USB: ene_usb6250: fix DMA to the stack

commit 628c2893 upstream.

The ene_usb6250 sub-driver in usb-storage does USB I/O to buffers on
the stack, which doesn't work with vmapped stacks.  This patch fixes
the problem by allocating a separate 512-byte buffer at probe time and
using it for all of the offending I/O operations.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: Andreas Hartmann <andihartmann@01019freenet.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/storage/ene_ub6250.c

@@ -431,6 +431,10 @@ struct ms_lib_ctrl {
 #define SD_BLOCK_LEN  9
 
 struct ene_ub6250_info {
+
+	/* I/O bounce buffer */
+	u8		*bbuf;
+
 	/* for 6250 code */
 	struct SD_STATUS	SD_Status;
 	struct MS_STATUS	MS_Status;
@@ -478,8 +482,11 @@ static int ene_load_bincode(struct us_data *us, unsigned char flag);
 
 static void ene_ub6250_info_destructor(void *extra)
 {
+	struct ene_ub6250_info *info = (struct ene_ub6250_info *) extra;
+
 	if (!extra)
 		return;
+	kfree(info->bbuf);
 }
 
 static int ene_send_scsi_cmd(struct us_data *us, u8 fDir, void *buf, int use_sg)
@@ -843,8 +850,9 @@ static int ms_read_readpage(struct us_data *us, u32 PhyBlockAddr,
 		u8 PageNum, u32 *PageBuf, struct ms_lib_type_extdat *ExtraDat)
 {
 	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
+	struct ene_ub6250_info *info = (struct ene_ub6250_info *) us->extra;
+	u8 *bbuf = info->bbuf;
 	int result;
-	u8 ExtBuf[4];
 	u32 bn = PhyBlockAddr * 0x20 + PageNum;
 
 	/* printk(KERN_INFO "MS --- MS_ReaderReadPage,
@@ -887,7 +895,7 @@ static int ms_read_readpage(struct us_data *us, u32 PhyBlockAddr,
 	bcb->CDB[2]     = (unsigned char)(PhyBlockAddr>>16);
 	bcb->CDB[6]     = 0x01;
 
-	result = ene_send_scsi_cmd(us, FDIR_READ, &ExtBuf, 0);
+	result = ene_send_scsi_cmd(us, FDIR_READ, bbuf, 0);
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
 
@@ -896,9 +904,9 @@ static int ms_read_readpage(struct us_data *us, u32 PhyBlockAddr,
 	ExtraDat->status0  = 0x10;  /* Not yet,fireware support */
 
 	ExtraDat->status1  = 0x00;  /* Not yet,fireware support */
-	ExtraDat->ovrflg   = ExtBuf[0];
-	ExtraDat->mngflg   = ExtBuf[1];
-	ExtraDat->logadr   = memstick_logaddr(ExtBuf[2], ExtBuf[3]);
+	ExtraDat->ovrflg   = bbuf[0];
+	ExtraDat->mngflg   = bbuf[1];
+	ExtraDat->logadr   = memstick_logaddr(bbuf[2], bbuf[3]);
 
 	return USB_STOR_TRANSPORT_GOOD;
 }
@@ -1324,8 +1332,9 @@ static int ms_lib_read_extra(struct us_data *us, u32 PhyBlock,
 				u8 PageNum, struct ms_lib_type_extdat *ExtraDat)
 {
 	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
+	struct ene_ub6250_info *info = (struct ene_ub6250_info *) us->extra;
+	u8 *bbuf = info->bbuf;
 	int result;
-	u8 ExtBuf[4];
 
 	/* printk("MS_LibReadExtra --- PhyBlock = %x, PageNum = %x\n", PhyBlock, PageNum); */
 	memset(bcb, 0, sizeof(struct bulk_cb_wrap));
@@ -1340,7 +1349,7 @@ static int ms_lib_read_extra(struct us_data *us, u32 PhyBlock,
 	bcb->CDB[2]     = (unsigned char)(PhyBlock>>16);
 	bcb->CDB[6]     = 0x01;
 
-	result = ene_send_scsi_cmd(us, FDIR_READ, &ExtBuf, 0);
+	result = ene_send_scsi_cmd(us, FDIR_READ, bbuf, 0);
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
 
@@ -1348,9 +1357,9 @@ static int ms_lib_read_extra(struct us_data *us, u32 PhyBlock,
 	ExtraDat->intr     = 0x80;  /* Not yet, waiting for fireware support */
 	ExtraDat->status0  = 0x10;  /* Not yet, waiting for fireware support */
 	ExtraDat->status1  = 0x00;  /* Not yet, waiting for fireware support */
-	ExtraDat->ovrflg   = ExtBuf[0];
-	ExtraDat->mngflg   = ExtBuf[1];
-	ExtraDat->logadr   = memstick_logaddr(ExtBuf[2], ExtBuf[3]);
+	ExtraDat->ovrflg   = bbuf[0];
+	ExtraDat->mngflg   = bbuf[1];
+	ExtraDat->logadr   = memstick_logaddr(bbuf[2], bbuf[3]);
 
