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Get rid of constructor/destructor in libzerotierintercept, and simplify a few things.

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This commit is contained in:
Adam Ierymenko 2016-01-11 15:27:22 -08:00
parent ba9fcb31d0
commit c6571073fe
2 changed files with 77 additions and 121 deletions
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173
netcon/Intercept.c
View File

@ -58,15 +58,11 @@
#include "RPC.h" #include "RPC.h"
#include "common.inc.c" #include "common.inc.c"
static void load_symbols(void);
static void set_up_intercept();
/*------------------------------------------------------------------------------ /*------------------------------------------------------------------------------
------------------- Intercept<--->Service Comm mechanisms ---------------------- ------------------- Intercept<--->Service Comm mechanisms ----------------------
------------------------------------------------------------------------------*/ ------------------------------------------------------------------------------*/
static int thispid = -1; static char *network_pathname = (char *)0;
char *network_pathname;
/* Check whether the socket is mapped to the service or not. We /* Check whether the socket is mapped to the service or not. We
need to know if this is a regular AF_LOCAL socket or an end of a socketpair need to know if this is a regular AF_LOCAL socket or an end of a socketpair
@ -87,59 +83,48 @@ static int connected_to_service(int sockfd)
dwr(MSG_DEBUG_EXTRA,"connected_to_service(): Yes, %s\n", addr_un->sun_path); dwr(MSG_DEBUG_EXTRA,"connected_to_service(): Yes, %s\n", addr_un->sun_path);
return 1; return 1;
} }
} }
dwr(MSG_DEBUG_EXTRA,"connected_to_service(): Not connected to service\n"); dwr(MSG_DEBUG_EXTRA,"connected_to_service(): Not connected to service\n");
return 0; return 0;
} }
/*static void my_dest(void) __attribute__ ((destructor));
/*------------------------------------------------------------------------------
------------------------ ctors and dtors (and friends) ------------------------
------------------------------------------------------------------------------*/
static void my_dest(void) __attribute__ ((destructor));
static void my_dest(void) { static void my_dest(void) {
dwr(MSG_DEBUG,"closing connections to service...\n"); dwr(MSG_DEBUG,"closing connections to service...\n");
rpc_mutex_destroy(); rpc_mutex_destroy();
} }*/
static void load_symbols(void)
{
if(thispid == getpid()) {
dwr(MSG_DEBUG,"detected duplicate call to global constructor (pid=%d).\n", thispid);
}
thispid = getpid();
realconnect = dlsym(RTLD_NEXT, "connect");
realbind = dlsym(RTLD_NEXT, "bind");
realaccept = dlsym(RTLD_NEXT, "accept");
reallisten = dlsym(RTLD_NEXT, "listen");
realsocket = dlsym(RTLD_NEXT, "socket");
realbind = dlsym(RTLD_NEXT, "bind");
realsetsockopt = dlsym(RTLD_NEXT, "setsockopt");
realgetsockopt = dlsym(RTLD_NEXT, "getsockopt");
realaccept4 = dlsym(RTLD_NEXT, "accept4");
realclone = dlsym(RTLD_NEXT, "clone");
realclose = dlsym(RTLD_NEXT, "close");
realsyscall = dlsym(RTLD_NEXT, "syscall");
realdup2 = dlsym(RTLD_NEXT, "dup2");
realdup3 = dlsym(RTLD_NEXT, "dup3");
realgetsockname = dlsym(RTLD_NEXT, "getsockname");
}
/* Private Function Prototypes */ /* Private Function Prototypes */
static void _init(void) __attribute__ ((constructor)); /*static void _init(void) __attribute__ ((constructor));
static void _init(void) { set_up_intercept(); } static void _init(void) { set_up_intercept(); } */
/* get symbols and initialize mutexes */ /* get symbols and initialize mutexes */
static void set_up_intercept() static int set_up_intercept()
{ {
network_pathname = getenv("ZT_NC_NETWORK"); if (!realconnect) {
