YJN/selfpatch-slr
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selfpatch instruction dispatcher

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York Jasper Niebuhr 2025-10-26 22:06:03 +01:00
parent a3191d6101
commit 10e56ffd47
1 changed files with 49 additions and 4 deletions
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53
selfpatch/src/selfpatch.c
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@ -4,14 +4,59 @@
#include <spslr_program.h>
// TODO
static int spslr_target(uint32_t uid, uint32_t size, uint32_t fieldcnt) { return 0; }
static int spslr_field(uint32_t offset, uint32_t size, uint32_t flags) { return 0; }
static int spslr_randomize(uint32_t target) { return 0; }
static int spslr_mprot(void* base, uint32_t pagecnt, uint8_t perm) { return 0; }
static int spslr_ipatch(void* ptr, uint32_t target, uint32_t field) { return 0; }
static int spslr_dpatch(void* ptr, uint32_t target) { return 0; }
/*
To allow ASLR, all patcher addresses are relative to &__spslr_program
Postprocessing tool patches the value of __spslr_program to point to the SPSLR program section.
With ASLR, there are 2 options to make it function correctly:
1. Make sure __spslr_program is relocated with program image shift (preferred)
2. __spslr_program = spslr_ptr_absolute((uint64_t)__spslr_program) and postprocessor inserts relative value (kinda weird)
*/
const uint8_t* __spslr_program = NULL;
static const uint8_t* __spslr_program = NULL;
static void* spslr_ptr_absolute(uint64_t relative) {
// To allow ASLR, all patcher addresses are relative to &__spslr_program
return ((uint8_t*)&__spslr_program) + relative;
}
static int spslr_do(const struct SPSLR_INST* inst) {
// TODO -> dispatch different instructions, make args/pointers absolute
return 0;
if (!inst)
return -1;
static uint32_t pending_fields = 0;
if (pending_fields) {
if (inst->opcode != SPSLR_FIELD) {
fprintf(stderr, "spslr_do encountered non field instruction where a field instruction was expected\n");
return -1;
}
pending_fields--;
}
switch (inst->opcode) {
case SPSLR_TARGET:
pending_fields = inst->op2.target_fieldcnt;
return spslr_target(inst->op0.target_uid, inst->op1.target_size, inst->op2.target_fieldcnt);
case SPSLR_FIELD:
return spslr_field(inst->op0.field_offset, inst->op1.field_size, inst->op2.field_flags);
case SPSLR_RANDOMIZE:
return spslr_randomize(inst->op0.randomize_target);
case SPSLR_MPROT:
return spslr_mprot(spslr_ptr_absolute(inst->op0.mprot_ptr), inst->op1.mprot_pagecnt, inst->op2.mprot_perm);
case SPSLR_IPATCH:
return spslr_ipatch(spslr_ptr_absolute(inst->op0.ipatch_ptr), inst->op1.ipatch_target, inst->op2.ipatch_field);
case SPSLR_DPATCH:
return spslr_dpatch(spslr_ptr_absolute(inst->op0.dpatch_ptr), inst->op1.dpatch_target);
default:
return -1;
}
}
void spslr_selfpatch() {