100 lines
2.9 KiB
NASM
100 lines
2.9 KiB
NASM
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; © 2023-2024 John Breaux
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; Comtains spoilers for Microcorruption Halifax! Be warned!
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; just hash the first 0x140 B and stick them in memory
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const:
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.define msize 0x1 ; length of each hash in bytes
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.define hsize 0x3 ; bytes kept per hash (only needs to be 3 to determine 1 byte of sram)
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.define sr_len 0x140 ; number of bytes in sram to dump
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.define ha_len 0x3c0 ; number of bytes in hash array (hsize * sr_len)
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.define haddr 0x7000 ; address of the big hash array
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.define iaddr 0x8000 ; address of the sram input buffer
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.define kaddr 0x9000 ; address of the key buffer
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external_data:
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.define HEX_LUT 0x4710; "0123456789ABCDEF"
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external_func:
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; INT(int interrupt, ...)
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.define INT #0x4550
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; getsn(void *dest, size_t len)
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.define getsn #0x4568
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; putchar(char character)
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.define putchar #0x4578
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; puts(char *str)
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.define puts #0x4586
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; memcpy(void *dest, void *src, size_t len)
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.define memcpy #0x45a4
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; sha256_internal(void * sram_addr, size_t sr_len, void * sha_buf)
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.define sha256_internal #0x45b6
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; memset(void* buf, char value, size_t length)
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.define memset #0x45c8
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get_sram_hashes:
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clr r11 ; loop variable in r11
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mov #msize, r14 ; r14 = 1
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mov #haddr, r13 ; set destination to 0x8000
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sr_loop:
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mov r11, r15 ; mov addr r15
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call sha256_internal ; <sha256_internal>
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add #hsize, r13 ; keep 3 bytes of the output
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inc r11 ; inc r11
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cmp #sr_len, r11 ; do that 0x1000 times
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jnc sr_loop
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print_hex:
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clr r11;
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ph_loop:
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mov.b haddr(r11), r14
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mov.b r14, r15
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rra r15 ; using rra here instead of rra.b means the value won't roll into the highest bit
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rra r15 ; which negates the need to and 0xf, r15
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rra r15
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rra r15
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clrc
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and #0xf, r14
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mov.b HEX_LUT(r15), r15
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call putchar ; <putchar>
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mov.b HEX_LUT(r14), r15
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call putchar ; <putchar>
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inc r11 ; inc r11
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cmp #ha_len, r11 ; do that sram_length*3 times
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jnc ph_loop
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mov.b #0xa, r15 ; '\n'
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call #0x4578 ; putchar ('\n')
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take_input:
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mov #sr_len, r14
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mov #iaddr, r15
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call getsn ; <getsn>
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check_all_passwords:
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;for i in 0..sr_len:
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clr r9
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pw_loop:
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; memcpy(kaddr, iaddr + i, len)
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mov #0x10, r13
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mov #iaddr, r14
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add r9, r14
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mov #kaddr, r15
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call memcpy
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; INT (0x42, key)
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push #kaddr
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push #0x42
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call INT
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add #4, sp
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; INT(7f)
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unlock7f:
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push #0
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push #0
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push #0x7f
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call INT
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add #6, sp
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inc r9
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cmp #sr_len, r9
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jl pw_loop
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end:
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ret
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