[thirdparty/systemd.git] / src / libsystemd-network / dhcp-option.c

/* SPDX-License-Identifier: LGPL-2.1+ */
/***
  Copyright © 2013 Intel Corporation. All rights reserved.
***/

#include <errno.h>
#include <stdint.h>
#include <stdio.h>

#include "alloc-util.h"
#include "dhcp-internal.h"
#include "dhcp-server-internal.h"
#include "memory-util.h"
#include "strv.h"
#include "utf8.h"

static int option_append(uint8_t options[], size_t size, size_t *offset,
                         uint8_t code, size_t optlen, const void *optval) {
        assert(options);
        assert(offset);

        if (code != SD_DHCP_OPTION_END)
                /* always make sure there is space for an END option */
                size--;

        switch (code) {

        case SD_DHCP_OPTION_PAD:
        case SD_DHCP_OPTION_END:
                if (*offset + 1 > size)
                        return -ENOBUFS;

                options[*offset] = code;
                *offset += 1;
                break;

        case SD_DHCP_OPTION_USER_CLASS: {
                size_t total = 0;
                char **s;

                STRV_FOREACH(s, (char **) optval) {
                        size_t len = strlen(*s);

                        if (len > 255)
                                return -ENAMETOOLONG;

                        total += 1 + len;
                }

                if (*offset + 2 + total > size)
                        return -ENOBUFS;

                options[*offset] = code;
                options[*offset + 1] =  total;
                *offset += 2;

                STRV_FOREACH(s, (char **) optval) {
                        size_t len = strlen(*s);

                        options[*offset] = len;

                        memcpy(&options[*offset + 1], *s, len);
                        *offset += 1 + len;
                }

                break;
        }
        case SD_DHCP_OPTION_SIP_SERVER:
                if (*offset + 3 + optlen > size)
                        return -ENOBUFS;

                options[*offset] = code;
                options[*offset + 1] = optlen + 1;
                options[*offset + 2] = 1;

                memcpy_safe(&options[*offset + 3], optval, optlen);
                *offset += 3 + optlen;

                break;
        case SD_DHCP_OPTION_VENDOR_SPECIFIC: {
                OrderedHashmap *s = (OrderedHashmap *) optval;
                struct sd_dhcp_option *p;
                size_t l = 0;
                Iterator i;

                ORDERED_HASHMAP_FOREACH(p, s, i)
                        l += p->length + 2;

                if (*offset + l + 2 > size)
                        return -ENOBUFS;

                options[*offset] = code;
                options[*offset + 1] = l;

                *offset += 2;

                ORDERED_HASHMAP_FOREACH(p, s, i) {
                        options[*offset] = p->option;
                        options[*offset + 1] = p->length;
                        memcpy(&options[*offset + 2], p->data, p->length);
                        *offset += 2 + p->length;
                }

                break;
        }
        default:
                if (*offset + 2 + optlen > size)
                        return -ENOBUFS;

                options[*offset] = code;
                options[*offset + 1] = optlen;

                memcpy_safe(&options[*offset + 2], optval, optlen);
                *offset += 2 + optlen;

                break;
        }

        return 0;
}

int dhcp_option_append(DHCPMessage *message, size_t size, size_t *offset,
                       uint8_t overload,
                       uint8_t code, size_t optlen, const void *optval) {
        const bool use_file = overload & DHCP_OVERLOAD_FILE;
        const bool use_sname = overload & DHCP_OVERLOAD_SNAME;
        int r;

        assert(message);
        assert(offset);

        /* If *offset is in range [0, size), we are writing to ->options,
         * if *offset is in range [size, size + sizeof(message->file)) and use_file, we are writing to ->file,
         * if *offset is in range [size + use_file*sizeof(message->file), size + use_file*sizeof(message->file) + sizeof(message->sname))
         * and use_sname, we are writing to ->sname.
         */

        if (*offset < size) {
                /* still space in the options array */
                r = option_append(message->options, size, offset, code, optlen, optval);
                if (r >= 0)
                        return 0;
                else if (r == -ENOBUFS && (use_file || use_sname)) {
                        /* did not fit, but we have more buffers to try
                           close the options array and move the offset to its end */
                        r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
                        if (r < 0)
                                return r;

                        *offset = size;
                } else
                        return r;
        }

        if (use_file) {
                size_t file_offset = *offset - size;

                if (file_offset < sizeof(message->file)) {
                        /* still space in the 'file' array */
                        r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval);
                        if (r >= 0) {
                                *offset = size + file_offset;
                                return 0;
                        } else if (r == -ENOBUFS && use_sname) {
                                /* did not fit, but we have more buffers to try
                                   close the file array and move the offset to its end */
                                r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
                                if (r < 0)
                                        return r;

