keyutils.c

/* keyutils.c: key utility library
 *
 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <dlfcn.h>
#include <errno.h>
#include <asm/unistd.h>
#include "keyutils.h"

#ifdef NO_GLIBC_KEYERR
static int error_inited;
static void (*libc_perror)(const char *msg);
static char *(*libc_strerror_r)(int errnum, char *buf, size_t n);
//static int (*libc_xpg_strerror_r)(int errnum, char *buf, size_t n);
#define RTLD_NEXT      ((void *) -1L)
#endif

#define __weak __attribute__((weak))

key_serial_t __weak add_key(const char *type,
			    const char *description,
			    const void *payload,
			    size_t plen,
			    key_serial_t ringid)
{
	return syscall(__NR_add_key,
		       type, description, payload, plen, ringid);
}

key_serial_t __weak request_key(const char *type,
				const char *description,
				const char * callout_info,
				key_serial_t destringid)
{
	return syscall(__NR_request_key,
		       type, description, callout_info, destringid);
}

static inline long __keyctl(int cmd,
			    unsigned long arg2,
			    unsigned long arg3,
			    unsigned long arg4,
			    unsigned long arg5)
{
	return syscall(__NR_keyctl,
		       cmd, arg2, arg3, arg4, arg5);
}

long __weak keyctl(int cmd, ...)
{
	va_list va;
	unsigned long arg2, arg3, arg4, arg5;

	va_start(va, cmd);
	arg2 = va_arg(va, unsigned long);
	arg3 = va_arg(va, unsigned long);
	arg4 = va_arg(va, unsigned long);
	arg5 = va_arg(va, unsigned long);
	va_end(va);

	return __keyctl(cmd, arg2, arg3, arg4, arg5);
}

key_serial_t keyctl_get_keyring_ID(key_serial_t id, int create)
{
	return keyctl(KEYCTL_GET_KEYRING_ID, id, create);
}

key_serial_t keyctl_join_session_keyring(const char *name)
{
	return keyctl(KEYCTL_JOIN_SESSION_KEYRING, name);
}

long keyctl_update(key_serial_t id, const void *payload, size_t plen)
{
	return keyctl(KEYCTL_UPDATE, id, payload, plen);
}

long keyctl_revoke(key_serial_t id)
{
	return keyctl(KEYCTL_REVOKE, id);
}

long keyctl_chown(key_serial_t id, uid_t uid, gid_t gid)
{
	return keyctl(KEYCTL_CHOWN, id, uid, gid);
}

long keyctl_setperm(key_serial_t id, key_perm_t perm)
{
	return keyctl(KEYCTL_SETPERM, id, perm);
}

long keyctl_describe(key_serial_t id, char *buffer, size_t buflen)
{
	return keyctl(KEYCTL_DESCRIBE, id, buffer, buflen);
}

long keyctl_clear(key_serial_t ringid)
{
	return keyctl(KEYCTL_CLEAR, ringid);
}

long keyctl_link(key_serial_t id, key_serial_t ringid)
{
	return keyctl(KEYCTL_LINK, id, ringid);
}

long keyctl_unlink(key_serial_t id, key_serial_t ringid)
{
	return keyctl(KEYCTL_UNLINK, id, ringid);
}

long keyctl_search(key_serial_t ringid,
		   const char *type,
		   const char *description,
		   key_serial_t destringid)
{
	return keyctl(KEYCTL_SEARCH, ringid, type, description, destringid);
}

long keyctl_read(key_serial_t id, char *buffer, size_t buflen)
{
	return keyctl(KEYCTL_READ, id, buffer, buflen);
}

long keyctl_instantiate(key_serial_t id,
			const void *payload,
			size_t plen,
			key_serial_t ringid)
{
	return keyctl(KEYCTL_INSTANTIATE, id, payload, plen, ringid);
}

long keyctl_negate(key_serial_t id, unsigned timeout, key_serial_t ringid)
{
	return keyctl(KEYCTL_NEGATE, id, timeout, ringid);
}

long keyctl_set_reqkey_keyring(int reqkey_defl)
{
	return keyctl(KEYCTL_SET_REQKEY_KEYRING, reqkey_defl);
}

long keyctl_set_timeout(key_serial_t id, unsigned timeout)
{
	return keyctl(KEYCTL_SET_TIMEOUT, id, timeout);
}

long keyctl_assume_authority(key_serial_t id)
{
	return keyctl(KEYCTL_ASSUME_AUTHORITY, id);
}

long keyctl_get_security(key_serial_t id, char *buffer, size_t buflen)
{
	return keyctl(KEYCTL_GET_SECURITY, id, buffer, buflen);
}

long keyctl_session_to_parent(void)
{
	return keyctl(KEYCTL_SESSION_TO_PARENT);
}

/*****************************************************************************/
/*
 * fetch key description into an allocated buffer
 * - resulting string is NUL terminated
 * - returns count not including NUL
 */
int keyctl_describe_alloc(key_serial_t id, char **_buffer)
{
	char *buf;
	long buflen, ret;

	ret = keyctl_describe(id, NULL, 0);
	if (ret < 0)
		return -1;

	buflen = ret;
	buf = malloc(buflen);
	if (!buf)
		return -1;

	for (;;) {
		ret = keyctl_describe(id, buf, buflen);
		if (ret < 0)
			return -1;

		if (buflen >= ret)
			break;

		buflen = ret;
		buf = realloc(buf, buflen);
		if (!buf)
			return -1;
	}

	*_buffer = buf;
	return buflen - 1;

