[0/4] Fix multiple race condition vulnerabilities in dvb-core and device driver

Message ID	20221115131822.6640-1-imv4bel@gmail.com
Headers	show Return-Path: <linux-usb-owner@kernel.org> From: imv4bel@gmail.com To: mchehab@kernel.org Cc: Hyunwoo Kim <imv4bel@gmail.com>, kernel@tuxforce.de, linux-media@vger.kernel.org, linux-usb@vger.kernel.org, cai.huoqing@linux.dev, tiwai@suse.de Subject: [PATCH 0/4] Fix multiple race condition vulnerabilities in dvb-core and device driver Date: Tue, 15 Nov 2022 05:18:18 -0800 Message-Id: <20221115131822.6640-1-imv4bel@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	Fix multiple race condition vulnerabilities in dvb-core and device driver \| expand [0/4] Fix multiple race condition vulnerabilities in dvb-core and device driver [2/4] media: dvb-core: Fix use-after-free due to race condition occurring in dvb_net [4/4] media: ttusb-dec: Fix memory leak in ttusb_dec_exit_dvb()

From: Hyunwoo Kim <imv4bel@gmail.com> Dear, This patch set is a security patch for various race condition vulnerabilities that occur in 'dvb-core' and 'ttusb_dec', a dvb-based device driver. # 1. media: dvb-core: Fix use-after-free due to race condition occurring in dvb_frontend This is a security patch for a race condition that occurs in the dvb_frontend system of dvb-core. The race condition that occurs here will occur with _any_ device driver using dvb_frontend. The race conditions that occur in dvb_frontend are as follows (Description is based on drivers/media/usb/as102/as102_drv.c using dvb_frontend): ``` cpu0 cpu1 1. open() dvb_frontend_open() dvb_frontend_get() // kref : 3 2. as102_usb_disconnect() as102_dvb_unregister() dvb_unregister_frontend() dvb_frontend_put() // kref : 2 dvb_frontend_detach() dvb_frontend_put() // kref : 1 3. close() __fput() dvb_frontend_release() dvb_frontend_put() // kref : 0 dvb_frontend_free() __dvb_frontend_free() dvb_free_device() kfree (dvbdev->fops); ... fops_put(file->f_op); // UAF!! ``` UAF occurs in the following order: '.probe -> open() -> .disconnect -> close()'. The root cause of this is that wake_up() for dvbdev->wait_queue is implemented in the dvb_frontend_release() function, but wait_event() is not implemented in the dvb_frontend_stop() function. The KASAN log caused by this is as follows: ``` [ 60.754938] ================================================================== [ 60.754942] BUG: KASAN: use-after-free in __fput+0xa55/0xaf0 [ 60.754945] Read of size 8 at addr ffff888134ddf000 by task as102_test/2139 [ 60.754949] CPU: 3 PID: 2139 Comm: as102_test Not tainted 6.1.0-rc2+ #16 [ 60.754951] Hardware name: Gigabyte Technology Co., Ltd. B460MDS3H/B460M DS3H, BIOS F3 05/27/2020 [ 60.754953] Call Trace: [ 60.754954] <TASK> [ 60.754956] dump_stack_lvl+0x49/0x63 [ 60.754958] print_report+0x177/0x46e [ 60.754962] ? kasan_complete_mode_report_info+0x7c/0x210 [ 60.754965] ? __fput+0xa55/0xaf0 [ 60.754970] kasan_report+0xb0/0x140 [ 60.754976] ? __fput+0xa55/0xaf0 [ 