In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: fix out-of-bounds read in read_log_rec_buf() read_log_rec_bu

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

fs/ntfs3: fix out-of-bounds read in read_log_rec_buf()

read_log_rec_buf() copies a log record into a caller buffer starting at

 1u32 off = lsn_to_page_off(log, lsn) + log->record_header_len;

log->record_header_len (and log->data_off, used for the following pages)
comes verbatim from the on-disk restart area and is only checked for
8-byte alignment in is_rst_area_valid(), so off can exceed
log->page_size. "tail = log->page_size - off" then underflows and
memcpy() reads past the page_size-sized buffer returned by
read_log_page(), spilling adjacent slab memory into the replay buffer.

This is reachable by mounting a crafted NTFS image:

BUG: KASAN: slab-out-of-bounds in read_log_rec_buf+0x216/0x580
Read of size 64 at addr ffff88800a877ff8 by task exploit/127
read_log_rec_buf fs/ntfs3/fslog.c:2299
log_replay fs/ntfs3/fslog.c:4216
ntfs_loadlog_and_replay fs/ntfs3/fsntfs.c:324
ntfs_fill_super fs/ntfs3/super.c:1392
get_tree_bdev_flags fs/super.c:1694
__x64_sys_mount fs/namespace.c:4360
The buggy address is located 4088 bytes to the right of
the 4096-byte region [ffff88800a876000, ffff88800a877000)

Reject an in-page offset outside the current page before the copy.

[almaz.alexandrovich@paragon-software.com: replaced the >= sign with >]