[PATCH 3.2 143/152] scsi: arcmsr: Buffer overflow in arcmsr_iop_message_xfer()

[Ben Hutchings]

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

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

From: Dan Carpenter <dan.carpen...@oracle.com>

commit 7bc2b55a5c030685b399bb65b6baa9ccc3d1f167 upstream.

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

Reported-by: Marco Grassi <marco....@gmail.com>
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>
Reviewed-by: Tomas Henzl <the...@redhat.com>
Signed-off-by: Martin K. Petersen <martin.peter...@oracle.com>
[bwh: Backported to 3.2:
 - Adjust context
 - Use literal 1032 insetad of ARCMSR_API_DATA_BUFLEN]
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
--- a/drivers/scsi/arcmsr/arcmsr_hba.c
+++ b/drivers/scsi/arcmsr/arcmsr_hba.c
@@ -1803,7 +1803,8 @@ 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);
@@ -1820,6 +1821,11 @@ 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;