[riot-devel] RPL security extension

Martin L. martin.landsmann at haw-hamburg.de
Tue Feb 11 16:48:58 CET 2014


OK,
So the threats to be resisted should be (in short),
allow an attacking node to:
- pretend an arbitrary low rank to pull routes and traffic
- replay a previously learned rank advertizement of lower ranked nodes, also to pull routes and traffic
which would allow to: 
- degenerate the routing tree 
- isolate parts of the network 
- create a routing blackhole 
- sniff traffic
- ...

The goal of the scheme is to (also in short):
- provide security hooks in the implementation of RPL in the crucial points to protect against the threats
- define interfaces for the hooks to enable a modular security specific scheme development
- try to define security interfaces for the hooks that not only apply to RPL (e.g. securing 'Next Hop') (<- this is future)

Basic sketch (probably a too naiive approach):
The first security hook I would think will be directly implemented in:
sys/net/routing/rpl/rpl_dodag.c
rpl_parent_t *rpl_new_parent(rpl_dodag_t *dodag, ipv6_addr_t *address, uint16_t rank)

here the parent verification process would be initiated and performed, 
i.e. request for credentials identifying the potential parent as trustworthy.

only if the credentials are provided by the potencial parent it will be added to the list of parents:
rpl_parent_t parents[RPL_MAX_PARENTS];

The interface could look similar to:

/** @brief defines interface functions implemented throuh the specific used security module */
#include "routing_security_hooks.h"

/**
 * @brief   Returns if the security scheme identified parent as trustworthy
 * @param[in]   address   ponter to ipv6 address of potential parent
 * @param[in]   rank      nummeric provided rank from potential parent 
 * @return      char      1 if verified; 0 if not verified; 255 if timeout
 */
char is_potential_parent_trustworthy(ipv6_addr_t *address, uint16_t rank);


The second part would be in: 
sys/net/routing/rpl/rpl.c
void rpl_send(ipv6_addr_t *destination, uint8_t *payload, uint16_t p_len, uint8_t next_header);

/** @brief defines interface functions implemented throuh the specific used security module */
#include "routing_security_hooks.h"

/**
 * @brief   Returns if the security scheme identified destination as trustworthy
 * @param[in]   destination   ponter to ipv6 address of potential parent
 * @return      char      1 if verified; 0 if not verified;
 */
char is_destination_trustworthy(ipv6_addr_t *destination);

Securing to only send the packet if the security scheme returned the destination as trusted. 


The actual implementation of the security modules handles all managing of decision, credential requests, timeouts ...

So far the basic sketch of the possible security hooks.
I hope its not a too chaotic description.
I will provide a more mature description soon. 

Best regards,
Martin





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