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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Ian Abbott <abbotti@mev.co.uk>,
	Johan Hovold <johan@kernel.org>
Subject: [PATCH 4.14 15/22] comedi: dt9812: fix DMA buffers on stack
Date: Wed, 10 Nov 2021 19:43:35 +0100	[thread overview]
Message-ID: <20211110182003.156571211@linuxfoundation.org> (raw)
In-Reply-To: <20211110182002.666244094@linuxfoundation.org>

From: Johan Hovold <johan@kernel.org>

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>
---
 drivers/staging/comedi/drivers/dt9812.c |  115 +++++++++++++++++++++++---------
 1 file changed, 86 insertions(+), 29 deletions(-)

--- a/drivers/staging/comedi/drivers/dt9812.c
+++ b/drivers/staging/comedi/drivers/dt9812.c
@@ -41,6 +41,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/errno.h>
+#include <linux/slab.h>
 #include <linux/uaccess.h>
 
 #include "../comedi_usb.h"
@@ -246,22 +247,42 @@ static int dt9812_read_info(struct comed
 {
 	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,
@@ -270,22 +291,42 @@ static int dt9812_read_multiple_register
 {
 	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;
+
+	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;
+	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;
 
-	return usb_bulk_msg(usb, usb_rcvbulkpipe(usb, devpriv->cmd_rd.addr),
-			    value, reg_count, &count, DT9812_USB_TIMEOUT);
+	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 ret;
 }
 
 static int dt9812_write_multiple_registers(struct comedi_device *dev,
@@ -294,19 +335,27 @@ static int dt9812_write_multiple_registe
 {
 	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.cmd = cpu_to_le32(DT9812_W_MULTI_BYTE_REG);
-	cmd.u.read_multi_info.count = reg_count;
+	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;
 	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,
@@ -315,17 +364,25 @@ static int dt9812_rmw_multiple_registers
 {
 	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)



  parent reply	other threads:[~2021-11-10 18:47 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-10 18:43 [PATCH 4.14 00/22] 4.14.255-rc1 review Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 01/22] scsi: core: Put LLD module refcnt after SCSI device is released Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 02/22] media: firewire: firedtv-avc: fix a buffer overflow in avc_ca_pmt() Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 03/22] mm/zsmalloc: Prepare to variable MAX_PHYSMEM_BITS Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 04/22] arch: pgtable: define MAX_POSSIBLE_PHYSMEM_BITS where needed Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 05/22] ARM: 9120/1: Revert "amba: make use of -1 IRQs warn" Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 06/22] IB/qib: Use struct_size() helper Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 07/22] IB/qib: Protect from buffer overflow in struct qib_user_sdma_pkt fields Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 08/22] block: introduce multi-page bvec helpers Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 09/22] Revert "x86/kvm: fix vcpu-id indexed array sizes" Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 10/22] usb: gadget: Mark USB_FSL_QE broken on 64-bit Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 11/22] usb: musb: Balance list entry in musb_gadget_queue Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 12/22] usb-storage: Add compatibility quirk flags for iODD 2531/2541 Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 13/22] printk/console: Allow to disable console output by using console="" or console=null Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 14/22] isofs: Fix out of bound access for corrupted isofs image Greg Kroah-Hartman
2021-11-10 18:43 ` Greg Kroah-Hartman [this message]
2021-11-10 18:43 ` [PATCH 4.14 16/22] comedi: ni_usb6501: fix NULL-deref in command paths Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 17/22] comedi: vmk80xx: fix transfer-buffer overflows Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 18/22] comedi: vmk80xx: fix bulk-buffer overflow Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 19/22] comedi: vmk80xx: fix bulk and interrupt message timeouts Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 20/22] staging: r8712u: fix control-message timeout Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 21/22] staging: rtl8192u: fix control-message timeouts Greg Kroah-Hartman
2021-11-10 18:43 ` [PATCH 4.14 22/22] rsi: fix control-message timeout Greg Kroah-Hartman
2021-11-11 18:26 ` [PATCH 4.14 00/22] 4.14.255-rc1 review Naresh Kamboju
2021-11-12  0:58 ` Guenter Roeck
2021-11-12 15:41 ` Jon Hunter

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