From 15ee89c3347fbf58a4361011eda5ac2731e45126 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 27 May 2013 14:44:40 +0200 Subject: [PATCH] USB: mos7840: fix DMA to stack Fix regression introduced by commit 0eafe4de1a ("USB: serial: mos7840: add support for MCS7810 devices") which used stack-allocated buffers for control messages. Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/mos7840.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c index a0d5ea545982..7e998081e1cd 100644 --- a/drivers/usb/serial/mos7840.c +++ b/drivers/usb/serial/mos7840.c @@ -2142,13 +2142,21 @@ static int mos7840_ioctl(struct tty_struct *tty, static int mos7810_check(struct usb_serial *serial) { int i, pass_count = 0; + u8 *buf; __u16 data = 0, mcr_data = 0; __u16 test_pattern = 0x55AA; + int res; + + buf = kmalloc(VENDOR_READ_LENGTH, GFP_KERNEL); + if (!buf) + return 0; /* failed to identify 7810 */ /* Store MCR setting */ - usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), + res = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), MCS_RDREQ, MCS_RD_RTYPE, 0x0300, MODEM_CONTROL_REGISTER, - &mcr_data, VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT); + buf, VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT); + if (res == VENDOR_READ_LENGTH) + mcr_data = *buf; for (i = 0; i < 16; i++) { /* Send the 1-bit test pattern out to MCS7810 test pin */ @@ -2158,9 +2166,12 @@ static int mos7810_check(struct usb_serial *serial) MODEM_CONTROL_REGISTER, NULL, 0, MOS_WDR_TIMEOUT); /* Read the test pattern back */ - usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), - MCS_RDREQ, MCS_RD_RTYPE, 0, GPIO_REGISTER, &data, - VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT); + res = usb_control_msg(serial->dev, + usb_rcvctrlpipe(serial->dev, 0), MCS_RDREQ, + MCS_RD_RTYPE, 0, GPIO_REGISTER, buf, + VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT); + if (res == VENDOR_READ_LENGTH) + data = *buf; /* If this is a MCS7810 device, both test patterns must match */ if (((test_pattern >> i) ^ (~data >> 1)) & 0x0001) @@ -2174,6 +2185,8 @@ static int mos7810_check(struct usb_serial *serial) MCS_WR_RTYPE, 0x0300 | mcr_data, MODEM_CONTROL_REGISTER, NULL, 0, MOS_WDR_TIMEOUT); + kfree(buf); + if (pass_count == 16) return 1; @@ -2183,11 +2196,17 @@ static int mos7810_check(struct usb_serial *serial) static int mos7840_calc_num_ports(struct usb_serial *serial) { __u16 data = 0x00; + u8 *buf; int mos7840_num_ports; - usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), - MCS_RDREQ, MCS_RD_RTYPE, 0, GPIO_REGISTER, &data, - VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT); + buf = kzalloc(VENDOR_READ_LENGTH, GFP_KERNEL); + if (buf) { + usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0), + MCS_RDREQ, MCS_RD_RTYPE, 0, GPIO_REGISTER, buf, + VENDOR_READ_LENGTH, MOS_WDR_TIMEOUT); + data = *buf; + kfree(buf); + } if (serial->dev->descriptor.idProduct == MOSCHIP_DEVICE_ID_7810 || serial->dev->descriptor.idProduct == MOSCHIP_DEVICE_ID_7820) { -- 2.39.5