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Commit ed777e9e authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

logd: serialize accesses to stats helpers 

Quick low-risk to resolve possible hash table corruption.
Resolved an unlikely path memory leak.

ToDo: replace lock with nested lock so no lock
      helpers are required.

Bug: 22068332
Change-Id: I303ab06608502c7d61d42f111a9c43366f184d0c
parent 1a3334f2

logd/LogAudit.cpp

+11 −2
Original line number Diff line number Diff line
@@ -145,7 +145,9 @@ int LogAudit::logPrint(const char *fmt, ...) { 
            ++cp;

        }

        tid = pid;

        logbuf->lock();

        uid = logbuf->pidToUid(pid);

        logbuf->unlock();

        memmove(pidptr, cp, strlen(cp) + 1);

    }
@@ -180,15 +182,21 @@ int LogAudit::logPrint(const char *fmt, ...) { 
    static const char comm_str[] = " comm=\"";

    const char *comm = strstr(str, comm_str);

    const char *estr = str + strlen(str);

    char *commfree = NULL;

    if (comm) {

        estr = comm;

        comm += sizeof(comm_str) - 1;

    } else if (pid == getpid()) {

        pid = tid;

        comm = "auditd";

    } else if (!(comm = logbuf->pidToName(pid))) {

    } else {

        logbuf->lock();

        comm = commfree = logbuf->pidToName(pid);

        logbuf->unlock();

        if (!comm) {

            comm = "unknown";

        }

    }



    const char *ecomm = strchr(comm, '"');

    if (ecomm) {
@@ -218,6 +226,7 @@ int LogAudit::logPrint(const char *fmt, ...) { 
        }

    }



    free(commfree);

    free(str);



    if (notify) {

logd/LogBuffer.h

+3 −1
Original line number Diff line number Diff line
@@ -71,10 +71,12 @@ public: 
    // *strp uses malloc, use free to release.

    void formatPrune(char **strp) { mPrune.format(strp); }



    // helper

    // helper must be protected directly or implicitly by lock()/unlock()

    char *pidToName(pid_t pid) { return stats.pidToName(pid); }

    uid_t pidToUid(pid_t pid) { return stats.pidToUid(pid); }

    char *uidToName(uid_t uid) { return stats.uidToName(uid); }

    void lock() { pthread_mutex_lock(&mLogElementsLock); }

    void unlock() { pthread_mutex_unlock(&mLogElementsLock); }



private:

    void maybePrune(log_id_t id);

logd/LogBufferElement.cpp

+4 −0
Original line number Diff line number Diff line
@@ -111,13 +111,17 @@ size_t LogBufferElement::populateDroppedMessage(char *&buffer, 
    }



    static const char format_uid[] = "uid=%u%s%s expire %u line%s";

    parent->lock();

    char *name = parent->uidToName(mUid);

    parent->unlock();

    char *commName = android::tidToName(mTid);

    if (!commName && (mTid != mPid)) {

        commName = android::tidToName(mPid);

    }

    if (!commName) {

        parent->lock();

        commName = parent->pidToName(mPid);

        parent->unlock();

    }

    size_t len = name ? strlen(name) : 0;

    if (len && commName && !strncmp(name, commName, len)) {

logd/LogStatistics.h

+1 −1
Original line number Diff line number Diff line
@@ -334,7 +334,7 @@ public: 
    // *strp = malloc, balance with free

    void format(char **strp, uid_t uid, unsigned int logMask);



    // helper

    // helper (must be locked directly or implicitly by mLogElementsLock)

    char *pidToName(pid_t pid);

    uid_t pidToUid(pid_t pid);

    char *uidToName(uid_t uid);