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Added payload masking to interfaces with IFAC enabled

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This commit is contained in:
Mark Qvist 2023-02-02 20:48:52 +01:00
parent ac07ba1368
commit 4df67304d6
1 changed files with 44 additions and 2 deletions
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46
RNS/Transport.py
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@ -586,12 +586,36 @@ class Transport:
# Calculate packet access code
ifac = interface.ifac_identity.sign(raw)[-interface.ifac_size:]
# Generate mask
mask = RNS.Cryptography.hkdf(
length=len(raw)+interface.ifac_size,
derive_from=interface.ifac_signature+ifac,
salt=RNS.Reticulum.IFAC_SALT,
context=None,
)
# Set IFAC flag
new_header = bytes([raw[0] | 0x80, raw[1]])
# Assemble new payload with IFAC and send it
# Assemble new payload with IFAC
new_raw = new_header+ifac+raw[2:]
interface.processOutgoing(new_raw)
# Mask payload
i = 0; masked_raw = b""
for byte in new_raw:
if i == 1 or i > interface.ifac_size+1:
masked_raw += bytes([byte ^ mask[i]])
else:
masked_raw += bytes([byte])
i += 1
# Send it
interface.processOutgoing(masked_raw)
# TODO: Remove
# RNS.log("Mask material : "+RNS.hexrep(mask_material), RNS.LOG_DEBUG)
# RNS.log("Before masking : "+RNS.hexrep(new_raw), RNS.LOG_DEBUG)
# RNS.log("After masking : "+RNS.hexrep(masked_raw), RNS.LOG_DEBUG)
else:
interface.processOutgoing(raw)
@ -905,6 +929,24 @@ class Transport:
# Extract IFAC
ifac = raw[2:2+interface.ifac_size]
# Generate mask
mask = RNS.Cryptography.hkdf(
length=len(raw),
derive_from=interface.ifac_signature+ifac,
salt=RNS.Reticulum.IFAC_SALT,
context=None,
)
# Unmask payload
i = 0; unmasked_raw = b""
for byte in raw:
if i == 1 or i > interface.ifac_size+1:
unmasked_raw += bytes([byte ^ mask[i]])
else:
unmasked_raw += bytes([byte])
i += 1
raw = unmasked_raw
# Unset IFAC flag
new_header = bytes([raw[0] & 0x7f, raw[1]])