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author | Kartik Agaram <vc@akkartik.com> | 2019-09-19 15:26:24 -0700 |
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committer | Kartik Agaram <vc@akkartik.com> | 2019-09-19 15:26:24 -0700 |
commit | dc8790941e39efb25c40de0420fdd4bce03f2761 (patch) | |
tree | e14e01797522c3027d5e343db50c4427950bb1e1 /034check_operand_bounds.cc | |
parent | 68666b07b88fb4d72ff824550dd271b84520fdf5 (diff) | |
download | mu-dc8790941e39efb25c40de0420fdd4bce03f2761.tar.gz |
5670
Diffstat (limited to '034check_operand_bounds.cc')
-rw-r--r-- | 034check_operand_bounds.cc | 143 |
1 files changed, 143 insertions, 0 deletions
diff --git a/034check_operand_bounds.cc b/034check_operand_bounds.cc new file mode 100644 index 00000000..72a66e3f --- /dev/null +++ b/034check_operand_bounds.cc @@ -0,0 +1,143 @@ +//:: Check that the different operands of an instruction aren't too large for their bitfields. + +void test_check_bitfield_sizes() { + Hide_errors = true; + run( + "== code 0x1\n" + "01/add 4/mod 3/rm32 1/r32\n" // add ECX to EBX + ); + CHECK_TRACE_CONTENTS( + "error: '4/mod' too large to fit in bitfield mod\n" + ); +} + +:(before "End Globals") +map<string, uint32_t> Operand_bound; +:(before "End One-time Setup") +put_new(Operand_bound, "subop", 1<<3); +put_new(Operand_bound, "mod", 1<<2); +put_new(Operand_bound, "rm32", 1<<3); +put_new(Operand_bound, "base", 1<<3); +put_new(Operand_bound, "index", 1<<3); +put_new(Operand_bound, "scale", 1<<2); +put_new(Operand_bound, "r32", 1<<3); +put_new(Operand_bound, "disp8", 1<<8); +put_new(Operand_bound, "disp16", 1<<16); +// no bound needed for disp32 +put_new(Operand_bound, "imm8", 1<<8); +// no bound needed for imm32 + +:(before "Pack Operands(segment code)") +check_operand_bounds(code); +if (trace_contains_errors()) return; +:(code) +void check_operand_bounds(const segment& code) { + trace(3, "transform") << "-- check operand bounds" << end(); + for (int i = 0; i < SIZE(code.lines); ++i) { + const line& inst = code.lines.at(i); + for (int j = first_operand(inst); j < SIZE(inst.words); ++j) + check_operand_bounds(inst.words.at(j)); + if (trace_contains_errors()) return; // stop at the first mal-formed instruction + } +} + +void check_operand_bounds(const word& w) { + for (map<string, uint32_t>::iterator p = Operand_bound.begin(); p != Operand_bound.end(); ++p) { + if (!has_operand_metadata(w, p->first)) continue; + if (!looks_like_hex_int(w.data)) continue; // later transforms are on their own to do their own bounds checking + int32_t x = parse_int(w.data); + if (x >= 0) { + if (p->first == "disp8" || p->first == "disp16") { + if (static_cast<uint32_t>(x) >= p->second/2) + raise << "'" << w.original << "' too large to fit in signed bitfield " << p->first << '\n' << end(); + } + else { + if (static_cast<uint32_t>(x) >= p->second) + raise << "'" << w.original << "' too large to fit in bitfield " << p->first << '\n' << end(); + } + } + else { + // hacky? assuming bound is a power of 2 + if (x < -1*static_cast<int32_t>(p->second/2)) + raise << "'" << w.original << "' too large to fit in bitfield " << p->first << '\n' << end(); + } + } +} + +void test_check_bitfield_sizes_for_imm8() { + run( + "== code 0x1\n" + "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX 0xff/imm8" // shift EBX left + ); + CHECK(!trace_contains_errors()); +} + +void test_check_bitfield_sizes_for_imm8_error() { + Hide_errors = true; + run( + "== code 0x1\n" + "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX 0x100/imm8" // shift EBX left + ); + CHECK_TRACE_CONTENTS( + "error: '0x100/imm8' too large to fit in bitfield imm8\n" + ); +} + +void test_check_bitfield_sizes_for_negative_imm8() { + run( + "== code 0x1\n" + "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX -0x80/imm8" // shift EBX left + ); + CHECK(!trace_contains_errors()); +} + +void test_check_bitfield_sizes_for_negative_imm8_error() { + Hide_errors = true; + run( + "== code 0x1\n" + "c1/shift 4/subop/left 3/mod/direct 1/rm32/ECX -0x81/imm8" // shift EBX left + ); + CHECK_TRACE_CONTENTS( + "error: '-0x81/imm8' too large to fit in bitfield imm8\n" + ); +} + +void test_check_bitfield_sizes_for_disp8() { + // not bothering to run + transform( + "== code 0x1\n" + "01/add 1/mod/*+disp8 3/rm32 1/r32 0x7f/disp8\n" // add ECX to *(EBX+0x7f) + ); + CHECK(!trace_contains_errors()); +} + +void test_check_bitfield_sizes_for_disp8_error() { + Hide_errors = true; + run( + "== code 0x1\n" + "01/add 1/mod/*+disp8 3/rm32 1/r32 0x80/disp8\n" // add ECX to *(EBX+0x80) + ); + CHECK_TRACE_CONTENTS( + "error: '0x80/disp8' too large to fit in signed bitfield disp8\n" + ); +} + +void test_check_bitfield_sizes_for_negative_disp8() { + // not bothering to run + transform( + "== code 0x1\n" + "01/add 1/mod/*+disp8 3/rm32 1/r32 -0x80/disp8\n" // add ECX to *(EBX-0x80) + ); + CHECK(!trace_contains_errors()); +} + +void test_check_bitfield_sizes_for_negative_disp8_error() { + Hide_errors = true; + run( + "== code 0x1\n" + "01/add 1/mod/*+disp8 3/rm32 1/r32 -0x81/disp8\n" // add ECX to *(EBX-0x81) + ); + CHECK_TRACE_CONTENTS( + "error: '-0x81/disp8' too large to fit in bitfield disp8\n" + ); +} |