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Commit 8ab18ba2 authored by Praveen Moongalam Thyagarajan's avatar Praveen Moongalam Thyagarajan Committed by Ken Chen
Browse files

Support RDNS on cache and uid/pid tagging 

RDNS on local cache

Function that performs RDNS on local cache. Takes
ip address and net id as input and gives domain
name as output.

Tag DNS query

Function that tags the uid and pid of the application
that sends DNS query.

Bug: 131051938
Test: build, flash, boot

Change-Id: I34abfc63d65f37e00dd813c9121ff483e4f85e7d
parent 7803769c

DnsProxyListener.cpp

+6 −5
Original line number Diff line number Diff line
@@ -147,7 +147,7 @@ bool hasPermissionToBypassPrivateDns(uid_t uid) { 
    return false;

}



void maybeFixupNetContext(android_net_context* ctx) {

void maybeFixupNetContext(android_net_context* ctx, pid_t pid) {

    if (requestingUseLocalNameservers(ctx->flags) && !hasPermissionToBypassPrivateDns(ctx->uid)) {

        // Not permitted; clear the flag.

        ctx->flags &= ~NET_CONTEXT_FLAG_USE_LOCAL_NAMESERVERS;
@@ -161,6 +161,7 @@ void maybeFixupNetContext(android_net_context* ctx) { 
            ctx->flags |= NET_CONTEXT_FLAG_USE_DNS_OVER_TLS | NET_CONTEXT_FLAG_USE_EDNS;

        }

    }

    ctx->pid = pid;

}



void addIpAddrWithinLimit(std::vector<std::string>* ip_addrs, const sockaddr* addr,
@@ -669,7 +670,7 @@ void DnsProxyListener::GetAddrInfoHandler::run() { 


    addrinfo* result = nullptr;

    Stopwatch s;

    maybeFixupNetContext(&mNetContext);

    maybeFixupNetContext(&mNetContext, mClient->getPid());

    const uid_t uid = mClient->getUid();

    int32_t rv = 0;

    NetworkDnsEventReported event;
@@ -856,7 +857,7 @@ void DnsProxyListener::ResNSendHandler::run() { 
               << mNetContext.dns_mark << " " << mNetContext.uid << " " << mNetContext.flags << "}";



    Stopwatch s;

    maybeFixupNetContext(&mNetContext);

    maybeFixupNetContext(&mNetContext, mClient->getPid());



    // Decode

    std::vector<uint8_t> msg(MAXPACKET, 0);
@@ -1073,7 +1074,7 @@ void DnsProxyListener::GetHostByNameHandler::doDns64Synthesis(int32_t* rv, hoste 


void DnsProxyListener::GetHostByNameHandler::run() {

    Stopwatch s;

    maybeFixupNetContext(&mNetContext);

    maybeFixupNetContext(&mNetContext, mClient->getPid());

    const uid_t uid = mClient->getUid();

    hostent* hp = nullptr;

    hostent hbuf;
@@ -1236,7 +1237,7 @@ void DnsProxyListener::GetHostByAddrHandler::doDns64ReverseLookup(hostent* hbuf, 


void DnsProxyListener::GetHostByAddrHandler::run() {

    Stopwatch s;

    maybeFixupNetContext(&mNetContext);

    maybeFixupNetContext(&mNetContext, mClient->getPid());

    const uid_t uid = mClient->getUid();

    hostent* hp = nullptr;

    hostent hbuf;

DnsTlsSocket.cpp

+2 −1
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <netdutils/SocketOption.h>

#include <netdutils/ThreadUtil.h>



#include "netd_resolv/resolv.h"

#include "private/android_filesystem_config.h"  // AID_DNS

#include "resolv_private.h"
@@ -95,7 +96,7 @@ Status DnsTlsSocket::tcpConnect() { 
        return Status(errno);