                                *offset = size + sizeof(message->file);
                        } else
                                return r;
                }
        }

        if (use_sname) {
                size_t sname_offset = *offset - size - use_file*sizeof(message->file);

                if (sname_offset < sizeof(message->sname)) {
                        /* still space in the 'sname' array */
                        r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval);
                        if (r >= 0) {
                                *offset = size + use_file*sizeof(message->file) + sname_offset;
                                return 0;
                        } else
                                /* no space, or other error, give up */
                                return r;
                }
        }

        return -ENOBUFS;
}

static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload,
                         uint8_t *message_type, char **error_message, dhcp_option_callback_t cb,
                         void *userdata) {
        uint8_t code, len;
        const uint8_t *option;
        size_t offset = 0;

        while (offset < buflen) {
                code = options[offset ++];

                switch (code) {
                case SD_DHCP_OPTION_PAD:
                        continue;

                case SD_DHCP_OPTION_END:
                        return 0;
                }

                if (buflen < offset + 1)
                        return -ENOBUFS;

                len = options[offset ++];

                if (buflen < offset + len)
                        return -EINVAL;

                option = &options[offset];

                switch (code) {
                case SD_DHCP_OPTION_MESSAGE_TYPE:
                        if (len != 1)
                                return -EINVAL;

                        if (message_type)
                                *message_type = *option;

                        break;

                case SD_DHCP_OPTION_ERROR_MESSAGE:
                        if (len == 0)
                                return -EINVAL;

                        if (error_message) {
                                _cleanup_free_ char *string = NULL;

                                /* Accept a trailing NUL byte */
                                if (memchr(option, 0, len - 1))
                                        return -EINVAL;

                                string = memdup_suffix0((const char *) option, len);
                                if (!string)
                                        return -ENOMEM;

                                if (!ascii_is_valid(string))
                                        return -EINVAL;

                                free_and_replace(*error_message, string);
                        }

                        break;
                case SD_DHCP_OPTION_OVERLOAD:
                        if (len != 1)
                                return -EINVAL;

                        if (overload)
                                *overload = *option;

                        break;

                default:
                        if (cb)
                                cb(code, len, option, userdata);

                        break;
                }

                offset += len;
        }

        if (offset < buflen)
                return -EINVAL;

        return 0;
}

int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t cb, void *userdata, char **_error_message) {
        _cleanup_free_ char *error_message = NULL;
        uint8_t overload = 0;
        uint8_t message_type = 0;
        int r;

        if (!message)
                return -EINVAL;

        if (len < sizeof(DHCPMessage))
                return -EINVAL;

        len -= sizeof(DHCPMessage);

        r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata);
        if (r < 0)
                return r;

        if (overload & DHCP_OVERLOAD_FILE) {
                r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata);
                if (r < 0)
                        return r;
        }

        if (overload & DHCP_OVERLOAD_SNAME) {
                r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata);
                if (r < 0)
                        return r;
        }

        if (message_type == 0)
                return -ENOMSG;

        if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
                *_error_message = TAKE_PTR(error_message);

        return message_type;
}

static sd_dhcp_option* dhcp_option_free(sd_dhcp_option *i) {
        if (!i)
                return NULL;

        free(i->data);
        return mfree(i);
}

int sd_dhcp_option_new(uint8_t option, const void *data, size_t length, sd_dhcp_option **ret) {
        assert_return(ret, -EINVAL);
        assert_return(length == 0 || data, -EINVAL);

        _cleanup_free_ void *q = memdup(data, length);
        if (!q)
                return -ENOMEM;

        sd_dhcp_option *p = new(sd_dhcp_option, 1);
        if (!p)
                return -ENOMEM;

        *p = (sd_dhcp_option) {
                .n_ref = 1,
                .option = option,
                .length = length,
                .data = TAKE_PTR(q),
        };

