Red Hat Security Advisory: kernel security update

Important

In the Linux kernel, the following vulnerability has been resolved: serial: core: fix transmit-buffer reset and memleak Commit 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close") converted serial core to use tty_port_close() but failed to notice that the transmit buffer still needs to be freed on final close. Not freeing the transmit buffer means that the buffer is no longer cleared on next open so that any ioctl() waiting for the buffer to drain might wait indefinitely (e.g. on termios changes) or that stale data can end up being transmitted in case tx is restarted. Furthermore, the buffer of any port that has been opened would leak on driver unbind. Note that the port lock is held when clearing the buffer pointer due to the ldisc race worked around by commit a5ba1d95e46e ("uart: fix race between uart_put_char() and uart_shutdown()"). Also note that the tty-port shutdown() callback is not called for console ports so it is not strictly necessary to free the buffer page after releasing the lock (cf. d72402145ace ("tty/serial: do not free trasnmit buffer page under port lock")).

CWE-400 - Uncontrolled Resource Consumption

A flaw was found in the Linux kernel. A potential memleak in papr_get_attr() may lead to compromised availability.

A vulnerability was found in the Linux kernel's user mode (um) subsystem, specifically within the Local Descriptor Table (LDT) setup functionality. The issue arises from the syscall_stub_data() function misinterpreting the data_count parameter as a byte count rather than a count of longs, leading to an out-of-bounds read. This flaw could expose sensitive kernel memory and cause system instability.

CWE-125 - Out-of-bounds Read