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"""Tests for the x86/x86-64 labeled-taint tracker."""
import pytest
from ablation.analyzers.taint_tracker_x86_labeled import (
CLEAN, Finding, Policy, Taint, TaintState, TaintTracker,
)
from ablation.analyzers.insn_x86 import from_listing
from ablation.analyzers.isa_x86 import Abi, Mode
# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------
def run(listing, mode=Mode.X64, taints=(("rdi", "user"),), policy=None, mem=()):
t = TaintTracker(mode, policy=policy)
for r, l in taints:
t.taint_register(r, l)
for b, off, l in mem:
t.taint_memory(b, off, l)
t.run(list(from_listing(listing)))
return t
def run32(listing, taints=(("eax", "user"),), policy=None):
return run(listing, mode=Mode.X86, taints=taints, policy=policy)
def kinds(t):
return [f.kind for f in t.findings]
# ---------------------------------------------------------------------------
# Copies
# ---------------------------------------------------------------------------
def test_mov_reg_reg_propagates():
t = run("mov rax, rdi")
assert t.state.get("rax").labels == {"user"}
def test_mov_reg_reg_32_zext():
t = run("mov edi, edi", taints=(("rdi", "user"),))
assert t.state.get("rdi").labels == {"user"}
def test_movzx_bounds_byte():
t = run("movzx eax, dil")
assert t.state.get("rax").bound == 0xFF
def test_movzx_bounds_word():
t = run("movzx eax, di")
assert t.state.get("rax").bound == 0xFFFF
def test_movsx_drops_bound():
t = run("movzx eax, dil\n movsxd rax, eax")
assert t.state.get("rax").tainted
assert t.state.get("rax").bound is None
def test_xchg_swaps():
t = run("xchg rax, rdi", taints=(("rdi", "user"),))
assert t.state.get("rax").labels == {"user"}
assert not t.state.get("rdi").tainted
# ---------------------------------------------------------------------------
# Zero idioms
# ---------------------------------------------------------------------------
def test_xor_self_clears():
t = run("mov rax, rdi\n xor eax, eax")
assert not t.state.get("rax").tainted
def test_sub_self_clears():
t = run("mov rax, rdi\n sub rax, rax")
assert not t.state.get("rax").tainted
def test_xor_self_sets_const_zero():
t = run("xor eax, eax", taints=())
# In x64 mode, eax family is rax
assert t.state.consts.get(t.state.fam("eax")) == 0
# ---------------------------------------------------------------------------
# Bounds (and / shl / shr / imul)
# ---------------------------------------------------------------------------
def test_and_positive_imm_bounds():
t = run("and rdi, 0xff\n mov rax, rdi")
assert t.state.get("rax").bound == 0xFF
def test_and_alignment_mask_no_bound():
t = run("and rsp, -16", taints=(("rsp", "u"),))
assert t.state.get("rsp").bound is None
<
10BC8
/div>def test_shl_scales_bound():
t = run("and rdi, 0xff\n shl rdi, 3")
assert t.state.get("rdi").bound == 0xFF << 3
def test_shr_shrinks_bound():
t = run("and rdi, 0xff\n shr rdi, 2")
assert t.state.get("rdi").bound == 0xFF >> 2
def test_imul_imm_scales_bound():
t = run("and rdi, 0xff\n imul rax, rdi, 8")
assert t.state.get("rax").bound == 0xFF * 8
def test_bounded_load_not_reported():
t = run("and rdi, 0xff\n add rax, rdi\n mov rbx, [rax]",
taints=(("rdi", "user"),))
assert "tainted-load-address" not in kinds(t)
def test_unbounded_load_reported():
t = run("add rax, rdi\n mov rbx, [rax]",
taints=(("rdi", "user"),))
assert "tainted-load-address" in kinds(t)
# ---------------------------------------------------------------------------
# LEA
# ---------------------------------------------------------------------------
def test_lea_tainted_base_propagates_bound():
t = run("and rdi, 0xff\n lea rax, [rdi + 16]")
# disp is constant; bound tracks attacker contribution only
assert t.state.get("rax").bound == 0xFF
def test_lea_rip_relative_is_const():
t = run("lea rax, [rip + 0x100]", taints=())
assert t.state.consts.get("rax") is not None
# ---------------------------------------------------------------------------
# Stack frame tracking
# ---------------------------------------------------------------------------
def test_spill_reload():
t = run("""
sub rsp, 32
mov [rsp+8], rdi
sub rsp, 16
mov rax, [rsp+24]
add rsp, 48
""")
assert t.state.get("rax").labels == {"user"}
def test_rbp_alias():
t = run("""
push rbp
mov rbp, rsp
sub rsp, 32
mov [rbp-8], rdi
mov rax, [rbp-8]
""")
assert t.state.get("rax").labels == {"user"}
def test_leave_restores_rbp():
t = run("""
push rbp
mov rbp, rsp
sub rsp, 32
mov [rbp-8], rdi
leave
""")
def test_saved_ra_overwrite_reported():
