In the Linux kernel, the following vulnerability has been resolved:
9p/net: fix improper handling of bogus negative read/write replies
In p9_client_write() and p9_client_read_once(), if the server incorrectly replies with success but a negative write/read count then we would consider written (negative) <= rsize (positive) because both variables were signed.
Make variables unsigned to avoid this problem.
The reproducer linked below now fails with the following error instead of a null pointer deref: 9pnet: bogus RWRITE count (4294967295 > 3)