Fix various issues

This commit is contained in:
topjohnwu 2017-04-16 02:28:12 +08:00
parent a92c9fc226
commit 743c4f554d
3 changed files with 130 additions and 62 deletions

13
misc.c
View File

@ -8,6 +8,7 @@
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "magisk.h"
#include "su.h"
@ -52,3 +53,15 @@ char *get_command(const struct su_request *to) {
return DEFAULT_SHELL;
}
int fork_zero_fucks() {
int pid = fork();
if (pid) {
int status;
waitpid(pid, &status, 0);
return pid;
} else {
if (fork() != 0)
exit(0);
return 0;
}
}

1
su.h
View File

@ -130,5 +130,6 @@ policy_t database_check(struct su_context *ctx);
void setup_sighandlers(void (*handler)(int));
void set_identity(unsigned uid);
char *get_command(const struct su_request *to);
int fork_zero_fucks();
#endif

View File

@ -20,32 +20,13 @@
#include "su.h"
#include "pts.h"
// Constants for the atty bitfield
#define ATTY_IN 1
#define ATTY_OUT 2
#define ATTY_ERR 4
int from_uid, from_pid;
struct su_daemon_info {
int child;
int client;
};
static void *wait_result(void *args) {
struct su_daemon_info *info = args;
LOGD("su: wait_result waiting for %d\n", info->child);
err_handler = exit_thread;
int status, code;
if (waitpid(info->child, &status, 0) > 0)
code = WEXITSTATUS(status);
else
code = -1;
// Pass the return code back to the client
write_int(info->client, code);
LOGD("su: return code to client: %d\n", code);
close(info->client);
free(info);
return NULL;
}
static void sighandler(int sig) {
restore_stdin();
@ -71,27 +52,46 @@ static void sighandler(int sig) {
void su_daemon_receiver(int client) {
LOGD("su: get request\n");
if (fork_zero_fucks()) {
// Root daemon
close(client);
return;
}
// Set the error handler back to normal
err_handler = exit_proc;
// Fork a new process, the child process will need to setsid,
// open a pseudo-terminal, and will eventually run exec
// The parent process (the root daemon) will open a new thread to
// The parent process will wait for the result and
// send the return code back to our client
int child = fork();
if (child < 0) {
PLOGE("fork");
write(client, &child, sizeof(child));
close(client);
PLOGE("fork");
return;
} else if (child != 0) {
pthread_t wait_thread;
struct su_daemon_info *info = xmalloc(sizeof(*info));
info->client = client;
info->child = child;
// Wait result
LOGD("su: wait_result waiting for %d\n", child);
int status, code;
// In parent, open a new thread to wait for the child to exit,
// and send the exit code across the wire.
xpthread_create(&wait_thread, NULL, wait_result, info);
return;
// Change to a fancy name
strcpy(argv0, "magisksu");
if (waitpid(child, &status, 0) > 0)
code = WEXITSTATUS(status);
else
code = -1;
// Pass the return code back to the client
write_int(client, code);
LOGD("su: return code to client: %d\n", code);
close(client);
exit(code);
}
LOGD("su: child process started\n");
@ -99,9 +99,6 @@ void su_daemon_receiver(int client) {
// ack
write_int(client, 1);
// Here we're in the child
// Set the error handler back to normal
err_handler = exit_proc;
// Become session leader
xsetsid();
@ -139,33 +136,50 @@ void su_daemon_receiver(int client) {
char *pts_slave = read_string(client);
LOGD("su: pts_slave=[%s]\n", pts_slave);
// The the FDs for each of the streams
int infd = recv_fd(client);
int outfd = recv_fd(client);
int errfd = recv_fd(client);
// We no longer need the access to socket in the child, close it
close(client);
if (pts_slave[0]) {
//Check pts_slave file is owned by daemon_from_uid
int ptsfd;
struct stat stbuf;
int res = xstat(pts_slave, &stbuf);
xstat(pts_slave, &stbuf);
//If caller is not root, ensure the owner of pts_slave is the caller
if(stbuf.st_uid != credentials.uid && credentials.uid != 0) {
LOGE("Wrong permission of pts_slave");
LOGE("su: Wrong permission of pts_slave");
exit(1);
}
// Opening the TTY has to occur after the
// fork() and setsid() so that it becomes
// our controlling TTY and not the daemon's
ptsfd = xopen(pts_slave, O_RDWR);
int ptsfd = xopen(pts_slave, O_RDWR);
if (infd < 0) {
LOGD("su: stdin using PTY");
infd = ptsfd;
}
if (outfd < 0) {
LOGD("su: stdout using PTY");
outfd = ptsfd;
}
if (errfd < 0) {
LOGD("su: stderr using PTY");
errfd = ptsfd;
}
}
free(pts_slave);
// Swap out stdin, stdout, stderr
xdup2(ptsfd, STDIN_FILENO);
xdup2(ptsfd, STDOUT_FILENO);
xdup2(ptsfd, STDERR_FILENO);
close(ptsfd);
xdup2(infd, STDIN_FILENO);
xdup2(outfd, STDOUT_FILENO);
xdup2(errfd, STDERR_FILENO);
su_daemon_main(argc, argv);
}
@ -195,19 +209,59 @@ int su_client_main(int argc, char *argv[]) {
getcwd(buffer, sizeof(buffer));
write_string(socketfd, buffer);
// Determine which one of our streams are attached to a TTY
int atty = 0;
if (isatty(STDIN_FILENO)) atty |= ATTY_IN;
if (isatty(STDOUT_FILENO)) atty |= ATTY_OUT;
if (isatty(STDERR_FILENO)) atty |= ATTY_ERR;
if (atty) {
// We need a PTY. Get one.
ptmx = pts_open(buffer, sizeof(buffer));
} else {
buffer[0] = '\0';
}
// Send the pts_slave path to the daemon
write_string(socketfd, buffer);
// Send stdin
if (atty & ATTY_IN) {
// Using PTY
send_fd(socketfd, -1);
} else {
send_fd(socketfd, STDIN_FILENO);
}
// Send stdout
if (atty & ATTY_OUT) {
// Forward SIGWINCH
watch_sigwinch_async(STDOUT_FILENO, ptmx);
// Send the slave path to the daemon
write_string(socketfd, buffer);
// Using PTY
send_fd(socketfd, -1);
} else {
send_fd(socketfd, STDOUT_FILENO);
}
// Send stderr
if (atty & ATTY_ERR) {
// Using PTY
send_fd(socketfd, -1);
} else {
send_fd(socketfd, STDERR_FILENO);
}
// Wait for acknowledgement from daemon
read_int(socketfd);
if (atty & ATTY_IN) {
setup_sighandlers(sighandler);
pump_stdin_async(ptmx);
}
if (atty & ATTY_OUT) {
pump_stdout_blocking(ptmx);
}
// Get the exit code
int code = read_int(socketfd);