Files
vphone-cli/scripts/patchers/kernel_patch_bsd_init.py

47 lines
1.8 KiB
Python

"""Mixin: bsd_init rootvp patch."""
from .kernel_asm import MOV_X0_0, NOP
class KernelPatchBsdInitMixin:
def patch_bsd_init_rootvp(self):
"""Patch 3: NOP the conditional branch guarding the 'rootvp not authenticated' panic."""
self._log("\n[3] _bsd_init: rootvp not authenticated panic")
str_off = self.find_string(b"rootvp not authenticated after mounting")
if str_off < 0:
self._log(" [-] string not found")
return False
refs = self.find_string_refs(str_off, *self.kern_text)
if not refs:
self._log(" [-] no code refs in kernel __text")
return False
for adrp_off, add_off, _ in refs:
# Find the BL _panic after the string ref
bl_panic_off = -1
for scan in range(add_off, min(add_off + 0x40, self.size), 4):
bl_target = self._is_bl(scan)
if bl_target == self.panic_off:
bl_panic_off = scan
break
if bl_panic_off < 0:
continue
# Search backwards for a conditional branch whose target is in
# the error path (the block ending with BL _panic).
# The error path is typically a few instructions before BL _panic.
err_lo = bl_panic_off - 0x40 # error block start (generous)
err_hi = bl_panic_off + 4 # error block end
for back in range(adrp_off - 4, max(adrp_off - 0x400, 0), -4):
target, kind = self._decode_branch_target(back)
if target is not None and err_lo <= target <= err_hi:
self.emit(back, NOP, f"NOP {kind} (rootvp auth) [_bsd_init]")
return True
self._log(" [-] conditional branch into panic path not found")
return False