 	return USB_STOR_TRANSPORT_GOOD;
 }
@@ -1554,9 +1563,9 @@ static int ms_lib_scan_logicalblocknumber(struct us_data *us, u16 btBlk1st)
 	u16 PhyBlock, newblk, i;
 	u16 LogStart, LogEnde;
 	struct ms_lib_type_extdat extdat;
-	u8 buf[0x200];
 	u32 count = 0, index = 0;
 	struct ene_ub6250_info *info = (struct ene_ub6250_info *) us->extra;
+	u8 *bbuf = info->bbuf;
 
 	for (PhyBlock = 0; PhyBlock < info->MS_Lib.NumberOfPhyBlock;) {
 		ms_lib_phy_to_log_range(PhyBlock, &LogStart, &LogEnde);
@@ -1570,14 +1579,16 @@ static int ms_lib_scan_logicalblocknumber(struct us_data *us, u16 btBlk1st)
 			}
 
 			if (count == PhyBlock) {
-				ms_lib_read_extrablock(us, PhyBlock, 0, 0x80, &buf);
+				ms_lib_read_extrablock(us, PhyBlock, 0, 0x80,
+						bbuf);
 				count += 0x80;
 			}
 			index = (PhyBlock % 0x80) * 4;
 
-			extdat.ovrflg = buf[index];
-			extdat.mngflg = buf[index+1];
-			extdat.logadr = memstick_logaddr(buf[index+2], buf[index+3]);
+			extdat.ovrflg = bbuf[index];
+			extdat.mngflg = bbuf[index+1];
+			extdat.logadr = memstick_logaddr(bbuf[index+2],
+					bbuf[index+3]);
 
 			if ((extdat.ovrflg & MS_REG_OVR_BKST) != MS_REG_OVR_BKST_OK) {
 				ms_lib_setacquired_errorblock(us, PhyBlock);
@@ -2066,9 +2077,9 @@ static int ene_ms_init(struct us_data *us)
 {
 	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
 	int result;
-	u8 buf[0x200];
 	u16 MSP_BlockSize, MSP_UserAreaBlocks;
 	struct ene_ub6250_info *info = (struct ene_ub6250_info *) us->extra;
+	u8 *bbuf = info->bbuf;
 
 	printk(KERN_INFO "transport --- ENE_MSInit\n");
 
@@ -2087,13 +2098,13 @@ static int ene_ms_init(struct us_data *us)
 	bcb->CDB[0]     = 0xF1;
 	bcb->CDB[1]     = 0x01;
 
-	result = ene_send_scsi_cmd(us, FDIR_READ, &buf, 0);
+	result = ene_send_scsi_cmd(us, FDIR_READ, bbuf, 0);
 	if (result != USB_STOR_XFER_GOOD) {
 		printk(KERN_ERR "Execution MS Init Code Fail !!\n");
 		return USB_STOR_TRANSPORT_ERROR;
 	}
 	/* the same part to test ENE */
-	info->MS_Status = *(struct MS_STATUS *)&buf[0];
+	info->MS_Status = *(struct MS_STATUS *) bbuf;
 
 	if (info->MS_Status.Insert && info->MS_Status.Ready) {
 		printk(KERN_INFO "Insert     = %x\n", info->MS_Status.Insert);
@@ -2102,15 +2113,15 @@ static int ene_ms_init(struct us_data *us)
 		printk(KERN_INFO "IsMSPHG    = %x\n", info->MS_Status.IsMSPHG);
 		printk(KERN_INFO "WtP= %x\n", info->MS_Status.WtP);
 		if (info->MS_Status.IsMSPro) {
-			MSP_BlockSize      = (buf[6] << 8) | buf[7];
-			MSP_UserAreaBlocks = (buf[10] << 8) | buf[11];
+			MSP_BlockSize      = (bbuf[6] << 8) | bbuf[7];
+			MSP_UserAreaBlocks = (bbuf[10] << 8) | bbuf[11];
 			info->MSP_TotalBlock = MSP_BlockSize * MSP_UserAreaBlocks;
 		} else {
 			ms_card_init(us); /* Card is MS (to ms.c)*/
 		}
 		US_DEBUGP("MS Init Code OK !!\n");
 	} else {
-		US_DEBUGP("MS Card Not Ready --- %x\n", buf[0]);
+		US_DEBUGP("MS Card Not Ready --- %x\n", bbuf[0]);
 		return USB_STOR_TRANSPORT_ERROR;
 	}
 
@@ -2120,9 +2131,9 @@ static int ene_ms_init(struct us_data *us)
 static int ene_sd_init(struct us_data *us)
 {
 	int result;
-	u8  buf[0x200];
 	struct bulk_cb_wrap *bcb = (struct bulk_cb_wrap *) us->iobuf;
 	struct ene_ub6250_info *info = (struct ene_ub6250_info *) us->extra;
+	u8 *bbuf = info->bbuf;
 
