CVE-2023-53582: kernel: wifi: brcmfmac: ensure CLM version is null-terminated to prevent stack-out-of-bounds
Component: kernel
Severity: Moderate
CWE: CWE-125 (Out-of-bounds Read)
CVSS v3: 6 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H)
Public date: 2025-10-04T00:00:00+00:00

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

wifi: brcmfmac: ensure CLM version is null-terminated to prevent stack-out-of-bounds

Fix a stack-out-of-bounds read in brcmfmac that occurs
when 'buf' that is not null-terminated is passed as an argument of
strreplace() in brcmf_c_preinit_dcmds(). This buffer is filled with
a CLM version string by memcpy() in brcmf_fil_iovar_data_get().
Ensure buf is null-terminated.

Found by a modified version of syzkaller.

[   33.004414][ T1896] brcmfmac: brcmf_c_process_clm_blob: no clm_blob available (err=-2), device may have limited channels available
[   33.013486][ T1896] brcmfmac: brcmf_c_preinit_dcmds: Firmware: BCM43236/3 wl0: Nov 30 2011 17:33:42 version 5.90.188.22
[   33.021554][ T1896] ==================================================================
[   33.022379][ T1896] BUG: KASAN: stack-out-of-bounds in strreplace+0xf2/0x110
[   33.023122][ T1896] Read of size 1 at addr ffffc90001d6efc8 by task kworker/0:2/1896
[   33.023852][ T1896]
[   33.024096][ T1896] CPU: 0 PID: 1896 Comm: kworker/0:2 Tainted: G           O      5.14.0+ #132
[   33.024927][ T1896] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[   33.026065][ T1896] Workqueue: usb_hub_wq hub_event
[   33.026581][ T1896] Call Trace:
[   33.026896][ T1896]  dump_stack_lvl+0x57/0x7d
[   33.027372][ T1896]  print_address_description.constprop.0.cold+0xf/0x334
[   33.028037][ T1896]  ? strreplace+0xf2/0x110
[   33.028403][ T1896]  ? strreplace+0xf2/0x110
[   33.028807][ T1896]  kasan_report.cold+0x83/0xdf
[   33.029283][ T1896]  ? strreplace+0xf2/0x110
[   33.029666][ T1896]  strreplace+0xf2/0x110
[   33.029966][ T1896]  brcmf_c_preinit_dcmds+0xab1/0xc40
[   33.030351][ T1896]  ? brcmf_c_set_joinpref_default+0x100/0x100
[   33.030787][ T1896]  ? rcu_read_lock_sched_held+0xa1/0xd0
[   33.031223][ T1896]  ? rcu_read_lock_bh_held+0xb0/0xb0
[   33.031661][ T1896]  ? lock_acquire+0x19d/0x4e0
[   33.032091][ T1896]  ? find_held_lock+0x2d/0x110
[   33.032605][ T1896]  ? brcmf_usb_deq+0x1a7/0x260
[   33.033087][ T1896]  ? brcmf_usb_rx_fill_all+0x5a/0xf0
[   33.033582][ T1896]  brcmf_attach+0x246/0xd40
[   33.034022][ T1896]  ? wiphy_new_nm+0x1476/0x1d50
[   33.034383][ T1896]  ? kmemdup+0x30/0x40
[   33.034722][ T1896]  brcmf_usb_probe+0x12de/0x1690
[   33.035223][ T1896]  ? brcmf_usbdev_qinit.constprop.0+0x470/0x470
[   33.035833][ T1896]  usb_probe_interface+0x25f/0x710
[   33.036315][ T1896]  really_probe+0x1be/0xa90
[   33.036656][ T1896]  __driver_probe_device+0x2ab/0x460
[   33.037026][ T1896]  ? usb_match_id.part.0+0x88/0xc0
[   33.037383][ T1896]  driver_probe_device+0x49/0x120
[   33.037790][ T1896]  __device_attach_driver+0x18a/0x250
[   33.038300][ T1896]  ? driver_allows_async_probing+0x120/0x120
[   33.038986][ T1896]  bus_for_each_drv+0x123/0x1a0
[   33.039906][ T1896]  ? bus_rescan_devices+0x20/0x20
[   33.041412][ T1896]  ? lockdep_hardirqs_on_prepare+0x273/0x3e0
[   33.041861][ T1896]  ? trace_hardirqs_on+0x1c/0x120
[   33.042330][ T1896]  __device_attach+0x207/0x330
[   33.042664][ T1896]  ? device_bind_driver+0xb0/0xb0
[   33.043026][ T1896]  ? kobject_uevent_env+0x230/0x12c0
[   33.043515][ T1896]  bus_probe_device+0x1a2/0x260
[   33.043914][ T1896]  device_add+0xa61/0x1ce0
[   33.044227][ T1896]  ? __mutex_unlock_slowpath+0xe7/0x660
[   33.044891][ T1896]  ? __fw_devlink_link_to_suppliers+0x550/0x550
[   33.045531][ T1896]  usb_set_configuration+0x984/0x1770
[   33.046051][ T1896]  ? kernfs_create_link+0x175/0x230
[   33.046548][ T1896]  usb_generic_driver_probe+0x69/0x90
[   33.046931][ T1896]  usb_probe_device+0x9c/0x220
[   33.047434][ T1896]  really_probe+0x1be/0xa90
[   33.047760][ T1896]  __driver_probe_device+0x2ab/0x460
[   33.048134][ T1896]  driver_probe_device+0x49/0x120
[   33.048516][ T1896]  __device_attach_driver+0x18a/0x250
[   33.048910][ T1896]  ? driver_allows_async_probing+0x120/0x120
---truncated---


Affected upstream versions: 4.15
Fixed upstream versions: 0, 4.19.276, 5.10.173, 5.15.99, 5.4.235, 6.1.16, 6.2.3, 6.3
Upstream repository: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Upstream fix commit: 3b173b4ad9c001a555f44adc7836d6fe3afbe9ec