rose: Add length checks to CALL_REQUEST parsing

Define some constant offsets for CALL_REQUEST based on the description
at <http://www.techfest.com/networking/wan/x25plp.htm> and the
definition of ROSE as using 10-digit (5-byte) addresses.  Use them
consistently.  Validate all implicit and explicit facilities lengths.
Validate the address length byte rather than either trusting or
assuming its value.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 1 deletions

diff --git a/include/net/rose.h b/include/net/rose.h
index 5ba9f02731eb..555dd198aab7 100644
--- a/include/net/rose.h
+++ b/include/net/rose.h
@@ -14,6 +14,12 @@
 
 #define ROSE_MIN_LEN                    3
 
+#define ROSE_CALL_REQ_ADDR_LEN_OFF      3
+#define ROSE_CALL_REQ_ADDR_LEN_VAL      0xAA    /* each address is 10 digits */
+#define ROSE_CALL_REQ_DEST_ADDR_OFF     4
+#define ROSE_CALL_REQ_SRC_ADDR_OFF      9
+#define ROSE_CALL_REQ_FACILITIES_OFF    14
+
 #define ROSE_GFI                        0x10
 #define ROSE_Q_BIT                      0x80
 #define ROSE_D_BIT                      0x40
@@ -214,7 +220,7 @@ extern void rose_requeue_frames(struct sock *);
 extern int  rose_validate_nr(struct sock *, unsigned short);
 extern void rose_write_internal(struct sock *, int);
 extern int  rose_decode(struct sk_buff *, int *, int *, int *, int *, int *);
-extern int  rose_parse_facilities(unsigned char *, struct rose_facilities_struct *);
+extern int  rose_parse_facilities(unsigned char *, unsigned int, struct rose_facilities_struct *);
 extern void rose_disconnect(struct sock *, int, int, int);
 
 /* rose_timer.c */