From: Johan Hovold johan@kernel.org

stable inclusion from stable-v4.19.217 commit 39ea61037ae78f14fa121228dd962ea3280eacf3 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RD6O CVE: CVE-2021-47477

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 536de747bc48262225889a533db6650731ab25d3 upstream.

USB transfer buffers are typically mapped for DMA and must not be allocated on the stack or transfers will fail.

Allocate proper transfer buffers in the various command helpers and return an error on short transfers instead of acting on random stack data.

Note that this also fixes a stack info leak on systems where DMA is not used as 32 bytes are always sent to the device regardless of how short the command is.

Fixes: 63274cd7d38a ("Staging: comedi: add usb dt9812 driver") Cc: stable@vger.kernel.org # 2.6.29 Reviewed-by: Ian Abbott abbotti@mev.co.uk Signed-off-by: Johan Hovold johan@kernel.org Link: https://lore.kernel.org/r/20211027093529.30896-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Wang Hai wanghai38@huawei.com --- drivers/staging/comedi/drivers/dt9812.c | 115 ++++++++++++++++++------ 1 file changed, 86 insertions(+), 29 deletions(-)

diff --git a/drivers/staging/comedi/drivers/dt9812.c b/drivers/staging/comedi/drivers/dt9812.c index 75cc9e8e5b94..ee0402bf6e67 100644 --- a/drivers/staging/comedi/drivers/dt9812.c +++ b/drivers/staging/comedi/drivers/dt9812.c @@ -32,6 +32,7 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/errno.h> +#include <linux/slab.h> #include <linux/uaccess.h>

#include "../comedi_usb.h" @@ -237,22 +238,42 @@ static int dt9812_read_info(struct comedi_device *dev, { struct usb_device *usb = comedi_to_usb_dev(dev); struct dt9812_private *devpriv = dev->private; - struct dt9812_usb_cmd cmd; + struct dt9812_usb_cmd *cmd; + size_t tbuf_size; int count, ret; + void *tbuf;

- cmd.cmd = cpu_to_le32(DT9812_R_FLASH_DATA); - cmd.u.flash_data_info.address = + tbuf_size = max(sizeof(*cmd), buf_size); + + tbuf = kzalloc(tbuf_size, GFP_KERNEL); + if (!tbuf) + return -ENOMEM; + + cmd = tbuf; + + cmd->cmd = cpu_to_le32(DT9812_R_FLASH_DATA); + cmd->u.flash_data_info.address = cpu_to_le16(DT9812_DIAGS_BOARD_INFO_ADDR + offset); - cmd.u.flash_data_info.numbytes = cpu_to_le16(buf_size); + cmd->u.flash_data_info.numbytes = cpu_to_le16(buf_size);

/* DT9812 only responds to 32 byte writes!! */ ret = usb_bulk_msg(usb, usb_sndbulkpipe(usb, devpriv->cmd_wr.addr), - &cmd, 32, &count, DT9812_USB_TIMEOUT); + cmd, sizeof(*cmd), &count, DT9812_USB_TIMEOUT); if (ret) - return ret; + goto out; + + ret = usb_bulk_msg(usb, usb_rcvbulkpipe(usb, devpriv->cmd_rd.addr), + tbuf, buf_size, &count, DT9812_USB_TIMEOUT); + if (!ret) { + if (count == buf_size) + memcpy(buf, tbuf, buf_size); + else + ret = -EREMOTEIO; + } +out: + kfree(tbuf);

- return usb_bulk_msg(usb, usb_rcvbulkpipe(usb, devpriv->cmd_rd.addr), - buf, buf_size, &count, DT9812_USB_TIMEOUT); + return ret; }

static int dt9812_read_multiple_registers(struct comedi_device *dev, @@ -261,22 +282,42 @@ static int dt9812_read_multiple_registers(struct comedi_device *dev, { struct usb_device *usb = comedi_to_usb_dev(dev); struct dt9812_private *devpriv = dev->private; - struct dt9812_usb_cmd cmd; + struct dt9812_usb_cmd *cmd; int i, count, ret; + size_t buf_size; + void *buf;

