[PATCH] selinux_testsuite: Add socketpair test

[PATCH] selinux_testsuite: Add socketpair test

[Richard Haines]

Test SO_PEERSEC for sockets created by socketpair(2) added in kernel 4.18

Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
---
 policy/test_unix_socket.te     |   7 ++
 tests/unix_socket/.gitignore   |   1 +
 tests/unix_socket/Makefile     |   5 +
 tests/unix_socket/socketpair.c | 190 +++++++++++++++++++++++++++++++++
 tests/unix_socket/test         |  26 ++++-
 5 files changed, 226 insertions(+), 3 deletions(-)
 create mode 100644 tests/unix_socket/socketpair.c

diff --git a/policy/test_unix_socket.te b/policy/test_unix_socket.te
index 7dd3362..0ff790a 100644
--- a/policy/test_unix_socket.te
+++ b/policy/test_unix_socket.te
@@ -60,6 +60,13 @@ allow test_unix_dgram_client_t test_unix_server_t:unix_dgram_socket sendto;
 allow test_unix_server_t test_unix_client_sockfile_t:sock_file write;
 allow test_unix_server_t test_unix_dgram_client_t:unix_dgram_socket sendto;
 
+# Domain for socketpair(2) process.
+type test_socketpair_t;
+domain_type(test_socketpair_t)
+unconfined_runs_test(test_socketpair_t)
+typeattribute test_socketpair_t testdomain;
+typeattribute test_socketpair_t unixsocketdomain;
+
 # Allow all of these domains to be entered from the sysadm domain.
 miscfiles_domain_entry_test_files(unixsocketdomain)
 userdom_sysadm_entry_spec_domtrans_to(unixsocketdomain)
diff --git a/tests/unix_socket/.gitignore b/tests/unix_socket/.gitignore
index f2ad853..05ed268 100644
--- a/tests/unix_socket/.gitignore
+++ b/tests/unix_socket/.gitignore
@@ -1,2 +1,3 @@
 client
 server
+socketpair
diff --git a/tests/unix_socket/Makefile b/tests/unix_socket/Makefile
index 5266096..7770f0b 100644
--- a/tests/unix_socket/Makefile
+++ b/tests/unix_socket/Makefile
@@ -2,6 +2,11 @@ TARGETS=client server
 