dwr(MSG_DEBUG,"Connecting to service at: %s\n", network_pathname); realconnect = dlsym(RTLD_NEXT, "connect");
if (!getenv("ZT_NC_NETWORK")) realbind = dlsym(RTLD_NEXT, "bind");
return; realaccept = dlsym(RTLD_NEXT, "accept");
/* Hook/intercept Posix net API symbols */ reallisten = dlsym(RTLD_NEXT, "listen");
rpc_mutex_init(); realsocket = dlsym(RTLD_NEXT, "socket");
load_symbols(); realbind = dlsym(RTLD_NEXT, "bind");
realsetsockopt = dlsym(RTLD_NEXT, "setsockopt");
realgetsockopt = dlsym(RTLD_NEXT, "getsockopt");
realaccept4 = dlsym(RTLD_NEXT, "accept4");
realclose = dlsym(RTLD_NEXT, "close");
realsyscall = dlsym(RTLD_NEXT, "syscall");
realgetsockname = dlsym(RTLD_NEXT, "getsockname");
}
if (!network_pathname) {
network_pathname = getenv("ZT_NC_NETWORK");
if (!network_pathname)
return 0;
dwr(MSG_DEBUG,"Connecting to service at: %s\n", network_pathname);
/* Hook/intercept Posix net API symbols */
rpc_mutex_init();
}
return 1;
} }
/*------------------------------------------------------------------------------ /*------------------------------------------------------------------------------
@ -149,10 +134,9 @@ static void set_up_intercept()
/* int socket, int level, int option_name, const void *option_value, socklen_t option_len */ /* int socket, int level, int option_name, const void *option_value, socklen_t option_len */
int setsockopt(SETSOCKOPT_SIG) int setsockopt(SETSOCKOPT_SIG)
{ {
if(realsetsockopt == NULL){ if (!set_up_intercept())
dwr(MSG_ERROR,"setsockopt(): SYMBOL NOT FOUND.\n"); return realsetsockopt(socket, level, option_name, option_value, option_len);
return -1;
}
dwr(MSG_DEBUG,"setsockopt(%d)\n", socket); dwr(MSG_DEBUG,"setsockopt(%d)\n", socket);
/* return(realsetsockopt(socket, level, option_name, option_value, option_len)); */ /* return(realsetsockopt(socket, level, option_name, option_value, option_len)); */
if(level == SOL_IPV6 && option_name == IPV6_V6ONLY) if(level == SOL_IPV6 && option_name == IPV6_V6ONLY)
@ -177,10 +161,9 @@ int setsockopt(SETSOCKOPT_SIG)
/* int sockfd, int level, int optname, void *optval, socklen_t *optlen */ /* int sockfd, int level, int optname, void *optval, socklen_t *optlen */
int getsockopt(GETSOCKOPT_SIG) int getsockopt(GETSOCKOPT_SIG)
{ {
if(realgetsockopt == NULL){ if (!set_up_intercept())
dwr(MSG_ERROR,"getsockopt(): SYMBOL NOT FOUND.\n"); return realgetsockopt(sockfd, level, optname, optval, optlen);
return -1;
}
dwr(MSG_DEBUG,"getsockopt(%d)\n", sockfd); dwr(MSG_DEBUG,"getsockopt(%d)\n", sockfd);
if(!connected_to_service(sockfd)) { if(!connected_to_service(sockfd)) {
return realgetsockopt(sockfd, level, optname, optval, optlen); return realgetsockopt(sockfd, level, optname, optval, optlen);
@ -200,9 +183,10 @@ int getsockopt(GETSOCKOPT_SIG)
/* int socket_family, int socket_type, int protocol /* int socket_family, int socket_type, int protocol
socket() intercept function */ socket() intercept function */
int socket(SOCKET_SIG) int socket(SOCKET_SIG)
{ {
if(realsocket == NULL) if (!set_up_intercept())
set_up_intercept(); return realsocket(socket_family, socket_type, protocol);
dwr(MSG_DEBUG,"socket():\n"); dwr(MSG_DEBUG,"socket():\n");
/* Check that type makes sense */ /* Check that type makes sense */
int flags = socket_type & ~SOCK_TYPE_MASK; int flags = socket_type & ~SOCK_TYPE_MASK;
@ -246,10 +230,9 @@ int socket(SOCKET_SIG)
connect() intercept function */ connect() intercept function */
int connect(CONNECT_SIG) int connect(CONNECT_SIG)
{ {
if(realconnect == NULL){ if (!set_up_intercept())
dwr(MSG_ERROR,"connect(): SYMBOL NOT FOUND.\n"); return realconnect(__fd, __addr, __len);
return -1;
}
dwr(MSG_DEBUG,"connect(%d):\n", __fd); dwr(MSG_DEBUG,"connect(%d):\n", __fd);
