/*

 * Copyright 2015 IBM

 * Author: Jan Willeke <willeke@linux.vnet.com.com>

 */

#include <stdlib.h>

#include <errno.h>

#include <string.h>

#include <linux/audit.h>

#include "arch.h"

#include "arch-s390.h"

/* s390 syscall numbers */

#define __s390_NR_socketcall		102

#define __s390_NR_ipc			117

const struct arch_def arch_def_s390 = {

	.token = SCMP_ARCH_S390,

	.token_bpf = AUDIT_ARCH_S390,

	.size = ARCH_SIZE_32,

	.endian = ARCH_ENDIAN_BIG,

	.syscall_resolve_name = s390_syscall_resolve_name,

	.syscall_resolve_num = s390_syscall_resolve_num,

	.syscall_rewrite = s390_syscall_rewrite,

	.rule_add = s390_rule_add,

};

/**

 * Convert a multiplexed pseudo syscall into a direct syscall

 * @param syscall the multiplexed pseudo syscall number

 *

 * Return the related direct syscall number, __NR_SCMP_UNDEF is there is

 * no related syscall, or __NR_SCMP_ERROR otherwise.

 *

 */

static int _s390_syscall_demux(int syscall)

{

	switch (syscall) {

	case -101:

		/* socket */

		return 359;

	case -102:

		/* bind */

		return 361;

	case -103:

		/* connect */

		return 362;

	case -104:

		/* listen */

		return 363;

	case -105:

		/* accept - not defined */

		return __NR_SCMP_UNDEF;

	case -106:

		/* getsockname */

		return 367;

	case -107:

		/* getpeername */

		return 368;

	case -108:

		/* socketpair */

		return 360;

	case -109:

		/* send - not defined */

		return __NR_SCMP_UNDEF;

	case -110:

		/* recv - not defined */

		return __NR_SCMP_UNDEF;

	case -111:

		/* sendto */

		return 369;

	case -112:

		/* recvfrom */

		return 371;

	case -113:

		/* shutdown */

		return 373;

	case -114:

		/* setsockopt */

		return 366;

	case -115:

		/* getsockopt */

		return 365;

	case -116:

		/* sendmsg */

		return 370;

	case -117:

		/* recvmsg */

		return 372;

	case -118:

		/* accept4 */

		return 364;

	case -119:

		/* recvmmsg */

		return 337;

	case -120:

		/* sendmmsg */

		return 345;

	case -201:

		/* semop - not defined */

		return __NR_SCMP_UNDEF;

	case -202:

		/* semget */

		return 393;

	case -203:

		/* semctl */

		return 394;

	case -204:

		/* semtimedop - not defined */

		return __NR_SCMP_UNDEF;

	case -211:

		/* msgsnd */

		return 400;

	case -212:

		/* msgrcv */

		return 401;

	case -213:

		/* msgget */

		return 399;

	case -214:

		/* msgctl */

		return 402;

	case -221:

		/* shmat */

		return 397;

	case -222:

		/* shmdt */

		return 398;

	case -223:

		/* shmget */

		return 395;

	case -224:

		/* shmctl */

		return 396;

	}

	return __NR_SCMP_ERROR;

}

/**

 * Convert a direct socket syscall into multiplexed pseudo socket syscall

 * @param syscall the direct syscall

 *

 * Return the related multiplexed pseduo syscall number, __NR_SCMP_UNDEF is

 * there is no related pseudo syscall, or __NR_SCMP_ERROR otherwise.

