Skip to content

CVE-2024-40966 kernel: tty: add the option to have a tty reject a new ldisc

John W. Linvillerequested to merge
linville-rh/centos-stream-9-linville:RHEL-48254 into main

Merge Request Required Information

Summary of Changes

tty: add the option to have a tty reject a new ldisc

Approved Development Ticket

JIRA: https://issues.redhat.com/browse/RHEL-48254

CVE: CVE-2024-40966

tty: add the option to have a tty reject a new ldisc

... and use it to limit the virtual terminals to just N_TTY. They are kind of special, and in particular, the "con_write()" routine violates the "writes cannot sleep" rule that some ldiscs rely on.

This avoids the

BUG: sleeping function called from invalid context at kernel/printk/printk.c:2659

when N_GSM has been attached to a virtual console, and gsmld_write() calls con_write() while holding a spinlock, and con_write() then tries to get the console lock.

Signed-off-by: John W. Linville linville@redhat.com

Edited by John W. Linville

Merge request reports