 	US_DEBUGP("transport --- ENE_SDInit\n");
 	/* SD Init Part-1 */
@@ -2156,15 +2167,15 @@ static int ene_sd_init(struct us_data *us)
 	bcb->Flags              = 0x80;
 	bcb->CDB[0]             = 0xF1;
 
-	result = ene_send_scsi_cmd(us, FDIR_READ, &buf, 0);
+	result = ene_send_scsi_cmd(us, FDIR_READ, bbuf, 0);
 	if (result != USB_STOR_XFER_GOOD) {
 		US_DEBUGP("Execution SD Init Code Fail !!\n");
 		return USB_STOR_TRANSPORT_ERROR;
 	}
 
-	info->SD_Status =  *(struct SD_STATUS *)&buf[0];
+	info->SD_Status =  *(struct SD_STATUS *) bbuf;
 	if (info->SD_Status.Insert && info->SD_Status.Ready) {
-		ene_get_card_status(us, (unsigned char *)&buf);
+		ene_get_card_status(us, bbuf);
 		US_DEBUGP("Insert     = %x\n", info->SD_Status.Insert);
 		US_DEBUGP("Ready      = %x\n", info->SD_Status.Ready);
 		US_DEBUGP("IsMMC      = %x\n", info->SD_Status.IsMMC);
@@ -2172,7 +2183,7 @@ static int ene_sd_init(struct us_data *us)
 		US_DEBUGP("HiSpeed    = %x\n", info->SD_Status.HiSpeed);
 		US_DEBUGP("WtP        = %x\n", info->SD_Status.WtP);
 	} else {
-		US_DEBUGP("SD Card Not Ready --- %x\n", buf[0]);
+		US_DEBUGP("SD Card Not Ready --- %x\n", bbuf[0]);
 		return USB_STOR_TRANSPORT_ERROR;
 	}
 	return USB_STOR_TRANSPORT_GOOD;
@@ -2182,13 +2193,15 @@ static int ene_sd_init(struct us_data *us)
 static int ene_init(struct us_data *us)
 {
 	int result;
-	u8  misc_reg03 = 0;
+	u8  misc_reg03;
 	struct ene_ub6250_info *info = (struct ene_ub6250_info *)(us->extra);
+	u8 *bbuf = info->bbuf;
 
-	result = ene_get_card_type(us, REG_CARD_STATUS, &misc_reg03);
+	result = ene_get_card_type(us, REG_CARD_STATUS, bbuf);
 	if (result != USB_STOR_XFER_GOOD)
 		return USB_STOR_TRANSPORT_ERROR;
 
+	misc_reg03 = bbuf[0];
 	if (misc_reg03 & 0x01) {
 		if (!info->SD_Status.Ready) {
 			result = ene_sd_init(us);
@@ -2304,8 +2317,9 @@ static int ene_ub6250_probe(struct usb_interface *intf,
 			 const struct usb_device_id *id)
 {
 	int result;
-	u8  misc_reg03 = 0;
+	u8  misc_reg03;
 	struct us_data *us;
+	struct ene_ub6250_info *info;
 
 	result = usb_stor_probe1(&us, intf, id,
 		   (id - ene_ub6250_usb_ids) + ene_ub6250_unusual_dev_list);
@@ -2313,11 +2327,16 @@ static int ene_ub6250_probe(struct usb_interface *intf,
 		return result;
 
 	/* FIXME: where should the code alloc extra buf ? */
-	if (!us->extra) {
-		us->extra = kzalloc(sizeof(struct ene_ub6250_info), GFP_KERNEL);
-		if (!us->extra)
-			return -ENOMEM;
-		us->extra_destructor = ene_ub6250_info_destructor;
+	us->extra = kzalloc(sizeof(struct ene_ub6250_info), GFP_KERNEL);
+	if (!us->extra)
+		return -ENOMEM;
+	us->extra_destructor = ene_ub6250_info_destructor;
+
+	info = (struct ene_ub6250_info *)(us->extra);
+	info->bbuf = kmalloc(512, GFP_KERNEL);
+	if (!info->bbuf) {
+		kfree(us->extra);
+		return -ENOMEM;
 	}
 
 	us->transport_name = "ene_ub6250";
@@ -2329,12 +2348,13 @@ static int ene_ub6250_probe(struct usb_interface *intf,
 		return result;
 
 	/* probe card type */
-	result = ene_get_card_type(us, REG_CARD_STATUS, &misc_reg03);
+	result = ene_get_card_type(us, REG_CARD_STATUS, info->bbuf);
 	if (result != USB_STOR_XFER_GOOD) {
 		usb_stor_disconnect(intf);
 		return USB_STOR_TRANSPORT_ERROR;
 	}
 
+	misc_reg03 = info->bbuf[0];
 	if (!(misc_reg03 & 0x01)) {
 		pr_info("ums_eneub6250: The driver only supports SD/MS card. "
 			"To use SM card, please build driver/staging/keucr\n");