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Commit cf6a8b47 authored by Felipe Leme's avatar Felipe Leme
Browse files

Don't use su to when calling am or dumpsys. 

su is not available on user builds anymore, hence the bugreport
notifications would never be sent on those builds. Instead, it should
explicitly drop root using system calls.

BUG: 27583193
Change-Id: Ia6256b241fdd6ab4c059fb764b10b4445ad6551d
parent d3d45c3d

cmds/dumpstate/dumpstate.cpp

+3 −47
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ 
#include <stdlib.h>

#include <string>

#include <string.h>

#include <sys/capability.h>

#include <sys/prctl.h>

#include <sys/resource.h>

#include <sys/stat.h>
@@ -967,49 +966,6 @@ static std::string SHA256_file_hash(std::string filepath) { 
    return std::string(hash_buffer);

}



/* switch to non-root user and group */

bool drop_root() {

    /* ensure we will keep capabilities when we drop root */

    if (prctl(PR_SET_KEEPCAPS, 1) < 0) {

        MYLOGE("prctl(PR_SET_KEEPCAPS) failed: %s\n", strerror(errno));

        return false;

    }



    gid_t groups[] = { AID_LOG, AID_SDCARD_R, AID_SDCARD_RW,

            AID_MOUNT, AID_INET, AID_NET_BW_STATS, AID_READPROC };

    if (setgroups(sizeof(groups)/sizeof(groups[0]), groups) != 0) {

        MYLOGE("Unable to setgroups, aborting: %s\n", strerror(errno));

        return false;

    }

    if (setgid(AID_SHELL) != 0) {

        MYLOGE("Unable to setgid, aborting: %s\n", strerror(errno));

        return false;

    }

    if (setuid(AID_SHELL) != 0) {

        MYLOGE("Unable to setuid, aborting: %s\n", strerror(errno));

        return false;

    }



    struct __user_cap_header_struct capheader;

    struct __user_cap_data_struct capdata[2];

    memset(&capheader, 0, sizeof(capheader));

    memset(&capdata, 0, sizeof(capdata));

    capheader.version = _LINUX_CAPABILITY_VERSION_3;

    capheader.pid = 0;



    capdata[CAP_TO_INDEX(CAP_SYSLOG)].permitted = CAP_TO_MASK(CAP_SYSLOG);

    capdata[CAP_TO_INDEX(CAP_SYSLOG)].effective = CAP_TO_MASK(CAP_SYSLOG);

    capdata[0].inheritable = 0;

    capdata[1].inheritable = 0;



    if (capset(&capheader, &capdata[0]) < 0) {

        MYLOGE("capset failed: %s\n", strerror(errno));

        return false;

    }



    return true;

}



int main(int argc, char *argv[]) {

    struct sigaction sigact;

    int do_add_date = 0;
@@ -1254,8 +1210,8 @@ int main(int argc, char *argv[]) { 


    // Invoking the following dumpsys calls before dump_traces() to try and

    // keep the system stats as close to its initial state as possible.

    run_command("DUMPSYS MEMINFO", 30, SU_PATH, "shell", "dumpsys", "meminfo", "-a", NULL);

    run_command("DUMPSYS CPUINFO", 30, SU_PATH, "shell", "dumpsys", "cpuinfo", "-a", NULL);

    run_command_as_shell("DUMPSYS MEMINFO", 30, "dumpsys", "meminfo", "-a", NULL);

    run_command_as_shell("DUMPSYS CPUINFO", 30, "dumpsys", "cpuinfo", "-a", NULL);



    /* collect stack traces from Dalvik and native processes (needs root) */

    dump_traces_path = dump_traces();
@@ -1265,7 +1221,7 @@ int main(int argc, char *argv[]) { 
    add_dir(RECOVERY_DIR, true);

    add_mountinfo();



    if (!drop_root()) {

    if (!drop_root_user()) {

        return -1;

    }

cmds/dumpstate/dumpstate.h

+8 −1
Original line number Diff line number Diff line
@@ -100,13 +100,20 @@ int dump_files(const char *title, const char *dir, 
        bool (*skip)(const char *path),

        int (*dump_from_fd)(const char *title, const char *path, int fd));



// TODO: need to refactor all those run_command variations; there shold be just one, receiving an

// optional CommandOptions objects with values such as run_always, drop_root, etc...



/* forks a command and waits for it to finish -- terminate args with NULL */

int run_command_as_shell(const char *title, int timeout_seconds, const char *command, ...);

int run_command(const char *title, int timeout_seconds, const char *command, ...);



/* forks a command and waits for it to finish

   first element of args is the command, and last must be NULL.

   command is always ran, even when _DUMPSTATE_DRY_RUN_ is defined. */

int run_command_always(const char *title, int timeout_seconds, const char *args[]);

int run_command_always(const char *title, bool drop_root, int timeout_seconds, const char *args[]);



/* switch to non-root user and group */

bool drop_root_user();



/* sends a broadcast using Activity Manager */

void send_broadcast(const std::string& action, const std::vector<std::string>& args);

cmds/dumpstate/utils.cpp

+93 −7
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <stdlib.h>

#include <string>

#include <string.h>

#include <sys/capability.h>

#include <sys/inotify.h>

#include <sys/stat.h>

#include <sys/sysconf.h>
@@ -640,13 +641,48 @@ int run_command(const char *title, int timeout_seconds, const char *command, ... 


