[PATCH 3.16 332/346] scsi: arcmsr: Buffer overflow in arcmsr_iop_message_xfer()

[Ben Hutchings]

3.16.39-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

commit 7bc2b55a5c030685b399bb65b6baa9ccc3d1f167 upstream.

We need to put an upper bound on "user_len" so the memcpy() doesn't
overflow.

Reported-by: Marco Grassi <marco.gra@xxxxxxxxx>
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Tomas Henzl <thenzl@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
[bwh: Backported to 3.16:
 - Adjust context
 - Use literal 1032 insetad of ARCMSR_API_DATA_BUFLEN]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
--- a/drivers/scsi/arcmsr/arcmsr_hba.c
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c
@@ -1802,7 +1802,8 @@ static int arcmsr_iop_message_xfer(struc
 
 	case ARCMSR_MESSAGE_WRITE_WQBUFFER: {
 		unsigned char *ver_addr;
-		int32_t my_empty_len, user_len, wqbuf_firstindex, wqbuf_lastindex;
+		uint32_t user_len;
+		int32_t my_empty_len, wqbuf_firstindex, wqbuf_lastindex;
 		uint8_t *pQbuffer, *ptmpuserbuffer;
 
 		ver_addr = kmalloc(1032, GFP_ATOMIC);
@@ -1819,6 +1820,11 @@ static int arcmsr_iop_message_xfer(struc
 		}
 		ptmpuserbuffer = ver_addr;
 		user_len = pcmdmessagefld->cmdmessage.Length;
+		if (user_len > 1032) {
+			retvalue = ARCMSR_MESSAGE_FAIL;
+			kfree(ver_addr);
+			goto message_out;
+		}
 		memcpy(ptmpuserbuffer, pcmdmessagefld->messagedatabuffer, user_len);
 		wqbuf_lastindex = acb->wqbuf_lastindex;
 		wqbuf_firstindex = acb->wqbuf_firstindex;