# Entry RA is at (rsp, 0). sub rsp,16 rebases it to (rsp, 16). Write there fires.
t = run("""
sub rsp, 16
mov [rsp+16], rdi
""")
assert "tainted-overwrite-of-saved-ra" in kinds(t)
# ---------------------------------------------------------------------------
# Push / pop
# ---------------------------------------------------------------------------
def test_push_pop_round_trip():
t = run("push rdi\n pop rax")
assert t.state.get("rax").labels == {"user"}
def test_push_imm_is_clean():
t = run("push 42")
sp = t.state.mode.sp
assert not t.state.mem_get(sp, 0).tainted
# ---------------------------------------------------------------------------
# Call ABI
# ---------------------------------------------------------------------------
def test_call_clobbers_caller_saved():
t = run("mov rcx, rdi\n mov r10, rdi\n call 0x20000")
assert not t.state.get("rcx").tainted
assert not t.state.get("r10").tainted
def test_call_preserves_callee_saved():
t = run("mov rbx, rdi\n call 0x20000")
assert t.state.get("rbx").labels == {"user"}
def test_call_tainted_arg_taints_return():
t = run("call 0x20000")
assert t.state.get("rax").tainted
def test_call_clean_args_clean_return():
t = run("xor edi, edi\n call 0x20000")
assert not t.state.get("rax").tainted
def test_indirect_call_reported():
t = run("call rdi")
assert "tainted-indirect-call" in kinds(t)
def test_indirect_jump_reported():
t = run("jmp rdi")
assert "tainted-indirect-jump" in kinds(t)
# ---------------------------------------------------------------------------
# Return address
# ---------------------------------------------------------------------------
def test_ret_tainted_ra_reported():
# Write directly over the RA slot (rsp+0 at entry), then ret reads it back.
t = run("""
mov [rsp], rdi
ret
""")
assert "tainted-return-address" in kinds(t)
# ---------------------------------------------------------------------------
# Syscall
# ---------------------------------------------------------------------------
def test_syscall_read_taints_buffer():
t = run("""
xor eax, eax
xor edi, edi
sub rsp, 64
lea rsi, [rsp+16]
mov edx, 32
syscall
mov al, [rsp+16]
mov bl, [rsp+47]
mov cl, [rsp+48]
mov rdx, rax
""", taints=())
assert t.state.get("al").tainted
assert t.state.get("bl").tainted
assert not t.state.get("cl").tainted
assert t.state.get("rdx").tainted
def test_tainted_syscall_arg_reported():
t = run("mov eax, 1\n mov rdx, rdi\n syscall")
assert "tainted-syscall-arg" in kinds(t)
def test_tainted_syscall_nr_reported():
t = run("mov rax, rdi\n syscall")
assert "tainted-syscall-number" in kinds(t)
# ---------------------------------------------------------------------------
# int 0x80 (i386 syscall in 64-bit mode)
# ---------------------------------------------------------------------------
def test_int80_uses_i386_table():
# SYS_read = 3 in i386 table; eax=3 triggers the buffer taint
t = run("""
mov eax, 3
xor ebx, ebx
sub rsp, 64
lea ecx, [rsp+16]
mov edx, 32
int 0x80
mov al, [rsp+16]
""", taints=())
assert t.state.get("al").tainted
# ---------------------------------------------------------------------------
# String instructions
# ---------------------------------------------------------------------------
def test_rep_movsb_propagates():
t = run("""
sub rsp, 64
mov [rsp+8], rdi
lea rsi, [rsp+8]
lea rdi, [rsp+32]
mov ecx, 16
rep movsb
mov rax, [rsp+32]
