Skip to content

adding checks for maximum frame length, ensuring we give CryptoLib bu… #86

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
jppan-jpl merged 2 commits into from
Jul 29, 2026
Merged

adding checks for maximum frame length, ensuring we give CryptoLib bu… #86

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
b475aef
adding checks for maximum frame length, ensuring we give CryptoLib bu…
jppan-jpl Jul 28, 2026
b65b4be
adding header gvcid extraction for AOS to get_max_frame_size function
jppan-jpl Jul 28, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
84 changes: 76 additions & 8 deletions ...sdls/kmc_sdls_python/KmcSdlsClient/src/gov/nasa/jpl/ammos/kmc/sdlsclient/KmcSdlsClient.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,56 @@
frame_global_config = {}


def get_max_frame_size(type, input_byte_array) -> int:
'''
Get the maximum frame size for the given input byte array.

Args:
----------
input_byte_array : bytearray
The input byte array to get the maximum frame size for.

Returns
-------
max_frame_size : int
The maximum frame size.
'''
if type == 'tm':
# Extract GVCID from TM frame header to look up max frame size
# TM Primary Header format (CCSDS 132.0-B-3):
# Bits 0-1: TFVN
# Bits 2-11: SCID (10 bits)
# Bits 12-14: VCID (3 bits)
tfvn = (input_byte_array[0] & 0xC0) >> 6
scid = ((input_byte_array[0] & 0x3F) << 4) | ((input_byte_array[1] & 0xF0) >> 4)
vcid = (input_byte_array[1] & 0x0E) >> 1
elif type == 'aos':
# Extract GVCID from AOS frame header to look up max frame size
# AOS Primary Header format (CCSDS 732.0-B):
# Bits 0-1: TFVN (2 bits, binary '01')
# Bits 2-9: SCID (8 bits)
# Bits 10-15: VCID (6 bits)
tfvn = (input_byte_array[0] & 0xC0) >> 6
scid = ((input_byte_array[0] & 0x3F) << 2) | ((input_byte_array[1] & 0xC0) >> 6)
vcid = input_byte_array[1] & 0x3F
else:
raise SdlsClientException(SdlsClientException.SDLS_INITIALIZATION_ERROR, f"{type} frame type is invalid")

# Build frame key to look up managed parameters
frame_key = f"{type}.{scid}.{vcid}.{tfvn}"

# Get max frame size from config, or use conservative fallback
if frame_key in frame_global_config and "max_frame_length" in frame_global_config[frame_key]:
max_frame_size = frame_global_config[frame_key]["max_frame_length"]
else:
raise SdlsClientException(SdlsClientException.SDLS_INITIALIZATION_ERROR, f"max_frame_length must be configured for {type}.{tfvn}.{scid}.{vcid}")

if len(input_byte_array) > max_frame_size:
raise SdlsClientException(SdlsClientException.PROCESS_SECURITY_EXCEPTION, f"Input frame size is {len(input_byte_array)} bytes, which is larger than configured maximum {max_frame_size} bytes for {type}.{tfvn}.{scid}.{vcid}")

return max_frame_size


Comment thread
jppan-jpl marked this conversation as resolved.
class KmcSdlsClient:
ffi = None
global_dict = dict()
Expand Down Expand Up @@ -388,6 +438,7 @@ def __init__(self, config):
frame_global_config[frame_key] = {}
config_key = "cryptolib." + frame_key
managed_parameter_max_frame_length = int(config_dict.get(config_key + ".max_frame_length", 1024))
frame_global_config[frame_key]["max_frame_length"] = managed_parameter_max_frame_length
managed_parameter_has_ecf_enum = managed_parameter_has_ecf
if frame_type == 'tc':
if managed_parameter_has_ecf:
Expand Down Expand Up @@ -596,10 +647,15 @@ def apply_security_aos(self, input_byte_array):
"Input Transfer Frame is not a bytearray, actual type: %s" % type(
input_byte_array).__name__)

in_copy = bytearray(input_byte_array)
max_frame_size = get_max_frame_size("aos", input_byte_array)