struct sockaddr_in *connaddr; struct sockaddr_in *connaddr;
connaddr = (struct sockaddr_in *) __addr; connaddr = (struct sockaddr_in *) __addr;
@ -298,10 +281,9 @@ int connect(CONNECT_SIG)
bind() intercept function */ bind() intercept function */
int bind(BIND_SIG) int bind(BIND_SIG)
{ {
if(realbind == NULL){ if (!set_up_intercept())
dwr(MSG_ERROR,"bind(): SYMBOL NOT FOUND.\n"); return realbind(sockfd, addr, addrlen);
return -1;
}
dwr(MSG_DEBUG,"bind(%d):\n", sockfd); dwr(MSG_DEBUG,"bind(%d):\n", sockfd);
/* Check that this is a valid fd */ /* Check that this is a valid fd */
if(fcntl(sockfd, F_GETFD) < 0) { if(fcntl(sockfd, F_GETFD) < 0) {
@ -353,10 +335,6 @@ int bind(BIND_SIG)
/* int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags */ /* int sockfd, struct sockaddr *addr, socklen_t *addrlen, int flags */
int accept4(ACCEPT4_SIG) int accept4(ACCEPT4_SIG)
{ {
if(realaccept4 == NULL){
dwr(MSG_ERROR,"accept4(): SYMBOL NOT FOUND.\n");
return -1;
}
dwr(MSG_DEBUG,"accept4(%d):\n", sockfd); dwr(MSG_DEBUG,"accept4(%d):\n", sockfd);
if ((flags & SOCK_CLOEXEC)) if ((flags & SOCK_CLOEXEC))
fcntl(sockfd, F_SETFL, FD_CLOEXEC); fcntl(sockfd, F_SETFL, FD_CLOEXEC);
@ -373,10 +351,9 @@ int accept4(ACCEPT4_SIG)
accept() intercept function */ accept() intercept function */
int accept(ACCEPT_SIG) int accept(ACCEPT_SIG)
{ {
if(realaccept == NULL){ if (!set_up_intercept())
dwr(MSG_ERROR,"accept(): SYMBOL NOT FOUND.\n"); return realaccept(sockfd, addr, addrlen);
return -1;
}
dwr(MSG_DEBUG,"accept(%d):\n", sockfd); dwr(MSG_DEBUG,"accept(%d):\n", sockfd);
/* Check that this is a valid fd */ /* Check that this is a valid fd */
if(fcntl(sockfd, F_GETFD) < 0) { if(fcntl(sockfd, F_GETFD) < 0) {
@ -441,10 +418,9 @@ int accept(ACCEPT_SIG)
/* int sockfd, int backlog */ /* int sockfd, int backlog */
int listen(LISTEN_SIG) int listen(LISTEN_SIG)
{ {
if(reallisten == NULL){ if (!set_up_intercept())
dwr(MSG_ERROR,"listen(): SYMBOL NOT FOUND.\n"); return(reallisten(sockfd, backlog));
return -1;
}
dwr(MSG_DEBUG,"listen(%d):\n", sockfd); dwr(MSG_DEBUG,"listen(%d):\n", sockfd);
int sock_type; int sock_type;
socklen_t sock_type_len = sizeof(sock_type); socklen_t sock_type_len = sizeof(sock_type);
@ -479,23 +455,6 @@ int listen(LISTEN_SIG)
return rpc_send_command(RPC_LISTEN, sockfd, &rpc_st, sizeof(struct listen_st)); return rpc_send_command(RPC_LISTEN, sockfd, &rpc_st, sizeof(struct listen_st));
} }
/*------------------------------------------------------------------------------
-------------------------------------- clone() ---------------------------------
------------------------------------------------------------------------------*/
/* int (*fn)(void *), void *child_stack, int flags, void *arg, ... */
int clone(CLONE_SIG)
{
if(realclone == NULL){
dwr(MSG_ERROR,"clone(): SYMBOL NOT FOUND.\n");
return -1;
}
dwr(MSG_DEBUG,"clone()\n");
int err = realclone(fn, child_stack, flags, arg);
set_up_intercept();
return err;
}
/*------------------------------------------------------------------------------ /*------------------------------------------------------------------------------
------------------------------------- close() ---------------------------------- ------------------------------------- close() ----------------------------------
------------------------------------------------------------------------------*/ ------------------------------------------------------------------------------*/
@ -504,8 +463,7 @@ int clone(CLONE_SIG)
int close(CLOSE_SIG) int close(CLOSE_SIG)
{ {
dwr(MSG_DEBUG, "close(%d)\n", fd); dwr(MSG_DEBUG, "close(%d)\n", fd);
if(realclose == NULL) set_up_intercept();
set_up_intercept();
return realclose(fd); return realclose(fd);
} }
@ -516,10 +474,9 @@ int close(CLOSE_SIG)
