CVE-2024-50073: tty: n_gsm: Fix use-after-free in gsm_cleanup_mux
First published: Tue Oct 29 2024(Updated: )
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_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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | <6.1.114 | |
| Linux Kernel | >=6.2<6.6.58 | |
| Linux Kernel | >=6.7<6.11.5 | |
| Linux Kernel | =6.12-rc1 | |
| Linux Kernel | =6.12-rc2 | |
| Linux Kernel | =6.12-rc3 | |
| debian/linux | <=5.10.223-1<=5.10.226-1 | 6.1.123-1 6.1.128-1 6.12.12-1 6.12.15-1 |
| debian/linux-6.1 | 6.1.119-1~deb11u1 |
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Reference Links
- https://git.kernel.org/stable/c/bf171b5e86e41de4c1cf32fb7aefa275c3d7de49
- https://git.kernel.org/stable/c/c29f192e0d44cc1cbaf698fa1ff198f63556691a
- https://git.kernel.org/stable/c/0eec592c6a7460ba795d7de29f3dc95cb5422e62
- https://git.kernel.org/stable/c/9462f4ca56e7d2430fdb6dcc8498244acbfc4489
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-50073
- https://nvd.nist.gov/vuln/detail/CVE-2024-50073
- https://launchpad.net/bugs/cve/CVE-2024-50073
- https://security-tracker.debian.org/tracker/CVE-2024-50073
- https://ubuntu.com/security/CVE-2024-50073
- https://git.kernel.org/linus/9462f4ca56e7d2430fdb6dcc8498244acbfc4489
Frequently Asked Questions
What is the severity of CVE-2024-50073?
CVE-2024-50073 has a moderate severity level due to the potential for a use-after-free vulnerability in the Linux kernel.
What software versions are affected by CVE-2024-50073?
CVE-2024-50073 affects various versions of the Linux kernel, specifically versions below 6.1.114 and between 6.2 and 6.11.5, as well as 6.12-rc1, 6.12-rc2, and 6.12-rc3.
How do I fix CVE-2024-50073?
To fix CVE-2024-50073, you should update your Linux kernel to a version above 6.1.114 or apply the relevant patch provided by the maintainers.
Can CVE-2024-50073 lead to system compromise?
Yes, CVE-2024-50073 can potentially lead to system compromise due to the use-after-free vulnerability allowing for arbitrary code execution.
What mitigations are recommended for CVE-2024-50073 until a patch is applied?
Until a patch is applied for CVE-2024-50073, it is recommended to restrict access to the affected systems and monitor for unusual activity.
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