60.754979] __asan_report_load8_noabort+0x14/0x20 [ 60.754982] __fput+0xa55/0xaf0 [ 60.754985] ____fput+0xe/0x20 [ 60.754987] task_work_run+0x153/0x240 [ 60.754991] ? task_work_cancel+0x20/0x20 [ 60.754994] ? fput+0xab/0x140 [ 60.754997] exit_to_user_mode_prepare+0x18f/0x1a0 [ 60.754999] syscall_exit_to_user_mode+0x26/0x50 [ 60.755003] do_syscall_64+0x69/0x90 [ 60.755005] ? do_syscall_64+0x69/0x90 [ 60.755008] ? debug_smp_processor_id+0x17/0x20 [ 60.755010] ? fpregs_assert_state_consistent+0x52/0xc0 [ 60.755013] ? exit_to_user_mode_prepare+0x49/0x1a0 [ 60.755015] ? irqentry_exit_to_user_mode+0x9/0x20 [ 60.755018] ? irqentry_exit+0x3b/0x50 [ 60.755021] ? sysvec_apic_timer_interrupt+0x57/0xc0 [ 60.755024] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 60.755027] RIP: 0033:0x4537eb [ 60.755029] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 a8 02 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 11 a9 02 00 8b 44 [ 60.755031] RSP: 002b:00007ff8c1c001a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 [ 60.755034] RAX: 0000000000000000 RBX: 00007ff8c1c00640 RCX: 00000000004537eb [ 60.755036] RDX: 0000000000000000 RSI: 00007ff8bc000b70 RDI: 0000000000000003 [ 60.755038] RBP: 00007ff8c1c001d0 R08: 0000000000000000 R09: 0000000000000000 [ 60.755040] R10: 000000000000000a R11: 0000000000000293 R12: 00007ff8c1c00640 [ 60.755042] R13: 0000000000000000 R14: 000000000041b290 R15: 00007ff8c1400000 [ 60.755044] </TASK> [ 60.755047] Allocated by task 2114: [ 60.755049] kasan_save_stack+0x26/0x50 [ 60.755052] kasan_set_track+0x25/0x40 [ 60.755054] kasan_save_alloc_info+0x1e/0x30 [ 60.755056] __kasan_kmalloc+0xb4/0xc0 [ 60.755058] __kmalloc_node_track_caller+0x66/0x160 [ 60.755061] kmemdup+0x23/0x50 [ 60.755063] dvb_register_device+0x1cd/0x15c0 [dvb_core] [ 60.755070] dvb_register_frontend+0x3cb/0x630 [dvb_core] [ 60.755078] as102_dvb_register+0x335/0x4d0 [dvb_as102] [ 60.755083] as102_usb_probe.cold+0x680/0x6eb [dvb_as102] [ 60.755087] usb_probe_interface+0x266/0x740 [ 60.755089] really_probe+0x1fa/0xa80 [ 60.755092] __driver_probe_device+0x2cb/0x490 [ 60.755094] driver_probe_device+0x4e/0x140 [ 60.755096] __driver_attach+0x1a3/0x520 [ 60.755098] bus_for_each_dev+0x11e/0x1c0 [ 60.755100] driver_attach+0x3d/0x60 [ 60.755102] bus_add_driver+0x449/0x5a0 [ 60.755103] driver_register+0x219/0x390 [ 60.755105] usb_register_driver+0x228/0x400 [ 60.755107] 0xffffffffc04c8023 [ 60.755110] do_one_initcall+0x97/0x310 [ 60.755113] do_init_module+0x19a/0x630 [ 60.755115] load_module+0x6ca4/0x7d90 [ 60.755117] __do_sys_finit_module+0x134/0x1d0 [ 60.755119] __x64_sys_finit_module+0x72/0xb0 [ 60.755121] do_syscall_64+0x59/0x90 [ 60.755123] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 60.755126] Freed by task 2139: [ 60.755128] kasan_save_stack+0x26/0x50 [ 60.755130] kasan_set_track+0x25/0x40 [ 60.755132] kasan_save_free_info+0x2e/0x50 [ 60.755134] ____kasan_slab_free+0x174/0x1e0 [ 60.755136] __kasan_slab_free+0x12/0x20 [ 