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.

Co-developed-by: Seunghun Han <kkamagui@gmail.com>
Signed-off-by: Seunghun Han <kkamagui@gmail.com>
Co-developed-by: Jihoon Kwon <kjh010315@gmail.com>
Signed-off-by: Jihoon Kwon <kjh010315@gmail.com>
Signed-off-by: Jaehun Gou <p22gone@gmail.com>
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

0 files changed, 0 insertions, 0 deletions