 *

 */

static int _s390_syscall_mux(int syscall)

{

	switch (syscall) {

	case 337:

		/* recvmmsg */

		return -119;

	case 345:

		/* sendmmsg */

		return -120;

	case 359:

		/* socket */

		return -101;

	case 360:

		/* socketpair */

		return -108;

	case 361:

		/* bind */

		return -102;

	case 362:

		/* connect */

		return -103;

	case 363:

		/* listen */

		return -104;

	case 364:

		/* accept4 */

		return -118;

	case 365:

		/* getsockopt */

		return -115;

	case 366:

		/* setsockopt */

		return -114;

	case 367:

		/* getsockname */

		return -106;

	case 368:

		/* getpeername */

		return -107;

	case 369:

		/* sendto */

		return -111;

	case 370:

		/* sendmsg */

		return -116;

	case 371:

		/* recvfrom */

		return -112;

	case 372:

		/* recvmsg */

		return -117;

	case 373:

		/* shutdown */

		return -113;

	case 393:

		/* semget */

		return -202;

	case 394:

		/* semctl */

		return -203;

	case 400:

		/* msgsnd */

		return -211;

	case 401:

		/* msgrcv */

		return -212;

	case 399:

		/* msgget */

		return -213;

	case 402:

		/* msgctl */

		return -214;

	case 397:

		/* shmat */

		return -221;

	case 398:

		/* shmdt */

		return -222;

	case 395:

		/* shmget */

		return -223;

	case 396:

		/* shmctl */

		return -224;

	}

	return __NR_SCMP_ERROR;

}

/**

 * Rewrite a syscall value to match the architecture

 * @param syscall the syscall number

 *

 * Syscalls can vary across different architectures so this function rewrites

 * the syscall into the correct value for the specified architecture.  Returns

 * zero on success, negative values on failure.

 *

 */

int s390_syscall_rewrite(int *syscall)

{

	int sys = *syscall;

	if (sys <= -100 && sys >= -120)

		*syscall = __s390_NR_socketcall;

	else if (sys <= -200 && sys >= -224)

		*syscall = __s390_NR_ipc;

	else if (sys < 0)

		return -EDOM;

	return 0;

}

/**

 * add a new rule to the s390 seccomp filter

 * @param db the seccomp filter db

 * @param rule the filter rule

 *

 * This function adds a new syscall filter to the seccomp filter db, making any

 * necessary adjustments for the s390 ABI.  Returns zero on success, negative

 * values on failure.

 *

 * It is important to note that in the case of failure the db may be corrupted,

 * the caller must use the transaction mechanism if the db integrity is

 * important.

 *

 */

int s390_rule_add(struct db_filter *db, struct db_api_rule_list *rule)

{

	int rc = 0;

	unsigned int iter;

	int sys = rule->syscall;

	int sys_a, sys_b;

	struct db_api_rule_list *rule_a, *rule_b, *rule_dup = NULL;

	if ((sys <= -100 && sys >= -120) || (sys >= 359 && sys <= 373)) {

		/* (-100 to -120) : multiplexed socket syscalls

		   (359 to 373)   : direct socket syscalls, Linux 4.3+ */

		/* strict check for the multiplexed socket syscalls */

		for (iter = 0; iter < ARG_COUNT_MAX; iter++) {

			if ((rule->args[iter].valid != 0) && (rule->strict)) {

				rc = -EINVAL;

				goto add_return;

			}

		}

		/* determine both the muxed and direct syscall numbers */

		if (sys > 0) {

			sys_a = _s390_syscall_mux(sys);

			if (sys_a == __NR_SCMP_ERROR) {

				rc = __NR_SCMP_ERROR;

				goto add_return;

			}

			sys_b = sys;

		} else {

			sys_a = sys;

			sys_b = _s390_syscall_demux(sys);

			if (sys_b == __NR_SCMP_ERROR) {

				rc = __NR_SCMP_ERROR;

				goto add_return;

			}

		}

		/* use rule_a for the multiplexed syscall and use rule_b for

		 * the direct wired syscall */

		if (sys_a == __NR_SCMP_UNDEF) {

			rule_a = NULL;

			rule_b = rule;

		} else if (sys_b == __NR_SCMP_UNDEF) {

			rule_a = rule;

			rule_b = NULL;

		} else {

			/* need two rules, dup the first and link together */

			rule_a = rule;

			rule_dup = db_rule_dup(rule_a);

			rule_b = rule_dup;

			if (rule_b == NULL) {

				rc = -ENOMEM;

				goto add_return;