60.755138] slab_free_freelist_hook+0xd0/0x1a0 [ 60.755140] __kmem_cache_free+0x193/0x2c0 [ 60.755143] kfree+0x79/0x120 [ 60.755145] dvb_free_device+0x38/0x60 [dvb_core] [ 60.755151] dvb_frontend_put.cold+0xa6/0x15a [dvb_core] [ 60.755160] dvb_frontend_release.cold+0xc7/0xf6 [dvb_core] [ 60.755167] __fput+0x2ce/0xaf0 [ 60.755169] ____fput+0xe/0x20 [ 60.755171] task_work_run+0x153/0x240 [ 60.755173] exit_to_user_mode_prepare+0x18f/0x1a0 [ 60.755175] syscall_exit_to_user_mode+0x26/0x50 [ 60.755177] do_syscall_64+0x69/0x90 [ 60.755179] entry_SYSCALL_64_after_hwframe+0x63/0xcd ``` Also, UAF can occur for driver-specfic structures (such as 'struct XXX_dev'): ``` cpu0 cpu1 1. open() dvb_frontend_open() 2. as102_usb_disconnect() kref_put(&as102_dev->kref, as102_usb_release); // kref : 0 as102_usb_release() kfree(as102_dev); 3. close() dvb_frontend_release() mutex_lock(&fe->dvb->mdev_lock); // UAF ``` The KASAN log caused by this is as follows: ``` [ 82.144178] ================================================================== [ 82.144182] BUG: KASAN: use-after-free in mutex_lock+0x81/0xe0 [ 82.144189] Write of size 8 at addr ffff888121b6a168 by task as102_test/2356 [ 82.144193] CPU: 12 PID: 2356 Comm: as102_test Not tainted 6.1.0-rc2+ #16 [ 82.144196] Hardware name: Gigabyte Technology Co., Ltd. B460MDS3H/B460M DS3H, BIOS F3 05/27/2020 [ 82.144198] Call Trace: [ 82.144200] <TASK> [ 82.144201] dump_stack_lvl+0x49/0x63 [ 82.144205] print_report+0x177/0x46e [ 82.144208] ? kasan_complete_mode_report_info+0x7c/0x210 [ 82.144212] ? mutex_lock+0x81/0xe0 [ 82.144215] kasan_report+0xb0/0x140 [ 82.144218] ? mutex_lock+0x81/0xe0 [ 82.144222] kasan_check_range+0x3a/0x1d0 [ 82.144224] __kasan_check_write+0x14/0x20 [ 82.144226] mutex_lock+0x81/0xe0 [ 82.144229] ? __mutex_lock_slowpath+0x20/0x20 [ 82.144234] dvb_frontend_release.cold+0x178/0x4d2 [dvb_core] [ 82.144246] __fput+0x2ce/0xaf0 [ 82.144250] ____fput+0xe/0x20 [ 82.144253] task_work_run+0x153/0x240 [ 82.144257] ? task_work_cancel+0x20/0x20 [ 82.144260] ? fput+0xab/0x140 [ 82.144263] exit_to_user_mode_prepare+0x18f/0x1a0 [ 82.144266] syscall_exit_to_user_mode+0x26/0x50 [ 82.144270] do_syscall_64+0x69/0x90 [ 82.144273] ? debug_smp_processor_id+0x17/0x20 [ 82.144275] ? fpregs_assert_state_consistent+0x52/0xc0 [ 82.144279] ? exit_to_user_mode_prepare+0x49/0x1a0 [ 82.144281] ? irqentry_exit_to_user_mode+0x9/0x20 [ 82.144284] ? irqentry_exit+0x3b/0x50 [ 82.144287] ? sysvec_apic_timer_interrupt+0x57/0xc0 [ 82.144290] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 82.144293] RIP: 0033:0x4537eb [ 82.144296] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 a8 02 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 11 a9 02 00 8b 44 [ 82.144298] RSP: 002b:00007fc7600001a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 [ 82.144302] RAX: 0000000000000000 RBX: 00007fc760000640 RCX: 00000000004537eb [ 82.144304] RDX: 0000000000000000 RSI: 00007fc758000b70 RDI: 0000000000000003 [ 82.144306] RBP: 