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Commit 8fa8896d authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

logd: security buffer only AID_SYSTEM reader 

- limit AID_SYSTEM uid or gid to read security buffer messages
- adjust liblog tests to reflect the reality of this adjustment

To fully test all security buffer paths and modes

$ su 0,0,0 /data/nativetest/liblog-unit-tests/liblog-unit-tests --gtest_filter=liblog.__security*
$ su 1000,1000,1000 /data/nativetest/liblog-unit-tests/liblog-unit-tests --gtest_filter=liblog.__security*
$ su 2000,2000,2000 /data/nativetest/liblog-unit-tests/liblog-unit-tests --gtest_filter=liblog.__security*

ToDo: Integrate the above individually into the gTest Q/A testing

Bug: 26029733
Change-Id: Idcf5492db78fa6934ef6fb43f3ef861052675651
parent c2c0df90

liblog/tests/liblog_test.cpp

+51 −1
Original line number Diff line number Diff line
@@ -18,6 +18,8 @@ 
#include <inttypes.h>

#include <signal.h>

#include <string.h>

#include <sys/types.h>

#include <unistd.h>



#include <cutils/properties.h>

#include <gtest/gtest.h>
@@ -25,6 +27,7 @@ 
#include <log/logger.h>

#include <log/log_read.h>

#include <log/logprint.h>

#include <private/android_filesystem_config.h>

#include <private/android_logger.h>



// enhanced version of LOG_FAILURE_RETRY to add support for EAGAIN and
@@ -368,6 +371,48 @@ TEST(liblog, __security_buffer) { 
        return;

    }



    /* Matches clientHasLogCredentials() in logd */

    uid_t uid = getuid();

    gid_t gid = getgid();

    bool clientHasLogCredentials = true;

    if ((uid != AID_SYSTEM) && (uid != AID_ROOT) && (uid != AID_LOG)

     && (gid != AID_SYSTEM) && (gid != AID_ROOT) && (gid != AID_LOG)) {

        uid_t euid = geteuid();

        if ((euid != AID_SYSTEM) && (euid != AID_ROOT) && (euid != AID_LOG)) {

            gid_t egid = getegid();

            if ((egid != AID_SYSTEM) && (egid != AID_ROOT) && (egid != AID_LOG)) {

                int num_groups = getgroups(0, NULL);

                if (num_groups > 0) {

                    gid_t groups[num_groups];

                    num_groups = getgroups(num_groups, groups);

                    while (num_groups > 0) {

                        if (groups[num_groups - 1] == AID_LOG) {

                            break;

                        }

                        --num_groups;

                    }

                }

                if (num_groups <= 0) {

                    clientHasLogCredentials = false;

                }

            }

        }

    }

    if (!clientHasLogCredentials) {

        fprintf(stderr, "WARNING: "

                "not in system context, bypassing end-to-end test\n");



        log_time ts(CLOCK_MONOTONIC);



        buffer.type = EVENT_TYPE_LONG;

        buffer.data = *(static_cast<uint64_t *>((void *)&ts));



        // expect failure!

        ASSERT_GE(0, __android_log_security_bwrite(0, &buffer, sizeof(buffer)));



        return;

    }



    pid_t pid = getpid();



    ASSERT_TRUE(NULL != (logger_list = android_logger_list_open(
@@ -415,7 +460,12 @@ TEST(liblog, __security_buffer) { 


    android_logger_list_close(logger_list);



    EXPECT_EQ(1, count);

    bool clientHasSecurityCredentials = (uid == AID_SYSTEM) || (gid == AID_SYSTEM);

    if (!clientHasSecurityCredentials) {

        fprintf(stderr, "WARNING: "

                "not system, content submitted but can not check end-to-end\n");

    }

    EXPECT_EQ(clientHasSecurityCredentials ? 1 : 0, count);



}

logd/FlushCommand.cpp

+8 −0
Original line number Diff line number Diff line
@@ -93,3 +93,11 @@ void FlushCommand::runSocketCommand(SocketClient *client) { 
bool FlushCommand::hasReadLogs(SocketClient *client) {

    return clientHasLogCredentials(client);

}



static bool clientHasSecurityCredentials(SocketClient *client) {

    return (client->getUid() == AID_SYSTEM) || (client->getGid() == AID_SYSTEM);

}



bool FlushCommand::hasSecurityLogs(SocketClient *client) {

    return clientHasSecurityCredentials(client);

}

logd/FlushCommand.h

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ public: 
    virtual void runSocketCommand(SocketClient *client);



    static bool hasReadLogs(SocketClient *client);

    static bool hasSecurityLogs(SocketClient *client);

};



#endif

logd/LogBuffer.cpp

+6 −1
Original line number Diff line number Diff line
@@ -907,7 +907,8 @@ unsigned long LogBuffer::getSize(log_id_t id) { 
}



uint64_t LogBuffer::flushTo(

        SocketClient *reader, const uint64_t start, bool privileged,

        SocketClient *reader, const uint64_t start,

        bool privileged, bool security,

        int (*filter)(const LogBufferElement *element, void *arg), void *arg) {

    LogBufferElementCollection::iterator it;

    uint64_t max = start;
@@ -938,6 +939,10 @@ uint64_t LogBuffer::flushTo( 
            continue;

        }



        if (!security && (element->getLogId() == LOG_ID_SECURITY)) {

            continue;

        }



        if (element->getSequence() <= start) {

            continue;

        }

logd/LogBuffer.h

+1 −1
Original line number Diff line number Diff line
@@ -111,7 +111,7 @@ public: 
            uid_t uid, pid_t pid, pid_t tid,

            const char *msg, unsigned short len);

    uint64_t flushTo(SocketClient *writer, const uint64_t start,

                     bool privileged,

                     bool privileged, bool security,

                     int (*filter)(const LogBufferElement *element, void *arg) = NULL,

                     void *arg = NULL);