} /* end keyctl_describe_alloc() */

/*****************************************************************************/
/*
 * fetch key contents into an allocated buffer
 * - resulting buffer has an extra NUL added to the end
 * - returns count (not including extraneous NUL)
 */
int keyctl_read_alloc(key_serial_t id, void **_buffer)
{
	void *buf;
	long buflen, ret;

	ret = keyctl_read(id, NULL, 0);
	if (ret < 0)
		return -1;

	buflen = ret;
	buf = malloc(buflen + 1);
	if (!buf)
		return -1;

	for (;;) {
		ret = keyctl_read(id, buf, buflen);
		if (ret < 0)
			return -1;

		if (buflen >= ret)
			break;

		buflen = ret;
		buf = realloc(buf, buflen + 1);
		if (!buf)
			return -1;
	}

	((unsigned char *) buf)[buflen] = 0;
	*_buffer = buf;
	return buflen;

} /* end keyctl_read_alloc() */

/*****************************************************************************/
/*
 * fetch key security label into an allocated buffer
 * - resulting string is NUL terminated
 * - returns count not including NUL
 */
int keyctl_get_security_alloc(key_serial_t id, char **_buffer)
{
	char *buf;
	long buflen, ret;

	ret = keyctl_get_security(id, NULL, 0);
	if (ret < 0)
		return -1;

	buflen = ret;
	buf = malloc(buflen);
	if (!buf)
		return -1;

	for (;;) {
		ret = keyctl_get_security(id, buf, buflen);
		if (ret < 0)
			return -1;

		if (buflen >= ret)
			break;

		buflen = ret;
		buf = realloc(buf, buflen);
		if (!buf)
			return -1;
	}

	*_buffer = buf;
	return buflen - 1;
}

#ifdef NO_GLIBC_KEYERR
/*****************************************************************************/
/*
 * initialise error handling
 */
static void error_init(void)
{
	char *err;

	error_inited = 1;

	dlerror();

	libc_perror = dlsym(RTLD_NEXT,"perror");
	if (!libc_perror) {
		fprintf(stderr, "Failed to look up next perror\n");
		err = dlerror();
		if (err)
			fprintf(stderr, "%s\n", err);
		abort();
	}

	//fprintf(stderr, "next perror at %p\n", libc_perror);

	libc_strerror_r = dlsym(RTLD_NEXT,"strerror_r");
	if (!libc_strerror_r) {
		fprintf(stderr, "Failed to look up next strerror_r\n");
		err = dlerror();
		if (err)
			fprintf(stderr, "%s\n", err);
		abort();
	}

	//fprintf(stderr, "next strerror_r at %p\n", libc_strerror_r);

#if 0
	libc_xpg_strerror_r = dlsym(RTLD_NEXT,"xpg_strerror_r");
	if (!libc_xpg_strerror_r) {
		fprintf(stderr, "Failed to look up next xpg_strerror_r\n");
		err = dlerror();
		if (err)
			fprintf(stderr, "%s\n", err);
		abort();
	}

	//fprintf(stderr, "next xpg_strerror_r at %p\n", libc_xpg_strerror_r);
#endif

} /* end error_init() */

/*****************************************************************************/
/*
 * overload glibc's strerror_r() with a version that knows about key errors
 */
char *strerror_r(int errnum, char *buf, size_t n)
{
	const char *errstr;
	int len;

	printf("hello\n");

	if (!error_inited)
		error_init();

	switch (errnum) {
	case ENOKEY:
		errstr = "Requested key not available";
		break;

	case EKEYEXPIRED:
		errstr = "Key has expired";
		break;

	case EKEYREVOKED:
		errstr = "Key has been revoked";
		break;

	case EKEYREJECTED:
		errstr = "Key was rejected by service";
		break;

	default:
		return libc_strerror_r(errnum, buf, n);
	}

	len = strlen(errstr) + 1;
	if (n > len) {
		errno = ERANGE;
		if (n > 0) {
			memcpy(buf, errstr, n - 1);
			buf[n - 1] = 0;
		}
		return NULL;
	}
	else {
		memcpy(buf, errstr, len);
		return buf;
	}

} /* end strerror_r() */

#if 0
/*****************************************************************************/
/*
 * overload glibc's strerror_r() with a version that knows about key errors
 */
int xpg_strerror_r(int errnum, char *buf, size_t n)
{
	const char *errstr;
	int len;

	if (!error_inited)
		error_init();

	switch (errnum) {
	case ENOKEY:
		errstr = "Requested key not available";
		break;

	case EKEYEXPIRED:
		errstr = "Key has expired";
		break;

	case EKEYREVOKED:
		errstr = "Key has been revoked";
		break;

	case EKEYREJECTED:
		errstr = "Key was rejected by service";
		break;

	default:
		return libc_xpg_strerror_r(errnum, buf, n);
	}

	len = strlen(errstr) + 1;
	if (n > len) {
		errno = ERANGE;
		if (n > 0) {
			memcpy(buf, errstr, n - 1);
			buf[n - 1] = 0;
		}
		return -1;
	}
	else {
		memcpy(buf, errstr, len);
		return 0;
	}

} /* end xpg_strerror_r() */
#endif

/*****************************************************************************/
/*
 *
 */
void perror(const char *msg)
{
	if (!error_inited)
		error_init();

	switch (errno) {
	case ENOKEY:
		fprintf(stderr, "%s: Requested key not available\n", msg);
		return;

	case EKEYEXPIRED:
		fprintf(stderr, "%s: Key has expired\n", msg);
		return;

	case EKEYREVOKED:
		fprintf(stderr, "%s: Key has been revoked\n", msg);
		return;

	case EKEYREJECTED:
		fprintf(stderr, "%s: Key was rejected by service\n", msg);
		return;

	default:
		libc_perror(msg);
		return;
	}

} /* end perror() */
#endif