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- /*
- * Copyright (C) 2012 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #include <stdio.h>
- #include <string.h>
- #include <resolv.h>
- #include <cutils/list.h>
- #include <cutils/sockets.h>
- #include "sysdeps.h"
- #include "adb.h"
- #include "adb_auth.h"
- #include "fdevent.h"
- #include "mincrypt/rsa.h"
- #include <assert.h>
- #define TRACE_TAG TRACE_AUTH
- struct adb_public_key {
- struct listnode node;
- RSAPublicKey key;
- };
- static struct listnode key_list;
- char *external_key_path = NULL;
- static char *key_paths[] = {
- "/mnt/UDISK/adb_keys",
- NULL
- };
- static fdevent listener_fde;
- static int framework_fd = -1;
- static const char Base64[] =
- "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
- static const char Pad64 = '=';
- int
- b64_pton(src, target, targsize)
- char const *src;
- u_char *target;
- size_t targsize;
- {
- size_t tarindex;
- int state, ch;
- char *pos;
- assert(src != NULL);
- assert(target != NULL);
- state = 0;
- tarindex = 0;
- while ((ch = (u_char) *src++) != '\0') {
- if (isspace(ch)) /* Skip whitespace anywhere. */
- continue;
- if (ch == Pad64)
- break;
- pos = strchr(Base64, ch);
- if (pos == 0) /* A non-base64 character. */
- return (-1);
- switch (state) {
- case 0:
- if (target) {
- if (tarindex >= targsize)
- return (-1);
- target[tarindex] = (pos - Base64) << 2;
- }
- state = 1;
- break;
- case 1:
- if (target) {
- if (tarindex + 1 >= targsize)
- return (-1);
- target[tarindex] |=
- (u_int32_t)(pos - Base64) >> 4;
- target[tarindex+1] = ((pos - Base64) & 0x0f)
- << 4 ;
- }
- tarindex++;
- state = 2;
- break;
- case 2:
- if (target) {
- if (tarindex + 1 >= targsize)
- return (-1);
- target[tarindex] |=
- (u_int32_t)(pos - Base64) >> 2;
- target[tarindex+1] = ((pos - Base64) & 0x03)
- << 6;
- }
- tarindex++;
- state = 3;
- break;
- case 3:
- if (target) {
- if (tarindex >= targsize)
- return (-1);
- target[tarindex] |= (pos - Base64);
- }
- tarindex++;
- state = 0;
- break;
- default:
- abort();
- }
- }
- /*
- * We are done decoding Base-64 chars. Let's see if we ended
- * on a byte boundary, and/or with erroneous trailing characters.
- */
- if (ch == Pad64) { /* We got a pad char. */
- ch = *src++; /* Skip it, get next. */
- switch (state) {
- case 0: /* Invalid = in first position */
- case 1: /* Invalid = in second position */
- return (-1);
- case 2: /* Valid, means one byte of info */
- /* Skip any number of spaces. */
- for (; ch != '\0'; ch = (u_char) *src++)
- if (!isspace(ch))
- break;
- /* Make sure there is another trailing = sign. */
- if (ch != Pad64)
- return (-1);
- ch = *src++; /* Skip the = */
- /* Fall through to "single trailing =" case. */
- /* FALLTHROUGH */
- case 3: /* Valid, means two bytes of info */
- /*
- * We know this char is an =. Is there anything but
- * whitespace after it?
- */
- for (; ch != '\0'; ch = (u_char) *src++)
- if (!isspace(ch))
- return (-1);
- /*
- * Now make sure for cases 2 and 3 that the "extra"
- * bits that slopped past the last full byte were
- * zeros. If we don't check them, they become a
- * subliminal channel.
- */
- if (target && target[tarindex] != 0)
- return (-1);
- }
- } else {
- /*
- * We ended by seeing the end of the string. Make sure we
- * have no partial bytes lying around.