00007fc7600001d0 R08: 0000000000000000 R09: 0000000000000000 [ 82.144308] R10: 000000000000000a R11: 0000000000000293 R12: 00007fc760000640 [ 82.144310] R13: 0000000000000000 R14: 000000000041b290 R15: 00007fc75f800000 [ 82.144313] </TASK> [ 82.144315] Allocated by task 2225: [ 82.144317] kasan_save_stack+0x26/0x50 [ 82.144320] kasan_set_track+0x25/0x40 [ 82.144322] kasan_save_alloc_info+0x1e/0x30 [ 82.144325] __kasan_kmalloc+0xb4/0xc0 [ 82.144327] kmalloc_trace+0x4a/0xb0 [ 82.144329] as102_usb_probe.cold+0x58/0x6eb [dvb_as102] [ 82.144335] usb_probe_interface+0x266/0x740 [ 82.144338] really_probe+0x1fa/0xa80 [ 82.144341] __driver_probe_device+0x2cb/0x490 [ 82.144343] driver_probe_device+0x4e/0x140 [ 82.144345] __driver_attach+0x1a3/0x520 [ 82.144347] bus_for_each_dev+0x11e/0x1c0 [ 82.144348] driver_attach+0x3d/0x60 [ 82.144350] bus_add_driver+0x449/0x5a0 [ 82.144352] driver_register+0x219/0x390 [ 82.144354] usb_register_driver+0x228/0x400 [ 82.144356] 0xffffffffc0655023 [ 82.144358] do_one_initcall+0x97/0x310 [ 82.144361] do_init_module+0x19a/0x630 [ 82.144363] load_module+0x6ca4/0x7d90 [ 82.144365] __do_sys_finit_module+0x134/0x1d0 [ 82.144367] __x64_sys_finit_module+0x72/0xb0 [ 82.144369] do_syscall_64+0x59/0x90 [ 82.144371] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 82.144374] Freed by task 158: [ 82.144376] kasan_save_stack+0x26/0x50 [ 82.144378] kasan_set_track+0x25/0x40 [ 82.144380] kasan_save_free_info+0x2e/0x50 [ 82.144382] ____kasan_slab_free+0x174/0x1e0 [ 82.144384] __kasan_slab_free+0x12/0x20 [ 82.144386] slab_free_freelist_hook+0xd0/0x1a0 [ 82.144388] __kmem_cache_free+0x193/0x2c0 [ 82.144391] kfree+0x79/0x120 [ 82.144393] as102_usb_release+0x5d/0x75 [dvb_as102] [ 82.144397] as102_usb_disconnect+0x125/0x176 [dvb_as102] [ 82.144400] usb_unbind_interface+0x187/0x7c0 [ 82.144402] device_remove+0x117/0x170 [ 82.144404] device_release_driver_internal+0x418/0x660 [ 82.144407] device_release_driver+0x12/0x20 [ 82.144409] bus_remove_device+0x28f/0x540 [ 82.144410] device_del+0x501/0xc30 [ 82.144413] usb_disable_device+0x2a5/0x660 [ 82.144415] usb_disconnect.cold+0x1f9/0x620 [ 82.144417] hub_event+0x16d3/0x3d20 [ 82.144420] process_one_work+0x778/0x11c0 [ 82.144422] worker_thread+0x544/0x1180 [ 82.144424] kthread+0x280/0x320 [ 82.144426] ret_from_fork+0x1f/0x30 ``` # 2. media: dvb-core: Fix use-after-free due to race condition occurring in dvb_net This is a security patch for a race condition that occurs in the dvb_net system of dvb-core. The race condition that occurs here will occur with _any_ device driver using dvb_net. The race condition that occurs in dvb_net is: ``` cpu0 cpu1 1. .disconnect() dvb_net_release() dvbnet->exit = 1; if (dvbnet->dvbdev->users < 1) // improper reference counting 2. open() dvb_device_open() down_read(&minor_rwsem); dvb_generic_open() dvbdev->users--; // race condition up_read(&minor_rwsem); 3. dvb_unregister_device() dvb_remove_device() down_write(&minor_rwsem); dvb_minors[dvbdev->minor] = NULL; up_write(&minor_rwsem); dvb_free_device() kfree (dvbdev->fops); 4. close(fd) __x64_sys_close() close_fd() filp_close() retval = filp->f_op->flush(filp, id); // UAF ``` After the 'if (dvbnet->dvbdev->users < 1)' conditional of dvb_net_release() passes, 'dvbdev->users--;' of dvb_generic_open() is executed, improper reference counting occurs. The root cause of this is that you use the dvb_device_open() function, which does not implement a conditional statement that checks 'dvbnet->exit'. The KASAN log caused by this is as follows: ``` [ 952.372616] ================================================================== [ 952.372639] BUG: KASAN: use-after-free in filp_close+0x119/0x140 [ 952.372667] Read of size 8 at addr ffff888118abec78 by task dvb_net_test/2522 [ 952.372690] CPU: 3 PID: 2522 Comm: dvb_net_test Not tainted 6.1.0-rc2+ #16 [ 952.372707] Hardware name: Gigabyte Technology Co., Ltd. B460MDS3H/B460M DS3H, BIOS F3 05/27/2020 [ 952.372718] Call Trace: [ 952.372727] <TASK> [ 952.372736] dump_stack_lvl+0x49/0x63 [ 952.372754] print_report+0x177/0x46e [ 952.372775] ? kasan_complete_mode_report_info+0x7c/0x210 [ 952.372791] ? filp_close+0x119/0x140 [ 952.372810] kasan_report+0xb0/0x140 [ 952.372830] ? filp_close+0x119/0x140 [ 952.372850] __asan_report_load8_noabort+0x14/0x20 [ 952.372865] filp_close+0x119/0x140 [ 952.372883] close_fd+0x75/0x90 [ 952.372897] __x64_sys_close+0x30/0x80 [ 952.372915] do_syscall_64+0x59/0x90 [ 952.372930] ? fpregs_assert_state_consistent+0x52/0xc0 [ 952.372950] ? exit_to_user_mode_prepare+0x49/0x1a0 [ 952.372965] ? syscall_exit_to_user_mode+0x26/0x50 [ 952.372984] ? do_syscall_64+0x69/0x90 [ 952.373000] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 952.373016] RIP: 0033:0x4537eb [ 952.373031] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 a8 02 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 11 a9 02 00 8b 44 [ 952.373046] RSP: 002b:00007f98078001a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 [ 952.373066] RAX: ffffffffffffffda RBX: 00007f9807800640 RCX: 00000000004537eb [ 952.373078] RDX: 0000000000000000 RSI: 00007f9800000b70 RDI: 0000000000000003 [ 952.373089] RBP: 00007f98078001d0 R08: 0000000000000000 R09: 0000000000000000 [ 952.373100] R10: 00007f9807800180 R11: 0000000000000293 R12: 00007f9807800640 [ 952.373111] R13: 0000000000000000 R14: 000000000041b290 R15: 00007f9807000000 [ 952.373130] </TASK> [ 952.373145] Allocated by task 592: [ 952.373155] kasan_save_stack+0x26/0x50 [ 952.373171] kasan_set_track+0x25/0x40 [ 952.373185] kasan_save_alloc_info+0x1e/0x30 [ 952.373195] __kasan_kmalloc+0xb4/0xc0 [ 952.373212] __kmalloc_node_track_caller+0x66/0x160 [ 952.373233] kmemdup+0x23/0x50 [ 952.373250] dvb_register_device+0x1cd/0x15c0 [dvb_core] [ 952.373301] dvb_net_init+0xc7/0x100 [dvb_core] [ 952.373348] ttusb_dec_probe.cold+0x14de/0x1f1e [ttusb_dec] [ 952.373373] usb_probe_interface+0x266/0x740 [ 952.373388] really_probe+0x1fa/0xa80 [ 