| Message ID | 20230609082238.3671398-1-mchehab@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Revert "media: dvb-core: Fix use-after-free on race condition at dvb_frontend" | expand |
On Fri, 09 Jun 2023 10:22:38 +0200, Mauro Carvalho Chehab wrote: > > As reported by Thomas Voegtle <tv@lio96.de>, sometimes a DVB card does > not initialize properly booting Linux 6.4-rc4. This is not always, maybe > in 3 out of 4 attempts. > > After double-checking, the root cause seems to be related to the > UAF fix, which is causing a race issue: > > [ 26.332149] tda10071 7-0005: found a 'NXP TDA10071' in cold state, will try to load a firmware > [ 26.340779] tda10071 7-0005: downloading firmware from file 'dvb-fe-tda10071.fw' > [ 989.277402] INFO: task vdr:743 blocked for more than 491 seconds. > [ 989.283504] Not tainted 6.4.0-rc5-i5 #249 > [ 989.288036] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [ 989.295860] task:vdr state:D stack:0 pid:743 ppid:711 flags:0x00004002 > [ 989.295865] Call Trace: > [ 989.295867] <TASK> > [ 989.295869] __schedule+0x2ea/0x12d0 > [ 989.295877] ? asm_sysvec_apic_timer_interrupt+0x16/0x20 > [ 989.295881] schedule+0x57/0xc0 > [ 989.295884] schedule_preempt_disabled+0xc/0x20 > [ 989.295887] __mutex_lock.isra.16+0x237/0x480 > [ 989.295891] ? dvb_get_property.isra.10+0x1bc/0xa50 > [ 989.295898] ? dvb_frontend_stop+0x36/0x180 > [ 989.338777] dvb_frontend_stop+0x36/0x180 > [ 989.338781] dvb_frontend_open+0x2f1/0x470 > [ 989.338784] dvb_device_open+0x81/0xf0 > [ 989.338804] ? exact_lock+0x20/0x20 > [ 989.338808] chrdev_open+0x7f/0x1c0 > [ 989.338811] ? generic_permission+0x1a2/0x230 > [ 989.338813] ? link_path_walk.part.63+0x340/0x380 > [ 989.338815] ? exact_lock+0x20/0x20 > [ 989.338817] do_dentry_open+0x18e/0x450 > [ 989.374030] path_openat+0xca5/0xe00 > [ 989.374031] ? terminate_walk+0xec/0x100 > [ 989.374034] ? path_lookupat+0x93/0x140 > [ 989.374036] do_filp_open+0xc0/0x140 > [ 989.374038] ? __call_rcu_common.constprop.91+0x92/0x240 > [ 989.374041] ? __check_object_size+0x147/0x260 > [ 989.374043] ? __check_object_size+0x147/0x260 > [ 989.374045] ? alloc_fd+0xbb/0x180 > [ 989.374048] ? do_sys_openat2+0x243/0x310 > [ 989.374050] do_sys_openat2+0x243/0x310 > [ 989.374052] do_sys_open+0x52/0x80 > [ 989.374055] do_syscall_64+0x5b/0x80 > [ 989.421335] ? __task_pid_nr_ns+0x92/0xa0 > [ 989.421337] ? syscall_exit_to_user_mode+0x20/0x40 > [ 989.421339] ? do_syscall_64+0x67/0x80 > [ 989.421341] ? syscall_exit_to_user_mode+0x20/0x40 > [ 989.421343] ? do_syscall_64+0x67/0x80 > [ 989.421345] entry_SYSCALL_64_after_hwframe+0x63/0xcd > [ 989.421348] RIP: 0033:0x7fe895d067e3 > [ 989.421349] RSP: 002b:00007fff933c2ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 > [ 989.421351] RAX: ffffffffffffffda RBX: 00007fff933c2c10 RCX: 00007fe895d067e3 > [ 989.421352] RDX: 0000000000000802 RSI: 00005594acdce160 RDI: 00000000ffffff9c > [ 989.421353] RBP: 0000000000000802 R08: 0000000000000000 R09: 0000000000000000 > [ 989.421353] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 > [ 989.421354] R13: 00007fff933c2ca0 R14: 00000000ffffffff R15: 00007fff933c2c90 > [ 989.421355] </TASK> > > This reverts commit 6769a0b7ee0c3b31e1b22c3fadff2bfb642de23f. > > Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> Note that CVE-2022-45885 was assigned for the original issue as a security bug, and now it's reopened by this revert. Please let me know if you have a fix in another form. thanks, Takashi
diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index bc6950a5740f..9293b058ab99 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -817,26 +817,15 @@ static void dvb_frontend_stop(struct dvb_frontend *fe) dev_dbg(fe->dvb->device, "%s:\n", __func__); - mutex_lock(&fe->remove_mutex); - if (fe->exit != DVB_FE_DEVICE_REMOVED) fe->exit = DVB_FE_NORMAL_EXIT; mb(); - if (!fepriv->thread) { - mutex_unlock(&fe->remove_mutex); + if (!fepriv->thread) return; - } kthread_stop(fepriv->thread); - mutex_unlock(&fe->remove_mutex); - - if (fepriv->dvbdev->users < -1) { - wait_event(fepriv->dvbdev->wait_queue, - fepriv->dvbdev->users == -1); - } - sema_init(&fepriv->sem, 1); fepriv->state = FESTATE_IDLE; @@ -2780,13 +2769,9 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) struct dvb_adapter *adapter = fe->dvb; int ret; - mutex_lock(&fe->remove_mutex); - dev_dbg(fe->dvb->device, "%s:\n", __func__); - if (fe->exit == DVB_FE_DEVICE_REMOVED) { - ret = -ENODEV; - goto err_remove_mutex; - } + if (fe->exit == DVB_FE_DEVICE_REMOVED) + return -ENODEV; if (adapter->mfe_shared == 2) { mutex_lock(&adapter->mfe_lock); @@ -2794,8 +2779,7 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) if (adapter->mfe_dvbdev && !adapter->mfe_dvbdev->writers) { mutex_unlock(&adapter->mfe_lock); - ret = -EBUSY; - goto err_remove_mutex; + return -EBUSY; } adapter->mfe_dvbdev = dvbdev; } @@ -2818,10 +2802,8 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) while (mferetry-- && (mfedev->users != -1 || mfepriv->thread)) { if (msleep_interruptible(500)) { - if (signal_pending(current)) { - ret = -EINTR; - goto err_remove_mutex; - } + if (signal_pending(current)) + return -EINTR; } } @@ -2833,8 +2815,7 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) if (mfedev->users != -1 || mfepriv->thread) { mutex_unlock(&adapter->mfe_lock); - ret = -EBUSY; - goto err_remove_mutex; + return -EBUSY; } adapter->mfe_dvbdev = dvbdev; } @@ -2893,8 +2874,6 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) if (adapter->mfe_shared) mutex_unlock(&adapter->mfe_lock); - - mutex_unlock(&fe->remove_mutex); return ret; err3: @@ -2916,9 +2895,6 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) err0: if (adapter->mfe_shared) mutex_unlock(&adapter->mfe_lock); - -err_remove_mutex: - mutex_unlock(&fe->remove_mutex); return ret; } @@ -2929,8 +2905,6 @@ static int dvb_frontend_release(struct inode *inode, struct file *file) struct dvb_frontend_private *fepriv = fe->frontend_priv; int ret; - mutex_lock(&fe->remove_mutex); - dev_dbg(fe->dvb->device, "%s:\n", __func__); if ((file->f_flags & O_ACCMODE) != O_RDONLY) { @@ -2952,18 +2926,10 @@ static int dvb_frontend_release(struct inode *inode, struct file *file) } mutex_unlock(&fe->dvb->mdev_lock); #endif + if (fe->exit != DVB_FE_NO_EXIT) + wake_up(&dvbdev->wait_queue); if (fe->ops.ts_bus_ctrl) fe->ops.ts_bus_ctrl(fe, 0); - - if (fe->exit != DVB_FE_NO_EXIT) { - mutex_unlock(&fe->remove_mutex); - wake_up(&dvbdev->wait_queue); - } else { - mutex_unlock(&fe->remove_mutex); - } - - } else { - mutex_unlock(&fe->remove_mutex); } dvb_frontend_put(fe); @@ -3064,7 +3030,6 @@ int dvb_register_frontend(struct dvb_adapter *dvb, fepriv = fe->frontend_priv; kref_init(&fe->refcount); - mutex_init(&fe->remove_mutex); /* * After initialization, there need to be two references: one diff --git a/include/media/dvb_frontend.h b/include/media/dvb_frontend.h index 367d5381217b..e7c44870f20d 100644 --- a/include/media/dvb_frontend.h +++ b/include/media/dvb_frontend.h @@ -686,10 +686,7 @@ struct dtv_frontend_properties { * @id: Frontend ID * @exit: Used to inform the DVB core that the frontend * thread should exit (usually, means that the hardware - * got disconnected). - * @remove_mutex: mutex that avoids a race condition between a callback - * called when the hardware is disconnected and the - * file_operations of dvb_frontend. + * got disconnected. */ struct dvb_frontend { @@ -707,7 +704,6 @@ struct dvb_frontend { int (*callback)(void *adapter_priv, int component, int cmd, int arg); int id; unsigned int exit; - struct mutex remove_mutex; }; /**
