From dd3b1dc3dd050f1f47cd13e300732852414270f8 Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Fri, 4 Feb 2022 13:12:35 -0800 Subject: [PATCH 1/6] Bluetooth: hci_core: Fix leaking sent_cmd skb sent_cmd memory is not freed before freeing hci_dev causing it to leak it contents. Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann --- net/bluetooth/hci_core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 2b7bd3655b076..2882bc7d79d79 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2738,6 +2738,7 @@ void hci_release_dev(struct hci_dev *hdev) hci_dev_unlock(hdev); ida_simple_remove(&hci_index_ida, hdev->id); + kfree_skb(hdev->sent_cmd); kfree(hdev); } EXPORT_SYMBOL(hci_release_dev); From fa78d2d1d64f147062e384a4a10a26a5f89944b5 Mon Sep 17 00:00:00 2001 From: Lin Ma Date: Wed, 16 Feb 2022 12:37:14 +0800 Subject: [PATCH 2/6] Bluetooth: fix data races in smp_unregister(), smp_del_chan() Previous commit e04480920d1e ("Bluetooth: defer cleanup of resources in hci_unregister_dev()") defers all destructive actions to hci_release_dev() to prevent cocurrent problems like NPD, UAF. However, there are still some exceptions that are ignored. The smp_unregister() in hci_dev_close_sync() (previously in hci_dev_do_close) will release resources like the sensitive channel and the smp_dev objects. Consider the situations the device is detaching or power down while the kernel is still operating on it, the following data race could take place. thread-A hci_dev_close_sync | thread-B read_local_oob_ext_data | hci_dev_unlock() | ... | hci_dev_lock() if (hdev->smp_data) | chan = hdev->smp_data | | chan = hdev->smp_data (3) | hdev->smp_data = NULL (1) | if (!chan || !chan->data) (4) ... | smp = chan->data | smp = chan->data if (smp) | chan->data = NULL (2) | ... | kfree_sensitive(smp) | | // dereference smp trigger UFA That is, the objects hdev->smp_data and chan->data both suffer from the data races. In a preempt-enable kernel, the above schedule (when (3) is before (1) and (4) is before (2)) leads to UAF bugs. It can be reproduced in the latest kernel and below is part of the report: [ 49.097146] ================================================================ [ 49.097611] BUG: KASAN: use-after-free in smp_generate_oob+0x2dd/0x570 [ 49.097611] Read of size 8 at addr ffff888006528360 by task generate_oob/155 [ 49.097611] [ 49.097611] Call Trace: [ 49.097611] [ 49.097611] dump_stack_lvl+0x34/0x44 [ 49.097611] print_address_description.constprop.0+0x1f/0x150 [ 49.097611] ? smp_generate_oob+0x2dd/0x570 [ 49.097611] ? smp_generate_oob+0x2dd/0x570 [ 49.097611] kasan_report.cold+0x7f/0x11b [ 49.097611] ? smp_generate_oob+0x2dd/0x570 [ 49.097611] smp_generate_oob+0x2dd/0x570 [ 49.097611] read_local_oob_ext_data+0x689/0xc30 [ 49.097611] ? hci_event_packet+0xc80/0xc80 [ 49.097611] ? sysvec_apic_timer_interrupt+0x9b/0xc0 [ 49.097611] ? asm_sysvec_apic_timer_interrupt+0x12/0x20 [ 49.097611] ? mgmt_init_hdev+0x1c/0x240 [ 49.097611] ? mgmt_init_hdev+0x28/0x240 [ 49.097611] hci_sock_sendmsg+0x1880/0x1e70 [ 49.097611] ? create_monitor_event+0x890/0x890 [ 49.097611] ? create_monitor_event+0x890/0x890 [ 49.097611] sock_sendmsg+0xdf/0x110 [ 49.097611] __sys_sendto+0x19e/0x270 [ 49.097611] ? __ia32_sys_getpeername+0xa0/0xa0 [ 49.097611] ? kernel_fpu_begin_mask+0x1c0/0x1c0 [ 49.097611] __x64_sys_sendto+0xd8/0x1b0 [ 49.097611] ? syscall_exit_to_user_mode+0x1d/0x40 [ 49.097611] do_syscall_64+0x3b/0x90 [ 49.097611] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 49.097611] RIP: 0033:0x7f5a59f51f64 ... [ 49.097611] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5a59f51f64 [ 49.097611] RDX: 0000000000000007 RSI: 00007f5a59d6ac70 RDI: 0000000000000006 [ 49.097611] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 [ 49.097611] R10: 0000000000000040 R11: 0000000000000246 R12: 00007ffec26916ee [ 49.097611] R13: 00007ffec26916ef R14: 00007f5a59d6afc0 R15: 00007f5a59d6b700 To solve these data races, this patch places the smp_unregister() function in the protected area by the hci_dev_lock(). That is, the smp_unregister() function can not be concurrently executed when operating functions (most of them are mgmt operations in mgmt.c) hold the device lock. This patch is tested with kernel LOCK DEBUGGING enabled. The price from the extended holding time of the device lock is supposed to be low as the smp_unregister() function is fairly short and efficient. Signed-off-by: Lin Ma Signed-off-by: Marcel Holtmann --- net/bluetooth/hci_sync.