[PATCH v1 2/4] Bluetooth: prevent a race condition on hci_uart_tty_ioctl() call
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STALE3696d
SUPERSEDED
From: Dean Jenkins <hidden>
Date: 2016-09-07 14:15:08
Subsystem:
bluetooth drivers, the rest · Maintainers:
Marcel Holtmann, Luiz Augusto von Dentz, Linus Torvalds
Revision v1 of 2 in this series.
Revisions (2)
- v1 current
- v2 [diff vs current]
From: Vignesh Raman <redacted> Add global mutex lock to prevent reentrancy in the hci_uart_tty_ioctl() ioctl handling. This prevents concurrency of all function calls within hci_uart_tty_ioctl handling including hci_uart_set_proto(). Also removed multiple return statements in hci_uart_tty_ioctl call and added a single return statement since the mutex needs to be unlocked before exiting the function. Signed-off-by: Vignesh Raman <redacted> Signed-off-by: Dean Jenkins <redacted> Signed-off-by: Rajeev Kumar <redacted> --- drivers/bluetooth/hci_ldisc.c | 43 ++++++++++++++++++++++++++----------------- 1 file changed, 26 insertions(+), 17 deletions(-)
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 1e338d5..cf1883d 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c@@ -51,6 +51,8 @@ #define VERSION "2.3" +static DEFINE_MUTEX(ioctl_mutex); + static const struct hci_uart_proto *hup[HCI_UART_MAX_PROTO]; int hci_uart_register_proto(const struct hci_uart_proto *p)
@@ -685,7 +687,7 @@ static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg) { struct hci_uart *hu = tty->disc_data; - int err = 0; + int result = 0; BT_DBG("");
@@ -693,45 +695,52 @@ static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file *file, if (!hu) return -EBADF; + mutex_lock(&ioctl_mutex); switch (cmd) { case HCIUARTSETPROTO: if (!test_bit(HCI_UART_PROTO_SET, &hu->flags)) { - err = hci_uart_set_proto(hu, arg); - if (!err) + result = hci_uart_set_proto(hu, arg); + if (!result) set_bit(HCI_UART_PROTO_SET, &hu->flags); - else - return err; } else - return -EBUSY; + result = -EBUSY; break; case HCIUARTGETPROTO: if (test_bit(HCI_UART_PROTO_SET, &hu->flags)) - return hu->proto->id; - return -EUNATCH; + result = hu->proto->id; + else + result = -EUNATCH; + break; case HCIUARTGETDEVICE: if (test_bit(HCI_UART_REGISTERED, &hu->flags)) - return hu->hdev->id; - return -EUNATCH; + result = hu->hdev->id; + else + result = -EUNATCH; + break; case HCIUARTSETFLAGS: if (test_bit(HCI_UART_PROTO_SET, &hu->flags)) - return -EBUSY; - err = hci_uart_set_flags(hu, arg); - if (err) - return err; + result = -EBUSY; + else { + result = hci_uart_set_flags(hu, arg); + if (result) + return result; + } break; case HCIUARTGETFLAGS: - return hu->hdev_flags; + result = hu->hdev_flags; + break; default: - err = n_tty_ioctl_helper(tty, file, cmd, arg); + result = n_tty_ioctl_helper(tty, file, cmd, arg); break; } + mutex_unlock(&ioctl_mutex); - return err; + return result; } /*
--
2.7.4