Commit 72560d72 authored by Longlong Xia's avatar Longlong Xia Committed by Yi Yang
Browse files

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

mainline inclusion
from mainline-v6.12-rc4
commit 9462f4ca56e7d2430fdb6dcc8498244acbfc4489
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IB0EQM
CVE: CVE-2024-50073

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9462f4ca56e7d2430fdb6dcc8498244acbfc4489



--------------------------------

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_buf+0x176/0x280 drivers/tty/n_gsm.c:3609 [n_gsm]
 tty_ldisc_receive_buf+0x101/0x1e0 drivers/tty/tty_buffer.c:391
 tty_port_default_receive_buf+0x61/0xa0 drivers/tty/tty_port.c:39
 flush_to_ldisc+0x1b0/0x750 drivers/tty/tty_buffer.c:445
 process_scheduled_works+0x2b0/0x10d0 kernel/workqueue.c:3229
 worker_thread+0x3dc/0x950 kernel/workqueue.c:3391
 kthread+0x2a3/0x370 kernel/kthread.c:389
 ret_from_fork+0x2d/0x70 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:257

Freed by task 3367:
 kfree+0x126/0x420 mm/slub.c:4580
 gsm_cleanup_mux+0x36c/0x7b0 drivers/tty/n_gsm.c:3160 [n_gsm]
 gsmld_ioctl+0x395/0x1450 drivers/tty/n_gsm.c:3408 [n_gsm]
 tty_ioctl+0x643/0x1100 drivers/tty/tty_io.c:2818

[Analysis]
gsm_msg on the tx_ctrl_list or tx_data_list of gsm_mux
can be freed by multi threads through ioctl,which leads
to the occurrence of uaf. Protect it by gsm tx lock.

Signed-off-by: default avatarLonglong Xia <xialonglong@kylinos.cn>
Cc: stable <stable@kernel.org>
Suggested-by: default avatarJiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20240926130213.531959-1-xialonglong@kylinos.cn


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Conflicts:
	drivers/tty/n_gsm.c
[Commit 54da6a09("locking: Introduce __cleanup() based
infrastructure") not merged, The guard() function is not introduced.]
Signed-off-by: default avatarYi Yang <yiyang13@huawei.com>
parent 0d426553

drivers/tty/n_gsm.c

+4 −0
Original line number Diff line number Diff line
@@ -2043,6 +2043,7 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc) 
	int i;

	struct gsm_dlci *dlci;

	struct gsm_msg *txq, *ntxq;

	unsigned long flags;



	gsm->dead = 1;

	mutex_lock(&gsm->mutex);
@@ -2077,9 +2078,12 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm, bool disc) 
			gsm_dlci_release(gsm->dlci[i]);

	mutex_unlock(&gsm->mutex);

	/* Now wipe the queues */



	spin_lock_irqsave(&gsm->tx_lock, flags);

	list_for_each_entry_safe(txq, ntxq, &gsm->tx_list, list)

		kfree(txq);

	INIT_LIST_HEAD(&gsm->tx_list);

	spin_unlock_irqrestore(&gsm->tx_lock, flags);

}



/**