952.373400] __driver_probe_device+0x2cb/0x490 [ 952.373412] driver_probe_device+0x4e/0x140 [ 952.373424] __device_attach_driver+0x197/0x2b0 [ 952.373437] bus_for_each_drv+0x129/0x1c0 [ 952.373447] __device_attach+0x2ad/0x4f0 [ 952.373459] device_initial_probe+0x13/0x20 [ 952.373470] bus_probe_device+0x198/0x240 [ 952.373481] device_add+0xa1b/0x1cc0 [ 952.373491] usb_set_configuration+0x9ca/0x17f0 [ 952.373502] usb_generic_driver_probe+0x86/0xb0 [ 952.373513] usb_probe_device+0xa7/0x260 [ 952.373524] really_probe+0x1fa/0xa80 [ 952.373535] __driver_probe_device+0x2cb/0x490 [ 952.373547] driver_probe_device+0x4e/0x140 [ 952.373558] __device_attach_driver+0x197/0x2b0 [ 952.373570] bus_for_each_drv+0x129/0x1c0 [ 952.373580] __device_attach+0x2ad/0x4f0 [ 952.373591] device_initial_probe+0x13/0x20 [ 952.373603] bus_probe_device+0x198/0x240 [ 952.373614] device_add+0xa1b/0x1cc0 [ 952.373623] usb_new_device.cold+0x462/0xc46 [ 952.373637] hub_event+0x1d23/0x3d20 [ 952.373652] process_one_work+0x778/0x11c0 [ 952.373664] worker_thread+0x544/0x1180 [ 952.373676] kthread+0x280/0x320 [ 952.373686] ret_from_fork+0x1f/0x30 [ 952.373707] Freed by task 592: [ 952.373717] kasan_save_stack+0x26/0x50 [ 952.373731] kasan_set_track+0x25/0x40 [ 952.373744] kasan_save_free_info+0x2e/0x50 [ 952.373754] ____kasan_slab_free+0x174/0x1e0 [ 952.373767] __kasan_slab_free+0x12/0x20 [ 952.373780] slab_free_freelist_hook+0xd0/0x1a0 [ 952.373793] __kmem_cache_free+0x193/0x2c0 [ 952.373805] kfree+0x79/0x120 [ 952.373817] dvb_free_device.part.0+0x33/0x70 [dvb_core] [ 952.373858] dvb_unregister_device+0x40/0x54 [dvb_core] [ 952.373905] dvb_net_release+0x264/0x316 [dvb_core] [ 952.373952] ttusb_dec_disconnect+0x391/0x4e1 [ttusb_dec] [ 952.373973] usb_unbind_interface+0x187/0x7c0 [ 952.373986] device_remove+0x117/0x170 [ 952.373997] device_release_driver_internal+0x418/0x660 [ 952.374010] device_release_driver+0x12/0x20 [ 952.374022] bus_remove_device+0x28f/0x540 [ 952.374032] device_del+0x501/0xc30 [ 952.374047] usb_disable_device+0x2a5/0x660 [ 952.374058] usb_disconnect.cold+0x1f9/0x620 [ 952.374070] hub_event+0x16d3/0x3d20 [ 952.374084] process_one_work+0x778/0x11c0 [ 952.374096] worker_thread+0x544/0x1180 [ 952.374107] kthread+0x280/0x320 [ 952.374117] ret_from_fork+0x1f/0x30 ``` # 3. media: dvb-core: Fix use-after-free due to race condition occurring in dvb_register_device() This is a security patch for a race condition that occurs in the dvb_register_device() function. This race condition can occur _anywhere_ the dvb_register_device() function is called: dvb_demux, dvb_dvr, dvb_frontend, dvb_net, etc. The race condition flow is as follows (dvb_net is used as an example): `````` cpu0 cpu1 1. open() dvb_device_open() 2. close() __fput() dvb_net_close() 3. .disconnect() dvb_net_release() dvb_unregister_device() dvb_free_device() kfree (dvbdev->fops); 4. ... fops_put(file->f_op); // UAF!! ``` UAF occurs in '.probe -> open() -> close() -> .disconnect' flow. The root cause of