Staging: bcm: use get_user() to access user pointers

This fixes some places that dereference user pointers directly instead
of using get_user().

Please especially check my changes to IOCTL_BCM_GET_CURRENT_STATUS.  The
original code modified the struct which "arg" was pointing to.  I think
this was a bug in the original code and that we only wanted to write to
the OutputBuffer. Also with the original code you could read as much
memory as you wanted so I had to put a cap on OutputLength.  The only
value of OutputLength that makes sense is sizeof(LINK_STATE) so now if
OutputLength is not sizeof(LINK_STATE) it returns -EINVAL.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 32 insertions, 17 deletions

diff --git a/drivers/staging/bcm/Bcmchar.c b/drivers/staging/bcm/Bcmchar.c
index 77fdfe24d999..fead9c56162e 100644
--- a/drivers/staging/bcm/Bcmchar.c
+++ b/drivers/staging/bcm/Bcmchar.c
@@ -1001,13 +1001,15 @@ static long bcm_char_ioctl(struct file *filp, UINT cmd, ULONG arg)
                 }
 #endif
                 case IOCTL_BE_BUCKET_SIZE:
-                        Adapter->BEBucketSize = *(PULONG)arg;
-                        Status = STATUS_SUCCESS;
+                        Status = 0;
+                        if (get_user(Adapter->BEBucketSize, (unsigned long __user *)arg))
+                                Status = -EFAULT;
                         break;
 
                 case IOCTL_RTPS_BUCKET_SIZE:
-                        Adapter->rtPSBucketSize = *(PULONG)arg;
-                        Status = STATUS_SUCCESS;
+                        Status = 0;
+                        if (get_user(Adapter->rtPSBucketSize, (unsigned long __user *)arg))
+                                Status = -EFAULT;
                         break;
                 case IOCTL_CHIP_RESET:
             {
@@ -1028,11 +1030,15 @@ static long bcm_char_ioctl(struct file *filp, UINT cmd, ULONG arg)
                 case IOCTL_QOS_THRESHOLD:
                 {
                         USHORT uiLoopIndex;
-                        for(uiLoopIndex = 0 ; uiLoopIndex < NO_OF_QUEUES ; uiLoopIndex++)
-                        {
-                                Adapter->PackInfo[uiLoopIndex].uiThreshold = *(PULONG)arg;
+
+                        Status = 0;
+                        for (uiLoopIndex = 0; uiLoopIndex < NO_OF_QUEUES; uiLoopIndex++) {
+                                if (get_user(Adapter->PackInfo[uiLoopIndex].uiThreshold,
+                                                (unsigned long __user *)arg)) {
+                                        Status = -EFAULT;
+                                        break;
+                                }
                         }
-                        Status = STATUS_SUCCESS;
                         break;
                 }
 
@@ -1093,7 +1099,8 @@ static long bcm_char_ioctl(struct file *filp, UINT cmd, ULONG arg)
                 }
                 case IOCTL_BCM_GET_CURRENT_STATUS:
                 {
-                        LINK_STATE *plink_state = NULL;
+                        LINK_STATE plink_state;
+
                         /* Copy Ioctl Buffer structure */
                         if(copy_from_user(&IoBuffer, argp, sizeof(IOCTL_BUFFER)))
                         {
@@ -1101,13 +1108,19 @@ static long bcm_char_ioctl(struct file *filp, UINT cmd, ULONG arg)
                                 Status = -EFAULT;
                                 break;
                         }
-                        plink_state = (LINK_STATE*)arg;
-                        plink_state->bIdleMode = (UCHAR)Adapter->IdleMode;
-                        plink_state->bShutdownMode = Adapter->bShutStatus;
-                        plink_state->ucLinkStatus = (UCHAR)Adapter->LinkStatus;
-                        if(copy_to_user(IoBuffer.OutputBuffer,
-                                (PUCHAR)plink_state, (UINT)IoBuffer.OutputLength))
-                        {
+                        if (IoBuffer.OutputLength != sizeof(plink_state)) {
+                                Status = -EINVAL;
+                                break;
+                        }
+
+                        if (copy_from_user(&plink_state, (void __user *)arg, sizeof(plink_state))) {
+                                Status = -EFAULT;
+                                break;
+                        }
+                        plink_state.bIdleMode = (UCHAR)Adapter->IdleMode;
+                        plink_state.bShutdownMode = Adapter->bShutStatus;
+                        plink_state.ucLinkStatus = (UCHAR)Adapter->LinkStatus;
+                        if (copy_to_user(IoBuffer.OutputBuffer, &plink_state, IoBuffer.OutputLength)) {
                                 BCM_DEBUG_PRINT(Adapter,DBG_TYPE_PRINTK, 0, 0, "Copy_to_user Failed..\n");
                                 Status = -EFAULT;
                                 break;
@@ -1331,7 +1344,9 @@ static long bcm_char_ioctl(struct file *filp, UINT cmd, ULONG arg)
                                                 BCM_DEBUG_PRINT(Adapter,DBG_TYPE_PRINTK, 0, 0,"Copy From User space failed. status :%d", Status);
                                                 return -EFAULT;
                                         }
-                                        uiSectorSize = *((PUINT)(IoBuffer.InputBuffer)); /* FIXME: unchecked __user access */
+                                        if (get_user(uiSectorSize, (unsigned int __user *)IoBuffer.InputBuffer))
+                                                return -EFAULT;
+
                                         if((uiSectorSize < MIN_SECTOR_SIZE) || (uiSectorSize > MAX_SECTOR_SIZE))
                                         {