Linux Kernel TOMOYO Control Write Function Large Allocation Warning Vulnerability

A vulnerability in the Linux kernel's TOMOYO subsystem has been addressed. The issue arose in the 'tomoyo_write_control()' function, where the system emitted a warning about excessively large memory allocation. This warning was triggered because a user could write an extremely long line without a newline character. The vulnerability was resolved by using a memory allocation flag that prevents warnings for large requests, rather than relying on a maximum allocation size check. Practically, a valid line should always be shorter than 32KB, where the 'too small to fail' memory-allocation rule applies. While it is possible to attempt writing a line longer than 32KB, such requests will likely fail with an out-of-memory error. Therefore, the decision was made to return an invalid argument error for lines exceeding the maximum allocation size, as this distinction was deemed unnecessary.

Impact

The vulnerability could lead to excessive memory allocation, potentially causing performance issues or memory exhaustion.