        *ret = TAKE_PTR(p);
        return 0;
}

DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_option, sd_dhcp_option, dhcp_option_free);
DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
                dhcp_option_hash_ops,
                void,
                trivial_hash_func,
                trivial_compare_func,
                sd_dhcp_option,
                sd_dhcp_option_unref);
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
524cf458	2	/***
810adae9	3	Copyright © 2013 Intel Corporation. All rights reserved.
524cf458 PF	4	***/
524cf458 PF	5
524cf458	6	#include <errno.h>
cf0fbc49	7	#include <stdint.h>
524cf458 PF	8	#include <stdio.h>
524cf458 PF	9
f693e9b3	10	#include "alloc-util.h"
524cf458	11	#include "dhcp-internal.h"
564ca984	12	#include "dhcp-server-internal.h"
0a970718 LP	13	#include "memory-util.h"
	14	#include "strv.h"
	15	#include "utf8.h"
524cf458	16
04b28be1 TG	17	static int option_append(uint8_t options[], size_t size, size_t *offset,
04b28be1 TG	18	uint8_t code, size_t optlen, const void *optval) {
20b958bf TG	19	assert(options);
20b958bf TG	20	assert(offset);
524cf458	21
22805d92	22	if (code != SD_DHCP_OPTION_END)
2688ef60	23	/* always make sure there is space for an END option */
313cefa1	24	size--;
2688ef60	25
524cf458 PF	26	switch (code) {
524cf458 PF	27
22805d92 BG	28	case SD_DHCP_OPTION_PAD:
22805d92 BG	29	case SD_DHCP_OPTION_END:
bc67342e	30	if (*offset + 1 > size)
524cf458 PF	31	return -ENOBUFS;
524cf458 PF	32
20b958bf TG	33	options[*offset] = code;
20b958bf TG	34	*offset += 1;
524cf458 PF	35	break;
524cf458 PF	36
af1c0de0	37	case SD_DHCP_OPTION_USER_CLASS: {
bc67342e	38	size_t total = 0;
af1c0de0 SS	39	char **s;
af1c0de0 SS	40
bc67342e ZJS	41	STRV_FOREACH(s, (char **) optval) {
	42	size_t len = strlen(*s);
	43
	44	if (len > 255)
	45	return -ENAMETOOLONG;
	46
	47	total += 1 + len;
	48	}
af1c0de0	49
bc67342e	50	if (*offset + 2 + total > size)
af1c0de0 SS	51	return -ENOBUFS;
	52
	53	options[*offset] = code;
bc67342e	54	options[*offset + 1] = total;
af1c0de0 SS	55	*offset += 2;
	56
	57	STRV_FOREACH(s, (char **) optval) {
bc67342e	58	size_t len = strlen(*s);
af1c0de0 SS	59
	60	options[*offset] = len;
	61
bc67342e ZJS	62	memcpy(&options[offset + 1], s, len);
bc67342e ZJS	63	*offset += 1 + len;
af1c0de0 SS	64	}
	65
	66	break;
	67	}
299d578f SS	68	case SD_DHCP_OPTION_SIP_SERVER:
	69	if (*offset + 3 + optlen > size)
	70	return -ENOBUFS;
	71
	72	options[*offset] = code;
	73	options[*offset + 1] = optlen + 1;
	74	options[*offset + 2] = 1;
	75
	76	memcpy_safe(&options[*offset + 3], optval, optlen);
	77	*offset += 3 + optlen;
	78
	79	break;
564ca984 SS	80	case SD_DHCP_OPTION_VENDOR_SPECIFIC: {
564ca984 SS	81	OrderedHashmap s = (OrderedHashmap ) optval;
461dbb2f	82	struct sd_dhcp_option *p;
564ca984 SS	83	size_t l = 0;
	84	Iterator i;
	85
	86	ORDERED_HASHMAP_FOREACH(p, s, i)
	87	l += p->length + 2;
	88
	89	if (*offset + l + 2 > size)
	90	return -ENOBUFS;
	91
	92	options[*offset] = code;
	93	options[*offset + 1] = l;
	94
	95	*offset += 2;
	96
	97	ORDERED_HASHMAP_FOREACH(p, s, i) {
461dbb2f	98	options[*offset] = p->option;
564ca984 SS	99	options[*offset + 1] = p->length;
	100	memcpy(&options[*offset + 2], p->data, p->length);
	101	*offset += 2 + p->length;
	102	}
	103
	104	break;
	105	}
524cf458	106	default:
bc67342e	107	if (*offset + 2 + optlen > size)
524cf458 PF	108	return -ENOBUFS;
524cf458 PF	109
20b958bf TG	110	options[*offset] = code;
20b958bf TG	111	options[*offset + 1] = optlen;
04b28be1	112
75f32f04	113	memcpy_safe(&options[*offset + 2], optval, optlen);
bc67342e	114	*offset += 2 + optlen;
524cf458 PF	115