# Allocate buffer with max frame size, then copy input data into it
in_copy = bytearray(max_frame_size)
in_copy[:len(input_byte_array)] = input_byte_array

aos_char_in_frame = self.ffi.from_buffer(in_copy, require_writable=True)
aos_char_star_in = aos_char_in_frame
aos_len_in = self.cast_uint16_t(len(aos_char_in_frame))
aos_len_in = self.cast_uint16_t(len(input_byte_array))
Comment thread
jppan-jpl marked this conversation as resolved.
apply_security_result = kmc_python_c_sdls_interface.lib.apply_security_aos(aos_char_star_in, aos_len_in)
if apply_security_result != SUCCESS:
raise SdlsClientException(SdlsClientException.APPLY_SECURITY_EXCEPTION,
Expand All @@ -622,8 +678,11 @@ def process_security_aos(self, input_byte_array):
raise SdlsClientException(SdlsClientException.BAD_DATA_FORMAT,
"Input Transfer Frame is not a bytearray, actual type: %s" % type(
input_byte_array).__name__)
max_frame_size = get_max_frame_size("aos", input_byte_array)

in_copy = bytearray(input_byte_array)
# Allocate buffer with max frame size, then copy input data into it
in_copy = bytearray(max_frame_size)
in_copy[:len(input_byte_array)] = input_byte_array
aos_char = self.ffi.from_buffer(in_copy, require_writable=True)
aos_len = self.ffi.new("int *")
aos_len[0] = len(aos_char)
Expand Down Expand Up @@ -698,15 +757,20 @@ def apply_security_tm(self, input_byte_array):
"Input Transfer Frame is not a bytearray, actual type: %s" % type(
input_byte_array).__name__)

in_copy = bytearray(input_byte_array)
max_frame_size = get_max_frame_size("tm", input_byte_array)

# Allocate buffer with max frame size, then copy input data into it
in_copy = bytearray(max_frame_size)
in_copy[:len(input_byte_array)] = input_byte_array

tm_char_in_frame = self.ffi.from_buffer(in_copy, require_writable=True)
tm_char_star_in = tm_char_in_frame
tm_len_in = self.cast_uint16_t(len(tm_char_in_frame))
tm_len_in = self.cast_uint16_t(len(input_byte_array))
apply_security_result = kmc_python_c_sdls_interface.lib.apply_security_tm(tm_char_star_in, tm_len_in)
if apply_security_result != SUCCESS:
raise SdlsClientException(SdlsClientException.APPLY_SECURITY_EXCEPTION,
"KMC CryptoLib Apply Security Exception.", apply_security_result)
buf = self.ffi.buffer(tm_char_star_in, int(tm_len_in))
buf = self.ffi.buffer(tm_char_star_in, int(max_frame_size))
return bytearray(buf)

def process_security_tm(self, input_byte_array):
Expand All @@ -724,8 +788,11 @@ def process_security_tm(self, input_byte_array):
raise SdlsClientException(SdlsClientException.BAD_DATA_FORMAT,
"Input Transfer Frame is not a bytearray, actual type: %s" % type(
input_byte_array).__name__)
max_frame_size = get_max_frame_size("tm", input_byte_array)

in_copy = bytearray(input_byte_array)
# Allocate buffer with max frame size, then copy input data into it
in_copy = bytearray(max_frame_size)
in_copy[:len(input_byte_array)] = input_byte_array
tm_char = self.ffi.from_buffer(in_copy, require_writable=True)
tm_len = self.ffi.new("int *")
tm_len[0] = len(tm_char)
Expand Down Expand Up @@ -1003,7 +1070,8 @@ def hex(self):
if self.sn_field_len > 0:
res.extend(self.sn)
if self.pad_field_len > 0:
res.extend(self.pad)
# res.extend(self.pad.to_bytes(2, byteorder='big'))
res.extend(struct.pack('>H', self.pad))
return res.hex()


Expand Down
Loading