T0b1/fadec
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

encode: Fix encoding of memory operand

Browse Source 
When a modrm_idx is used without a ModRM being present, the encoder
attempted to encode memory operands using O/OA/AO encodings.
This commit is contained in:
Alexis Engelke
2021-04-02 10:54:04 +02:00
parent 51ffe2598e
commit 2d9587bc16
2 changed files with 5 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
parseinstrs.py
View File

@@ -142,7 +142,7 @@ class InstrDesc(NamedTuple):
def optype_str(self): def optype_str(self):
optypes = ["", "", "", ""] optypes = ["", "", "", ""]
flags = ENCODINGS[self.encoding] flags = ENCODINGS[self.encoding]
if flags.modrm_idx: optypes[flags.modrm_idx^3] = "M" if flags.modrm_idx: optypes[flags.modrm_idx^3] = "rM"[flags.modrm]
if flags.modreg_idx: optypes[flags.modreg_idx^3] = "r" if flags.modreg_idx: optypes[flags.modreg_idx^3] = "r"
if flags.vexreg_idx: optypes[flags.vexreg_idx^3] = "r" if flags.vexreg_idx: optypes[flags.vexreg_idx^3] = "r"
if flags.zeroreg_idx: optypes[flags.zeroreg_idx^3] = "r" if flags.zeroreg_idx: optypes[flags.zeroreg_idx^3] = "r"

5
tests/test_encode.c
View File

@@ -82,6 +82,8 @@ main(int argc, char** argv)
TEST("\x66\x0f\xa0", FE_PUSH16r, FE_FS); TEST("\x66\x0f\xa0", FE_PUSH16r, FE_FS);
TEST("\x0f\xa8", FE_PUSHr, FE_GS); TEST("\x0f\xa8", FE_PUSHr, FE_GS);
TEST("\x66\x0f\xa8", FE_PUSH16r, FE_GS); TEST("\x66\x0f\xa8", FE_PUSH16r, FE_GS);
TEST("\xff\x30", FE_PUSHm, FE_MEM(FE_AX, 0, 0, 0));
TEST("\xff\x31", FE_PUSHm, FE_MEM(FE_CX, 0, 0, 0));
TEST("\x9c", FE_PUSHF); TEST("\x9c", FE_PUSHF);
TEST("\xd2\xe4", FE_SHL8rr, FE_AH, FE_CX); TEST("\xd2\xe4", FE_SHL8rr, FE_AH, FE_CX);
TEST("", FE_SHL8rr, FE_AH, FE_DX); TEST("", FE_SHL8rr, FE_AH, FE_DX);
@@ -90,7 +92,6 @@ main(int argc, char** argv)
TEST("\xc1\xe0\x02", FE_SHL32ri, FE_AX, 2); TEST("\xc1\xe0\x02", FE_SHL32ri, FE_AX, 2);
TEST("\x48\xc1\xe0\x02", FE_SHL64ri, FE_AX, 2); TEST("\x48\xc1\xe0\x02", FE_SHL64ri, FE_AX, 2);
TEST("\x48\xf7\x28", FE_IMUL64m, FE_MEM(FE_AX, 0, 0, 0)); TEST("\x48\xf7\x28", FE_IMUL64m, FE_MEM(FE_AX, 0, 0, 0));
// TEST("\x66\x90", FE_XCHG16rr, FE_AX, FE_AX);
TEST("\xc2\x00\x00", FE_RETi, 0); TEST("\xc2\x00\x00", FE_RETi, 0);
TEST("\xff\xd0", FE_CALLr, FE_AX); TEST("\xff\xd0", FE_CALLr, FE_AX);
TEST("\x05\x00\x01\x00\x00", FE_ADD32ri, FE_AX, 0x100); TEST("\x05\x00\x01\x00\x00", FE_ADD32ri, FE_AX, 0x100);
@@ -134,6 +135,8 @@ main(int argc, char** argv)
TEST("\x66\x90", FE_XCHG16rr, FE_AX, FE_AX); TEST("\x66\x90", FE_XCHG16rr, FE_AX, FE_AX);
TEST("\x87\xc0", FE_XCHG32rr, FE_AX, FE_AX); TEST("\x87\xc0", FE_XCHG32rr, FE_AX, FE_AX);
TEST("\x48\x90", FE_XCHG64rr, FE_AX, FE_AX); TEST("\x48\x90", FE_XCHG64rr, FE_AX, FE_AX);
TEST("\x87\x00", FE_XCHG32mr, FE_MEM(FE_AX, 0, 0, 0), FE_AX);
TEST("\x87\x08", FE_XCHG32mr, FE_MEM(FE_AX, 0, 0, 0), FE_CX);
TEST("\x90", FE_NOP); TEST("\x90", FE_NOP);
TEST("\x0f\x1f\xc0", FE_NOP32r, FE_AX); TEST("\x0f\x1f\xc0", FE_NOP32r, FE_AX);
TEST("\x26\x01\x00", FE_ADD32mr|FE_SEG(FE_ES), FE_MEM(FE_AX, 0, 0, 0), FE_AX); TEST("\x26\x01\x00", FE_ADD32mr|FE_SEG(FE_ES), FE_MEM(FE_AX, 0, 0, 0), FE_AX);