patchelfcrc/man/patchelfcrc.1.md

7.1 KiB

% patchelfcrc(1) !version! % Mario Huettel % October 2022

NAME

patchelfcrc - Patch CRC checksums into ELF files

SYNOPSYS

patchelfcrc [-lrv?V] [-g GRANULARITY] [-p POLYNOMIAL] [-s STARTVALUE] [-x XORVAL] [-F FORMAT] [-O OUTPUTSECTION] [-S SEC] [--granularity=GRANULARITY] [--little-endian] [--dry-run] [--xsd] [--poly=POLYNOMIAL] [--reversed] [--start-value=STARTVALUE] [--verbose] [--xor-out=XORVAL] [--end-magic=MAGIC] [--crc-format=FORMAT] [--use-vma] [--list-crcs] [--output-section=OUTPUTSECTION] [--export=XMLFILE] [--import=XMLFILE] [--start-magic=MAGIC] [--section=SECTION] [--help] [--usage] [--version] ELF

DESCRIPTION

patchelfcrc reads in sections of an ELF file and computes CRC checksums over the data. The calculated CRCs are placed in an output section of the ELFFILE. The output section must already exist inside the ELF file and must be big enough to hold all generated CRC checksums.

patchelfcrc supports multiple predefined CRCs as well as custom polynomials.

OPTIONS

-h, --help
Display help
--usage
Display usage information
-p POLYNOMIAL, --polynomial=POLYNOMIAL
Polynomial to use for CRC calculation. For a n bit wide CRC supply a number with n+1 bits and the MSB set. Alternatively, a predifined name can be supplied. See --list-crcs for details. At maximum a 32 bit wide CRC can be calculated. If nothing is given, crc-32-mpeg is used.
-s STARTVALUE, --start-value=STARTVALUE
Start value to preload CRC register with. This value is XORed with the XORVAL (see option -x).
-x XORVAL, --xor-value=XORVAL
XOR Value applied to initial start value (-s) and to the final CRC result.
-r, --reversed
Use bitreversed CRC. This is not implemented yet!
-g GRANULARITY, --granularity=GRANULARITY
CRC calculation granularity. This has no effect if big endian layout is used. For little endian layout, it specifies the sizes of the individual elements the CRC is computed over.

GRANULARITY = [word | halfword | byte]. Defaults to byte.

-l, --little-endian
The memory layout of the ELFFILE is in little-endian format.
-F FORMAT, --crc-format=FORMAT
Output format to place in output section. Options for FORMAT are bare or struct
--use_vma
Use the virtual memory address (VMA) instead of the load memory address (LMA) for the address fields in the struct output. This option is only considered if the format is struct
--start-magic=MAGIC, --endmagic=MAGIC
MAGIC numbers (32 bit unsigned) that are expected to be found at the start and the end of the given output section. This serves as safety guard against accidental corruption of the output file. It is highly recommended to use these options.
--export=XMLFILE
Export the calculated files to an XML file XMLFILE.
--import=XMLFILE
Import the CRCs from an XML file XMLFILE and do not caclulate anything in the given ELF
--help, -h, -?
Print help.
--dry-run
Dry run. Do all calculations but do not write changes to file. ELF file will only be opened readonly. This mode implicitly activates the verbose output
-v, --verbose
Activate verbose output
-V, --version
Print version number
--list-crcs
List the possible predefined CRCs
--xsd
Print the XSD file used to validate the XML import to stdout
--usage
Print usage hints on command line options.
--no-color
Force output on stdout and stderr to be pure text without color codes.

EXAMPLES

patchelfcrc --list-crcs

Name Polynomial Reversed Start Value Output XOR
crc-8 0x107 no 0x0 0x0
crc-8-darc 0x139 yes 0x0 0x0
crc-8-i-code 0x11d no 0xfd 0x0
crc-8-itu 0x107 no 0x55 0x55
crc-8-maxim 0x131 yes 0x0 0x0
crc-8-rohc 0x107 yes 0xff 0x0
crc-8-wcdma 0x19b yes 0x0 0x0
crc-16 0x18005 yes 0x0 0x0
crc-16-buypass 0x18005 no 0x0 0x0
crc-16-dds-110 0x18005 no 0x800d 0x0
crc-16-dect 0x10589 no 0x1 0x1
crc-16-dnp 0x13d65 yes 0xffff 0xffff
crc-16-en-13757 0x13d65 no 0xffff 0xffff
crc-16-genibus 0x11021 no 0x0 0xffff
crc-16-maxim 0x18005 yes 0xffff 0xffff
crc-16-mcrf4xx 0x11021 yes 0xffff 0x0
crc-16-riello 0x11021 yes 0x554d 0x0
crc-16-t10-dif 0x18bb7 no 0x0 0x0
crc-16-teledisk 0x1a097 no 0x0 0x0
crc-16-usb 0x18005 yes 0x0 0xffff
x-25 0x11021 yes 0x0 0xffff
xmodem 0x11021 no 0x0 0x0
modbus 0x18005 yes 0xffff 0x0
kermit 0x11021 yes 0x0 0x0
crc-ccitt-false 0x11021 no 0xffff 0x0
crc-aug-ccitt 0x11021 no 0x1d0f 0x0
crc-24 0x1864cfb no 0xb704ce 0x0
crc-24-flexray-a 0x15d6dcb no 0xfedcba 0x0
crc-24-flexray-b 0x15d6dcb no 0xabcdef 0x0
crc-32 0x104c11db7 yes 0x0 0xffffffff
crc-32-bzip2 0x104c11db7 no 0x0 0xffffffff
crc-32c 0x11edc6f41 yes 0x0 0xffffffff
crc-32d 0x1a833982b yes 0x0 0xffffffff
crc-32-mpeg 0x104c11db7 no 0xffffffff 0x0
posix 0x104c11db7 no 0xffffffff 0xffffffff
crc-32q 0x1814141ab no 0x0 0x0
jamcrc 0x104c11db7 yes 0xffffffff 0x0
xfer 0x1000000af no 0x0 0x0
patchelfcrc -l -g word --start-magic=0x12345678 --end-magic=0x8754321 -p crc-32-mpeg -f bare -O .outputsection -S .text executable.elf
Calculate the CRC over .text section and place the result in the .outputsection section. The output sections start and end are checked for the given magic numbers in order to assure correct memory layout. CRC-32-MPEG is used as CRC algorothm. The memory is interpreted as little endian and the CRC calculation granularity is a 32 bit word.

BUGS

None