CVE-2026-63892
2026-07-19
16h17 +00:00
16h17 +00:00
Thông báo cho một CVE
Luôn được thông báo về mọi thay đổi đối với một CVE cụ thể.
Mô tả CVE
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: property: Reject dir_len < 4 to prevent size_t underflow
On the non-root path, __tb_property_parse_dir() takes dir_len from
entry->length (u16 widened to size_t). Two distinct OOB conditions
follow when entry->length < 4:
1. The non-root path begins with kmemdup(&block[dir_offset],
sizeof(*dir->uuid), ...) which always reads 4 dwords from
dir_offset. tb_property_entry_valid() only enforces
dir_offset + entry->length <= block_len, so a crafted entry
with dir_offset close to the end of the property block and
entry->length in 0..3 passes that gate but lets the UUID copy
run off the block (e.g. dir_offset = 497, dir_len = 3 in a
500-dword block reads block[497..501]).
2. After the kmemdup, content_len = dir_len - 4 underflows size_t
to ~SIZE_MAX, nentries becomes SIZE_MAX / 4, and the entry
walk runs OOB on each iteration until an entry fails
validation or the kernel oopses on an unmapped page.
Reject dir_len < 4 on the non-root path *before* the UUID kmemdup,
which closes both holes.
Also move INIT_LIST_HEAD(&dir->properties) up to immediately after
the dir allocation so the new error-return path (and the existing
uuid-alloc failure path) calling tb_property_free_dir() sees a
walkable list rather than the zero-initialized NULL next/prev that
list_for_each_entry_safe() would oops on.
