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

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/***
  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;

                if (strv_isempty((char **) optval))
                        return -EINVAL;

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

                        if (len > 255 || len == 0)
                                return -EINVAL;

                        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;

                ORDERED_HASHMAP_FOREACH(p, s)
                        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) {
                        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
db9ecf05	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
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
e4336c0a YW	41	if (strv_isempty((char **) optval))
	42	return -EINVAL;
	43
bc67342e ZJS	44	STRV_FOREACH(s, (char **) optval) {
	45	size_t len = strlen(*s);
	46
e4336c0a YW	47	if (len > 255 \|\| len == 0)
e4336c0a YW	48	return -EINVAL;
bc67342e ZJS	49
	50	total += 1 + len;
	51	}
af1c0de0	52
bc67342e	53	if (*offset + 2 + total > size)
af1c0de0 SS	54	return -ENOBUFS;
	55
	56	options[*offset] = code;
e4336c0a	57	options[*offset + 1] = total;
af1c0de0 SS	58	*offset += 2;
	59
	60	STRV_FOREACH(s, (char **) optval) {
bc67342e	61	size_t len = strlen(*s);
af1c0de0 SS	62
af1c0de0 SS	63	options[*offset] = len;
bc67342e ZJS	64	memcpy(&options[offset + 1], s, len);
bc67342e ZJS	65	*offset += 1 + len;
af1c0de0 SS	66	}
	67
	68	break;
	69	}
299d578f SS	70	case SD_DHCP_OPTION_SIP_SERVER:
	71	if (*offset + 3 + optlen > size)
	72	return -ENOBUFS;
	73
	74	options[*offset] = code;
	75	options[*offset + 1] = optlen + 1;
	76	options[*offset + 2] = 1;
	77
	78	memcpy_safe(&options[*offset + 3], optval, optlen);
	79	*offset += 3 + optlen;
	80
	81	break;
564ca984 SS	82	case SD_DHCP_OPTION_VENDOR_SPECIFIC: {
564ca984 SS	83	OrderedHashmap s = (OrderedHashmap ) optval;
461dbb2f	84	struct sd_dhcp_option *p;
564ca984	85	size_t l = 0;
564ca984	86
90e74a66	87	ORDERED_HASHMAP_FOREACH(p, s)
564ca984 SS	88	l += p->length + 2;
	89
	90	if (*offset + l + 2 > size)
	91	return -ENOBUFS;
	92
	93	options[*offset] = code;
	94	options[*offset + 1] = l;
	95
	96	*offset += 2;
	97
90e74a66	98	ORDERED_HASHMAP_FOREACH(p, s) {
461dbb2f	99	options[*offset] = p->option;
564ca984 SS	100	options[*offset + 1] = p->length;
	101	memcpy(&options[*offset + 2], p->data, p->length);
	102	*offset += 2 + p->length;
	103	}
	104
	105	break;
	106	}
524cf458	107	default:
bc67342e	108	if (*offset + 2 + optlen > size)
524cf458 PF	109	return -ENOBUFS;
524cf458 PF	110
20b958bf TG	111	options[*offset] = code;
20b958bf TG	112	options[*offset + 1] = optlen;
04b28be1	113
75f32f04	114	memcpy_safe(&options[*offset + 2], optval, optlen);
bc67342e	115	*offset += 2 + optlen;
524cf458 PF	116
	117	break;
	118	}
	119
	120	return 0;
	121	}
	122
04b28be1 TG	123	int dhcp_option_append(DHCPMessage message, size_t size, size_t offset,
	124	uint8_t overload,
	125	uint8_t code, size_t optlen, const void *optval) {
bc67342e ZJS	126	const bool use_file = overload & DHCP_OVERLOAD_FILE;
bc67342e ZJS	127	const bool use_sname = overload & DHCP_OVERLOAD_SNAME;
04b28be1 TG	128	int r;
	129
	130	assert(message);
	131	assert(offset);
	132
bc67342e ZJS	133	/* If *offset is in range [0, size), we are writing to ->options,
	134	* if *offset is in range [size, size + sizeof(message->file)) and use_file, we are writing to ->file,