/* int sockfd, struct sockaddr *addr, socklen_t *addrlen */ /* int sockfd, struct sockaddr *addr, socklen_t *addrlen */
int getsockname(GETSOCKNAME_SIG) int getsockname(GETSOCKNAME_SIG)
{ {
if (realgetsockname == NULL) { if (!set_up_intercept())
dwr(MSG_ERROR,"getsockname(): SYMBOL NOT FOUND. \n"); return realgetsockname(sockfd, addr, addrlen);
return -1;
}
dwr(MSG_DEBUG,"getsockname(%d)\n", sockfd); dwr(MSG_DEBUG,"getsockname(%d)\n", sockfd);
if(connected_to_service(sockfd) == 0) { if(connected_to_service(sockfd) == 0) {
dwr(MSG_DEBUG,"getsockname(): not used by service\n"); dwr(MSG_DEBUG,"getsockname(): not used by service\n");
@ -537,11 +494,11 @@ int getsockname(GETSOCKNAME_SIG)
/* read address info from service */ /* read address info from service */
char addrbuf[sizeof(struct sockaddr_storage)]; char addrbuf[sizeof(struct sockaddr_storage)];
memset(&addrbuf, 0, sizeof(struct sockaddr_storage)); memset(&addrbuf, 0, sizeof(struct sockaddr_storage));
if(rpcfd > -1) if(rpcfd > -1)
if(read(rpcfd, &addrbuf, sizeof(struct sockaddr_storage)) > 0) if(read(rpcfd, &addrbuf, sizeof(struct sockaddr_storage)) > 0)
close(rpcfd); close(rpcfd);
struct sockaddr_storage sock_storage; struct sockaddr_storage sock_storage;
memcpy(&sock_storage, addrbuf, sizeof(struct sockaddr_storage)); memcpy(&sock_storage, addrbuf, sizeof(struct sockaddr_storage));
*addrlen = sizeof(struct sockaddr_in); *addrlen = sizeof(struct sockaddr_in);
@ -554,8 +511,8 @@ int getsockname(GETSOCKNAME_SIG)
------------------------------------ syscall() --------------------------------- ------------------------------------ syscall() ---------------------------------
------------------------------------------------------------------------------*/ ------------------------------------------------------------------------------*/
long syscall(SYSCALL_SIG){ long syscall(SYSCALL_SIG)
dwr(MSG_DEBUG_EXTRA,"syscall(%u, ...):\n", number); {
va_list ap; va_list ap;
uintptr_t a,b,c,d,e,f; uintptr_t a,b,c,d,e,f;
va_start(ap, number); va_start(ap, number);
@ -567,8 +524,10 @@ long syscall(SYSCALL_SIG){
f=va_arg(ap, uintptr_t); f=va_arg(ap, uintptr_t);
va_end(ap); va_end(ap);
if(realsyscall == NULL) if (!set_up_intercept())
return -1; return realsyscall(number,a,b,c,d,e,f);
dwr(MSG_DEBUG_EXTRA,"syscall(%u, ...):\n", number);
#if defined(__i386__) #if defined(__i386__)
/* TODO: Implement for 32-bit systems: syscall(__NR_socketcall, 18, args); /* TODO: Implement for 32-bit systems: syscall(__NR_socketcall, 18, args);

25
netcon/Intercept.h
View File

@ -69,19 +69,16 @@ int dup2(DUP2_SIG);
int dup3(DUP3_SIG); int dup3(DUP3_SIG);
int getsockname(GETSOCKNAME_SIG); int getsockname(GETSOCKNAME_SIG);
static int (*realconnect)(CONNECT_SIG); static int (*realconnect)(CONNECT_SIG) = 0;
static int (*realbind)(BIND_SIG); static int (*realbind)(BIND_SIG) = 0;
static int (*realaccept)(ACCEPT_SIG); static int (*realaccept)(ACCEPT_SIG) = 0;
static int (*reallisten)(LISTEN_SIG); static int (*reallisten)(LISTEN_SIG) = 0;
static int (*realsocket)(SOCKET_SIG); static int (*realsocket)(SOCKET_SIG) = 0;
static int (*realsetsockopt)(SETSOCKOPT_SIG); static int (*realsetsockopt)(SETSOCKOPT_SIG) = 0;
static int (*realgetsockopt)(GETSOCKOPT_SIG); static int (*realgetsockopt)(GETSOCKOPT_SIG) = 0;
static int (*realaccept4)(ACCEPT4_SIG); static int (*realaccept4)(ACCEPT4_SIG) = 0;
static long (*realsyscall)(SYSCALL_SIG); static long (*realsyscall)(SYSCALL_SIG) = 0;
static int (*realclose)(CLOSE_SIG); static int (*realclose)(CLOSE_SIG) = 0;
static int (*realclone)(CLONE_SIG); static int (*realgetsockname)(GETSOCKNAME_SIG) = 0;
static int (*realdup2)(DUP2_SIG);
static int (*realdup3)(DUP3_SIG);
static int (*realgetsockname)(GETSOCKNAME_SIG);
#endif #endif