    ON_DRY_RUN({ update_progress(timeout_seconds); va_end(ap); return 0; });



    int status = run_command_always(title, timeout_seconds, args);

    int status = run_command_always(title, false, timeout_seconds, args);

    va_end(ap);

    return status;

}



int run_command_as_shell(const char *title, int timeout_seconds, const char *command, ...) {

    DurationReporter duration_reporter(title);

    fflush(stdout);



    const char *args[1024] = {command};

    size_t arg;

    va_list ap;

    va_start(ap, command);

    if (title) printf("------ %s (%s", title, command);

    bool null_terminated = false;

    for (arg = 1; arg < sizeof(args) / sizeof(args[0]); ++arg) {

        args[arg] = va_arg(ap, const char *);

        if (args[arg] == nullptr) {

            null_terminated = true;

            break;

        }

        if (title) printf(" %s", args[arg]);

    }

    if (title) printf(") ------\n");

    fflush(stdout);

    if (!null_terminated) {

        // Fail now, otherwise execvp() call on run_command_always() might hang.

        std::string cmd;

        format_args(command, args, &cmd);

        MYLOGE("skipping command %s because its args were not NULL-terminated", cmd.c_str());

        return -1;

    }



    ON_DRY_RUN({ update_progress(timeout_seconds); va_end(ap); return 0; });



    int status = run_command_always(title, true, timeout_seconds, args);

    va_end(ap);

    return status;

}



/* forks a command and waits for it to finish */

int run_command_always(const char *title, int timeout_seconds, const char *args[]) {

int run_command_always(const char *title, bool drop_root, int timeout_seconds, const char *args[]) {

    /* TODO: for now we're simplifying the progress calculation by using the timeout as the weight.

     * It's a good approximation for most cases, except when calling dumpsys, where its weight

     * should be much higher proportionally to its timeout. */
@@ -664,6 +700,10 @@ int run_command_always(const char *title, int timeout_seconds, const char *args[ 


    /* handle child case */

    if (pid == 0) {

        if (drop_root && !drop_root_user()) {

            printf("*** could not drop root before running %s: %s\n", command, strerror(errno));

            _exit(-1);

        }



        /* make sure the child dies when dumpstate dies */

        prctl(PR_SET_PDEATHSIG, SIGKILL);
@@ -726,14 +766,60 @@ int run_command_always(const char *title, int timeout_seconds, const char *args[ 
    return status;

}



bool drop_root_user() {

    if (getgid() == AID_SHELL && getuid() == AID_SHELL) {

        MYLOGD("drop_root_user(): already running as Shell");

        return true;

    }

    /* ensure we will keep capabilities when we drop root */

    if (prctl(PR_SET_KEEPCAPS, 1) < 0) {

        MYLOGE("prctl(PR_SET_KEEPCAPS) failed: %s\n", strerror(errno));

        return false;

    }



    gid_t groups[] = { AID_LOG, AID_SDCARD_R, AID_SDCARD_RW,

            AID_MOUNT, AID_INET, AID_NET_BW_STATS, AID_READPROC };

    if (setgroups(sizeof(groups)/sizeof(groups[0]), groups) != 0) {

        MYLOGE("Unable to setgroups, aborting: %s\n", strerror(errno));

        return false;

    }

    if (setgid(AID_SHELL) != 0) {

        MYLOGE("Unable to setgid, aborting: %s\n", strerror(errno));

        return false;

    }

    if (setuid(AID_SHELL) != 0) {

        MYLOGE("Unable to setuid, aborting: %s\n", strerror(errno));

        return false;

    }



    struct __user_cap_header_struct capheader;

    struct __user_cap_data_struct capdata[2];

    memset(&capheader, 0, sizeof(capheader));

    memset(&capdata, 0, sizeof(capdata));

    capheader.version = _LINUX_CAPABILITY_VERSION_3;

    capheader.pid = 0;



    capdata[CAP_TO_INDEX(CAP_SYSLOG)].permitted = CAP_TO_MASK(CAP_SYSLOG);

    capdata[CAP_TO_INDEX(CAP_SYSLOG)].effective = CAP_TO_MASK(CAP_SYSLOG);

    capdata[0].inheritable = 0;

    capdata[1].inheritable = 0;



    if (capset(&capheader, &capdata[0]) < 0) {

        MYLOGE("capset failed: %s\n", strerror(errno));

        return false;

    }



    return true;

}



void send_broadcast(const std::string& action, const std::vector<std::string>& args) {

    if (args.size() > 1000) {

        MYLOGE("send_broadcast: too many arguments (%d)\n", (int) args.size());

        return;

    }

    const char *am_args[1024] = { SU_PATH, "shell", "/system/bin/am", "broadcast",

                                  "--user", "0", "-a", action.c_str() };

    size_t am_index = 7; // Starts at the index of last initial value above.

    const char *am_args[1024] = { "/system/bin/am", "broadcast", "--user", "0", "-a",

                                  action.c_str() };

    size_t am_index = 5; // Starts at the index of last initial value above.

    for (const std::string& arg : args) {

        am_args[++am_index] = arg.c_str();

    }
@@ -742,7 +828,7 @@ void send_broadcast(const std::string& action, const std::vector<std::string>& a 
    std::string args_string;

    format_args(am_index + 1, am_args, &args_string);

    MYLOGD("send_broadcast command: %s\n", args_string.c_str());

    run_command_always(NULL, 5, am_args);

    run_command_always(NULL, 5, true, am_args);

}



size_t num_props = 0;
@@ -1081,7 +1167,7 @@ void update_progress(int delta) { 


void take_screenshot(const std::string& path) {

    const char *args[] = { "/system/bin/screencap", "-p", path.c_str(), NULL };

    run_command_always(NULL, 10, args);

    run_command_always(NULL, false, 10, args);

}



void vibrate(FILE* vibrator, int ms) {