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Commit 40da03b7 authored by Tom Cherry's avatar Tom Cherry
Browse files

Revert "logd: validate and fill in socket credentials" 

We don't want to fake socket credentials if they were not provided by
the kernel.  If there is a bug preventing us from reading the
credentials then it must be solved directly.

Test: logd, liblog unit tests
Test: boot and ensure overflow uid doesn't show up

This reverts commit c4e4823b.

Change-Id: I683129a8a214637635f163ae25c39bb8a47cd50f
parent 52f61717

logd/LogBuffer.h

+1 −6
Original line number Diff line number Diff line
@@ -159,12 +159,7 @@ class LogBuffer : public LogBufferInterface { 
    const char* pidToName(pid_t pid) {

        return stats.pidToName(pid);

    }

    virtual uid_t pidToUid(pid_t pid) override {

        return stats.pidToUid(pid);

    }

    virtual pid_t tidToPid(pid_t tid) override {

        return stats.tidToPid(tid);

    }

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

    const char* uidToName(uid_t uid) {

        return stats.uidToName(uid);

    }

logd/LogBufferInterface.cpp

+1 −9
Original line number Diff line number Diff line
@@ -15,15 +15,7 @@ 
 */



#include "LogBufferInterface.h"

#include "LogUtils.h"



LogBufferInterface::LogBufferInterface() {

}

LogBufferInterface::~LogBufferInterface() {

}

uid_t LogBufferInterface::pidToUid(pid_t pid) {

    return android::pidToUid(pid);

}

pid_t LogBufferInterface::tidToPid(pid_t tid) {

    return android::tidToPid(tid);

}
 
LogBufferInterface::~LogBufferInterface() {}
 
 No newline at end of file

logd/LogBufferInterface.h

+0 −3
Original line number Diff line number Diff line
@@ -33,9 +33,6 @@ class LogBufferInterface { 
    virtual int log(log_id_t log_id, log_time realtime, uid_t uid, pid_t pid,

                    pid_t tid, const char* msg, uint16_t len) = 0;



    virtual uid_t pidToUid(pid_t pid);

    virtual pid_t tidToPid(pid_t tid);



   private:

    DISALLOW_COPY_AND_ASSIGN(LogBufferInterface);

};

logd/LogListener.cpp

+1 −27
Original line number Diff line number Diff line
@@ -14,9 +14,7 @@ 
 * limitations under the License.

 */



#include <ctype.h>

#include <limits.h>

#include <stdio.h>

#include <sys/cdefs.h>

#include <sys/prctl.h>

#include <sys/socket.h>
@@ -78,11 +76,8 @@ bool LogListener::onDataAvailable(SocketClient* cli) { 
        cmsg = CMSG_NXTHDR(&hdr, cmsg);

    }



    struct ucred fake_cred;

    if (cred == nullptr) {

        cred = &fake_cred;

        cred->pid = 0;

        cred->uid = DEFAULT_OVERFLOWUID;

        return false;

    }



    if (cred->uid == AID_LOGD) {
@@ -106,27 +101,6 @@ bool LogListener::onDataAvailable(SocketClient* cli) { 
        return false;

    }



    // Check credential validity, acquire corrected details if not supplied.

    if (cred->pid == 0) {

        cred->pid = logbuf ? logbuf->tidToPid(header->tid)

                           : android::tidToPid(header->tid);

        if (cred->pid == getpid()) {

            // We expect that /proc/<tid>/ is accessible to self even without

            // readproc group, so that we will always drop messages that come

            // from any of our logd threads and their library calls.

            return false;  // ignore self

        }

    }

    if (cred->uid == DEFAULT_OVERFLOWUID) {

        uid_t uid =

            logbuf ? logbuf->pidToUid(cred->pid) : android::pidToUid(cred->pid);

        if (uid == AID_LOGD) {

            uid = logbuf ? logbuf->pidToUid(header->tid)

                         : android::pidToUid(cred->pid);

        }

        if (uid != AID_LOGD) cred->uid = uid;

    }



    char* msg = ((char*)buffer) + sizeof(android_log_header_t);

    n -= sizeof(android_log_header_t);

logd/LogListener.h

+0 −10
Original line number Diff line number Diff line
@@ -20,16 +20,6 @@ 
#include <sysutils/SocketListener.h>

#include "LogReader.h"



// DEFAULT_OVERFLOWUID is defined in linux/highuid.h, which is not part of

// the uapi headers for userspace to use.  This value is filled in on the

// out-of-band socket credentials if the OS fails to find one available.

// One of the causes of this is if SO_PASSCRED is set, all the packets before

// that point will have this value.  We also use it in a fake credential if

// no socket credentials are supplied.

#ifndef DEFAULT_OVERFLOWUID

#define DEFAULT_OVERFLOWUID 65534

#endif



class LogListener : public SocketListener {

    LogBufferInterface* logbuf;

    LogReader* reader;