[riot-devel] hmac_sha256 and microcoap example

Theodore Kotsonis kotsonis at aueb.gr
Fri Apr 8 18:05:59 CEST 2016


Hi everyone

I use hmac_sha256 function in microcoap example ( to be more specific  
I call it in an endopoint I create in coap.c file )

I am using STM32F401RE nucleo board

I want to use a key 64 bytes and I want to call hmac fuction.

But when I run it on the board and send a url from coap_client a get  
an error for stack overflow.

2016-04-08 15:27:29,948 - INFO # Waiting for incoming UDP packet...
2016-04-08 15:27:33,735 - INFO # Received packet: 40 01 35 4E B4 68 6D  
61 63 07 6D 65 73 73 61 67 65
2016-04-08 15:27:33,735 - INFO # content:
2016-04-08 15:27:33,736 - INFO # Header:
2016-04-08 15:27:33,736 - INFO #   ver  0x01
2016-04-08 15:27:33,736 - INFO #   t    0x01
2016-04-08 15:27:33,736 - INFO #   tkl  0x00
2016-04-08 15:27:33,736 - INFO #   code 0x01
2016-04-08 15:27:33,741 - INFO #   id   0x354E
2016-04-08 15:27:33,741 - INFO #  Options:
2016-04-08 15:27:33,747 - INFO #   0x0B [ 68 6D 61 63 ]
2016-04-08 15:27:33,747 - INFO #   0x0B [ 6D 65 73 73 61 67 65 ]
2016-04-08 15:27:33,747 - INFO # Payload:
2016-04-08 15:27:33,747 - INFO # Se
2016-04-08 15:27:33,748 - INFO # Context before hardfault:
2016-04-08 15:27:33,748 - INFO # 2   r0: 0x200002f8
2016-04-08 15:27:33,753 - INFO #    r1: 0x10fec917
2016-04-08 15:27:33,753 - INFO #    r2: 0x200002f8
2016-04-08 15:27:33,753 - INFO #    r3: 0x20000184
2016-04-08 15:27:33,754 - INFO #   r12: 0x10080286
2016-04-08 15:27:33,759 - INFO #    lr: 0x08000279
2016-04-08 15:27:33,759 - INFO #    pc: 0x080004b8
2016-04-08 15:27:33,760 - INFO #   psr: 0x0100000e
2016-04-08 15:27:33,760 - INFO #
2016-04-08 15:27:33,760 - INFO # FSR/FAR:
2016-04-08 15:27:33,765 - INFO #  CFSR: 0x01000000
2016-04-08 15:27:33,771 - INFO #  HFSR: 0x40000000
2016-04-08 15:27:33,771 - INFO #  DFSR: 0x00000008
2016-04-08 15:27:33,772 - INFO #  AFSR: 0x00000000
2016-04-08 15:27:33,772 - INFO # Misc
2016-04-08 15:27:33,772 - INFO # EXC_RET: 0xfffffff1
2016-04-08 15:27:33,773 - INFO # Attempting to reconstruct state for  
debugging...
2016-04-08 15:27:33,777 - INFO # In GDB:
2016-04-08 15:27:33,777 - INFO #   set $pc=0x80004b8
2016-04-08 15:27:33,777 - INFO #   frame 0
2016-04-08 15:27:33,778 - INFO #   bt
2016-04-08 15:27:33,778 - INFO #
2016-04-08 15:27:33,783 - INFO # ISR stack overflowed by at least 40 bytes.


When I use a key for 4-8-16-32 bytes it run perfectly on board ( I  
send a request from coap-client and I get an  response )

I tried to see if it is a problem of hmac_sha256 so I create an  
example ( main.c ) for my board to use it without microcoap and it  
runs without any problem in 64 bytes.

Is there a limitation on bytes can use in endpoint microcoap?
-------------- next part --------------
A non-text attachment was scrubbed...
Name: coap.c
Type: text/x-c
Size: 4744 bytes
Desc: not available
URL: <http://lists.riot-os.org/pipermail/devel/attachments/20160408/1d0d9cf8/attachment.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: main.c
Type: text/x-c
Size: 1782 bytes
Desc: not available
URL: <http://lists.riot-os.org/pipermail/devel/attachments/20160408/1d0d9cf8/attachment-0001.bin>


More information about the devel mailing list