Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: ntfs3: fix out-of-bounds read in ntfs_dir_emit() and hdr_find_e() The bounds check in ntfs_dir_emit() compares fname->name_len (a character count) against e->size (a byte count) without accounting for the 2-byte-per-character UTF-16LE encoding or the ATTR_FILE_NAME header size: if (fname->name_len + sizeof(struct NTFS_DE) > le16_to_cpu(e->size)) This computes: name_len + 16 > e_size The correct check must account for the ATTR_FILE_NAME header (66 bytes before the name) and the UTF-16LE character size (2 bytes each): sizeof(NTFS_DE) + offsetof(ATTR_FILE_NAME, name) + name_len * sizeof(short) > e_size Which computes: 16 + 66 + name_len * 2 > e_size The correct calculation already exists as fname_full_size() in ntfs.h and is used in cmp_fnames(), namei.c, and fslog.c, but was not used in the readdir path. A crafted NTFS image with an index entry containing a small e->size but large fname->name_len bypasses the current check, causing ntfs_utf16_to_nls() to read past the entry boundary. Additionally, add a key_size validation in hdr_find_e() to ensure the declared key_size does not exceed the available entry data, preventing comparison functions from reading past entry boundaries on the lookup path.

Affected versions

Linux: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before ed6da1abeec50db9060d714f03743fe0b63e4fe4 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before 6a8149a20e46086c756c2a9202e377c0b649a0c3 (git); 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 through before aa1bdbb39f49c5bc9779316891c40005517842a5 (git); before 6.12.111 (semver); before 6.18.53 (semver) Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.