[tor-commits] [torsocks/master] Add syscall(2) support
dgoulet at torproject.org
dgoulet at torproject.org
Fri Apr 4 22:40:25 UTC 2014
commit ce460ba3e9931a5ab8d7f27c9dc46eb325bcbf07
Author: David Goulet <dgoulet at ev0ke.net>
Date: Wed Aug 7 08:01:28 2013 -0400
Add syscall(2) support
At this commit, only close, connect and socket are handled through
syscall(2).
Signed-off-by: David Goulet <dgoulet at ev0ke.net>
---
src/lib/Makefile.am | 2 +-
src/lib/socket.c | 3 ++
src/lib/syscall.c | 111 +++++++++++++++++++++++++++++++++++++++++++++++++++
src/lib/torsocks.h | 25 ++++++++++++
4 files changed, 140 insertions(+), 1 deletion(-)
diff --git a/src/lib/Makefile.am b/src/lib/Makefile.am
index d107fc8..0f764f1 100644
--- a/src/lib/Makefile.am
+++ b/src/lib/Makefile.am
@@ -12,7 +12,7 @@ lib_LTLIBRARIES = libtorsocks.la
libtorsocks_la_SOURCES = torsocks.c torsocks.h \
connect.c gethostbyname.c getaddrinfo.c close.c \
- getpeername.c socket.c
+ getpeername.c socket.c syscall.c
libtorsocks_la_LIBADD = \
$(top_builddir)/src/common/libcommon.la \
diff --git a/src/lib/socket.c b/src/lib/socket.c
index 69d28e6..1f543e5 100644
--- a/src/lib/socket.c
+++ b/src/lib/socket.c
@@ -26,6 +26,9 @@
*/
LIBC_SOCKET_RET_TYPE tsocks_socket(LIBC_SOCKET_SIG)
{
+ DBG("[socket] Creating socket with domain %d, type %d and protocol %d",
+ __domain, __type, __protocol);
+
switch (__type) {
case SOCK_STREAM:
break;
diff --git a/src/lib/syscall.c b/src/lib/syscall.c
new file mode 100644
index 0000000..5cb9e8f
--- /dev/null
+++ b/src/lib/syscall.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2013 - David Goulet <dgoulet at ev0ke.net>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <assert.h>
+#include <stdarg.h>
+
+#include <common/log.h>
+
+#include "torsocks.h"
+
+/*
+ * Handle close syscall to be called with tsocks call.
+ */
+static LIBC_CLOSE_RET_TYPE handle_close(va_list args)
+{
+ int fd;
+
+ fd = va_arg(args, int);
+
+ return tsocks_close(fd);
+}
+
+/*
+ * Handle socket syscall to go through Tor.
+ */
+static LIBC_SOCKET_RET_TYPE handle_socket(va_list args)
+{
+ int domain, type, protocol;
+
+ domain = va_arg(args, int);
+ type = va_arg(args, int);
+ protocol = va_arg(args, int);
+
+ return tsocks_socket(domain, type, protocol);
+}
+
+/*
+ * Handle connect syscall to go through Tor.
+ */
+static LIBC_CONNECT_RET_TYPE handle_connect(va_list args)
+{
+ int sockfd;
+ const struct sockaddr *addr;
+ socklen_t addrlen;
+
+ sockfd = va_arg(args, int);
+ addr = va_arg(args, const struct sockaddr *);
+ addrlen = va_arg(args, socklen_t);
+
+ return tsocks_connect(sockfd, addr, addrlen);
+}
+
+/*
+ * Torsocks call for syscall(2)
+ */
+LIBC_SYSCALL_RET_TYPE tsocks_syscall(long int __number, va_list args)
+{
+ long int ret;
+
+ DBG("[syscall] Syscall libc wrapper number %ld called", __number);
+
+ switch (__number) {
+ case __NR_socket:
+ ret = handle_socket(args);
+ break;
+ case __NR_connect:
+ ret = handle_connect(args);
+ break;
+ case __NR_close:
+ ret = handle_close(args);
+ break;
+ default:
+ ret = tsocks_libc_syscall(__number, args);
+ break;
+ }
+
+ return ret;
+}
+
+/*
+ * Libc hijacked symbol syscall(2).