- */
- if (state != 0)
- return (-1);
- }
- return (tarindex);
- }
- static void read_keys(const char *file, struct listnode *list)
- {
- struct adb_public_key *key;
- FILE *f;
- char buf[MAX_PAYLOAD];
- char *sep;
- int ret;
- f = fopen(file, "r");
- if (!f) {
- D("Can't open '%s'\n", file);
- return;
- }
- while (fgets(buf, sizeof(buf), f)) {
- /* Allocate 4 extra bytes to decode the base64 data in-place */
- key = calloc(1, sizeof(*key) + 4);
- if (!key) {
- D("Can't malloc key\n");
- break;
- }
- sep = strpbrk(buf, " \t");
- if (sep)
- *sep = '\0';
- ret = b64_pton(buf, (u_char *)&key->key, sizeof(key->key) + 4);
- if (ret != sizeof(key->key)) {
- D("%s: Invalid base64 data ret=%d\n", file, ret);
- free(key);
- continue;
- }
- if (key->key.len != RSANUMWORDS) {
- D("%s: Invalid key len %d\n", file, key->key.len);
- free(key);
- continue;
- }
- list_add_tail(list, &key->node);
- }
- fclose(f);
- }
- static void free_keys(struct listnode *list)
- {
- struct listnode *item;
- while (!list_empty(list)) {
- item = list_head(list);
- list_remove(item);
- free(node_to_item(item, struct adb_public_key, node));
- }
- }
- void adb_auth_reload_keys(void)
- {
- char *path;
- char **paths = key_paths;
- struct stat buf;
- free_keys(&key_list);
- if (external_key_path != NULL
- && !stat(external_key_path, &buf))
- read_keys(external_key_path, &key_list);
- while ((path = *paths++)) {
- if (!stat(path, &buf)) {
- D("Loading keys from '%s'\n", path);
- read_keys(path, &key_list);
- }
- }
- }
- int adb_auth_generate_token(void *token, size_t token_size)
- {
- FILE *f;
- int ret;
- f = fopen("/dev/urandom", "r");
- if (!f)
- return 0;
- ret = fread(token, token_size, 1, f);
- fclose(f);
- return ret * token_size;
- }
- int adb_auth_verify(void *token, void *sig, int siglen)
- {
- struct listnode *item;
- struct adb_public_key *key;
- int ret;
- if (siglen != RSANUMBYTES)
- return 0;
- list_for_each(item, &key_list) {
- key = node_to_item(item, struct adb_public_key, node);
- ret = RSA_verify(&key->key, sig, siglen, token);
- if (ret)
- return 1;
- }
- return 0;
- }
- static void adb_auth_event(int fd, unsigned events, void *data)
- {
- atransport *t = data;
- char response[2];
- int ret;
- if (events & FDE_READ) {
- ret = unix_read(fd, response, sizeof(response));
- if (ret < 0) {
- D("Disconnect");
- fdevent_remove(&t->auth_fde);
- framework_fd = -1;
- }
- else if (ret == 2 && response[0] == 'O' && response[1] == 'K') {
- adb_auth_reload_keys();
- adb_auth_verified(t);
- }
- }
- }
- void adb_auth_confirm_key(unsigned char *key, size_t len, atransport *t)
- {
- char msg[MAX_PAYLOAD];
- int ret;
- if (framework_fd < 0) {
- D("Client not connected\n");
- return;
- }
- if (key[len - 1] != '\0') {
- D("Key must be a null-terminated string\n");
- return;
- }
- ret = snprintf(msg, sizeof(msg), "PK%s", key);
- if (ret >= (signed)sizeof(msg)) {
- D("Key too long. ret=%d", ret);
- return;
- }
- D("Sending '%s'\n", msg);
- ret = unix_write(framework_fd, msg, ret);
- if (ret < 0) {
- D("Failed to write PK, errno=%d\n", errno);
- return;
- }
- fdevent_install(&t->auth_fde, framework_fd, adb_auth_event, t);
- fdevent_add(&t->auth_fde, FDE_READ);
- }
- static void adb_auth_listener(int fd, unsigned events, void *data)
- {
- struct sockaddr addr;
- socklen_t alen;
- int s;
- alen = sizeof(addr);
- s = adb_socket_accept(fd, &addr, &alen);
- if (s < 0) {
- D("Failed to accept: errno=%d\n", errno);
- return;
- }
- framework_fd = s;
- }
- void adb_auth_init(void)
- {
- int fd, ret;
- D("adb_auth_init\n");
- list_init(&key_list);
- adb_auth_reload_keys();
- fd = android_get_control_socket("adbd");
- if (fd < 0) {
- D("Failed to get adbd socket\n");
- return;
- }
- ret = listen(fd, 4);
- if (ret < 0) {
- D("Failed to listen on '%d'\n", fd);
- return;
- }
- fdevent_install(&listener_fde, fd, adb_auth_listener, NULL);
- fdevent_add(&listener_fde, FDE_READ);
- }
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