[PATCH] [10/106] irda: prevent heap corruption on invalid nickname

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>

commit d50e7e3604778bfc2dc40f440e0742dbae399d54 upstream.

Invalid nicknames containing only spaces will result in an underflow in
a memcpy size calculation, subsequently destroying the heap and
panicking.

v2 also catches the case where the provided nickname is longer than the
buffer size, which can result in controllable heap corruption.

Signed-off-by: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

---
 net/irda/irnet/irnet_ppp.c |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-2.6.35.y/net/irda/irnet/irnet_ppp.c
===================================================================
--- linux-2.6.35.y.orig/net/irda/irnet/irnet_ppp.c
+++ linux-2.6.35.y/net/irda/irnet/irnet_ppp.c
@@ -106,6 +106,9 @@ irnet_ctrl_write(irnet_socket *	ap,
 	      while(isspace(start[length - 1]))
 		length--;
 
+	      DABORT(length < 5 || length > NICKNAME_MAX_LEN + 5,
+		     -EINVAL, CTRL_ERROR, "Invalid nickname.\n");
+
 	      /* Copy the name for later reuse */
 	      memcpy(ap->rname, start + 5, length - 5);
 	      ap->rname[length - 5] = '\0';
--
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