79 lines
3.1 KiB
Python
Executable file
79 lines
3.1 KiB
Python
Executable file
#!/usr/bin/env python3
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import sys
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import base64
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if len(sys.argv) < 4:
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print("USAGE: mkfirm.py <kernel9.elf> <kernel11.elf> <output.firm>")
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sighax_sig=base64.a85decode(b'DZ:iLO%T*f"sal5!m5:QU$Gmm[dg)m,&2*<U<LK%FP[g"\'Kc#M==?kH6r/uA>-HJLBEU+9e;EeCligEb]Qpn^2!Gp5_g%-,]IDC-MMahK=@9T\\,0,4&6MDgNaP\'t06CY.qpSb;KMn)+PR1>e0IbaRdgDC5J-m3DLB2d$%DNZn-W7=ADNLl+s&Z2gs%A?=ZJ:91F?66n9DXZ.-lL+5$#ebaKH5IB)Y&DTGd%!,O4me2`$F["\\.$Tr)%\\,h,n.Q]LTQGQRH:#a?1l(T-i_m7b\\7Mg5Ga7LDUacTc`!af0V`"\'-*]I]3%SL)@)ll701ok)i')
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import struct
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import hashlib
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def get_elf_seg(f): #Return entry,section_beg,section_size,section
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f.seek(0)
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if f.read(4) != b"\x7FELF":
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raise Exception("Not an ELF file!")
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if f.read(1) != b"\x01":
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raise Exception("ELF64s are not supported!")
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if f.read(1) != b"\x01":
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raise Exception("Little Endian ELF required!")
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if f.read(1) != b"\x01":
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raise Exception("Unknown ELF version!")
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f.read(9)
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if struct.unpack("<H",f.read(2))[0] != 2:
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raise Exception("Invalid ELF format")
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if struct.unpack("<H",f.read(2))[0] != 0x28:
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raise Exception("This is not an ELF for ARM!")
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if struct.unpack("<I",f.read(4))[0] != 1:
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raise Exception("Unknown ELF version!")
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loadAddr = struct.unpack("<I",f.read(4))[0]
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phoff = struct.unpack("<I",f.read(4))[0]
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f.seek(0x2C)
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no_ent = struct.unpack("<H",f.read(2))[0]
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f.seek(phoff)
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section_begin = 0
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section_size = 0
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section = b''
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for ent in range(no_ent):
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f.seek(phoff+ent*0x20)
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if struct.unpack("<I",f.read(4))[0] != 1:
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continue
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off,vaddr,filesz,memsz=struct.unpack("<IIxxxxII",f.read(20))
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section_begin = vaddr
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section_size = memsz
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f.seek(off)
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section = f.read(filesz)
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section = section + b'\x00'*(memsz-filesz)
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break
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print("Loading section of size {} to {} with entrypoint {}".format(section_size,hex(section_begin),hex(loadAddr)))
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return (loadAddr,section_begin,section_size,section)
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f1 = open(sys.argv[1],"rb")
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f2 = open(sys.argv[2],"rb")
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f = open(sys.argv[3],"wb")
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arm9_entry,arm9_section_beg,arm9_section_size,arm9_section = get_elf_seg(f1)
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arm11_entry,arm11_section_beg,arm11_section_size,arm11_section = get_elf_seg(f2)
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def align(a,b):
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if a % b:
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return a + b - (a%b)
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return a
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def align2(a,b):
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if len(a) % b:
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return a + bytes(512-(len(a)%b))
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return a
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arm9_section_size=align(arm9_section_size,512)
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arm11_section_size=align(arm11_section_size,512)
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arm9_section=align2(arm9_section,512)
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arm11_section=align2(arm11_section,512)
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arm9_hash=hashlib.sha256(arm9_section).digest()
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arm11_hash=hashlib.sha256(arm11_section).digest()
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arm9_off = 0x200
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arm11_off = 0x200+arm9_section_size
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f.write(b'FIRM')
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f.write(struct.pack("<III",0,arm11_entry,arm9_entry))
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f.write(b'\x00'*0x30)
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def write_seg(section_beg, section_size, hash, off):
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f.write(struct.pack("<IIII",off,section_beg,section_size,2))
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f.write(hash)
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write_seg(arm9_section_beg,arm9_section_size,arm9_hash,arm9_off)
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write_seg(arm11_section_beg,arm11_section_size,arm11_hash,arm11_off)
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f.write(b'\x00'*0x60)
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f.write(sighax_sig)
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f.write(arm9_section)
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f.write(arm11_section)
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