Error with RSA sign

[K7cl]

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Describe the bug RSA sign fail in mem info

To Reproduce Steps to reproduce the behavior:

1. clone the master branch
2. edit client/src/cmdflashmem.c at line 459, change bool shall_sign = false, shall_write = false; to bool shall_sign = true, shall_write = true;
3. make clean && make all %% make install
4. connect to pm3 and run comman mem info

Expected behavior sign then write to pm3, to override empty sign. To fix wrong return in rdv4 device detection.

Screenshots

Desktop (please complete the following information):

• OS: Kali 2021.1

• inside proxmark3 client run the following commands and paste the output here. [usb] pm3 --> hw version

  [ Proxmark3 RFID instrument ]

  [ CLIENT ] client: RRG/Iceman/master/v4.9237-3239-g5657e392f-dirt...-unclean 2021-03-03 03:46:26 compiled with GCC 10.2.1 20210110 OS:Linux ARCH:x86_64

  [ PROXMARK3 ] device.................... RDV4 // I edit the cmdhw.c at 972 from if (rdv4_validate(&mem) == PM3_SUCCESS) { to if (rdv4_validate(&mem) == PM3_EFAILD) { for find the error raeson, so it shows the right return this time. firmware.................. RDV4 external flash............ present smartcard reader.......... present FPC USART for BT add-on... present

  [ ARM ] bootrom: RRG/Iceman/master/v4.9237-3239-g5657e392f-dirt...-unclean 2021-03-03 03:46:57 os: RRG/Iceman/master/v4.9237-3239-g5657e392f-dirt...-unclean 2021-03-03 03:47:13 compiled with GCC 8.3.1 20190703 (release) [gcc-8-branch revision 273027]

  [ FPGA ] LF image built for 2s30vq100 on 2020-07-08 at 23: 8: 7 HF image built for 2s30vq100 on 2020-07-08 at 23: 8:19 HF FeliCa image built for 2s30vq100 on 2020-07-08 at 23: 8:30

  [ Hardware ] --= uC: AT91SAM7S512 Rev A --= Embedded Processor: ARM7TDMI --= Internal SRAM size: 64K bytes --= Architecture identifier: AT91SAM7Sxx Series --= Embedded flash memory 512K bytes ( 59% used )

[usb] pm3 --> hw status [#] Memory [#] BigBuf_size.............40248 [#] Available memory........40248 [#] Tracing [#] tracing ................1 [#] traceLen ...............0 [#] dma8 memory.............-2113920 [#] dma16 memory............-2113920 [#] toSend memory...........-2113920 [#] Current FPGA image [#] mode.................... HF image built for 2s30vq100 on 2020-07-08 at 23: 8:19 [#] Flash memory [#] Baudrate................24 MHz [#] Init....................OK [#] Memory size.............2 mbits / 256 kb [#] Unique ID...............0xD567A882A76AC526 [#] Smart card module (ISO 7816) [#] version.................v3.11 [#] LF Sampling config [#] [q] divisor.............95 ( 125.00 kHz ) [#] [b] bits per sample.....8 [#] [d] decimation..........1 [#] [a] averaging...........Yes [#] [t] trigger threshold...0 [#] [s] samples to skip.....0 [#] LF Sampling Stack [#] Max stack usage.........3960 / 8480 bytes [#] LF T55XX config [#] [r] [a] [b] [c] [d] [e] [f] [g] [#] mode |start|write|write|write| read|write|write [#] | gap | gap | 0 | 1 | gap | 2 | 3 [#] ---------------------------+-----+-----+-----+-----+-----+-----+------ [#] fixed bit length (default) | 29 | 17 | 15 | 47 | 15 | N/A | N/A | [#] long leading reference | 29 | 17 | 18 | 50 | 15 | N/A | N/A | [#] leading zero | 29 | 17 | 18 | 40 | 15 | N/A | N/A | [#] 1 of 4 coding reference | 29 | 17 | 15 | 31 | 15 | 47 | 63 | [#] [#] HF 14a config [#] [a] Anticol override....std : follow standard [#] [b] BCC override........std : follow standard [#] [2] CL2 override........std : follow standard [#] [3] CL3 override........std : follow standard [#] [r] RATS override.......std : follow standard [#] Transfer Speed [#] Sending packets to client... [#] Time elapsed............500ms [#] Bytes transferred.......282112 [#] Transfer Speed PM3 -> Client = 564224 bytes/s [#] Various [#] Max stack usage.........4104 / 8480 bytes [#] DBGLEVEL................1 ( ERROR ) [#] ToSendMax...............-1 [#] ToSend BUFFERSIZE.......2308 [#] Slow clock..............30364 Hz [#] Installed StandAlone Mode [#] HF - Reading Visa cards & Emulating a Visa MSD Transaction(ISO14443) - (Salvador Mendoza) [#] Flash memory dictionary loaded [#] Mifare..................1018 keys [#] T55x7...................113 keys [#] iClass..................9 keys [usb] pm3 --> data tune [=] REMINDER: 'hw tune' doesn't actively tune your antennas, it's only informative [=] Measuring antenna characteristics, please wait... 🕛 9 [=] ---------- LF Antenna ---------- [+] LF antenna: 36.89 V - 125.00 kHz [+] LF antenna: 27.45 V - 134.83 kHz [+] LF optimal: 36.89 V - 125.00 kHz [+] Approx. Q factor (): 5.6 by frequency bandwidth measurement [+] Approx. Q factor (): 6.4 by peak voltage measurement [+] LF antenna is OK [=] ---------- HF Antenna ---------- [+] HF antenna: 46.09 V - 13.56 MHz [+] Approx. Q factor (*): 8.0 by peak voltage measurement [+] HF antenna is OK

(*) Q factor must be measured without tag on the antenna

[+] Displaying LF tuning graph. Divisor 88 (blue) is 134.83 kHz, 95 (red) is 125.00 kHz.

[iceman1001]

That code is disabled by choice, of course the private key isn't there.

[K7cl]

Thanks! So the private key coded under the pub key is not real?

[iceman1001]

As mentioned in the source https://github.com/RfidResearchGroup/proxmark3/blob/master/client/src/cmdflashmem.c#L42-L43