""", taints=(("rsi", "user"), ("rdi", "user")))
def test_rep_count_tainted_reported():
t = run("rep movsb", taints=(("ecx", "user"),),
policy=Policy(report_rep_count=True))
assert "tainted-rep-count" in kinds(t)
# ---------------------------------------------------------------------------
# cmov / setcc
# ---------------------------------------------------------------------------
def test_cmovz_merges_both_paths():
t = run("cmovz rax, rdi", taints=(("rdi", "user"),))
assert t.state.get("rax").tainted
def test_setne_from_clean_flags():
t = run("cmp rax, 0\n setne al", taints=())
assert not t.state.get("rax").tainted
def test_setne_from_tainted_flags():
t = run("cmp rdi, 0\n setne al")
assert t.state.get("rax").tainted
assert t.state.get("rax").bound == 1
# ---------------------------------------------------------------------------
# Widening (cbw / cwde / cdqe / cwd / cdq / cqo)
# ---------------------------------------------------------------------------
def test_cdqe_widens_eax():
t = run("movzx eax, dil\n cdqe")
assert t.state.get("rax").tainted
def test_cqo_taints_rdx():
t = run("mov rax, rdi\n cqo")
assert t.state.get("rdx").tainted
# ---------------------------------------------------------------------------
# mul / div implicit
# ---------------------------------------------------------------------------
def test_mul_taints_rdx_rax():
t = run("mul rdi")
assert t.state.get("rdx").tainted
assert t.state.get("rax").tainted
def test_div_taints_quotient_remainder():
t = run("mov rax, rdi\n div rcx", taints=(("rdi", "u"), ("rcx", "v")))
assert t.state.get("rax").tainted
assert t.state.get("rdx").tainted
# ---------------------------------------------------------------------------
# Branch condition reporting
# ---------------------------------------------------------------------------
def test_branch_reporting_opt_in():
assert kinds(run("cmp rdi, 0\n je 0x1000c")) == []
assert "tainted-branch-condition" in kinds(
run("cmp rdi, 0\n je 0x1000c", policy=Policy(report_tainted_branch=True))
)
# ---------------------------------------------------------------------------
# 32-bit mode (i386 cdecl)
# ---------------------------------------------------------------------------
def test_32bit_copy():
t = run32("mov ecx, eax")
assert t.state.get("ecx").labels == {"user"}
def test_32bit_stack_spill():
t = run32("""
sub esp, 16
mov [esp+4], eax
mov ecx, [esp+4]
""")
assert t.state.get("ecx").labels == {"user"}
def test_32bit_syscall_read_taints_buffer():
# SYS_read = 3 in i386 table
t = run32("""
mov eax, 3
xor ebx, ebx
sub esp, 64
lea ecx, [esp+16]
mov edx, 32
int 0x80
mov al, [esp+16]
""", taints=())
assert t.state.get("eax").tainted
# ---------------------------------------------------------------------------
# TaintState lattice
# ---------------------------------------------------------------------------
def test_join_unions_labels():
a = TaintState(Mode.X64); a.taint_reg("rax", "x")
b = TaintState(Mode.X64); b.taint_reg("rax", "y")
j = a.join(b)
assert j.get("rax").labels == {"x", "y"}
def test_join_two_bounds_takes_max():
a = TaintState(Mode.X64); a.regs["rax"] = Taint(frozenset({"x"}), 0x0F)
b = TaintState(Mode.X64); b.regs["rax"] = Taint(frozenset({"x"}), 0xFF)
j = a.join(b)
assert j.get("rax").bound == 0xFF
def test_join_widen_different_bounds_becomes_none():
