crucible | https://github.com/usbarmory/crucible
Copyright (c) WithSecure Corporation
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Where SoCs meet their fate.
Andrea Barisani
[email protected] | [email protected]
Andrej Rosano
[email protected] | [email protected]
The crucible utility provides user space support for reading, and writing,
One-Time-Programmable (OTP) fuses of System-on-Chip (SoC) application
processors through the Linux NVMEM framework.
The habtool utility provides support functions for NXP HABv4
Secure Boot
provisioning and executable signing.
The current support targets application processors from the NXP i.MX series (see Supported drivers).
Fusing SoC OTPs is an irreversible action that permanently fuses values on the device. This means that any errors in the process, or lost fused data such as cryptographic key material, might result in a bricked device.
The use of these tools is therefore at your own risk.
Pre-compiled binaries for Linux and Windows are released here.
You can also automatically download, compile and install the package, under your GOPATH, as follows:
# crucible fusing tool
go install github.com/usbarmory/crucible/cmd/crucible@latest
# NXP HABv4 tool
go install github.com/usbarmory/crucible/cmd/habtool@latest
Alternatively you can manually compile it from source:
git clone https://github.com/usbarmory/crucible
cd crucible && make
All targets can be cross compiled for ARM as follows:
- 32-bit arm:
make GOARCH=arm - 64-bit arm:
make GOARCH=arm64 - To just build the crucible executable for 64-bit arm:
make crucible GOARCH=arm64
The habtool utility can be cross compiled Windows as follows:
make habtool.exe
Usage: crucible [options] [read|blow] [fuse/register name] [value]
-Y do not prompt for confirmation (DANGEROUS)
-b int
value base/format (2,10,16)
-e string
value endianness (big,little)
-f string
YAML fusemaps directory (default "fusemaps")
-l list fusemaps
visualize fusemap (with -m and -r)
visualize read value (with read operation on a register)
visualize read fusemap (with read operation and no register)
-m string
processor model
-n string
NVMEM device (default "/sys/bus/nvmem/devices/imx-ocotp0/nvmem")
-r string
reference manual revision
-s use syslog, print only result value to stdout
The -b option controls value argument base/format and must be explicitly set
for all operations. For instance binary values like 0b10 or 10 are treated as
binary with -b 2, while values such as 0x0a or 0a are treated as hexadecimal
values with -b 16. Similarly the option controls the output value format
when reading.
The -e option controls value argument endianness and must be explicitly set
for blow operations. Typically most values should remain big-endian, however
certain tools, such as the ones creating the SRK_HASH for secure boot
purposes, may prepare their output in little-endian format. On read operations
the endianness is set to big-endian by default, however the option can be used
to force big-endian interpretation.
The syslog flag (-s) can be used to ease batch processing and limiting
standard output to solely read or blown values while redirecting all logs to
syslog, this mode requires to force all operations (-Y).
Example use:
# blow hex value (note: confirmation prompt not shown)
crucible -m IMX6UL -r 1 -b 16 -e big blow MAC1_ADDR 0x001f7b1007e3
soc:IMX6UL ref:1 otp:MAC1_ADDR op:blow addr:0x88 off:0 len:48 val:0x001f7b1007e3 res:0xe307107b1f000000
# read hex value
crucible -m IMX6UL -r 1 -b 16 read MAC1_ADDR
soc:IMX6UL ref:1 otp:MAC1_ADDR op:read addr:0x88 off:0 len:48 val:0x001f7b1007e3
# read hex value with minimal standard output
crucible -s -m IMX6UL -r 1 -b 16 read MAC1_ADDR
001f7b1007e3
# read binary value
crucible -m IMX6UL -r 1 -b 2 read SI_REV
soc:IMX6UL ref:1 otp:SI_REV op:read addr:0xc off:16 len:4 val:0b0001
# read binary value with minimal standard output
crucible -s -m IMX6UL -r 1 -b 2 read SI_REV
0001
# read register value with bit map visualization
crucible -l -m IMX6UL -r 1 -b 16 read OCOTP_CFG2
soc:IMX6UL ref:1 otp:OCOTP_CFG2 op:read addr:0xc off:0 len:32 val:0x703100ec
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 OCOTP_CFG2
┏━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┓ Bank:0 Word:3
┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃1 1 ┃0 0 0 1 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ R: 0x0000000c
┗━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━╋━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━╋━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━╋━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━┛ W: 0x0000000c
21 20 ─────────────────────────────────────────────────────────── TAMPER_PIN_DISABLE
19 ┄┄ ┄┄ 16 ─────────────────────────────────────────────── SI_REV
The crucible tool relies on register definition files in YAML format (see
fusemaps directory for examples) to map register/fuse names and address
information for read and write operations.
The definition format tries to adhere, as much as possible, to the information contained in the relevant P/N reference manuals.
The syntax is the following:
processor: <string> # processor model
reference: <string> # reference manual number (for P/N revision match)
#
driver: <string> # Linux driver name
bank_size: <int> # bank size
#
gaps: # gap definitions
<string>: # name of first register after gap
read: <bool> # applies to read operation
write: <bool> # applies to write operation
len: <uint32> # gap length in bytes
#
registers: # register definitions
<string>: # register name
bank: <uint32> # bank index
word: <uint32> # word index
fuses: # individual OTP fuse definitions
<string>: # fuse name
offset: <uint32> # fuse offset within register word
len: <uint32> # fuse length in bits
When loaded, the fusemap undergoes some basic sanity checks to ensure unique names, unique register addresses, bank and word indices compatible with the specified driver.
Development of new fusemaps can be facilitated with the -l flag, in
combination with the fusemap selection (-m and -r flags), to visualize bit
allocation and ease reference manual table comparison.
crucible -m IMX6UL -r 1 -l
...
