This patch fixes a stack-out-of-bounds read in brcmfmac that occurs when 'buf' that is not null-terminated is passed as an argument of strsep() in brcmf_c_preinit_dcmds(). This buffer is filled with a firmware version string by memcpy() in brcmf_fil_iovar_data_get(). The patch ensures buf is null-terminated. Found by a modified version of syzkaller. [ 47.569679][ T1897] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43236b for chip BCM43236/3 [ 47.582839][ T1897] brcmfmac: brcmf_c_process_clm_blob: no clm_blob available (err=-2), device may have limited channels available [ 47.601565][ T1897] ================================================================== [ 47.602574][ T1897] BUG: KASAN: stack-out-of-bounds in strsep+0x1b2/0x1f0 [ 47.603447][ T1897] Read of size 1 at addr ffffc90001f6f000 by task kworker/0:2/1897 [ 47.604336][ T1897] [ 47.604621][ T1897] CPU: 0 PID: 1897 Comm: kworker/0:2 Tainted: G O 5.14.0+ #131 [ 47.605617][ T1897] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 [ 47.606907][ T1897] Workqueue: usb_hub_wq hub_event [ 47.607453][ T1897] Call Trace: [ 47.607801][ T1897] dump_stack_lvl+0x8e/0xd1 [ 47.608295][ T1897] print_address_description.constprop.0.cold+0xf/0x334 [ 47.609009][ T1897] ? strsep+0x1b2/0x1f0 [ 47.609434][ T1897] ? strsep+0x1b2/0x1f0 [ 47.609863][ T1897] kasan_report.cold+0x83/0xdf [ 47.610366][ T1897] ? strsep+0x1b2/0x1f0 [ 47.610882][ T1897] strsep+0x1b2/0x1f0 [ 47.611300][ T1897] ? brcmf_fil_iovar_data_get+0x3a/0xf0 [ 47.611883][ T1897] brcmf_c_preinit_dcmds+0x995/0xc40 [ 47.612434][ T1897] ? brcmf_c_set_joinpref_default+0x100/0x100 [ 47.613078][ T1897] ? rcu_read_lock_sched_held+0xa1/0xd0 [ 47.613662][ T1897] ? rcu_read_lock_bh_held+0xb0/0xb0 [ 47.614208][ T1897] ? lock_acquire+0x19d/0x4e0 [ 47.614704][ T1897] ? find_held_lock+0x2d/0x110 [ 47.615236][ T1897] ? brcmf_usb_deq+0x1a7/0x260 [ 47.615741][ T1897] ? brcmf_usb_rx_fill_all+0x5a/0xf0 [ 47.616288][ T1897] brcmf_attach+0x246/0xd40 [ 47.616758][ T1897] ? wiphy_new_nm+0x1703/0x1dd0 [ 47.617280][ T1897] ? kmemdup+0x43/0x50 [ 47.617720][ T1897] brcmf_usb_probe+0x12de/0x1690 [ 47.618244][ T1897] ? brcmf_usbdev_qinit.constprop.0+0x470/0x470 [ 47.618901][ T1897] usb_probe_interface+0x2aa/0x760 [ 47.619429][ T1897] ? usb_probe_device+0x250/0x250 [ 47.619950][ T1897] really_probe+0x205/0xb70 [ 47.620435][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.621048][ T1897] __driver_probe_device+0x311/0x4b0 [ 47.621595][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.622209][ T1897] driver_probe_device+0x4e/0x150 [ 47.622739][ T1897] __device_attach_driver+0x1cc/0x2a0 [ 47.623287][ T1897] bus_for_each_drv+0x156/0x1d0 [ 47.623796][ T1897] ? bus_rescan_devices+0x30/0x30 [ 47.624309][ T1897] ? lockdep_hardirqs_on_prepare+0x273/0x3e0 [ 47.624907][ T1897] ? trace_hardirqs_on+0x46/0x160 [ 47.625437][ T1897] __device_attach+0x23f/0x3a0 [ 47.625924][ T1897] ? device_bind_driver+0xd0/0xd0 [ 47.626433][ T1897] ? kobject_uevent_env+0x287/0x14b0 [ 47.627057][ T1897] bus_probe_device+0x1da/0x290 [ 47.627557][ T1897] device_add+0xb7b/0x1eb0 [ 47.628027][ T1897] ? wait_for_completion+0x290/0x290 [ 47.628593][ T1897] ? __fw_devlink_link_to_suppliers+0x5a0/0x5a0 [ 47.629249][ T1897] usb_set_configuration+0xf59/0x16f0 [ 47.629829][ T1897] usb_generic_driver_probe+0x82/0xa0 [ 47.630385][ T1897] usb_probe_device+0xbb/0x250 [ 47.630927][ T1897] ? usb_suspend+0x590/0x590 [ 47.631397][ T1897] really_probe+0x205/0xb70 [ 47.631855][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.632469][ T1897] __driver_probe_device+0x311/0x4b0 [ 47.633002][ T1897] ? usb_generic_driver_match+0x75/0x90 [ 47.633573][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.634170][ T1897] driver_probe_device+0x4e/0x150 [ 47.634703][ T1897] __device_attach_driver+0x1cc/0x2a0 [ 47.635248][ T1897] bus_for_each_drv+0x156/0x1d0 [ 47.635748][ T1897] ? bus_rescan_devices+0x30/0x30 [ 47.636271][ T1897] ? lockdep_hardirqs_on_prepare+0x273/0x3e0 [ 47.636881][ T1897] ? trace_hardirqs_on+0x46/0x160 [ 47.637396][ T1897] __device_attach+0x23f/0x3a0 [ 47.637904][ T1897] ? device_bind_driver+0xd0/0xd0 [ 47.638426][ T1897] ? kobject_uevent_env+0x287/0x14b0 [ 47.638985][ T1897] bus_probe_device+0x1da/0x290 [ 47.639512][ T1897] device_add+0xb7b/0x1eb0 [ 47.639977][ T1897] ? __fw_devlink_link_to_suppliers+0x5a0/0x5a0 [ 47.640612][ T1897] ? kfree+0x14a/0x6b0 [ 47.641055][ T1897] ? __usb_get_extra_descriptor+0x116/0x160 [ 47.641679][ T1897] usb_new_device.cold+0x49c/0x1029 [ 47.642245][ T1897] ? hub_disconnect+0x450/0x450 [ 47.642756][ T1897] ? rwlock_bug.part.0+0x90/0x90 [ 47.643273][ T1897] ? _raw_spin_unlock_irq+0x24/0x30 [ 47.643822][ T1897] ? lockdep_hardirqs_on_prepare+0x273/0x3e0 [ 47.644445][ T1897] hub_event+0x1c98/0x3950 [ 47.644939][ T1897] ? hub_port_debounce+0x2e0/0x2e0 [ 47.645467][ T1897] ? check_irq_usage+0x861/0xf20 [ 47.645975][ T1897] ? drain_workqueue+0x280/0x360 [ 47.646506][ T1897] ? lock_release+0x640/0x640 [ 47.646994][ T1897] ? rcu_read_lock_sched_held+0xa1/0xd0 [ 47.647572][ T1897] ? rcu_read_lock_bh_held+0xb0/0xb0 [ 47.648111][ T1897] ? lockdep_hardirqs_on_prepare+0x273/0x3e0 [ 47.648735][ T1897] process_one_work+0x92b/0x1460 [ 47.649262][ T1897] ? pwq_dec_nr_in_flight+0x330/0x330 [ 47.649816][ T1897] ? rwlock_bug.part.0+0x90/0x90 [ 47.650336][ T1897] worker_thread+0x95/0xe00 [ 47.650830][ T1897] ? __kthread_parkme+0x115/0x1e0 [ 47.651361][ T1897] ? process_one_work+0x1460/0x1460 [ 47.651904][ T1897] kthread+0x3a1/0x480 [ 47.652329][ T1897] ? set_kthread_struct+0x120/0x120 [ 47.652878][ T1897] ret_from_fork+0x1f/0x30 [ 47.653370][ T1897] [ 47.653608][ T1897] [ 47.653848][ T1897] addr ffffc90001f6f000 is located in stack of task kworker/0:2/1897 at offset 512 in frame: [ 47.654891][ T1897] brcmf_c_preinit_dcmds+0x0/0xc40 [ 47.655442][ T1897] [ 47.655690][ T1897] this frame has 4 objects: [ 47.656151][ T1897] [48, 56) 'ptr' [ 47.656159][ T1897] [80, 148) 'revinfo' [ 47.656534][ T1897] [192, 210) 'eventmask' [ 47.656953][ T1897] [256, 512) 'buf' [ 47.657410][ T1897] [ 47.658035][ T1897] Memory state around the buggy address: [ 47.658743][ T1897] ffffc90001f6ef00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 47.659577][ T1897] ffffc90001f6ef80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 47.660394][ T1897] >ffffc90001f6f000: f3 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00 [ 47.661199][ T1897] ^ [ 47.661625][ T1897] ffffc90001f6f080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 47.662455][ T1897] ffffc90001f6f100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 [ 47.663318][ T1897] ================================================================== [ 47.664147][ T1897] Disabling lock debugging due to kernel taint Reported-by: Dokyung Song <dokyungs@xxxxxxxxxxxx> Reported-by: Jisoo Jang <jisoo.jang@xxxxxxxxxxxx> Reported-by: Minsuk Kang <linuxlovemin@xxxxxxxxxxxx> Signed-off-by: Jisoo Jang <jisoo.jang@xxxxxxxxxxxx> --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c index 74020fa10065..d2209e11b40c 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/common.c @@ -298,6 +298,7 @@ int brcmf_c_preinit_dcmds(struct brcmf_if *ifp) err); goto done; } + buf[sizeof(buf) - 1] = '\0'; ptr = (char *)buf; strsep(&ptr, "\n"); -- 2.25.1
