arno
/
bddisasm
mirror of https://github.com/bitdefender/bddisasm.git
1
0
Fork 0
Code Issues Releases Wiki Activity

Added some comments.

Browse Source
pull/79/head
BITDEFENDER\vlutas 1 year ago
parent 089e6d5e7e
commit 0093439855
1 changed files with 45 additions and 0 deletions
Show Stats Download Patch File Download Diff File

45
disasmtool/disasmtool.c
Unescape View File

@ -495,6 +495,7 @@ hex_to_bin(
__in char HexByte
)
{
// Transforms one hex-digit to a number.
if ((HexByte >= '0') && (HexByte <= '9'))
{
return HexByte - '0';
@ -542,6 +543,7 @@ match_gpr(
__out DWORD* Index
)
{
// Check if the provided argument is a register.
if (Arg[0] == '-')
{
INT32 idx = regstr_to_idx(Arg + 1); // this will be the name of the register or the NULL terminator
@ -1218,6 +1220,7 @@ handle_shemu(
memcpy((BYTE *)ctx.Shellcode, (BYTE *)buffer, fsize);
memset(ctx.Intbuf, 0, shellSize + STACK_SIZE);
// Use the provided RIP, if any. Otherwise, use a hard-coded value.
ctx.ShellcodeBase = (rip != 0 ? rip & PAGE_MASK : 0x200000);
ctx.ShellcodeSize = (DWORD)shellSize;
ctx.StackBase = (ctx.ShellcodeBase & PAGE_MASK) - STACK_SIZE - 0x1000;
@ -1369,6 +1372,8 @@ handle_shemu(
if (fNameDecoded != NULL)
{
// If a decoded file name is present, dump the code, as it look after emulation, on disk.
// If the shellcode decrypted itself, the decoded file will contain the plain-text version.
hFile = CreateFileA(fNameDecoded, GENERIC_WRITE, FILE_SHARE_READ, NULL,
CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
if (INVALID_HANDLE_VALUE == hFile)
@ -1581,17 +1586,22 @@ parse_input(
return FALSE;
}
// Since we expect a hex string, the buffer must be even-sized.
if (Options->Size % 2 == 1)
{
printf("Even-sized hex buffer expected!\n");
return FALSE;
}
// If the buffer starts with \x, assume it's escaped format. Note that we only check
// the first two characters for \x - afterwards, we will only look after the hex-digits
// at offsets 2 & 3 inside each 4-characters chunk.
if (Options->FileName[0] == '\\' && Options->FileName[1] == 'x')
{
sx = 1;
}
// If escaped format is used, buffer must be at least 4 characters long (1 byte).
if (sx && Options->Size < 4)
{
printf("Min 1-byte buffer needed!\n");
@ -1609,12 +1619,14 @@ parse_input(
of = 0;
}
// Check for maximum size.
if (Options->Size / mx > sizeof(hexbuf))
{
printf("Max %zu bytes buffer accepted!\n", sizeof(hexbuf));
return FALSE;
}
// Extract each byte from the provided hex input.
for (idx = 0; idx < Options->Size / mx; idx++)
{
hexbuf[idx] = ((hex_to_bin(Options->FileName[idx * mx + of]) << 4) |
@ -1626,6 +1638,7 @@ parse_input(
Options->Buffer = hexbuf;
}
// Make sure the offset is valid & points within the buffer.
if (Options->Offset >= Options->Size)
{
printf("The offset exceeds the buffer size!\n");
@ -1670,6 +1683,7 @@ parse_arguments(
if (match_gpr(argv[i], &gprIdx))
{
// Register value (used by shemu).
if (i + 1 >= argc)
{
printf("No value given for %s!\n", argv[i]);
@ -1683,10 +1697,12 @@ parse_arguments(
}
else if (strcmp(argv[i], "shemu") == 0)
{
// shemu command - will emulate.
Options->Command = commandShemu;
}
else if (argv[i][0] == '-' && argv[i][1] == 'f' && argv[i][2] == 0)
{
// File input mode.
if (i + 1 < argc)
{
Options->InputMode = inputFile;
@ -1696,6 +1712,7 @@ parse_arguments(
}
else if (argv[i][0] == '-' && argv[i][1] == 'h' && argv[i][2] == 0)
{
// Hex-string input mode.
if (i + 1 < argc)
{
Options->InputMode = inputHex;
@ -1705,6 +1722,7 @@ parse_arguments(
}
else if (argv[i][0] == '-' && argv[i][1] == 'o' && argv[i][2] == 0)
{
// Offset inside the provided buffer.
