Linux Kernel Vulnerability in 9p Network Protocol Handling

CVE-2025-37879

Summary

A vulnerability exists in the Linux kernel's handling of the 9p network protocol. In functions p9_client_write() and p9_client_read_once(), the server's negligent response of a negative count for read or write operations doesn't get handled correctly. Due to the use of signed variables, the system would misinterpret a negative count as valid if it was less than a positive read size. Changing these variables to unsigned will rectify the issue, ensuring proper validation and avoiding potential null pointer dereference errors. The flaw has been fixed, but the implications could have led to unexpected behavior and instability in the handling of the 9p protocol.

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