103 lines
3.5 KiB
Bash
Executable File
103 lines
3.5 KiB
Bash
Executable File
#!/bin/sh
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# Repacker for DPT pkg
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# HappyZ
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# Thanks to anonymous contributer somewhere on earth
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# PKG FILE FORMAT
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# byte 1--4: DPUP - file recognizer
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# byte 5--8: data offset location A
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# byte 9--12: total data content size D
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# byte 13--16: nothing
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# byte 17--20: sigfile size B
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# byte 21--(20+B): sigfile data
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# byte (21+(-B%16)%16)--(25+(-B%16)%16): encrypted data aes key size (BE) C
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# byte (+1)--(+C): encrypted data aes key bytes
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# byte (+1)--(+32): initial vector --- up till now bytes shall equal to A
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# byte (A+1)--(A+D): encrypted data
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# byte (+1)--(+4): animation header size E
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# byte (+1)--(+4): animation data size F
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# byte (+1)--(+4): animation sigfile size G
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# byte (+1)--(+(-G%16)%16): animation sigfile --- here bytes shall be A+D+E
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# byte (A+D+E+1)--(A+D+E+F): animation data
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# zipped data format
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# FwUpdater
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# |- boot.img
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# |- boot.img.md5
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# |- system.img
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# |- system.img.md5
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# |- eufwupdater.sh
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# |- ...
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# we do not care about animation
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# params
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INDIR=$1 # input folder
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TMPDIR=$INDIR
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PKGFILE=$1/repacked.pkg # output pkg file
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SHA256KEY="./key.pub"
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SIGKEY="./key.private_sig" # unfortunately we do not have this
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DATAKEY_D="./key.private"
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# predefined outputs
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SIGFILE="$INDIR/signature"
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AESFILE="$INDIR/aes.key"
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IVFILE="$INDIR/init_vector"
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SIGFILE_ANIM="$INDIR/signature_animation"
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# check if input folder exists
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if [[ ! -d $INDIR ]]; then
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echo "! Err: input folder does not exist"
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exit 0
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fi
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echo "* zip data.."
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cd $INDIR && tar -czf repacked_pkg.tar.gz FwUpdater/ && cd ..
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echo "* encrypt zipped tar"
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openssl enc -e -aes-256-cbc -K `cat $AESFILE` -iv `cat $IVFILE` -in $INDIR/repacked_pkg.tar.gz -out $TMPDIR/tmp.step1
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OFFSET_DATA=0
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DATA_SIZE=$(wc -c < $TMPDIR/tmp.step1)
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echo "* add 32-byte initial vector"
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cat $IVFILE $TMPDIR/tmp.step1 > $TMPDIR/tmp.step2
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OFFSET_DATA=$((OFFSET_DATA + 32))
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echo "* encrypt the aes key with our private $DATAKEY_D"
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openssl rsautl -encrypt -inkey $DATAKEY_D -in $AESFILE -out $TMPDIR/tmp.step3.1
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DATAKEY_E_SIZE=$(wc -c < $TMPDIR/tmp.step3.1)
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cat $TMPDIR/tmp.step3.1 $TMPDIR/tmp.step2 > $TMPDIR/tmp.step3.2
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printf "%.8x" $((DATAKEY_E_SIZE)) | sed -E 's/(..)(..)(..)(..)/\4\3\2\1/' | xxd -r -p | cat - $TMPDIR/tmp.step3.2 > $TMPDIR/tmp.step3
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OFFSET_DATA=$((OFFSET_DATA + DATAKEY_E_SIZE + 4))
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echo "* sign w/ private key $SIGKEY"
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openssl dgst -sha256 -sign $SIGKEY -out $TMPDIR/tmp.step4.1 $TMPDIR/tmp.step1
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openssl dgst -sha256 -verify $SHA256KEY -signature $TMPDIR/tmp.step4.1 $TMPDIR/tmp.step1
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if [ $? -ne 0 ]; then
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echo "! Err: failed to verify sha256 - highly likely $SIGKEY is wrong"
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exit 0
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fi
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SIG_SIZE=$(wc -c < $TMPDIR/tmp.step4.1)
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if [ $(((-(SIG_SIZE % 16)) % 16)) -gt 0 ]; then
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echo "! Err: not supported for SIG_SIZE not mutiple of 16"
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exit -1
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fi
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cat $TMPDIR/tmp.step4.1 $TMPDIR/tmp.step3 > $TMPDIR/tmp.step4.2
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printf "%.8x" $((SIG_SIZE)) | sed -E 's/(..)(..)(..)(..)/\4\3\2\1/' | xxd -r -p | cat - $TMPDIR/tmp.step4.2 > $TMPDIR/tmp.step4
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OFFSET_DATA=$((OFFSET_DATA + SIG_SIZE + 4))
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echo "* assign data block size and offset"
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printf "%.8x" 0 | sed -E 's/(..)(..)(..)(..)/\4\3\2\1/' | xxd -r -p | cat - $TMPDIR/tmp.step4 > $TMPDIR/tmp.step5.1
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printf "%.8x" $((DATA_SIZE)) | sed -E 's/(..)(..)(..)(..)/\4\3\2\1/' | xxd -r -p | cat - $TMPDIR/tmp.step5.1 > $TMPDIR/tmp.step5.2
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OFFSET_DATA=$((OFFSET_DATA + 4 + 4 + 4 + 4))
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echo "OFFSET_DATA: $OFFSET_DATA, DATA_SIZE: $DATA_SIZE"
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printf "%.8x" $((OFFSET_DATA)) | sed -E 's/(..)(..)(..)(..)/\4\3\2\1/' | xxd -r -p | cat - $TMPDIR/tmp.step5.2 > $TMPDIR/tmp.step5
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echo "* add file header"
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printf "DPUP" | cat - $TMPDIR/tmp.step5 > $PKGFILE
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