[patch 15/22] Open IPMI BT overflow

[Greg KH]

From: Heikki Orsila <shd@xxxxxxxxxxxxxxxxxxxxxx>

[PATCH] Open IPMI BT overflow

I was looking into random driver code and found a suspicious looking
memcpy() in drivers/char/ipmi/ipmi_bt_sm.c on 2.6.17-rc1:

	if ((size < 2) || (size > IPMI_MAX_MSG_LENGTH))
		return -1;
	...
	memcpy(bt->write_data + 3, data + 1, size - 1);

where sizeof bt->write_data is IPMI_MAX_MSG_LENGTH.  It looks like the
memcpy would overflow by 2 bytes if size == IPMI_MAX_MSG_LENGTH.  A patch
attached to limit size to (IPMI_MAX_LENGTH - 2).

Cc: Corey Minyard <minyard@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 drivers/char/ipmi/ipmi_bt_sm.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-2.6.16.9.orig/drivers/char/ipmi/ipmi_bt_sm.c
+++ linux-2.6.16.9/drivers/char/ipmi/ipmi_bt_sm.c
@@ -165,7 +165,7 @@ static int bt_start_transaction(struct s
 {
 	unsigned int i;
 
-	if ((size < 2) || (size > IPMI_MAX_MSG_LENGTH))
+	if ((size < 2) || (size > (IPMI_MAX_MSG_LENGTH - 2)))
 	       return -1;
 
 	if ((bt->state != BT_STATE_IDLE) && (bt->state != BT_STATE_HOSED))

--
-
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