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00 OCOTP_CFG1
┏━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┳━━┓ Bank:0 Word:2
┃DIE-X-CORDINATE ┃DIE-Y-CORDINATE ┃WAFER_NO ┃LOT_NO_ENC[42:32] ┃ R: 0x00000008
┗━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━╋━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━╋━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━╋━━┻━━┻━━┻━━┻━━┻━━┻━━┻━━┛ W: 0x00000008
31 ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ 00 UNIQUE_ID[63:32]
31 ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ 24 ─────────────────────────────────────────────────────────────────────── DIE-X-CORDINATE
23 ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ 16 ─────────────────────────────────────────────── DIE-Y-CORDINATE
15 ┄┄ ┄┄ ┄┄ 11 ──────────────────────────────── WAFER_NO
10 ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ ┄┄ 00 LOT_NO_ENC[42:32]
...
A bundle of fusemaps
for all supported drivers is embedded in the crucible executable.
The following table summarizes the currently supported hardware in terms of driver and fusemap availability.
| Vendor | Model | Linux driver | Read | Write | Fusemap |
|---|---|---|---|---|---|
| NXP | i.MX53 | nvmem-imx-iim | yes | no | yes |
| NXP | i.MX6DL | nvmem-imx-ocotp | yes | yes | yes |
| NXP | i.MX6DQ | nvmem-imx-ocotp | yes | yes | yes |
| NXP | i.MX6SL | nvmem-imx-ocotp | yes | yes | no |
| NXP | i.MX6SLL | nvmem-imx-ocotp | yes | yes | no |
| NXP | i.MX6SX | nvmem-imx-ocotp | yes^ | yes | no |
| NXP | i.MX6UL | nvmem-imx-ocotp | yes^ | yes | yes |
| NXP | i.MX6ULL | nvmem-imx-ocotp | yes | yes | yes |
| NXP | i.MX6ULZ | nvmem-imx-ocotp | yes | yes | yes |
| NXP | i.MX7D | nvmem-imx-ocotp | yes | yes | yes |
| NXP | i.MX7ULP | nvmem-imx-ocotp | yes | yes | no |
| NXP | i.MX8M | nvmem-imx-ocotp | yes | yes | yes |
| NXP | i.MX8MM | nvmem-imx-ocotp | yes | yes | yes |
| NXP | i.MX8MP | nvmem-imx-ocotp | yes | yes | yes |
^ The nvmem-imx-ocotp driver does not handle addressing gaps between OTP banks, the fusemap supports gap information specifically to work this problem around and ensure correct reads (writes are unaffected). Such driver limitation however does not allow for the entire fusemap to be read as its maximum size is computed without accounting for the gaps, see comments within the fusemap for affected registers.
Usage: habtool [OPTIONS]
-h Show this help
-z <crypto backend> "file" (default) or "gcp"
SRK CA creation options:
-C <output path> SRK private key in PEM format
-c <output path> SRK public key in PEM format
CSF/IMG certificates creation options:
-C <input path> SRK private key in PEM format
-c <input path> SRK public key in PEM format
-A <output path> CSF private key in PEM format
-a <output path> CSF public key in PEM format
-B <output path> IMG private key in PEM format
-b <output path> IMG public key in PEM format
SRK table creation options:
-1 <input path> SRK public key 1 ('file': PEM format, 'gcp': resource ID)
-2 <input path> SRK public key 2 ('file': PEM format, 'gcp': resource ID)
-3 <input path> SRK public key 3 ('file': PEM format, 'gcp': resource ID)
-4 <input path> SRK public key 4 ('file': PEM format, 'gcp': resource ID)
-o <output path> Write SRK table hash to file
-t <output path> Write SRK table to file
Executable signing options:
-A <input path> CSF private key ('file': PEM format, 'gcp': resource ID)
-a <input path> CSF public key ('file': PEM format, 'gcp': resource ID)
-B <input path> IMG private key ('file': PEM format, 'gcp': resource ID)
-b <input path> IMG public key ('file': PEM format, 'gcp': resource ID)
-t <input path> Read SRK table from file
-x <1-4> Index for SRK key
-e <id> Crypto engine (e.g. 0x1b for HAB_ENG_DCP)
-i <input path> Image file w/ IVT header (e.g. boot.imx)
-o <output path> Write CSF to file
-s Serial download mode
-S <address> Serial download DCD OCRAM address
(depends on mfg tool, default: 0x00910000)
The USB armory guide for Secure Boot provides an introduction on HABv4 using the USB armory Mk II as reference platform.
When setting the -z flag to gcp, habtool will use the Google Cloud APIs to fetch certificates
and perform signing operations. This backend requires that public and private keys are referenced
using GCP Resource IDs
rather than on-disk files.
Signing keys must be stored in CloudHSM, and the particular
keys to use when signing the CSF and IMG payloads are passed as
CloudHSM Key Resource IDs to the -A and -Bflags, e.g:
projects/myProject/locations/global/keyRings/myKeyRing/cryptoKeys/myKey/cryptoKeyVersions/1.
Public key Resource IDs, passed via the -1, -2, -3, -4, -A, or -B flags, should reference either:
- a
Certificate
resource, e.g.:
projects/myProject/locations/us-central1/caPools/myPool/certificates/myCertificate - a CertificateAuthority
resource, e.g.:
projects/myProject/locations/us-central1/caPools/myPool/certificateAuthorities/myCertificateAuthority
In the later case, the authoritie's public key certificate will be used.
crucible | https://github.com/usbarmory/crucible
Copyright (c) WithSecure Corporation
This project is distributed under the BSD-style license found in the LICENSE file.