    }



    resolv_tag_socket(mSslFd.get(), AID_DNS);

    resolv_tag_socket(mSslFd.get(), AID_DNS, NET_CONTEXT_INVALID_PID);



    const socklen_t len = sizeof(mMark);

    if (setsockopt(mSslFd.get(), SOL_SOCKET, SO_MARK, &mMark, len) == -1) {

getaddrinfo.cpp

+1 −0
Original line number Diff line number Diff line
@@ -266,6 +266,7 @@ int getaddrinfo_numeric(const char* hostname, const char* servname, addrinfo hin 
            .dns_netid = NETID_UNSET,

            .dns_mark = MARK_UNSET,

            .uid = NET_CONTEXT_INVALID_UID,

            .pid = NET_CONTEXT_INVALID_PID,

    };

    NetworkDnsEventReported event;

    return android_getaddrinfofornetcontext(hostname, servname, &hints, &netcontext, result,

include/netd_resolv/resolv.h

+15 −3
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 


#include "params.h"



#include <arpa/nameser.h>

#include <netinet/in.h>



/*
@@ -43,6 +44,9 @@ 
 */

#define MARK_UNSET 0u



#define NET_CONTEXT_INVALID_UID ((uid_t)-1)

#define NET_CONTEXT_INVALID_PID ((pid_t)-1)



/*

 * A struct to capture context relevant to network operations.

 *
@@ -59,11 +63,12 @@ struct android_net_context { 
    unsigned app_mark;

    unsigned dns_netid;

    unsigned dns_mark;

    uid_t uid;

    uid_t uid = NET_CONTEXT_INVALID_UID;

    unsigned flags;

    // Variable to store the pid of the application sending DNS query.

    pid_t pid = NET_CONTEXT_INVALID_PID;

};



#define NET_CONTEXT_INVALID_UID ((uid_t) -1)

#define NET_CONTEXT_FLAG_USE_LOCAL_NAMESERVERS 0x00000001

#define NET_CONTEXT_FLAG_USE_EDNS 0x00000002

#define NET_CONTEXT_FLAG_USE_DNS_OVER_TLS 0x00000004
@@ -74,7 +79,7 @@ typedef bool (*check_calling_permission_callback)(const char* permission); 
typedef void (*get_network_context_callback)(unsigned netid, uid_t uid,

                                             android_net_context* netcontext);

typedef void (*log_callback)(const char* msg);

typedef int (*tagSocketCallback)(int sockFd, uint32_t tag, uid_t uid);

typedef int (*tagSocketCallback)(int sockFd, uint32_t tag, uid_t uid, pid_t pid);



/*

 * Some functions needed by the resolver (e.g. checkCallingPermission()) live in
@@ -95,3 +100,10 @@ LIBNETD_RESOLV_PUBLIC bool resolv_has_nameservers(unsigned netid); 


// Set callbacks and bring DnsResolver up.

LIBNETD_RESOLV_PUBLIC bool resolv_init(const ResolverNetdCallbacks* callbacks);



// Function that performs RDNS in local cache. The |domain_name_size| is the size of domain_name

// buffer, which is recommended to NS_MAXDNAME. Function return false if hostname not found or

// domain_name_size > NS_MAXDNAME.

LIBNETD_RESOLV_PUBLIC bool resolv_gethostbyaddr_from_local_cache(unsigned netId, char domain_name[],

                                                                 unsigned domain_name_size,

                                                                 char* ip_address);

include/netd_resolv/resolv_stub.h

+3 −0
Original line number Diff line number Diff line
@@ -37,6 +37,9 @@ extern struct ResolvStub { 
    bool (*resolv_has_nameservers)(unsigned netid);



    bool (*resolv_init)(const ResolverNetdCallbacks& callbacks);



    bool (*resolv_gethostbyaddr_from_local_cache)(unsigned netId, char domain_name[],

                                                  unsigned domain_name_size, char* ip_address);

} RESOLV_STUB;



int resolv_stub_init();