	135	* if offset is in range [size + use_filesizeof(message->file), size + use_file*sizeof(message->file) + sizeof(message->sname))
	136	* and use_sname, we are writing to ->sname.
	137	*/
04b28be1 TG	138
	139	if (*offset < size) {
	140	/* still space in the options array */
	141	r = option_append(message->options, size, offset, code, optlen, optval);
	142	if (r >= 0)
	143	return 0;
bc67342e	144	else if (r == -ENOBUFS && (use_file \|\| use_sname)) {
04b28be1 TG	145	/* did not fit, but we have more buffers to try
04b28be1 TG	146	close the options array and move the offset to its end */
22805d92	147	r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
04b28be1 TG	148	if (r < 0)
	149	return r;
	150
	151	*offset = size;
	152	} else
	153	return r;
	154	}
	155
bc67342e ZJS	156	if (use_file) {
bc67342e ZJS	157	size_t file_offset = *offset - size;
04b28be1 TG	158
	159	if (file_offset < sizeof(message->file)) {
	160	/* still space in the 'file' array */
	161	r = option_append(message->file, sizeof(message->file), &file_offset, code, optlen, optval);
	162	if (r >= 0) {
	163	*offset = size + file_offset;
	164	return 0;
bc67342e	165	} else if (r == -ENOBUFS && use_sname) {
04b28be1 TG	166	/* did not fit, but we have more buffers to try
04b28be1 TG	167	close the file array and move the offset to its end */
22805d92	168	r = option_append(message->options, size, offset, SD_DHCP_OPTION_END, 0, NULL);
04b28be1 TG	169	if (r < 0)
	170	return r;
	171
	172	*offset = size + sizeof(message->file);
	173	} else
	174	return r;
	175	}
	176	}
	177
bc67342e ZJS	178	if (use_sname) {
bc67342e ZJS	179	size_t sname_offset = offset - size - use_filesizeof(message->file);
04b28be1 TG	180
	181	if (sname_offset < sizeof(message->sname)) {
	182	/* still space in the 'sname' array */
	183	r = option_append(message->sname, sizeof(message->sname), &sname_offset, code, optlen, optval);
	184	if (r >= 0) {
bc67342e	185	offset = size + use_filesizeof(message->file) + sname_offset;
04b28be1	186	return 0;
bc67342e	187	} else
04b28be1 TG	188	/* no space, or other error, give up */
04b28be1 TG	189	return r;
04b28be1 TG	190	}
	191	}
	192
	193	return -ENOBUFS;
	194	}
	195
32008a96	196	static int parse_options(const uint8_t options[], size_t buflen, uint8_t *overload,
ccf86354	197	uint8_t message_type, char *error_message, dhcp_option_callback_t cb,
89ca10c6	198	void *userdata) {
32008a96	199	uint8_t code, len;
f693e9b3	200	const uint8_t *option;
32008a96	201	size_t offset = 0;
524cf458	202
32008a96	203	while (offset < buflen) {
f693e9b3	204	code = options[offset ++];
32008a96	205
f693e9b3	206	switch (code) {
22805d92	207	case SD_DHCP_OPTION_PAD:
f693e9b3	208	continue;
524cf458	209
22805d92	210	case SD_DHCP_OPTION_END:
524cf458	211	return 0;
f693e9b3	212	}
524cf458	213
f693e9b3 TG	214	if (buflen < offset + 1)
	215	return -ENOBUFS;
	216
	217	len = options[offset ++];
524cf458	218
f693e9b3 TG	219	if (buflen < offset + len)
	220	return -EINVAL;
	221
	222	option = &options[offset];
	223
	224	switch (code) {
22805d92	225	case SD_DHCP_OPTION_MESSAGE_TYPE:
32008a96	226	if (len != 1)
524cf458 PF	227	return -EINVAL;
	228
	229	if (message_type)
f693e9b3	230	message_type = option;
524cf458 PF	231
	232	break;
	233
22805d92	234	case SD_DHCP_OPTION_ERROR_MESSAGE:
f693e9b3	235	if (len == 0)
524cf458 PF	236	return -EINVAL;
524cf458 PF	237
f693e9b3 TG	238	if (error_message) {
f693e9b3 TG	239	_cleanup_free_ char *string = NULL;
