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reimplement inject overflow check

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This commit is contained in:
Connor Olding 2016-01-10 12:37:35 -08:00
parent 8f599e1e9f
commit 5b11974962
1 changed files with 21 additions and 17 deletions
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38
Lua/inject.lua
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@ -32,9 +32,9 @@ local injection_points = {
}
injection_points['O JP10'] = injection_points['O US10']
local header = [[
[overwritten]: 0x%08X
// note: this will fail when the overwritten function takes args on stack
local hook = [[
[hooked]: 0x%08X
// note: this will fail when the hooked function takes args on stack
sw ra, -4(sp)
sw a0, 0(sp)
sw a1, 4(sp)
@ -47,7 +47,7 @@ local header = [[
lw a1, 24(sp)
lw a2, 28(sp)
lw a3, 32(sp)
j @overwritten
j @hooked
addi sp, sp, 20
start:
]]
@ -71,6 +71,8 @@ function inject(fn)
-- what its value is normally supposed to be
local ow_before = point.ow_before
local inject_end = inject_addr + inject_maxlen
-- encode our jal instruction
local ow_after = 0x0C000000 + math.floor(inject_addr/4)
if R4(ow_addr) ~= ow_before and R4(ow_addr) ~= ow_after then
@ -81,36 +83,38 @@ function inject(fn)
-- decode the original address
local ow_before_addr = (ow_before % 0x4000000)*4
-- set up a header to handle calling our function and the original
local header = header:format(ow_before_addr)
-- set up a hook to handle calling our function and the original
local hook = hook:format(ow_before_addr)
local inject_bytes = {}
local length = 0
local size = 0
local cons_pos = inject_addr
local function write(pos, line)
length = length + #line/2
assert(#line == 2, "that ain't const")
dprint(("%08X"):format(pos), line)
pos = pos % 0x80000000
size = size + 1
if pos > cons_pos and (pos < inject_end or cons_pos == pos - 1) then
cons_pos = pos
end
inject_bytes[pos] = tonumber(line, 16)
end
-- offset assembly labels so they work properly, and assemble!
local true_offset = 0x80000000 + inject_addr
assemble(header, write, {unsafe=true, offset=true_offset})
assemble(asm_path, write, {unsafe=true, offset=true_offset + length})
assemble(hook, write, {unsafe=true, offset=true_offset})
assemble(asm_path, write, {unsafe=true, offset=true_offset + size})
printf("length: %i words", length/4)
--[[
-- FIXME: this only works properly when the asm doesn't use any .orgs
if length > inject_maxlen then
print_deferred()
printf("size: %i words", size/4)
if cons_pos >= inject_end then
print("Assembly too large!")
return
print("The game will probably crash.")
end
--]]
for pos, val in pairs(inject_bytes) do
W1(pos, val)
end
print_deferred()
-- finally, write our new jump over the original
printf('%08X: %08X', ow_addr, ow_after)