	116	break;
	117	}
	118
	119	return 0;
	120	}
	121
04b28be1 TG	122	int dhcp_option_append(DHCPMessage message, size_t size, size_t offset,
	123	uint8_t overload,
	124	uint8_t code, size_t optlen, const void *optval) {
bc67342e ZJS	125	const bool use_file = overload & DHCP_OVERLOAD_FILE;
bc67342e ZJS	126	const bool use_sname = overload & DHCP_OVERLOAD_SNAME;
04b28be1 TG	127	int r;
	128
	129	assert(message);
	130	assert(offset);
	131
bc67342e ZJS	132	/* If *offset is in range [0, size), we are writing to ->options,
	133	* if *offset is in range [size, size + sizeof(message->file)) and use_file, we are writing to ->file,
	134	* if offset is in range [size + use_filesizeof(message->file), size + use_file*sizeof(message->file) + sizeof(message->sname))
	135	* and use_sname, we are writing to ->sname.
	136	*/
04b28be1 TG	137
	138	if (*offset < size) {
	139	/* still space in the options array */
	140	r = option_append(message->options, size, offset, code, optlen, optval);
	141	if (r >= 0)
	142	return 0;
bc67342e	143	else if (r == -ENOBUFS && (use_file \|\| use_sname)) {
04b28be1 TG	144	/* did not fit, but we have more buffers to try
04b28be1 TG	145	close the options array and move the offset to its end */
22805d92	146	r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
04b28be1 TG	147	if (r < 0)
	148	return r;
	149
	150	*offset = size;
	151	} else
	152	return r;
	153	}
	154
bc67342e ZJS	155	if (use_file) {
bc67342e ZJS	156	size_t file_offset = *offset - size;
04b28be1 TG	157
	158	if (file_offset < sizeof(message->file)) {
	159	/* still space in the 'file' array */
	160	r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval);
	161	if (r >= 0) {
	162	*offset = size + file_offset;
	163	return 0;
bc67342e	164	} else if (r == -ENOBUFS && use_sname) {
04b28be1 TG	165	/* did not fit, but we have more buffers to try
04b28be1 TG	166	close the file array and move the offset to its end */
22805d92	167	r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
04b28be1 TG	168	if (r < 0)
	169	return r;
	170
	171	*offset = size + sizeof(message->file);
	172	} else
	173	return r;
	174	}
	175	}
	176
bc67342e ZJS	177	if (use_sname) {
bc67342e ZJS	178	size_t sname_offset = offset - size - use_filesizeof(message->file);
04b28be1 TG	179
	180	if (sname_offset < sizeof(message->sname)) {
	181	/* still space in the 'sname' array */
	182	r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval);
	183	if (r >= 0) {
bc67342e	184	offset = size + use_filesizeof(message->file) + sname_offset;
04b28be1	185	return 0;
bc67342e	186	} else
04b28be1 TG	187	/* no space, or other error, give up */
04b28be1 TG	188	return r;
04b28be1 TG	189	}
	190	}
	191
	192	return -ENOBUFS;
	193	}
	194
32008a96	195	static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload,
ccf86354	196	uint8_t message_type, char *error_message, dhcp_option_callback_t cb,
89ca10c6	197	void *userdata) {
32008a96	198	uint8_t code, len;
f693e9b3	199	const uint8_t *option;
32008a96	200	size_t offset = 0;
524cf458	201
32008a96	202	while (offset < buflen) {
f693e9b3	203	code = options[offset ++];
32008a96	204
f693e9b3	205	switch (code) {
22805d92	206	case SD_DHCP_OPTION_PAD:
f693e9b3	207	continue;
524cf458	208
22805d92	209	case SD_DHCP_OPTION_END:
524cf458	210	return 0;
f693e9b3	211	}
524cf458	212
f693e9b3 TG	213	if (buflen < offset + 1)
	214	return -ENOBUFS;
	215
	216	len = options[offset ++];
524cf458	217
f693e9b3 TG	218	if (buflen < offset + len)
	219	return -EINVAL;
	220
	221	option = &options[offset];
	222
	223	switch (code) {
22805d92	224	case SD_DHCP_OPTION_MESSAGE_TYPE:
32008a96	225	if (len != 1)
524cf458 PF	226	return -EINVAL;
