Magisk/native/jni/magiskboot/pattern.cpp
2020-03-22 13:41:55 -07:00

79 lines
1.8 KiB
C++

#include <malloc.h>
#include <string.h>
#include <utils.hpp>
#include "magiskboot.hpp"
#define MATCH(p) else if (strncmp(s + skip, p, sizeof(p) - 1) == 0) skip += (sizeof(p) - 1)
static int check_verity_pattern(const char *s) {
int skip = s[0] == ',';
if (0) {}
MATCH("verifyatboot");
MATCH("verify");
MATCH("avb_keys");
MATCH("avb");
MATCH("support_scfs");
MATCH("fsverity");
else return -1;
if (s[skip] == '=') {
while (s[skip] != '\0' && s[skip] != ' ' && s[skip] != '\n' && s[skip] != ',')
++skip;
}
return skip;
}
#undef MATCH
#define MATCH(p) else if (strncmp(s, p, sizeof(p) - 1) == 0) return (sizeof(p) - 1)
static int check_encryption_pattern(const char *s) {
if (0) {}
MATCH("forceencrypt");
MATCH("forcefdeorfbe");
MATCH("fileencryption");
else return -1;
}
char *patch_verity(const void *buf, uint32_t &size, bool inplace) {
auto src = static_cast<const char *>(buf);
auto dest = (char *)(inplace ? buf : xmalloc(size));
int src_size = size;
bool found = false;
int write = 0;
for (int read = 0; read < src_size;) {
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;
} else {
dest[write++] = src[read++];
}
}
dest[write] = '\0';
if (!found) {
if (!inplace)
free(dest);
return nullptr;
}
return dest;
}
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';
}