FpgaDownloadAndGoEx() with keep_em false does BigBuf_free() plus
BigBuf_Clear_ext(): the emulator memory pointer is nulled and all of BigBuf is
zeroed. iso14443a_setup() calls that variant, and Mifare1ksim(),
SimulateIso14443aTagEx() and SimulateIso14443aTagAID() build their precompiled
anticollision responses in BigBuf first. CMD_HF_MIFARE_EML_MEMGET had it the
other way round - it downloaded, then read the memory it had just wiped, so
'hf mf eview' and 'hf mf esave' returned their own zeros after any lf hitag,
hf iclass or hf 15 command. A download already cached early-returns, so which
image the FPGA held decided whether any of this happened.
All five now call FpgaDownloadAndGo_keep_EM() before any BigBuf allocation.
Free-BigBuf floor at download time goes 16384 -> 20480 (ring plus the 4096 byte
emulator block); BigBuf measures 29084..31420 across all standalone configs on
RDV4 and 40120 on a PM3 Easy.
The sim paths also clear the trace before taking their modulation buffer -
BigBuf_malloc() refuses memory a stale trace holds, and MifareSimInit() ignored
the NULL, leaving prepare_tag_modulation() to memcpy 571 bytes over the vector
table at address 0.
'hf mf eload' now zeroes emulator memory device side: CMD_HF_MIFARE_EML_MEMSET
takes a flags byte, set on the first chunk only, so 'hf mf esetblk' and every
other partial write still touch only their own blocks. That byte is why
CAPABILITIES_VERSION goes 9 -> 10; mismatched client and firmware refuse to
connect rather than write everything one byte offset.
Reported in #2836, whose USB drop is separately addressed by bc289cf43.
Builds clean for PM3RDV4, PM5 and the client; astyle clean. Not yet verified on
hardware.
Co-Authored-By: Claude Opus 5 (1M context)
Thanks @TheArchitect0880 for pointing it out and suggested a first fix.
MifareAcquireEncryptedNonces packs two 4 byte encrypted nonces plus one
byte holding both their encrypted parity nibbles into every entry, but
the reply declared num_nonces * 4 bytes. The client walks that buffer 9
bytes at a time, so on RDV4 it read 612 bytes out of a 544 byte payload
and handed roughly 15 of every 136 nonces to add_nonce() from stale
packet buffer content. Those fake nonces went into the .bin nonce file
too.
Count pairs instead of bytes. num_nonces now reports whole pairs only,
so a button abort or a static nonce bailout part way through a pair
drops the dangling nonce rather than shipping a half built entry whose
parity nibble was never filled in.
MFC_NONCE_PAIR_SIZE and MFC_MAX_NONCE_PAIRS document the layout next to
mf_nonces_resp_t so the 9 vs 4 confusion cannot come back, and the
client now refuses a reply too short for the nonce count it carries.
Both acquisition functions collect straight into the reply buffer rather
than a second PM3_CMD_DATA_SIZE stack array, which halves the stack used
per call. MifareAcquireNonces also returned isOK = 2 on button press,
which is not a PM3_* status; that is PM3_EOPABORTED now.
Co-Authored-By: Claude Opus 5 (1M context)
Simulation now completes the full exchange with a genuine Paxton reader in
password mode, and crypto mode read/write passes Proxmark-to-Proxmark.
Firmware:
- SOF was one bit period short. The lead-in that compensated for the lost
head half bit was removed and nothing replaced it, so readers rejected
every answer with a second START_AUTH. Default is now 6.
- The edge-detect threshold was latched before being measured, so the value
chosen depended on whether the Proxmark was in a field when sim started.
It is now measured on field entry and re-armed when the reader leaves.
- The percentile walk latched on run-scoped variables, so one attempt made
outside a field poisoned every later one.
- Field loss was detected from TIMESTAMP, which is free-running MCU time and
never stalls. Detect it from receive silence instead.
- Frames of a length the protocol does not have no longer reach the state
machine; our own modulation tail was resetting the session and breaking
every write.
- A dropped edge merges two or three reader bit periods into one gap. Those
bits were discarded; they are now recovered by decomposition, which is what
made crypto mode work (AUTH decode 15% -> 100%).
- Threshold selection is limited to 20 and 32 and settles in under 25 ms.
Client:
- lf hitag info printed a hardcoded 0x06 and reported 'Password mode' for
every tag. It now reads page 3, takes -k (4 bytes password, 6 bytes
crypto), and says so when the config cannot be read.
- lf hitag restore: writes a dump back in dependency order - user pages,
then key material, then config last - validates the config byte, and
prints the credential the tag will require afterwards.
- lf hitag crack2 now reports why it failed instead of a bare 'fail'.
- trace list: bit count moved to its own column, relative mode shows a
Frame Delay Time row rather than renaming Start/End, --frame and -r
rejected together.
PM3_CMD_DATA_SIZE went 512 -> 624 without a capabilities bump, so a new
client connects to old firmware and every oversized command dies at the
device's length check with no message.
Append max_cmd_data_size, bump to v9. The client now accepts an older
capabilities struct - it only ever grows by appending, so an older layout
is a prefix - and defaults the frame size for pre-v9 firmware.
SendCommandNG bounds by the device value instead of the compile time one.
Also zero init capabilities_t on the device, it leaked stack bytes.
nkeys was a 6 bit field but the client chunked by what fits in a frame -
123 keys in segment mode. nkeys wrapped to 59 while memcpy copied all 123
and the loop advanced by 123, so 64 of every 123 keys were never tested
and never reported. Full key mode was unaffected, it chunks 30.
Give nkeys its own byte. MIFAREU3P_CHKKEY_HEADER goes 18 -> 19, costing
one byte of payload, and segment mode chunks 123 again
Payload layout changed: client and firmware must be updated together.
Thanks Claude!
The OLD frame size was tied to the NG one, but the bootloader only speaks
OLD - growing PM3_CMD_DATA_SIZE would silently change sizeof(PacketCommandOLD)
and break flashing against every deployed bootrom in both directions.
Pin the OLD structs to their own constant and use it on every OLD path:
reply_old and the OLD receive branch on both sides, the bootrom, and the
flasher's write_block/send_finish_write_cmd, which memcpy into a
PacketCommandOLD using the NG size.
No behaviour change - both constants are 512 and armsrc .text is
byte-identical before and after.
Niel Nielsen