	227
	228	if (message_type)
f693e9b3	229	message_type = option;
524cf458 PF	230
	231	break;
	232
22805d92	233	case SD_DHCP_OPTION_ERROR_MESSAGE:
f693e9b3	234	if (len == 0)
524cf458 PF	235	return -EINVAL;
524cf458 PF	236
f693e9b3 TG	237	if (error_message) {
f693e9b3 TG	238	_cleanup_free_ char *string = NULL;
524cf458	239
f693e9b3 TG	240	/* Accept a trailing NUL byte */
	241	if (memchr(option, 0, len - 1))
	242	return -EINVAL;
524cf458	243
79cd22d6	244	string = memdup_suffix0((const char *) option, len);
f693e9b3 TG	245	if (!string)
f693e9b3 TG	246	return -ENOMEM;
524cf458	247
f693e9b3 TG	248	if (!ascii_is_valid(string))
f693e9b3 TG	249	return -EINVAL;
524cf458	250
f9ecfd3b	251	free_and_replace(*error_message, string);
f693e9b3	252	}
524cf458	253
f693e9b3	254	break;
22805d92	255	case SD_DHCP_OPTION_OVERLOAD:
f693e9b3	256	if (len != 1)
524cf458	257	return -EINVAL;
524cf458	258
f693e9b3 TG	259	if (overload)
f693e9b3 TG	260	overload = option;
524cf458	261
f693e9b3 TG	262	break;
	263
	264	default:
	265	if (cb)
	266	cb(code, len, option, userdata);
524cf458 PF	267
	268	break;
	269	}
f693e9b3 TG	270
f693e9b3 TG	271	offset += len;
524cf458 PF	272	}
524cf458 PF	273
32008a96	274	if (offset < buflen)
524cf458 PF	275	return -EINVAL;
	276
	277	return 0;
	278	}
	279
ccf86354	280	int dhcp_option_parse(DHCPMessage message, size_t len, dhcp_option_callback_t cb, void userdata, char **_error_message) {
f693e9b3	281	_cleanup_free_ char *error_message = NULL;
524cf458 PF	282	uint8_t overload = 0;
524cf458 PF	283	uint8_t message_type = 0;
32008a96	284	int r;
524cf458 PF	285
	286	if (!message)
	287	return -EINVAL;
	288
3b7ca119	289	if (len < sizeof(DHCPMessage))
524cf458 PF	290	return -EINVAL;
524cf458 PF	291
3b7ca119	292	len -= sizeof(DHCPMessage);
524cf458	293
f693e9b3	294	r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata);
32008a96 TG	295	if (r < 0)
32008a96 TG	296	return r;
524cf458 PF	297
524cf458 PF	298	if (overload & DHCP_OVERLOAD_FILE) {
f693e9b3	299	r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata);
32008a96 TG	300	if (r < 0)
32008a96 TG	301	return r;
524cf458 PF	302	}
	303
	304	if (overload & DHCP_OVERLOAD_SNAME) {
f693e9b3	305	r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata);
32008a96 TG	306	if (r < 0)
32008a96 TG	307	return r;
524cf458 PF	308	}
524cf458 PF	309
f693e9b3 TG	310	if (message_type == 0)
	311	return -ENOMSG;
	312
ae2a15bc LP	313	if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
ae2a15bc LP	314	*_error_message = TAKE_PTR(error_message);
524cf458	315
f693e9b3	316	return message_type;
524cf458	317	}
461dbb2f YW	318
	319	static sd_dhcp_option* dhcp_option_free(sd_dhcp_option *i) {
	320	if (!i)
	321	return NULL;
	322
	323	free(i->data);
	324	return mfree(i);
	325	}
	326
	327	int sd_dhcp_option_new(uint8_t option, const void data, size_t length, sd_dhcp_option *ret) {
	328	assert_return(ret, -EINVAL);
	329	assert_return(length == 0 \|\| data, -EINVAL);
	330
	331	_cleanup_free_ void *q = memdup(data, length);
	332	if (!q)
	333	return -ENOMEM;
	334
	335	sd_dhcp_option *p = new(sd_dhcp_option, 1);
	336	if (!p)
	337	return -ENOMEM;
	338
	339	*p = (sd_dhcp_option) {
	340	.n_ref = 1,
	341	.option = option,
	342	.length = length,
	343	.data = TAKE_PTR(q),
	344	};
	345
	346	*ret = TAKE_PTR(p);
	347	return 0;
	348	}
	349
	350	DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_option, sd_dhcp_option, dhcp_option_free);
	351	DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
	352	dhcp_option_hash_ops,
	353	void,
	354	trivial_hash_func,
	355	trivial_compare_func,
	356	sd_dhcp_option,
	357	sd_dhcp_option_unref);