if (i + 1 < argc)
{
sscanf_s(argv[i + 1], "%zx", &Options->Offset);
@ -1713,6 +1731,7 @@ parse_arguments(
}
else if (argv[i][0] == '-' && argv[i][1] == 'r' && argv[i][2] == 0)
{
// Rip. Can be any value, as it's used only for disassembly.
if (i + 1 < argc)
{
sscanf_s(argv[i + 1], "%zx", &Options->Rip);
@ -1721,50 +1740,62 @@ parse_arguments(
}
else if (argv[i][0] == '-' && argv[i][1] == 'k' && argv[i][2] == 0)
{
// Kernel-mode for shemu.
Options->Ring = 0;
}
else if (argv[i][0] == '-' && argv[i][1] == 'b' && argv[i][2] == 'w' && argv[i][3] == 0)
{
// Bypass self writes in shemu.
Options->BypassSelfWrites = TRUE;
}
else if (0 == strcmp(argv[i], "-b16"))
{
// 16-bit mode.
Options->Mode = ND_CODE_16;
}
else if (0 == strcmp(argv[i], "-b32"))
{
// 32-bit mode.
Options->Mode = ND_CODE_32;
}
else if (0 == strcmp(argv[i], "-b64"))
{
// 64-bit mode.
Options->Mode = ND_CODE_64;
}
else if (0 == strcmp(argv[i], "-v intel"))
{
// Prefer Intel instructions.
Options->Vendor = ND_VEND_INTEL;
}
else if (0 == strcmp(argv[i], "-v amd"))
{
// Prefer AMD instructions.
Options->Vendor = ND_VEND_AMD;
}
else if (0 == strcmp(argv[i], "-v geode"))
{
// Prefer Geode instructions.
Options->Vendor = ND_VEND_GEODE;
}
else if (0 == strcmp(argv[i], "-v cyrix"))
{
// Prefer Cyrix instructions.
Options->Vendor = ND_VEND_CYRIX;
}
else if (0 == strcmp(argv[i], "-v any"))
{
// Try to decode everything.
Options->Vendor = ND_VEND_ANY;
}
else if (0 == strcmp(argv[i], "-t all"))
{
// Enable all features.
Options->Feature = ND_FEAT_ALL;
}
else if (0 == strcmp(argv[i], "-t mpx"))
{
// Enable MPX.
if (Options->Feature == ND_FEAT_ALL)
{
Options->Feature = 0;
@ -1774,6 +1805,7 @@ parse_arguments(
}
else if (0 == strcmp(argv[i], "-t cet"))
{
// Enable CET.
if (Options->Feature == ND_FEAT_ALL)
{
Options->Feature = 0;
@ -1783,6 +1815,7 @@ parse_arguments(
}
else if (0 == strcmp(argv[i], "-t cldm"))
{
// Enable Cache Line Demote.
if (Options->Feature == ND_FEAT_ALL)
{
Options->Feature = 0;
@ -1792,6 +1825,7 @@ parse_arguments(
}
else if (0 == strcmp(argv[i], "-t piti"))
{
// Enable Prefetch for instruction fetch.
if (Options->Feature == ND_FEAT_ALL)
{
Options->Feature = 0;
@ -1801,30 +1835,37 @@ parse_arguments(
}
else if (0 == strcmp(argv[i], "-t none"))
{
// No feature support.
Options->Feature = ND_FEAT_NONE;
}
else if (0 == strcmp(argv[i], "-nv"))
{
// Do not print anything.
Options->Print = FALSE;
}
else if (0 == strcmp(argv[i], "-hl"))
{
// Highlight instruction components.
Options->Highlight = TRUE;
}
else if (0 == strcmp(argv[i], "-iv"))
{
// Print statistics.
Options->Stats = TRUE;
}
else if (0 == strcmp(argv[i], "-exi"))
{
// Print extended instruction information.
Options->ExtendedInfo = TRUE;
}
else if (0 == strcmp(argv[i], "-bits"))
{
// Print instruction bitfields.
Options->BitFields = TRUE;
}
else if (0 == strcmp(argv[i], "-skip16"))
{
// Skip 16 bytes after each decoded instruction.
Options->Skip16 = TRUE;
}
else
@ -1835,6 +1876,7 @@ parse_arguments(
i++;
}
// Parse the input.
if (!parse_input(Options))
{
printf("Could not find a valid input!\n");
@ -1853,11 +1895,13 @@ main(
{
DISASM_OPTIONS options = { 0 };
// Parse arguments & extract relevant options.
if (!parse_arguments(argc, argv, &options))
{
return -1;
}
// Handle the indicated command.
if (options.Command == commandShemu)
{
handle_shemu(&options);
@ -1867,6 +1911,7 @@ main(
handle_disasm(&options);
}
// Will free any memory allocated during argument parsing, and will close any handles.
cleanup_context(&options);
return 0;

Write Preview
Loading…
Cancel
Save