a = TaintState(Mode.X64); a.regs["rax"] = Taint(frozenset({"x"}), 0x0F)
b = TaintState(Mode.X64); b.regs["rax"] = Taint(frozenset({"x"}), 0xFF)
j = a.join(b, widen=True)
assert j.get("rax").bound is None
def test_join_mem_union():
a = TaintState(Mode.X64); a.mem[("rsp", 8)] = Taint(frozenset({"x"}), None)
b = TaintState(Mode.X64); b.mem[("rsp", 16)] = Taint(frozenset({"y"}), None)
j = a.join(b)
assert j.mem_get("rsp", 8).tainted
assert j.mem_get("rsp", 16).tainted
def test_join_consts_intersect():
a = TaintState(Mode.X64); a.consts["rax"] = 5
b = TaintState(Mode.X64); b.consts["rax"] = 7
j = a.join(b)
assert "rax" not in j.consts
def test_join_consts_equal_survive():
a = TaintState(Mode.X64); a.consts["rax"] = 5
b = TaintState(Mode.X64); b.consts["rax"] = 5
j = a.join(b)
assert j.consts.get("rax") == 5
def test_same_as_true_on_copy():
a = TaintState(Mode.X64); a.taint_reg("rax", "x")
b = a.copy()
assert a.same_as(b)
def test_same_as_false_after_modify():
a = TaintState(Mode.X64); a.taint_reg("rax", "x")
b = a.copy(); b.taint_reg("rbx", "y")
assert not a.same_as(b)
def test_copy_is_independent():
a = TaintState(Mode.X64); a.taint_reg("rax", "x")
b = a.copy()
b.taint_reg("rcx", "z")
assert not a.get("rcx").tainted
# ---------------------------------------------------------------------------
# Policy knobs
# ---------------------------------------------------------------------------
def test_bounded_index_safe_suppresses_load():
p = Policy(bounded_index_is_safe=True)
t = run("and rdi, 0xff\n add rax, rdi\n mov rbx, [rax]", policy=p)
assert "tainted-load-address" not in kinds(t)
def test_bounded_index_unsafe_reports_load():
p = Policy(bounded_index_is_safe=False)
t = run("and rdi, 0xff\n add rax, rdi\n mov rbx, [rax]", policy=p)
assert "tainted-load-address" in kinds(t)
def test_report_bounded_emits_bounded_kind():
p = Policy(report_bounded=True)
t = run("and rdi, 0xff\n add rax, rdi\n mov rbx, [rax]", policy=p)
assert any("bounded-tainted-load-address" in f.kind for f in t.findings)
def test_unknown_mnemonic_conservative():
t = run("frobnop rax, rdi")
assert t.state.get("rax").tainted
assert "frobnop" in t.unknown
# ---------------------------------------------------------------------------
# Win64 ABI
# ---------------------------------------------------------------------------
def test_win64_abi_arg_regs():
t = TaintTracker(Mode.X64, abi=Abi.WIN64)
t.taint_register("rcx", "win-user")
insns = list(from_listing("call 0x20000"))
t.run(insns)
assert t.state.get("rax").tainted
def test_win64_preserves_rsi_rdi():
t = TaintTracker(Mode.X64, abi=Abi.WIN64)
t.taint_register("rsi", "s")
t.taint_register("rdi", "s")
t.run(list(from_listing("call 0x20000")))
assert t.state.get("rsi").tainted
assert t.state.get("rdi").tainted
# ---------------------------------------------------------------------------
# Taint through pointer
# ---------------------------------------------------------------------------
def test_taint_memory_slot_and_load():
t = TaintTracker(Mode.X64)
t.taint_memory("rsp", 8, "net")
t.run(list(from_listing("mov rax, [rsp+8]")))
assert t.state.get("rax").tainted
def test_taint_pointee_cdecl_model():
t = TaintTracker(Mode.X86)
t.taint_pointee("esp", 4, "net", length=32)
insns = list(from_listing("""
mov ecx, [esp+4]
mov al, [ecx]
"""))
t.run(insns)
assert t.state.get("eax").tainted