irda: Fix heap memory corruption in iriap.c

While parsing the GetValuebyClass command frame, we could potentially write
passed the skb->data pointer.

Cc: stable@kernel.org
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Samuel Ortiz <samuel@sortiz.org>

diff --git a/net/irda/iriap.c b/net/irda/iriap.c
index fce364c..5b743bd 100644 (file)
--- a/net/irda/iriap.c
+++ b/net/irda/iriap.c
@@ -502,7 +502,8 @@ static void iriap_getvaluebyclass_confirm(struct iriap_cb *self,
                IRDA_DEBUG(4, "%s(), strlen=%d\n", __func__, value_len);
 
                /* Make sure the string is null-terminated */
-               fp[n+value_len] = 0x00;
+               if (n + value_len < skb->len)
+                       fp[n + value_len] = 0x00;
                IRDA_DEBUG(4, "Got string %s\n", fp+n);
 
                /* Will truncate to IAS_MAX_STRING bytes */