As reported by Thomas Voegtle <tv@lio96.de>, sometimes a DVB card does not initialize properly booting Linux 6.4-rc4. This is not always, maybe in 3 out of 4 attempts. After double-checking, the root cause seems to be related to the UAF fix, which is causing a race issue: [ 26.332149] tda10071 7-0005: found a 'NXP TDA10071' in cold state, will try to load a firmware [ 26.340779] tda10071 7-0005: downloading firmware from file 'dvb-fe-tda10071.fw' [ 989.277402] INFO: task vdr:743 blocked for more than 491 seconds. [ 989.283504] Not tainted 6.4.0-rc5-i5 #249 [ 989.288036] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 989.295860] task:vdr state:D stack:0 pid:743 ppid:711 flags:0x00004002 [ 989.295865] Call Trace: [ 989.295867] <TASK> [ 989.295869] __schedule+0x2ea/0x12d0 [ 989.295877] ? asm_sysvec_apic_timer_interrupt+0x16/0x20 [ 989.295881] schedule+0x57/0xc0 [ 989.295884] schedule_preempt_disabled+0xc/0x20 [ 989.295887] __mutex_lock.isra.16+0x237/0x480 [ 989.295891] ? dvb_get_property.isra.10+0x1bc/0xa50 [ 989.295898] ? dvb_frontend_stop+0x36/0x180 [ 989.338777] dvb_frontend_stop+0x36/0x180 [ 989.338781] dvb_frontend_open+0x2f1/0x470 [ 989.338784] dvb_device_open+0x81/0xf0 [ 989.338804] ? exact_lock+0x20/0x20 [ 989.338808] chrdev_open+0x7f/0x1c0 [ 989.338811] ? generic_permission+0x1a2/0x230 [ 989.338813] ? link_path_walk.part.63+0x340/0x380 [ 989.338815] ? exact_lock+0x20/0x20 [ 989.338817] do_dentry_open+0x18e/0x450 [ 989.374030] path_openat+0xca5/0xe00 [ 989.374031] ? terminate_walk+0xec/0x100 [ 989.374034] ? path_lookupat+0x93/0x140 [ 989.374036] do_filp_open+0xc0/0x140 [ 989.374038] ? __call_rcu_common.constprop.91+0x92/0x240 [ 989.374041] ? __check_object_size+0x147/0x260 [ 989.374043] ? __check_object_size+0x147/0x260 [ 989.374045] ? alloc_fd+0xbb/0x180 [ 989.374048] ? do_sys_openat2+0x243/0x310 [ 989.374050] do_sys_openat2+0x243/0x310 [ 989.374052] do_sys_open+0x52/0x80 [ 989.374055] do_syscall_64+0x5b/0x80 [ 989.421335] ? __task_pid_nr_ns+0x92/0xa0 [ 989.421337] ? syscall_exit_to_user_mode+0x20/0x40 [ 989.421339] ? do_syscall_64+0x67/0x80 [ 989.421341] ? syscall_exit_to_user_mode+0x20/0x40 [ 989.421343] ? do_syscall_64+0x67/0x80 [ 989.421345] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 989.421348] RIP: 0033:0x7fe895d067e3 [ 989.421349] RSP: 002b:00007fff933c2ba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 [ 989.421351] RAX: ffffffffffffffda RBX: 00007fff933c2c10 RCX: 00007fe895d067e3 [ 989.421352] RDX: 0000000000000802 RSI: 00005594acdce160 RDI: 00000000ffffff9c [ 989.421353] RBP: 0000000000000802 R08: 0000000000000000 R09: 0000000000000000 [ 989.421353] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001 [ 989.421354] R13: 00007fff933c2ca0 R14: 00000000ffffffff R15: 00007fff933c2c90 [ 989.421355] </TASK> This reverts commit 6769a0b7ee0c3b31e1b22c3fadff2bfb642de23f. Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org> --- drivers/media/dvb-core/dvb_frontend.c | 53 +++++---------------------- include/media/dvb_frontend.h | 6 +-- 2 files changed, 10 insertions(+), 49 deletions(-)