Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

tty: n_gsm: Fix use-after-free in gsm_cleanup_mux

BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x77b/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm] Read of size 8 at addr ffff88815fe99c00 by task poc/3379 CPU: 0 UID: 0 PID: 3379 Comm: poc Not tainted 6.11.0+ #56 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 11/12/2020 Call Trace: <TASK> gsm_cleanup_mux+0x77b/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm] __pfx_gsm_cleanup_mux+0x10/0x10 drivers/tty/n_gsm.c:3124 [n_gsm] __pfx_sched_clock_cpu+0x10/0x10 kernel/sched/clock.c:389 update_load_avg+0x1c1/0x27b0 kernel/sched/fair.c:4500 __pfx_min_vruntime_cb_rotate+0x10/0x10 kernel/sched/fair.c:846 __rb_insert_augmented+0x492/0xbf0 lib/rbtree.c:161 gsmld_ioctl+0x395/0x1450 drivers/tty/n_gsm.c:3408 [n_gsm] _raw_spin_lock_irqsave+0x92/0xf0 arch/x86/include/asm/atomic.h:107 __pfx_gsmld_ioctl+0x10/0x10 drivers/tty/n_gsm.c:3822 [n_gsm] ktime_get+0x5e/0x140 kernel/time/timekeeping.c:195 ldsem_down_read+0x94/0x4e0 arch/x86/include/asm/atomic64_64.h:79 __pfx_ldsem_down_read+0x10/0x10 drivers/tty/tty_ldsem.c:338 __pfx_do_vfs_ioctl+0x10/0x10 fs/ioctl.c:805 tty_ioctl+0x643/0x1100 drivers/tty/tty_io.c:2818

Allocated by task 65: gsm_data_alloc.constprop.0+0x27/0x190 drivers/tty/n_gsm.c:926 [n_gsm] gsm_send+0x2c/0x580 drivers/tty/n_gsm.c:819 [n_gsm] gsm1_receive+0x547/0xad0 drivers/tty/n_gsm.c:3038 [n_gsm] gsmld_receive_…