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Atmosphere/fusee/fusee-secondary/src/extkeys.c

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6.3 KiB
C

/*
* Copyright (c) 2018-2020 Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include "extkeys.h"
/**
* Reads a line from file f and parses out the key and value from it.
* The format of a line must match /^ *[A-Za-z0-9_] *[,=] *.+$/.
* If a line ends in \r, the final \r is stripped.
* The input file is assumed to have been opened with the 'b' flag.
* The input file is assumed to contain only ASCII.
*
* A line cannot exceed 512 bytes in length.
* Lines that are excessively long will be silently truncated.
*
* On success, *key and *value will be set to point to the key and value in
* the input line, respectively.
* *key and *value may also be NULL in case of empty lines.
* On failure, *key and *value will be set to NULL.
* End of file is considered failure.
*
* Because *key and *value will point to a static buffer, their contents must be
* copied before calling this function again.
* For the same reason, this function is not thread-safe.
*
* The key will be converted to lowercase.
* An empty key is considered a parse error, but an empty value is returned as
* success.
*
* This function assumes that the file can be trusted not to contain any NUL in
* the contents.
*
* Whitespace (' ', ASCII 0x20, as well as '\t', ASCII 0x09) at the beginning of
* the line, at the end of the line as well as around = (or ,) will be ignored.
*
* @param f the file to read
* @param key pointer to change to point to the key
* @param value pointer to change to point to the value
* @return 0 on success,
* 1 on end of file,
* -1 on parse error (line too long, line malformed)
* -2 on I/O error
*/
static int get_kv(FILE *f, char **key, char **value) {
#define SKIP_SPACE(p) do {\
for (; *p == ' ' || *p == '\t'; ++p)\
;\
} while(0);
static char line[1024];
char *k, *v, *p, *end;
*key = *value = NULL;
errno = 0;
if (fgets(line, (int)sizeof(line), f) == NULL) {
if (feof(f))
return 1;
else
return -2;
}
if (errno != 0)
return -2;
if (*line == '\n' || *line == '\r' || *line == '\0')
return 0;
/* Not finding \r or \n is not a problem.
* The line might just be exactly 512 characters long, we have no way to
* tell.
* Additionally, it's possible that the last line of a file is not actually
* a line (i.e., does not end in '\n'); we do want to handle those.
*/
if ((p = strchr(line, '\r')) != NULL || (p = strchr(line, '\n')) != NULL) {
end = p;
*p = '\0';
} else {
end = line + strlen(line) + 1;
}
p = line;
SKIP_SPACE(p);
k = p;
/* Validate key and convert to lower case. */
for (; *p != ' ' && *p != ',' && *p != '\t' && *p != '='; ++p) {
if (*p == '\0')
return -1;
if (*p >= 'A' && *p <= 'Z') {
*p = 'a' + (*p - 'A');
continue;
}
if (*p != '_' &&
(*p < '0' || *p > '9') &&
(*p < 'a' || *p > 'z')) {
return -1;
}
}
/* Bail if the final ++p put us at the end of string */
if (*p == '\0')
return -1;
/* We should be at the end of key now and either whitespace or [,=]
* follows.
*/
if (*p == '=' || *p == ',') {
*p++ = '\0';
} else {
*p++ = '\0';
SKIP_SPACE(p);
if (*p != '=' && *p != ',')
return -1;
*p++ = '\0';
}
/* Empty key is an error. */
if (*k == '\0')
return -1;
SKIP_SPACE(p);
v = p;
/* Skip trailing whitespace */
for (p = end - 1; *p == '\t' || *p == ' '; --p)
;
*(p + 1) = '\0';
*key = k;
*value = v;
return 0;
#undef SKIP_SPACE
}
static int ishex(char c) {
if ('a' <= c && c <= 'f') return 1;
if ('A' <= c && c <= 'F') return 1;
if ('0' <= c && c <= '9') return 1;
return 0;
}
static char hextoi(char c) {
if ('a' <= c && c <= 'f') return c - 'a' + 0xA;
if ('A' <= c && c <= 'F') return c - 'A' + 0xA;
if ('0' <= c && c <= '9') return c - '0';
return 0;
}
void parse_hex_key(unsigned char *key, const char *hex, unsigned int len) {
if (strlen(hex) != 2 * len) {
fatal_error("Key (%s) must be %x hex digits!\n", hex, 2 * len);
}
for (unsigned int i = 0; i < 2 * len; i++) {
if (!ishex(hex[i])) {
fatal_error("Key (%s) must be %x hex digits!\n", hex, 2 * len);
}
}
memset(key, 0, len);
for (unsigned int i = 0; i < 2 * len; i++) {
char val = hextoi(hex[i]);
if ((i & 1) == 0) {
val <<= 4;
}
key[i >> 1] |= val;
}
}
void extkeys_initialize_keyset(fusee_extkeys_t *keyset, FILE *f) {
char *key, *value;
int ret;
while ((ret = get_kv(f, &key, &value)) != 1 && ret != -2) {
if (ret == 0) {
if (key == NULL || value == NULL) {
continue;
}
int matched_key = 0;
char test_name[0x100] = {0};
for (unsigned int i = 0; i < 0x20 && !matched_key; i++) {
snprintf(test_name, sizeof(test_name), "tsec_root_key_%02x", i);
if (strcmp(key, test_name) == 0) {
parse_hex_key(keyset->tsec_root_keys[i], value, sizeof(keyset->tsec_root_keys[i]));
matched_key = 1;
break;
}
snprintf(test_name, sizeof(test_name), "master_kek_%02x", i);
if (strcmp(key, test_name) == 0) {
parse_hex_key(keyset->master_keks[i], value, sizeof(keyset->master_keks[i]));
matched_key = 1;
break;
}
}
}
}
}