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 0feb68f125456..e34fc15b7d2c0 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -4106,9 +4106,9 @@ int hci_dev_close_sync(struct hci_dev *hdev) hci_inquiry_cache_flush(hdev); hci_pend_le_actions_clear(hdev); hci_conn_hash_flush(hdev); - hci_dev_unlock(hdev); - + /* Prevent data races on hdev->smp_data or hdev->smp_bredr_data */ smp_unregister(hdev); + hci_dev_unlock(hdev); hci_sock_dev_event(hdev, HCI_DEV_DOWN); From 29fb608396d6a62c1b85acc421ad7a4399085b9f Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Mon, 14 Feb 2022 17:59:38 -0800 Subject: [PATCH 3/6] Bluetooth: Fix bt_skb_sendmmsg not allocating partial chunks Since bt_skb_sendmmsg can be used with the likes of SOCK_STREAM it shall return the partial chunks it could allocate instead of freeing everything as otherwise it can cause problems like bellow. Fixes: 81be03e026dc ("Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg") Reported-by: Paul Menzel Link: https://lore.kernel.org/r/d7206e12-1b99-c3be-84f4-df22af427ef5@molgen.mpg.de BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215594 Signed-off-by: Luiz Augusto von Dentz Tested-by: Paul Menzel (Nokia N9 (MeeGo/Harmattan) Signed-off-by: Marcel Holtmann --- include/net/bluetooth/bluetooth.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h index 4b3d0b16c185e..a647e5fabdbd6 100644 --- a/include/net/bluetooth/bluetooth.h +++ b/include/net/bluetooth/bluetooth.h @@ -506,8 +506,7 @@ static inline struct sk_buff *bt_skb_sendmmsg(struct sock *sk, tmp = bt_skb_sendmsg(sk, msg, len, mtu, headroom, tailroom); if (IS_ERR(tmp)) { - kfree_skb(skb); - return tmp; + return skb; } len -= tmp->len; From 2e8ecb4bbc13d4752d64a9f8f5512d59125cab25 Mon Sep 17 00:00:00 2001 From: Wang Qing Date: Mon, 14 Feb 2022 18:01:56 -0800 Subject: [PATCH 4/6] Bluetooth: assign len after null check len should be assigned after a null check Signed-off-by: Wang Qing Signed-off-by: Marcel Holtmann --- net/bluetooth/mgmt_util.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/mgmt_util.c b/net/bluetooth/mgmt_util.c index edee60bbc7b46..37eef2ce55aec 100644 --- a/net/bluetooth/mgmt_util.c +++ b/net/bluetooth/mgmt_util.c @@ -77,11 +77,12 @@ int mgmt_send_event_skb(unsigned short channel, struct sk_buff *skb, int flag, { struct hci_dev *hdev; struct mgmt_hdr *hdr; - int len = skb->len; + int len; if (!skb) return -EINVAL; + len = skb->len; hdev = bt_cb(skb)->mgmt.hdev; /* Time stamp */ From 80740ebb7e1ad15ab9c11425dcd26e073f86d74b Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Thu, 24 Feb 2022 07:11:47 -0800 Subject: [PATCH 5/6] Bluetooth: hci_sync: Fix hci_update_accept_list_sync hci_update_accept_list_sync is returning the filter based on the error but that gets overwritten by hci_le_set_addr_resolution_enable_sync return instead of using the actual result of the likes of hci_le_add_accept_list_sync which was intended. Fixes: ad383c2c65a5b ("Bluetooth: hci_sync: Enable advertising when LL privacy is enabled") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann --- net/bluetooth/hci_sync.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index e34fc15b7d2c0..9d8490570b422 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -1841,6 +1841,7 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) struct bdaddr_list *b, *t; u8 num_entries = 0; bool pend_conn, pend_report; + u8 filter_policy; int err; /* Pause advertising if resolving list can be used as controllers are @@ -1927,6 +1928,8 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) err = -EINVAL; done: + filter_policy = err ? 