Magisk/native/jni/magiskboot/pattern.cpp
2019-09-26 03:14:56 -04:00

72 lines
1.7 KiB
C++

#include <malloc.h>
#include <string.h>
#include <utils.h>
#include "magiskboot.h"
static int check_verity_pattern(const char *s) {
int skip = 0;
if (s[0] == ',') ++skip;
if (strncmp(s + skip, "verify", 6) == 0)
skip += 6;
else if (strncmp(s + skip, "avb", 3) == 0)
skip += 3;
else
return -1;
if (s[skip] == '=') {
while (s[skip] != '\0' && s[skip] != ' ' && s[skip] != '\n' && s[skip] != ',') ++skip;
}
return skip;
}
static int check_encryption_pattern(const char *s) {
static const char *encrypt_list[] = { "forceencrypt", "forcefdeorfbe" };
for (auto enc : encrypt_list) {
int len = strlen(enc);
if (strncmp(s, enc, len) == 0)
return len;
}
return -1;
}
char *patch_verity(const void *buf, uint32_t &size, bool inplace) {
auto src = static_cast<const char *>(buf);
int src_size = size;
bool found = false;
auto patched = (char *)(inplace ? buf : xmalloc(size));
int write = 0;
for (int read = 0; read < src_size; ++read, ++write) {
if (int skip; (skip = check_verity_pattern(src + read)) > 0) {
fprintf(stderr, "Found pattern [%.*s]\n", skip, src + read);
size -= skip;
read += skip;
found = true;
}
patched[write] = src[read];
}
patched[write] = '\0';
if (!found) {
if (!inplace)
free(patched);
return nullptr;
}
return patched;
}
void patch_encryption(void *&buf, uint32_t &size) {
auto src = static_cast<char *>(buf);
int src_size = size;
int write = 0;
for (int read = 0; read < src_size; ++read, ++write) {
if (int skip; (skip = check_encryption_pattern(src + read)) > 0) {
fprintf(stderr, "Found pattern [%.*s]\n", skip, src + read);
size -= skip;
read += skip;
}
src[write] = src[read];
}
src[write] = '\0';
}