 LDLIBS+= -lselinux
 
+# Test SO_PEERSEC for sockets created by socketpair(2).
+ifneq ($(shell ../kvercmp $$(uname -r) 4.18),-1)
+	TARGETS += socketpair
+endif
+
 all: $(TARGETS)
 clean:
 	rm -f $(TARGETS)
diff --git a/tests/unix_socket/socketpair.c b/tests/unix_socket/socketpair.c
new file mode 100644
index 0000000..50cd3fa
--- /dev/null
+++ b/tests/unix_socket/socketpair.c
@@ -0,0 +1,190 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stddef.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <selinux/selinux.h>
+
+#ifndef SO_PEERSEC
+#define SO_PEERSEC 31
+#endif
+
+#ifndef SCM_SECURITY
+#define SCM_SECURITY 0x03
+#endif
+
+void print_usage(char *progname)
+{
+	fprintf(stderr,
+		"usage:  %s stream|dgram\n"
+		"Where:\n\t"
+		"stream     Use TCP protocol or:\n\t"
+		"dgram      use UDP protocol.\n", progname);
+	exit(-1);
+}
+
+int run_parent(int sock, int type)
+{
+	int result, on = 1;
+	char byte, peerlabel[256];
+	socklen_t labellen = sizeof(peerlabel);
+
+	result = setsockopt(sock, SOL_SOCKET, SO_PASSSEC, &on, sizeof(on));
+	if (result < 0) {
+		perror("setsockopt: SO_PASSSEC");
+		goto err;
+	}
+
+	if (type == SOCK_STREAM) {
+		result = read(sock, &byte, 1);
+		if (result < 0) {
+			perror("read");
+			goto err;
+		}
+
+		result = getsockopt(sock, SOL_SOCKET, SO_PEERSEC, peerlabel,
+				    &labellen);
+		if (result < 0) {
+			perror("getsockopt: SO_PEERSEC");
+			goto err;
+		}
+		printf("Parent got peer label=%s\n", peerlabel);
+
+		result = write(sock, peerlabel, sizeof(peerlabel));
+		if (result < 0) {
+			perror("write");
+			goto err;
+		}
+	} else {
+		struct iovec iov;
+		struct msghdr msg;
+		struct cmsghdr *cmsg;
+		char msglabel[256];
+		union {
+			struct cmsghdr cmsghdr;
+			char buf[CMSG_SPACE(sizeof(msglabel))];
+		} control;
+
+		memset(&iov, 0, sizeof(iov));
+		iov.iov_base = &byte;
+		iov.iov_len = 1;
+		memset(&msg, 0, sizeof(msg));
+		msg.msg_iov = &iov;
+		msg.msg_iovlen = 1;
+		msg.msg_control = &control;
+		msg.msg_controllen = sizeof(control);
+		result = recvmsg(sock, &msg, 0);
+		if (result < 0) {
+			perror("recvmsg");
+			goto err;
+		}
+
+		for (cmsg = CMSG_FIRSTHDR(&msg); cmsg;
+		     cmsg = CMSG_NXTHDR(&msg, cmsg)) {
+			;
+			if (cmsg->cmsg_level == SOL_SOCKET &&
+			    cmsg->cmsg_type == SCM_SECURITY) {
+				size_t len = cmsg->cmsg_len - CMSG_LEN(0);
+
+				if (len > 0 && len < sizeof(msglabel)) {
+					memcpy(msglabel, CMSG_DATA(cmsg), len);
+					msglabel[len] = 0;
+					printf("Parent got SCM_SECURITY=%s\n",
+					       msglabel);
+				}
+			}
+		}
+
+		result = sendto(sock, msglabel, strlen(msglabel), 0,
+				msg.msg_name, msg.msg_namelen);
+		if (result < 0) {
+			perror("sendto");
+			goto err;
+		}
+	}
+
+	result = 0;
+err:
+	close(sock);
+	return result;
+}
+
+int run_child(int sock)
+{
+	int result;
+	char byte = 0, label[256], *mycon;
+
+	result = write(sock, &byte, 1);
+	if (result < 0) {
+		perror("write");
+		goto err;
+	}
+
+	result = read(sock, label, sizeof(label));
+	if (result < 0) {
+		perror("read");
+		goto err;
+	}
+	label[result] = 0;
+
+	result = getcon(&mycon);
+	if (result < 0) {
+		perror("getcon");
+		goto err1;
+	}
+
+	if (strcmp(mycon, label)) {
+		fprintf(stderr, "Child expected %s, got %s\n", mycon, label);
+		result = -1;
+		goto err1;
+	}
+
+	result = 0;
+err1:
+	free(mycon);
+err:
+	close(sock);
+	return result;
+}
+
+int main(int argc, char **argv)
+{
+	int type, result, sockets[2];
+
+	if (argc != 2)
+		print_usage(argv[0]);
+
+	if (!strcmp(argv[1], "stream"))
+		type = SOCK_STREAM;
+	else if (!strcmp(argv[1], "dgram"))
+		type = SOCK_DGRAM;
+	else
+		print_usage(argv[0]);
+
+	result = socketpair(AF_UNIX, type, 0, sockets);
+	if (result < 0) {
+		perror("socketpair");
+		return -1;
+	}
+
+	result = fork();
+	if (result < 0) {
+		perror("fork");
+		close(sockets[0]);
+		close(sockets[1]);
+		return -1;
+	} else if (result > 0) {
+		close(sockets[0]);
+		result = run_parent(sockets[1], type);
+		return result;
+
+	} else {
+		close(sockets[1]);
+		result = run_child(sockets[0]);
+		return result;
+	}
+}
diff --git a/tests/unix_socket/test b/tests/unix_socket/test
index f5f03e8..48dde29 100755
--- a/tests/unix_socket/test
+++ b/tests/unix_socket/test
@@ -1,10 +1,21 @@
 #!/usr/bin/perl
 
 use Test;
-BEGIN { plan tests => 8 }
 
-$basedir = $0;
-$basedir =~ s|(.*)/[^/]*|$1|;
+BEGIN {
+    $basedir = $0;
+    $basedir =~ s|(.*)/[^/]*|$1|;
+
+    $test_count = 8;
+    $socketpair = 0;
+
+    if ( -e "$basedir/socketpair" ) {
+        $test_count += 2;
+        $socketpair = 1;
+    }
+
+    plan tests => $test_count;
+}
 