0x00 : 0x01; + /* Enable address resolution when LL Privacy is enabled. */ err = hci_le_set_addr_resolution_enable_sync(hdev, 0x01); if (err) @@ -1937,7 +1940,7 @@ static u8 hci_update_accept_list_sync(struct hci_dev *hdev) hci_resume_advertising_sync(hdev); /* Select filter policy to use accept list */ - return err ? 0x00 : 0x01; + return filter_policy; } /* Returns true if an le connection is in the scanning state */ From a56a1138cbd85e4d565356199d60e1cb94e5a77a Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Thu, 17 Feb 2022 13:10:38 -0800 Subject: [PATCH 6/6] Bluetooth: hci_sync: Fix not using conn_timeout When using hci_le_create_conn_sync it shall wait for the conn_timeout since the connection complete may take longer than just 2 seconds. Also fix the masking of HCI_EV_LE_ENHANCED_CONN_COMPLETE and HCI_EV_LE_CONN_COMPLETE so they are never both set so we can predict which one the controller will use in case of HCI_OP_LE_CREATE_CONN. Fixes: 6cd29ec6ae5e3 ("Bluetooth: hci_sync: Wait for proper events when connecting LE") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann --- include/net/bluetooth/hci_core.h | 8 ++++++++ net/bluetooth/hci_sync.c | 21 +++++++++++++++------ 2 files changed, 23 insertions(+), 6 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 586f69d084a2a..e336e9c1dda4f 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -1489,6 +1489,14 @@ void hci_conn_del_sysfs(struct hci_conn *conn); /* Extended advertising support */ #define ext_adv_capable(dev) (((dev)->le_features[1] & HCI_LE_EXT_ADV)) +/* BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E page 1789: + * + * C24: Mandatory if the LE Controller supports Connection State and either + * LE Feature (LL Privacy) or LE Feature (Extended Advertising) is supported + */ +#define use_enhanced_conn_complete(dev) (ll_privacy_capable(dev) || \ + ext_adv_capable(dev)) + /* ----- HCI protocols ----- */ #define HCI_PROTO_DEFER 0x01 diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index 9d8490570b422..9ba2a1a7d4819 100644 --- a/net/bluetooth/hci_sync.c +++ b/net/bluetooth/hci_sync.c @@ -3265,10 +3265,10 @@ static int hci_le_set_event_mask_sync(struct hci_dev *hdev) if (hdev->le_features[0] & HCI_LE_DATA_LEN_EXT) events[0] |= 0x40; /* LE Data Length Change */ - /* If the controller supports LL Privacy feature, enable - * the corresponding event. + /* If the controller supports LL Privacy feature or LE Extended Adv, + * enable the corresponding event. */ - if (hdev->le_features[0] & HCI_LE_LL_PRIVACY) + if (use_enhanced_conn_complete(hdev)) events[1] |= 0x02; /* LE Enhanced Connection Complete */ /* If the controller supports Extended Scanner Filter @@ -5188,7 +5188,7 @@ int hci_le_ext_create_conn_sync(struct hci_dev *hdev, struct hci_conn *conn, return __hci_cmd_sync_status_sk(hdev, HCI_OP_LE_EXT_CREATE_CONN, plen, data, HCI_EV_LE_ENHANCED_CONN_COMPLETE, - HCI_CMD_TIMEOUT, NULL); + conn->conn_timeout, NULL); } int hci_le_create_conn_sync(struct hci_dev *hdev, struct hci_conn *conn) @@ -5273,9 +5273,18 @@ int hci_le_create_conn_sync(struct hci_dev *hdev, struct hci_conn *conn) cp.min_ce_len = cpu_to_le16(0x0000); cp.max_ce_len = cpu_to_le16(0x0000); + /* BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 4, Part E page 2261: + * + * If this event is unmasked and the HCI_LE_Connection_Complete event + * is unmasked, only the HCI_LE_Enhanced_Connection_Complete event is + * sent when a new connection has been created. + */ err = __hci_cmd_sync_status_sk(hdev, HCI_OP_LE_CREATE_CONN, - sizeof(cp), &cp, HCI_EV_LE_CONN_COMPLETE, - HCI_CMD_TIMEOUT, NULL); + sizeof(cp), &cp, + use_enhanced_conn_complete(hdev) ? + HCI_EV_LE_ENHANCED_CONN_COMPLETE : + HCI_EV_LE_CONN_COMPLETE, + conn->conn_timeout, NULL); done: /* Re-enable advertising after the connection attempt is finished. */