+ */
+LIBC_SYSCALL_DECL
+{
+ LIBC_SYSCALL_RET_TYPE ret;
+ va_list args;
+
+ /* Find symbol if not already set. Exit if not found. */
+ tsocks_libc_syscall = tsocks_find_libc_symbol(LIBC_SYSCALL_NAME_STR,
+ TSOCKS_SYM_EXIT_NOT_FOUND);
+
+ va_start(args, __number);
+ ret = tsocks_syscall(__number, args);
+ va_end(args);
+
+ return ret;
+}
diff --git a/src/lib/torsocks.h b/src/lib/torsocks.h
index b8da8ca..c6191e2 100644
--- a/src/lib/torsocks.h
+++ b/src/lib/torsocks.h
@@ -30,6 +30,8 @@
*/
#define TSOCKS_LIBC_DECL(name, type, sig) \
type (*tsocks_libc_##name)(sig);
+#define TSOCKS_DECL(name, type, sig) \
+ extern type tsocks_##name(sig);
#if (defined(__linux__) || defined(__FreeBSD__) || defined(__darwin__))
@@ -154,6 +156,21 @@ struct hostent **__result, int *__h_errnop
#error "OS not supported."
#endif /* __linux__ , __FreeBSD__, __darwin__ */
+#if (defined(__linux__))
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <sys/syscall.h>
+
+/* syscall(2) */
+#define LIBC_SYSCALL_NAME syscall
+#define LIBC_SYSCALL_NAME_STR XSTR(LIBC_SYSCALL_NAME)
+#define LIBC_SYSCALL_RET_TYPE long int
+#define LIBC_SYSCALL_SIG long int __number, ...
+#define LIBC_SYSCALL_ARGS __number
+
+#endif /* __linux__ */
+
/*
* The following defines are libc function declarations using the macros
* defined above on a per OS basis.
@@ -161,16 +178,24 @@ struct hostent **__result, int *__h_errnop
/* connect(2) */
TSOCKS_LIBC_DECL(connect, LIBC_CONNECT_RET_TYPE, LIBC_CONNECT_SIG)
+TSOCKS_DECL(connect, LIBC_CONNECT_RET_TYPE, LIBC_CONNECT_SIG)
#define LIBC_CONNECT_DECL \
LIBC_CONNECT_RET_TYPE LIBC_CONNECT_NAME(LIBC_CONNECT_SIG)
/* socket(2) */
TSOCKS_LIBC_DECL(socket, LIBC_SOCKET_RET_TYPE, LIBC_SOCKET_SIG)
+TSOCKS_DECL(socket, LIBC_SOCKET_RET_TYPE, LIBC_SOCKET_SIG)
#define LIBC_SOCKET_DECL \
LIBC_SOCKET_RET_TYPE LIBC_SOCKET_NAME(LIBC_SOCKET_SIG)
+/* syscall(2) */
+TSOCKS_LIBC_DECL(syscall, LIBC_SYSCALL_RET_TYPE, LIBC_SYSCALL_SIG)
+#define LIBC_SYSCALL_DECL \
+ LIBC_SYSCALL_RET_TYPE LIBC_SYSCALL_NAME(LIBC_SYSCALL_SIG)
+
/* close(2) */
TSOCKS_LIBC_DECL(close, LIBC_CLOSE_RET_TYPE, LIBC_CLOSE_SIG)
+TSOCKS_DECL(close, LIBC_CLOSE_RET_TYPE, LIBC_CLOSE_SIG)
#define LIBC_CLOSE_DECL \
LIBC_CLOSE_RET_TYPE LIBC_CLOSE_NAME(LIBC_CLOSE_SIG)
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