- cmd.cmd = cpu_to_le32(DT9812_R_MULTI_BYTE_REG); - cmd.u.read_multi_info.count = reg_count; + buf_size = max_t(size_t, sizeof(*cmd), reg_count); + + buf = kzalloc(buf_size, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + cmd = buf; + + cmd->cmd = cpu_to_le32(DT9812_R_MULTI_BYTE_REG); + cmd->u.read_multi_info.count = reg_count; for (i = 0; i < reg_count; i++) - cmd.u.read_multi_info.address[i] = address[i]; + cmd->u.read_multi_info.address[i] = address[i];

/* DT9812 only responds to 32 byte writes!! */ ret = usb_bulk_msg(usb, usb_sndbulkpipe(usb, devpriv->cmd_wr.addr), - &cmd, 32, &count, DT9812_USB_TIMEOUT); + cmd, sizeof(*cmd), &count, DT9812_USB_TIMEOUT); if (ret) - return ret; + goto out; + + ret = usb_bulk_msg(usb, usb_rcvbulkpipe(usb, devpriv->cmd_rd.addr), + buf, reg_count, &count, DT9812_USB_TIMEOUT); + if (!ret) { + if (count == reg_count) + memcpy(value, buf, reg_count); + else + ret = -EREMOTEIO; + } +out: + kfree(buf);

- return usb_bulk_msg(usb, usb_rcvbulkpipe(usb, devpriv->cmd_rd.addr), - value, reg_count, &count, DT9812_USB_TIMEOUT); + return ret; }

static int dt9812_write_multiple_registers(struct comedi_device *dev, @@ -285,19 +326,27 @@ static int dt9812_write_multiple_registers(struct comedi_device *dev, { struct usb_device *usb = comedi_to_usb_dev(dev); struct dt9812_private *devpriv = dev->private; - struct dt9812_usb_cmd cmd; + struct dt9812_usb_cmd *cmd; int i, count; + int ret; + + cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); + if (!cmd) + return -ENOMEM;

- cmd.cmd = cpu_to_le32(DT9812_W_MULTI_BYTE_REG); - cmd.u.read_multi_info.count = reg_count; + cmd->cmd = cpu_to_le32(DT9812_W_MULTI_BYTE_REG); + cmd->u.read_multi_info.count = reg_count; for (i = 0; i < reg_count; i++) { - cmd.u.write_multi_info.write[i].address = address[i]; - cmd.u.write_multi_info.write[i].value = value[i]; + cmd->u.write_multi_info.write[i].address = address[i]; + cmd->u.write_multi_info.write[i].value = value[i]; }

/* DT9812 only responds to 32 byte writes!! */ - return usb_bulk_msg(usb, usb_sndbulkpipe(usb, devpriv->cmd_wr.addr), - &cmd, 32, &count, DT9812_USB_TIMEOUT); + ret = usb_bulk_msg(usb, usb_sndbulkpipe(usb, devpriv->cmd_wr.addr), + cmd, sizeof(*cmd), &count, DT9812_USB_TIMEOUT); + kfree(cmd); + + return ret; }

static int dt9812_rmw_multiple_registers(struct comedi_device *dev, @@ -306,17 +355,25 @@ static int dt9812_rmw_multiple_registers(struct comedi_device *dev, { struct usb_device *usb = comedi_to_usb_dev(dev); struct dt9812_private *devpriv = dev->private; - struct dt9812_usb_cmd cmd; + struct dt9812_usb_cmd *cmd; int i, count; + int ret; + + cmd = kzalloc(sizeof(*cmd), GFP_KERNEL); + if (!cmd) + return -ENOMEM;

- cmd.cmd = cpu_to_le32(DT9812_RMW_MULTI_BYTE_REG); - cmd.u.rmw_multi_info.count = reg_count; + cmd->cmd = cpu_to_le32(DT9812_RMW_MULTI_BYTE_REG); + cmd->u.rmw_multi_info.count = reg_count; for (i = 0; i < reg_count; i++) - cmd.u.rmw_multi_info.rmw[i] = rmw[i]; + cmd->u.rmw_multi_info.rmw[i] = rmw[i];

/* DT9812 only responds to 32 byte writes!! */ - return usb_bulk_msg(usb, usb_sndbulkpipe(usb, devpriv->cmd_wr.addr), - &cmd, 32, &count, DT9812_USB_TIMEOUT); + ret = usb_bulk_msg(usb, usb_sndbulkpipe(usb, devpriv->cmd_wr.addr), + cmd, sizeof(*cmd), &count, DT9812_USB_TIMEOUT); + kfree(cmd); + + return ret; }

static int dt9812_digital_in(struct comedi_device *dev, u8 *bits)