this is that fops used as an argument of replace_fops() in dvb_device_open() are kfree()d in the .disconnect flow. It's not common for fops used in replace_fops() to be dynamically allocated and kfree()d like this. The KASAN log caused by this is as follows: ``` [ 67.857811] ================================================================== [ 67.857830] BUG: KASAN: use-after-free in __fput+0xa55/0xaf0 [ 67.857855] Read of size 8 at addr ffff88810f7dfc00 by task dvb_net_fput/2152 [ 67.857879] CPU: 15 PID: 2152 Comm: dvb_net_fput Not tainted 6.1.0-rc2+ #17 [ 67.857896] Hardware name: Gigabyte Technology Co., Ltd. B460MDS3H/B460M DS3H, BIOS F3 05/27/2020 [ 67.857907] Call Trace: [ 67.857917] <TASK> [ 67.857928] dump_stack_lvl+0x49/0x63 [ 67.857947] print_report+0x177/0x46e [ 67.857967] ? kasan_complete_mode_report_info+0x7c/0x210 [ 67.857984] ? __fput+0xa55/0xaf0 [ 67.858001] kasan_report+0xb0/0x140 [ 67.858021] ? __fput+0xa55/0xaf0 [ 67.858039] __asan_report_load8_noabort+0x14/0x20 [ 67.858053] __fput+0xa55/0xaf0 [ 67.858072] ____fput+0xe/0x20 [ 67.858087] task_work_run+0x153/0x240 [ 67.858108] ? task_work_cancel+0x20/0x20 [ 67.858127] ? fput+0xab/0x140 [ 67.858144] exit_to_user_mode_prepare+0x18f/0x1a0 [ 67.858160] syscall_exit_to_user_mode+0x26/0x50 [ 67.858179] do_syscall_64+0x69/0x90 [ 67.858194] ? exit_to_user_mode_prepare+0x49/0x1a0 [ 67.858208] ? irqentry_exit_to_user_mode+0x9/0x20 [ 67.858226] ? irqentry_exit+0x3b/0x50 [ 67.858243] ? exc_page_fault+0x72/0xf0 [ 67.858262] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 67.858278] RIP: 0033:0x4537eb [ 67.858294] Code: 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 c3 a8 02 00 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 11 a9 02 00 8b 44 [ 67.858309] RSP: 002b:00007f607be001a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 [ 67.858330] RAX: 0000000000000000 RBX: 00007f607be00640 RCX: 00000000004537eb [ 67.858343] RDX: 0000000000000000 RSI: 00007f6074000b70 RDI: 0000000000000003 [ 67.858353] RBP: 00007f607be001d0 R08: 0000000000000000 R09: 0000000000000000 [ 67.858364] R10: 00007f607be00180 R11: 0000000000000293 R12: 00007f607be00640 [ 67.858375] R13: 0000000000000000 R14: 000000000041b2a0 R15: 00007f607b600000 [ 67.858392] </TASK> [ 67.858407] Allocated by task 2125: [ 67.858417] kasan_save_stack+0x26/0x50 [ 67.858433] kasan_set_track+0x25/0x40 [ 67.858447] kasan_save_alloc_info+0x1e/0x30 [ 67.858456] __kasan_kmalloc+0xb4/0xc0 [ 67.858469] __kmalloc_node_track_caller+0x66/0x160 [ 67.858483] kmemdup+0x23/0x50 [ 67.858495] dvb_register_device+0x1cd/0x15c0 [dvb_core] [ 67.858543] dvb_net_init+0xe1/0x120 [dvb_core] [ 67.858591] ttusb_dec_probe.cold+0x14de/0x1f1e [ttusb_dec] [ 67.858615] usb_probe_interface+0x266/0x740 [ 67.858629] really_probe+0x1fa/0xa80 [ 67.858642] __driver_probe_device+0x2cb/0x490 [ 67.858654] driver_probe_device+0x4e/0x140 [ 67.858666] __driver_attach+0x1a3/0x520 [ 67.858677] bus_for_each_dev+0x11e/0x1c0 [ 67.858688] driver_attach+0x3d/0x60 [ 67.858699] bus_add_driver+0x449/0x5a0 [ 67.858710] driver_register+0x219/0x390 [ 67.858722] usb_register_driver+0x228/0x400 [ 67.858733] 0xffffffffc0506023 [ 67.858744] do_one_initcall+0x97/0x310 [ 67.858758] do_init_module+0x19a/0x630 [ 67.858770] load_module+0x6ca4/0x7d90 [ 67.858781] __do_sys_finit_module+0x134/0x1d0 [ 67.858792] __x64_sys_finit_module+0x72/0xb0 [ 67.858803] do_syscall_64+0x59/0x90 [ 67.858815] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 67.858834] Freed by task 666: [ 67.858843] kasan_save_stack+0x26/0x50 [ 67.858857] kasan_set_track+0x25/0x40 [ 67.858870] kasan_save_free_info+0x2e/0x50 [ 67.858880] ____kasan_slab_free+0x174/0x1e0 [ 67.858893] __kasan_slab_free+0x12/0x20 [ 67.858907] slab_free_freelist_hook+0xd0/0x1a0 [ 67.858919] __kmem_cache_free+0x193/0x2c0 [ 67.858932] kfree+0x79/0x120 [ 67.858944] dvb_free_device.part.0+0x33/0x70 [dvb_core] [ 67.858984] dvb_unregister_device+0x40/0x54 [dvb_core] [ 67.859032] dvb_net_release+0x267/0x319 [dvb_core] [ 67.859080] ttusb_dec_disconnect+0x391/0x4e1 [ttusb_dec] [ 67.859102] usb_unbind_interface+0x187/0x7c0 [ 67.859115] device_remove+0x117/0x170 [ 67.859126] device_release_driver_internal+0x418/0x660 [ 67.859139] device_release_driver+0x12/0x20 [ 67.859150] bus_remove_device+0x28f/0x540 [ 67.859161] device_del+0x501/0xc30 [ 67.859176] usb_disable_device+0x2a5/0x660 [ 67.859187] usb_disconnect.cold+0x1f9/0x620 [ 67.859200] hub_event+0x16d3/0x3d20 [ 67.859215] process_one_work+0x778/0x11c0 [ 67.859228] worker_thread+0x544/0x1180 [ 67.859239] kthread+0x280/0x320 [ 67.859249] ret_from_fork+0x1f/0x30 ``` # 4. media: ttusb-dec: Fix memory leak in ttusb_dec_exit_dvb() This is a patch for a memory leak that occurs in the ttusb_dec_exit_dvb() function. Because ttusb_dec_exit_dvb() does not call dvb_frontend_detach(), several fe related structures are not kfree()d. Users can trigger a memory leak just by repeating connecting and disconnecting the ttusb_dec device. Finally, most of these patches are similar to this one, the security patch for CVE-2022-41218 that I reported: https://lore.kernel.org/linux-media/20221031100245.23702-1-tiwai@suse.de/ Regards, Hyunwoo Kim Hyunwoo Kim (4): media: dvb-core: Fix use-after-free due to race condition occurring in dvb_frontend media: dvb-core: Fix use-after-free due to race condition occurring in dvb_net media: dvb-core: Fix use-after-free due to race condition occurring in dvb_register_device() media: ttusb-dec: Fix memory leak in ttusb_dec_exit_dvb() drivers/media/dvb-core/dvb_frontend.c | 39 ++++++++++-- drivers/media/dvb-core/dvb_net.c | 37 ++++++++++- drivers/media/dvb-core/dvbdev.c | 83 ++++++++++++++++++------- drivers/media/usb/ttusb-dec/ttusb_dec.c | 3 +- include/media/dvb_frontend.h | 6 +- include/media/dvb_net.h | 4 ++ include/media/dvbdev.h | 15 +++++ 7 files changed, 155 insertions(+), 32 deletions(-)

[0/4] Fix multiple race condition vulnerabilities in dvb-core and device driver

Message