to the bug below.

fd = open("file1", O_RDWR | O_CREAT | O_TRUNC, 0666);

ftruncate(fd, 30);

pwrite(fd, "a", 1, (1UL << 40) + 5UL);

That happens because write_begin will succeed as when

ext4_generic_write_inline_data calls ext4_prepare_inline_data, pos + len

will be truncated, leading to ext4_prepare_inline_data parameter to be 6

instead of 0x10000000006.

Then, later when write_end is called, we hit:

BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);

at ext4_write_inline_data.

Fix it by using a loff_t type for the len parameter in

ext4_prepare_inline_data instead of an unsigned int.

[ 44.545164] ------------[ cut here ]------------

[ 44.545530] kernel BUG at fs/ext4/inline.c:240!

[ 44.545834] Oops: invalid opcode: 0000

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References