524cf458	240
f693e9b3 TG	241	/* Accept a trailing NUL byte */
	242	if (memchr(option, 0, len - 1))
	243	return -EINVAL;
524cf458	244
79cd22d6	245	string = memdup_suffix0((const char *) option, len);
f693e9b3 TG	246	if (!string)
f693e9b3 TG	247	return -ENOMEM;
524cf458	248
f693e9b3 TG	249	if (!ascii_is_valid(string))
f693e9b3 TG	250	return -EINVAL;
524cf458	251
f9ecfd3b	252	free_and_replace(*error_message, string);
f693e9b3	253	}
524cf458	254
f693e9b3	255	break;
22805d92	256	case SD_DHCP_OPTION_OVERLOAD:
f693e9b3	257	if (len != 1)
524cf458	258	return -EINVAL;
524cf458	259
f693e9b3 TG	260	if (overload)
f693e9b3 TG	261	overload = option;
524cf458	262
f693e9b3 TG	263	break;
	264
	265	default:
	266	if (cb)
	267	cb(code, len, option, userdata);
524cf458 PF	268
	269	break;
	270	}
f693e9b3 TG	271
f693e9b3 TG	272	offset += len;
524cf458 PF	273	}
524cf458 PF	274
32008a96	275	if (offset < buflen)
524cf458 PF	276	return -EINVAL;
	277
	278	return 0;
	279	}
	280
ccf86354	281	int dhcp_option_parse(DHCPMessage message, size_t len, dhcp_option_callback_t cb, void userdata, char **_error_message) {
f693e9b3	282	_cleanup_free_ char *error_message = NULL;
524cf458 PF	283	uint8_t overload = 0;
524cf458 PF	284	uint8_t message_type = 0;
32008a96	285	int r;
524cf458 PF	286
	287	if (!message)
	288	return -EINVAL;
	289
3b7ca119	290	if (len < sizeof(DHCPMessage))
524cf458 PF	291	return -EINVAL;
524cf458 PF	292
3b7ca119	293	len -= sizeof(DHCPMessage);
524cf458	294
f693e9b3	295	r = parse_options(message->options, len, &overload, &message_type, &error_message, cb, userdata);
32008a96 TG	296	if (r < 0)
32008a96 TG	297	return r;
524cf458 PF	298
524cf458 PF	299	if (overload & DHCP_OVERLOAD_FILE) {
f693e9b3	300	r = parse_options(message->file, sizeof(message->file), NULL, &message_type, &error_message, cb, userdata);
32008a96 TG	301	if (r < 0)
32008a96 TG	302	return r;
524cf458 PF	303	}
	304
	305	if (overload & DHCP_OVERLOAD_SNAME) {
f693e9b3	306	r = parse_options(message->sname, sizeof(message->sname), NULL, &message_type, &error_message, cb, userdata);
32008a96 TG	307	if (r < 0)
32008a96 TG	308	return r;
524cf458 PF	309	}
524cf458 PF	310
f693e9b3 TG	311	if (message_type == 0)
	312	return -ENOMSG;
	313
ae2a15bc LP	314	if (_error_message && IN_SET(message_type, DHCP_NAK, DHCP_DECLINE))
ae2a15bc LP	315	*_error_message = TAKE_PTR(error_message);
524cf458	316
f693e9b3	317	return message_type;
524cf458	318	}
461dbb2f YW	319
	320	static sd_dhcp_option* dhcp_option_free(sd_dhcp_option *i) {
	321	if (!i)
	322	return NULL;
	323
	324	free(i->data);
	325	return mfree(i);
	326	}
	327
	328	int sd_dhcp_option_new(uint8_t option, const void data, size_t length, sd_dhcp_option *ret) {
	329	assert_return(ret, -EINVAL);
	330	assert_return(length == 0 \|\| data, -EINVAL);
	331
	332	_cleanup_free_ void *q = memdup(data, length);
	333	if (!q)
	334	return -ENOMEM;
	335
	336	sd_dhcp_option *p = new(sd_dhcp_option, 1);
	337	if (!p)
	338	return -ENOMEM;
	339
	340	*p = (sd_dhcp_option) {
	341	.n_ref = 1,
	342	.option = option,
	343	.length = length,
	344	.data = TAKE_PTR(q),
	345	};
	346
	347	*ret = TAKE_PTR(p);
	348	return 0;
	349	}
	350
	351	DEFINE_TRIVIAL_REF_UNREF_FUNC(sd_dhcp_option, sd_dhcp_option, dhcp_option_free);
	352	DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
	353	dhcp_option_hash_ops,
	354	void,
	355	trivial_hash_func,
	356	trivial_compare_func,
	357	sd_dhcp_option,
	358	sd_dhcp_option_unref);