arch: fix a number of 32-bit x86 failures related to socket syscalls

It turns out there was still a few bugs with the 32-bit x86 socket
syscalls, especially on systems with older kernel headers installed.
This patch corrects these problems and perhaps more importantly,
returns the resolver API functions to returning the negative pseudo
syscall numbers in the case of 32-bit x86, this helps ensure things
continue to work as they did before as the API does not change.

It it important to note that libseccomp still generates filter code
for both multiplexed and direct socket syscalls regardless.

Signed-off-by: Paul Moore <paul@paul-moore.com>

src/arch-x86-syscalls.c

@@ -469,6 +469,48 @@ int x86_syscall_resolve_name(const char *name)
 	const struct arch_syscall_def *table = x86_syscall_table;
 
 	/* XXX - plenty of room for future improvement here */
+
+	if (strcmp(name, "accept") == 0)
+		return __PNR_accept;
+	if (strcmp(name, "accept4") == 0)
+		return __PNR_accept4;
+	else if (strcmp(name, "bind") == 0)
+		return __PNR_bind;
+	else if (strcmp(name, "connect") == 0)
+		return __PNR_connect;
+	else if (strcmp(name, "getpeername") == 0)
+		return __PNR_getpeername;
+	else if (strcmp(name, "getsockname") == 0)
+		return __PNR_getsockname;
+	else if (strcmp(name, "getsockopt") == 0)
+		return __PNR_getsockopt;
+	else if (strcmp(name, "listen") == 0)
+		return __PNR_listen;
+	else if (strcmp(name, "recv") == 0)
+		return __PNR_recv;
+	else if (strcmp(name, "recvfrom") == 0)
+		return __PNR_recvfrom;
+	else if (strcmp(name, "recvmsg") == 0)
+		return __PNR_recvmsg;
+	else if (strcmp(name, "recvmmsg") == 0)
+		return __PNR_recvmmsg;
+	else if (strcmp(name, "send") == 0)
+		return __PNR_send;
+	else if (strcmp(name, "sendmsg") == 0)
+		return __PNR_sendmsg;
+	else if (strcmp(name, "sendmmsg") == 0)
+		return __PNR_sendmmsg;
+	else if (strcmp(name, "sendto") == 0)
+		return __PNR_sendto;
+	else if (strcmp(name, "setsockopt") == 0)
+		return __PNR_setsockopt;
+	else if (strcmp(name, "shutdown") == 0)
+		return __PNR_shutdown;
+	else if (strcmp(name, "socket") == 0)
+		return __PNR_socket;
+	else if (strcmp(name, "socketpair") == 0)
+		return __PNR_socketpair;
+
 	for (iter = 0; table[iter].name != NULL; iter++) {
 		if (strcmp(name, table[iter].name) == 0)
 			return table[iter].num;
@@ -492,6 +534,48 @@ const char *x86_syscall_resolve_num(int num)
 	const struct arch_syscall_def *table = x86_syscall_table;
 
 	/* XXX - plenty of room for future improvement here */
+
+	if (num == __PNR_accept)
+		return "accept";
+	else if (num == __PNR_accept4)
+		return "accept4";
+	else if (num == __PNR_bind)
+		return "bind";
+	else if (num == __PNR_connect)
+		return "connect";
+	else if (num == __PNR_getpeername)
+		return "getpeername";
+	else if (num == __PNR_getsockname)
+		return "getsockname";
+	else if (num == __PNR_getsockopt)
+		return "getsockopt";
+	else if (num == __PNR_listen)
+		return "listen";
+	else if (num == __PNR_recv)
+		return "recv";
+	else if (num == __PNR_recvfrom)
+		return "recvfrom";
+	else if (num == __PNR_recvmsg)
+		return "recvmsg";
+	else if (num == __PNR_recvmmsg)
+		return "recvmmsg";
+	else if (num == __PNR_send)
+		return "send";
+	else if (num == __PNR_sendmsg)
+		return "sendmsg";
+	else if (num == __PNR_sendmmsg)
+		return "sendmmsg";
+	else if (num == __PNR_sendto)
+		return "sendto";
+	else if (num == __PNR_setsockopt)
+		return "setsockopt";
+	else if (num == __PNR_shutdown)
+		return "shutdown";
+	else if (num == __PNR_socket)
+		return "socket";
+	else if (num == __PNR_socketpair)
+		return "socketpair";
+
 	for (iter = 0; table[iter].num != __NR_SCMP_ERROR; iter++) {
 		if (num == table[iter].num)
 			return table[iter].name;

src/arch-x86.c

@@ -104,6 +104,15 @@ int _x86_sock_demux(int socketcall)
 	case -117:
 		/* recvmsg */
 		return 372;
+	case -118:
+		/* accept4 */
+		return 364;
+	case -119:
+		/* recvmmsg */
+		return 337;
+	case -120:
+		/* sendmmsg */
+		return 345;
 	}
 
 	return __NR_SCMP_ERROR;
@@ -120,6 +129,12 @@ int _x86_sock_demux(int socketcall)
 int _x86_sock_mux(int syscall)
 {
 	switch (syscall) {
+	case 337:
+		/* recvmmsg */
+		return -119;
+	case 345:
+		/* sendmmsg */
+		return -120;
 	case 359:
 		/* socket */
 		return -101;
@@ -137,7 +152,7 @@ int _x86_sock_mux(int syscall)
 		return -104;
 	case 364:
 		/* accept4 */
-		return __NR_SCMP_UNDEF;
+		return -118;
 	case 365:
 		/* getsockopt */
 		return -115;
@@ -183,7 +198,7 @@ int x86_syscall_rewrite(int *syscall)
 {
 	int sys = *syscall;
 
-	if (sys <= -100 && sys >= -117)
+	if (sys <= -100 && sys >= -120)
 		*syscall = __x86_NR_socketcall;
 	else if (sys <= -200 && sys >= -211)
 		*syscall = __x86_NR_ipc;
@@ -215,8 +230,8 @@ int x86_rule_add(struct db_filter_col *col, struct db_filter *db, bool strict,
 	int sys_a, sys_b;
 	struct db_api_rule_list *rule_a, *rule_b;
 
-	if ((sys <= -100 && sys >= -117) || (sys >= 359 && sys <= 373)) {
-		/* (-100 to -117) : multiplexed socket syscalls
+	if ((sys <= -100 && sys >= -120) || (sys >= 359 && sys <= 373)) {
+		/* (-100 to -120) : multiplexed socket syscalls
 		   (359 to 373)   : direct socket syscalls, Linux 4.4+ */
 
 		/* strict check for the multiplexed socket syscalls */

tests/30-sim-socket_syscalls.tests

@@ -18,7 +18,8 @@ test type: bpf-sim
 30-sim-socket_syscalls	+x86	373		0		1		2	N	N	N	ALLOW
 30-sim-socket_syscalls	+x86	accept		5		N		N	N	N	N	ALLOW
 30-sim-socket_syscalls	+x86	accept		0		1		2	N	N	N	KILL
-30-sim-socket_syscalls	+x86	accept4		0		1		2	N	N	N	ALLOW
+30-sim-socket_syscalls	+x86	accept4		18		1		2	N	N	N	ALLOW
+30-sim-socket_syscalls	+x86	accept4		0		1		2	N	N	N	KILL
 30-sim-socket_syscalls	+x86_64	socket		0		1		2	N	N	N	ALLOW
 30-sim-socket_syscalls	+x86_64	connect		0		1		2	N	N	N	ALLOW
 30-sim-socket_syscalls	+x86_64	accept4		0		1		2	N	N	N	ALLOW