CVE-2017-8068 (published 2017-04-23T05:59Z)

drivers/net/usb/pegasus.c in the Linux kernel 4.9.x before 4.9.11 interacts incorrectly with the CONFIG_VMAP_STACK option, which allows local users to cause a denial of service (system crash or memory corruption) or possibly have unspecified other impact by leveraging use of more than one virtual page for a DMA scatterlist.

Severity: HIGH
CVSS v2 base score: 7.2 (AV:L/AC:L/Au:N/C:C/I:C/A:C)
CVSS v3 base score: 7.8, HIGH (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)

Weakness information:
cwe_id: CWE-119
cwe_name: Improper Restriction of Operations within the Bounds of a Memory Buffer
description: The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
extended_description: 
            Certain languages allow direct addressing of memory locations and do not automatically ensure that these locations are valid for the memory buffer that is being referenced. This can cause read or write operations to be performed on memory locations that may be associated with other variables, data structures, or internal program data.
         
         

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Ben Hutchings
author_date: 2017-02-04 16:56:03+00:00
msg: pegasus: Use heap buffers for all register access

Allocating USB buffers on the stack is not portable, and no longer
works on x86_64 (with VMAP_STACK enabled as per default).

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
References: https://bugs.debian.org/852556
Reported-by: Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>
Tested-by: Lisandro Damián Nicanor Pérez Meyer <lisandro@debian.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: pegasus.c
change_type: ModificationType.MODIFY
diff: @@ -126,40 +126,61 @@ static void async_ctrl_callback(struct urb *urb)
 
 static int get_registers(pegasus_t *pegasus, __u16 indx, __u16 size, void *data)
 {
+	u8 *buf;
 	int ret;
 
+	buf = kmalloc(size, GFP_NOIO);
+	if (!buf)
+		return -ENOMEM;
+
 	ret = usb_control_msg(pegasus->usb, usb_rcvctrlpipe(pegasus->usb, 0),
 			      PEGASUS_REQ_GET_REGS, PEGASUS_REQT_READ, 0,
-			      indx, data, size, 1000);
+			      indx, buf, size, 1000);
 	if (ret < 0)
 		netif_dbg(pegasus, drv, pegasus->net,
 			  "%s returned %d\n", __func__, ret);
+	else if (ret <= size)
+		memcpy(data, buf, ret);
+	kfree(buf);
 	return ret;
 }
 
-static int set_registers(pegasus_t *pegasus, __u16 indx, __u16 size, void *data)
+static int set_registers(pegasus_t *pegasus, __u16 indx, __u16 size,
+			 const void *data)
 {
+	u8 *buf;
 	int ret;
 
+	buf = kmemdup(data, size, GFP_NOIO);
+	if (!buf)
+		return -ENOMEM;
+
 	ret = usb_control_msg(pegasus->usb, usb_sndctrlpipe(pegasus->usb, 0),
 			      PEGASUS_REQ_SET_REGS, PEGASUS_REQT_WRITE, 0,
-			      indx, data, size, 100);
+			      indx, buf, size, 100);
 	if (ret < 0)
 		netif_dbg(pegasus, drv, pegasus->net,
 			  "%s returned %d\n", __func__, ret);
+	kfree(buf);
 	return ret;
 }
 
 static int set_register(pegasus_t *pegasus, __u16 indx, __u8 data)
 {
+	u8 *buf;
 	int ret;
 
+	buf = kmemdup(&data, 1, GFP_NOIO);
+	if (!buf)
+		return -ENOMEM;
+
 	ret = usb_control_msg(pegasus->usb, usb_sndctrlpipe(pegasus->usb, 0),
 			      PEGASUS_REQ_SET_REG, PEGASUS_REQT_WRITE, data,
-			      indx, &data, 1, 1000);
+			      indx, buf, 1, 1000);
 	if (ret < 0)
 		netif_dbg(pegasus, drv, pegasus->net,
 			  "%s returned %d\n", __func__, ret);
+	kfree(buf);
 	return ret;
 }
 

programming_language: C