 #
 # Tests for sockets in the abstract namespace.
@@ -106,4 +117,13 @@ server_end($pid);
 # Clean up.
 system "rm -f $basedir/test_client_sock $basedir/test_server_sock";
 
+if ($socketpair) {
+    #### Test SO_PEERSEC for sockets created by socketpair(2) #####
+    $result = system "runcon -t test_socketpair_t $basedir/socketpair stream";
+    ok( $result, 0 );
+
+    $result = system "runcon -t test_socketpair_t $basedir/socketpair dgram";
+    ok( $result, 0 );
+}
+
 exit;
-- 
2.23.0

Re: [PATCH] selinux_testsuite: Add socketpair test

[Stephen Smalley]

On 12/4/19 9:32 AM, Richard Haines wrote:
> Test SO_PEERSEC for sockets created by socketpair(2) added in kernel 4.18
> 
> Signed-off-by: Richard Haines <richard_c_haines@btinternet.com>
> ---

> diff --git a/tests/unix_socket/Makefile b/tests/unix_socket/Makefile
> index 5266096..7770f0b 100644
> --- a/tests/unix_socket/Makefile
> +++ b/tests/unix_socket/Makefile
> @@ -2,6 +2,11 @@ TARGETS=client server
>   
>   LDLIBS+= -lselinux
>   
> +# Test SO_PEERSEC for sockets created by socketpair(2).
> +ifneq ($(shell ../kvercmp $$(uname -r) 4.18),-1)
> +	TARGETS += socketpair
> +endif
> +
>   all: $(TARGETS)
>   clean:
>   	rm -f $(TARGETS)

Wondering if we ought to unconditionally build all targets and only 
perform the kvercmp test in the test script itself, as we do in binder, 
inet_socket, keys, and sctp?  Only need to conditionalize the build if 
it won't build under older kernels.

> diff --git a/tests/unix_socket/socketpair.c b/tests/unix_socket/socketpair.c
> new file mode 100644
> index 0000000..50cd3fa
> --- /dev/null
> +++ b/tests/unix_socket/socketpair.c
> @@ -0,0 +1,190 @@
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <stddef.h>
> +#include <string.h>
> +#include <unistd.h>
> +#include <fcntl.h>
> +#include <errno.h>
> +#include <sys/types.h>
> +#include <sys/socket.h>
> +#include <selinux/selinux.h>
> +
> +#ifndef SO_PEERSEC
> +#define SO_PEERSEC 31
> +#endif
> +
> +#ifndef SCM_SECURITY
> +#define SCM_SECURITY 0x03
> +#endif
> +
> +void print_usage(char *progname)
> +{
> +	fprintf(stderr,
> +		"usage:  %s stream|dgram\n"
> +		"Where:\n\t"
> +		"stream     Use TCP protocol or:\n\t"
> +		"dgram      use UDP protocol.\n", progname);
> +	exit(-1);
> +}
> +
> +int run_parent(int sock, int type)
> +{
> +	int result, on = 1;
> +	char byte, peerlabel[256];
> +	socklen_t labellen = sizeof(peerlabel);
> +
> +	result = setsockopt(sock, SOL_SOCKET, SO_PASSSEC, &on, sizeof(on));
> +	if (result < 0) {
> +		perror("setsockopt: SO_PASSSEC");
> +		goto err;
> +	}
> +
> +	if (type == SOCK_STREAM) {
> +		result = read(sock, &byte, 1);
> +		if (result < 0) {
> +			perror("read");
> +			goto err;
> +		}
> +
> +		result = getsockopt(sock, SOL_SOCKET, SO_PEERSEC, peerlabel,
> +				    &labellen);
> +		if (result < 0) {
> +			perror("getsockopt: SO_PEERSEC");
> +			goto err;
> +		}
> +		printf("Parent got peer label=%s\n", peerlabel);
> +
> +		result = write(sock, peerlabel, sizeof(peerlabel));

You should be writing labellen bytes or strlen(peerlabel) bytes rather 
than sizeof(peerlabel); otherwise you are sending extra uninitialized 
bytes from the stack to the peer.  Looks like elsewhere we are sending 
strlen() of the label.