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bin_mz: Restructure check_bytes for clarity

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As checks have been added for file formats that include an MZ header but
are handled by a different plugin, bin_mz's check_bytes has gotten hard
to understand.  Restructure it as a default true with early exits to
simplify the logic.
This commit is contained in:
Rick Altherr 2017-11-11 20:52:58 -08:00 committed by radare
parent 1805de9202
commit f5689beef4
1 changed files with 31 additions and 35 deletions
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66
libr/bin/p/bin_mz.c
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@ -37,47 +37,43 @@ static bool checkEntrypoint(const ut8 *buf, ut64 length) {
}
static bool check_bytes(const ut8 *buf, ut64 length) {
unsigned int exth_offset;
int ret = false;
ut16 new_exe_header_offset;
if (!buf || length <= 0x3d) {
return false;
}
if (!memcmp (buf, "MZ", 2) || !memcmp (buf, "ZM", 2)) {
ret = true;
exth_offset = r_read_ble16 (buf + 0x3c, false);
if (length > exth_offset + 2) {
// check for PE
if (length > exth_offset + 0x20) {
if (!memcmp (buf, "MZ", 2)) {
if (!memcmp (buf + exth_offset, "PE", 2) &&
!memcmp (buf + exth_offset + 0x18,
"\x0b\x01", 2)) {
return false;
}
// check for Phar Lap TNT PL executable
if (!memcmp (buf + exth_offset, "PL", 2)) {
return false;
}
}
}
// Check for New Executable, LE/LX or Phar Lap executable
if (!memcmp (buf + exth_offset, "NE", 2) ||
!memcmp (buf + exth_offset, "LE", 2) ||
!memcmp (buf + exth_offset, "LX", 2) ||
!memcmp (buf + exth_offset, "PL", 2)) {
if (!checkEntrypoint (buf, length)) {
ret = false;
}
} else {
if (checkEntrypoint (buf, length)) {
/* raw plain MZ executable (watcom) */
} else {
ret = false;
}
// Check for MZ magic.
if (memcmp (buf, "MZ", 2) && memcmp (buf, "ZM", 2)) {
return false;
}
// See if there is a new exe header.
new_exe_header_offset = r_read_ble16 (buf + 0x3c, false);
if (length > new_exe_header_offset + 2) {
// check for PE
if (!memcmp (buf + new_exe_header_offset, "PE", 2) &&
(length > new_exe_header_offset + 0x20) &&
!memcmp (buf + new_exe_header_offset + 0x18, "\x0b\x01", 2)) {
return false;
}
// Check for New Executable, LE/LX or Phar Lap executable
if (!memcmp (buf + new_exe_header_offset, "NE", 2) ||
!memcmp (buf + new_exe_header_offset, "LE", 2) ||
!memcmp (buf + new_exe_header_offset, "LX", 2) ||
!memcmp (buf + new_exe_header_offset, "PL", 2)) {
if (!checkEntrypoint (buf, length)) {
return false;
}
}
}
return ret;
// Raw plain MZ executable (watcom)
if (!checkEntrypoint (buf, length)) {
return false;
}
return true;
}
static void * load_bytes(RBinFile *bf, const ut8 *buf, ut64 sz,