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mirror of https://github.com/RT-Thread/rt-thread.git synced 2025-02-22 01:05:20 +08:00
kenneth.liu a5b26bb588 components: libc: fix array overflow in rt_object name assignment
[Problem Description]
When assigning name to rt_object, strncpy() uses size equal to RT_NAME_MAX,
which causes missing null-terminator and overflows into adjacent 'type' field.
This corruption leads to unexpected system behavior.

[Problem Analysis]
The rt_object structure defines:
| char name[RT_NAME_MAX] | -> buffer
| rt_uint8_t type        | -> adjacent field

Original code calculates size as:
size = end - first + 1;
if (size > RT_NAME_MAX) size = RT_NAME_MAX;

When size equals RT_NAME_MAX, strncpy() will copy exactly RT_NAME_MAX bytes
without adding terminating '\0', causing two issues:
1. name buffer is not null-terminated
2. The implicit null-byte writes beyond name[] into type field

[Solution]
Change boundary check from:
if (size > RT_NAME_MAX) size = RT_NAME_MAX;
to:
if (size >= RT_NAME_MAX) size = RT_NAME_MAX - 1;

This ensures:
1. Always leaves space for null-terminator
2. Prevents overflow into type field
3. Maintains maximum valid name length (RT_NAME_MAX-1 + '\0')

Signed-off-by: Liu Gui <kenneth.liu@sophgo.com>
2025-02-20 22:38:06 -05:00
..
2022-01-25 13:40:10 +08:00