			}

			rule_b->prev = rule_a;

			rule_b->next = NULL;

			rule_a->next = rule_b;

		}

		/* multiplexed socket syscalls */

		if (rule_a != NULL) {

			rule_a->syscall = __s390_NR_socketcall;

			rule_a->args[0].arg = 0;

			rule_a->args[0].op = SCMP_CMP_EQ;

			rule_a->args[0].mask = DATUM_MAX;

			rule_a->args[0].datum = (-sys_a) % 100;

			rule_a->args[0].valid = 1;

		}

		/* direct wired socket syscalls */

		if (rule_b != NULL)

			rule_b->syscall = sys_b;

		/* we should be protected by a transaction checkpoint */

		if (rule_a != NULL) {

			rc = db_rule_add(db, rule_a);

			if (rc < 0)

				goto add_return;

		}

		if (rule_b != NULL) {

			rc = db_rule_add(db, rule_b);

			if (rc < 0)

				goto add_return;

		}

	} else if ((sys <= -200 && sys >= -224) || (sys >= 393 && sys <= 402)) {

		/* (-200 to -224) : multiplexed ipc syscalls

		   (393 to 402) : direct ipc syscalls */

		/* strict check for the multiplexed socket syscalls */

		for (iter = 0; iter < ARG_COUNT_MAX; iter++) {

			if ((rule->args[iter].valid != 0) && (rule->strict)) {

				rc = -EINVAL;

				goto add_return;

			}

		}

		/* determine both the muxed and direct syscall numbers */

		if (sys > 0) {

			sys_a = _s390_syscall_mux(sys);

			if (sys_a == __NR_SCMP_ERROR) {

				rc = __NR_SCMP_ERROR;

				goto add_return;

			}

			sys_b = sys;

		} else {

			sys_a = sys;

			sys_b = _s390_syscall_demux(sys);

			if (sys_b == __NR_SCMP_ERROR) {

				rc = __NR_SCMP_ERROR;

				goto add_return;

			}

		}

		/* use rule_a for the multiplexed syscall and use rule_b for

		 * the direct wired syscall */

		if (sys_a == __NR_SCMP_UNDEF) {

			rule_a = NULL;

			rule_b = rule;

		} else if (sys_b == __NR_SCMP_UNDEF) {

			rule_a = rule;

			rule_b = NULL;

		} else {

			/* need two rules, dup the first and link together */

			rule_a = rule;

			rule_dup = db_rule_dup(rule_a);

			rule_b = rule_dup;

			if (rule_b == NULL)

				goto add_return;

			rule_b->prev = rule_a;

			rule_b->next = NULL;

			rule_a->next = rule_b;

		}

		/* multiplexed socket syscalls */

		if (rule_a != NULL) {

			rule_a->syscall = __s390_NR_ipc;

			rule_a->args[0].arg = 0;

			rule_a->args[0].op = SCMP_CMP_EQ;

			rule_a->args[0].mask = DATUM_MAX;

			rule_a->args[0].datum = (-sys_a) % 200;

			rule_a->args[0].valid = 1;

		}

		/* direct wired socket syscalls */

		if (rule_b != NULL)

			rule_b->syscall = sys_b;

		/* we should be protected by a transaction checkpoint */

		if (rule_a != NULL) {

			rc = db_rule_add(db, rule_a);

			if (rc < 0)

				goto add_return;

		}

		if (rule_b != NULL) {

			rc = db_rule_add(db, rule_b);

			if (rc < 0)

				goto add_return;

		}

	} else if (sys >= 0) {

		/* normal syscall processing */

		rc = db_rule_add(db, rule);

		if (rc < 0)

			goto add_return;

	} else if (rule->strict) {

		rc = -EDOM;

		goto add_return;

	}

add_return:

	if (rule_dup != NULL)

		free(rule_dup);

	return rc;

}