Proper pattern matching

Fix #3998
This commit is contained in:
topjohnwu 2021-03-09 04:08:16 -08:00
parent 48bde7375f
commit 1ff45ac5f5

View File

@ -1,44 +1,47 @@
#include <malloc.h> #include <malloc.h>
#include <string.h>
#include <utils.hpp> #include <utils.hpp>
#include "magiskboot.hpp" #include "magiskboot.hpp"
#define CHECKED_MATCH(p) else if (strncmp(s + skip, p, sizeof(p) - 1) == 0) skip += (sizeof(p) - 1) #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) { static int skip_verity_pattern(const char *s) {
int skip = s[0] == ','; int skip = s[0] == ',';
if (0) {} if (0) {}
CHECKED_MATCH("verifyatboot"); MATCH("verifyatboot");
CHECKED_MATCH("verify"); MATCH("verify");
CHECKED_MATCH("avb_keys"); MATCH("avb_keys");
CHECKED_MATCH("avb"); MATCH("avb");
CHECKED_MATCH("support_scfs"); MATCH("support_scfs");
CHECKED_MATCH("fsverity"); MATCH("fsverity");
else return -1; else return -1;
if (s[skip] == '=') { if (s[skip] == '=') {
while (s[skip] != '\0' && s[skip] != ' ' && s[skip] != '\n' && s[skip] != ',') while (!strchr(" \n,", s[skip]))
++skip; ++skip;
} }
return skip; return skip;
} }
#undef CHECKED_MATCH static int skip_encryption_pattern(const char *s) {
#define CHECKED_MATCH(p) else if (strncmp(s, p, sizeof(p) - 1) == 0) return (sizeof(p) - 1) int skip = s[0] == ',';
static int check_encryption_pattern(const char *s) {
if (0) {} if (0) {}
CHECKED_MATCH("forceencrypt"); MATCH("forceencrypt");
CHECKED_MATCH("forcefdeorfbe"); MATCH("forcefdeorfbe");
CHECKED_MATCH("fileencryption"); MATCH("fileencryption");
else return -1; else return -1;
if (s[skip] == '=') {
while (!strchr(" \n,", s[skip]))
++skip;
}
return skip;
} }
static uint32_t remove_pattern(void *buf, uint32_t size, int(*pattern_skip)(const char *)) { static uint32_t remove_pattern(char *src, uint32_t size, int(*pattern_skip)(const char *)) {
auto src = static_cast<char *>(buf);
int orig_sz = size; int orig_sz = size;
int write = 0; int write = 0;
for (int read = 0; read < orig_sz;) { for (int read = 0; read < orig_sz;) {
@ -55,9 +58,9 @@ static uint32_t remove_pattern(void *buf, uint32_t size, int(*pattern_skip)(cons
} }
uint32_t patch_verity(void *buf, uint32_t size) { uint32_t patch_verity(void *buf, uint32_t size) {
return remove_pattern(buf, size, check_verity_pattern); return remove_pattern(static_cast<char *>(buf), size, skip_verity_pattern);
} }
uint32_t patch_encryption(void *buf, uint32_t size) { uint32_t patch_encryption(void *buf, uint32_t size) {
return remove_pattern(buf, size, check_encryption_pattern); return remove_pattern(static_cast<char *>(buf), size, skip_encryption_pattern);
} }