fs: ntfs3: fix infinite loop triggered by zero-sized ATTR_LIST

Overview

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

fs: ntfs3: fix infinite loop triggered by zero-sized ATTR_LIST

We found an infinite loop bug in the ntfs3 file system that can lead to a Denial-of-Service (DoS) condition.

A malformed NTFS image can cause an infinite loop when an ATTR_LIST attribute indicates a zero data size while the driver allocates memory for it.

When ntfs_load_attr_list() processes a resident ATTR_LIST with data_size set to zero, it still allocates memory because of al_aligned(0). This creates an inconsistent state where ni->attr_list.size is zero, but ni->attr_list.le is non-null. This causes ni_enum_attr_ex to incorrectly assume that no attribute list exists and enumerates only the primary MFT record. When it finds ATTR_LIST, the code reloads it and restarts the enumeration, repeating indefinitely. The mount operation never completes, hanging the kernel thread.

This patch adds validation to ensure that data_size is non-zero before memory allocation. When a zero-sized ATTR_LIST is detected, the function returns -EINVAL, preventing a DoS vulnerability.

Affected

• Linux >= be71b5cba2e6485e8959da7a9f9a44461a1bb074 < 9267d99fade76d44d4a133599524031fe684156e
• Linux >= be71b5cba2e6485e8959da7a9f9a44461a1bb074 < 976e6a7c51fabf150478decbe8ef5d9a26039b7c
• Linux >= be71b5cba2e6485e8959da7a9f9a44461a1bb074 < 8d8c70b57dbeda3eb165c0940b97e85373ca9354
• Linux >= be71b5cba2e6485e8959da7a9f9a44461a1bb074 < 7ef219656febf5ae06ae56b1fce47ebd05f92b68
• Linux >= be71b5cba2e6485e8959da7a9f9a44461a1bb074 < 9779a6eaaabdf47aa57910d352b398ad742e6a5f
• Linux >= be71b5cba2e6485e8959da7a9f9a44461a1bb074 < fd508939dbca5eceefb2d0c2564beb15469572f2
• Linux >= be71b5cba2e6485e8959da7a9f9a44461a1bb074 < 06909b2549d631a47fcda249d34be26f7ca1711d
• Linux 5.15

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.