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Commit c3c06294 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

logd: test: switch to /data/backup/ for sepolicy avc injection 

Resolve issues seen on continuous testing frame:

- statistics test, info instead of fail on missing radio log data.
- sepolicy switch from /data/misc/logd/ to /data/backup/ as the
  directory we access(2) to inject sepolicy violations.  The key here
  is we are still root, but we are in u:r:shell:s0, and the directory
  does not provide us DAC access (0700 system system) so we trigger
  the pair dac_override and dac_read_search on every try to get past
  the message de-duper.  /data/misc/logd is not always there, until
  logpersist is enabled, but /data/backup is always there.
- a stricter signature of '): avc: denied'
- put in a looser threshold for sepolicy_rate_limiter_spam test.

Test: gTest logd-unit-tests --gtest_filter=logd.sepolicy*
Bug: 34454758
Change-Id: I28ce4fdb51dc4869944e3253b593ce222d16ec98
parent 8dbab358

logd/tests/logd_test.cpp

+17 −11
Original line number Diff line number Diff line
@@ -196,7 +196,9 @@ TEST(logd, statistics) { 
    EXPECT_TRUE(NULL != main_logs);



    char *radio_logs = strstr(cp, "\nChattiest UIDs in radio ");

    EXPECT_TRUE(NULL != radio_logs);

    if (!radio_logs) GTEST_LOG_(INFO) << "Value of: NULL != radio_logs\n"

                                         "Actual: false\n"

                                         "Expected: false\n";



    char *system_logs = strstr(cp, "\nChattiest UIDs in system ");

    EXPECT_TRUE(NULL != system_logs);
@@ -942,8 +944,16 @@ static pid_t sepolicy_rate(unsigned rate, unsigned num) { 
        return 0;

    }



    // Requests dac_read_search, falls back to request dac_override

    rate /= 2;

    // The key here is we are root, but we are in u:r:shell:s0,

    // and the directory does not provide us DAC access

    // (eg: 0700 system system) so we trigger the pair dac_override

    // and dac_read_search on every try to get past the message

    // de-duper.  We will also rotate the file name in the directory

    // as another measure.

    static const char file[] = "/data/backup/cannot_access_directory_%u";

    static const unsigned avc_requests_per_access = 2;



    rate /= avc_requests_per_access;

    useconds_t usec;

    if (rate == 0) {

        rate = 1;
@@ -951,15 +961,12 @@ static pid_t sepolicy_rate(unsigned rate, unsigned num) { 
    } else {

        usec = (1000000 + (rate / 2)) / rate;

    }

    num = (num + 1) / 2;

    num = (num + (avc_requests_per_access / 2)) / avc_requests_per_access;



    if (usec < 2) usec = 2;



    while (num > 0) {

        if (access(android::base::StringPrintf(

                       "/data/misc/logd/cannot_access_directory_%u",

                       num).c_str(),

                   F_OK) == 0) {

        if (access(android::base::StringPrintf(file, num).c_str(), F_OK) == 0) {

            _exit(-1);

            // NOTREACHED

            return 0;
@@ -1002,7 +1009,7 @@ static int count_avc(pid_t pid) { 


        // int len = get4LE(eventData + 4 + 1);

        log_msg.buf[LOGGER_ENTRY_MAX_LEN] = '\0';

        const char *cp = strstr(eventData + 4 + 1 + 4, "): avc: ");

        const char *cp = strstr(eventData + 4 + 1 + 4, "): avc: denied");

        if (!cp) continue;



        ++count;
@@ -1055,8 +1062,7 @@ TEST(logd, sepolicy_rate_limiter_spam) { 
    // give logd another 3 seconds to react to the burst before checking

    sepolicy_rate(rate, rate * 3);

    // maximum period at double the maximum burst rate (spam filter kicked in)

    EXPECT_GE(((AUDIT_RATE_LIMIT_MAX * AUDIT_RATE_LIMIT_BURST_DURATION) * 130) /

                                        100, // +30% margin

    EXPECT_GE(threshold * 2,

              count_avc(sepolicy_rate(rate,

                                      rate * AUDIT_RATE_LIMIT_BURST_DURATION)));

    // cool down, and check unspammy rate still works