diff options
Diffstat (limited to 'src/libsystemd-network/dhcp-identifier.c')
| -rw-r--r-- | src/libsystemd-network/dhcp-identifier.c | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/src/libsystemd-network/dhcp-identifier.c b/src/libsystemd-network/dhcp-identifier.c new file mode 100644 index 0000000..04bf64c --- /dev/null +++ b/src/libsystemd-network/dhcp-identifier.c @@ -0,0 +1,209 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <linux/if_infiniband.h> +#include <net/if_arp.h> + +#include "sd-device.h" +#include "sd-id128.h" + +#include "dhcp-identifier.h" +#include "dhcp6-protocol.h" +#include "network-internal.h" +#include "siphash24.h" +#include "sparse-endian.h" +#include "stdio-util.h" +#include "virt.h" + +#define SYSTEMD_PEN 43793 +#define HASH_KEY SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09) +#define APPLICATION_ID SD_ID128_MAKE(a5,0a,d1,12,bf,60,45,77,a2,fb,74,1a,b1,95,5b,03) +#define USEC_2000 ((usec_t) 946684800000000) /* 2000-01-01 00:00:00 UTC */ + +int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len, bool strict) { + struct duid d; + + assert_cc(sizeof(d.raw) >= MAX_DUID_LEN); + if (duid_len > MAX_DUID_LEN) + return -EINVAL; + + if (!strict) { + /* Strict validation is not requested. We only ensure that the + * DUID is not too long. */ + return 0; + } + + switch (duid_type) { + case DUID_TYPE_LLT: + if (duid_len <= sizeof(d.llt)) + return -EINVAL; + break; + case DUID_TYPE_EN: + if (duid_len != sizeof(d.en)) + return -EINVAL; + break; + case DUID_TYPE_LL: + if (duid_len <= sizeof(d.ll)) + return -EINVAL; + break; + case DUID_TYPE_UUID: + if (duid_len != sizeof(d.uuid)) + return -EINVAL; + break; + default: + /* accept unknown type in order to be forward compatible */ + break; + } + return 0; +} + +int dhcp_identifier_set_duid_llt(struct duid *duid, usec_t t, const uint8_t *addr, size_t addr_len, uint16_t arp_type, size_t *len) { + uint16_t time_from_2000y; + + assert(duid); + assert(len); + assert(addr); + + if (arp_type == ARPHRD_ETHER) + assert_return(addr_len == ETH_ALEN, -EINVAL); + else if (arp_type == ARPHRD_INFINIBAND) + assert_return(addr_len == INFINIBAND_ALEN, -EINVAL); + else + return -EINVAL; + + if (t < USEC_2000) + time_from_2000y = 0; + else + time_from_2000y = (uint16_t) (((t - USEC_2000) / USEC_PER_SEC) & 0xffffffff); + + unaligned_write_be16(&duid->type, DUID_TYPE_LLT); + unaligned_write_be16(&duid->llt.htype, arp_type); + unaligned_write_be32(&duid->llt.time, time_from_2000y); + memcpy(duid->llt.haddr, addr, addr_len); + + *len = sizeof(duid->type) + sizeof(duid->llt.htype) + sizeof(duid->llt.time) + addr_len; + + return 0; +} + +int dhcp_identifier_set_duid_ll(struct duid *duid, const uint8_t *addr, size_t addr_len, uint16_t arp_type, size_t *len) { + assert(duid); + assert(len); + assert(addr); + + if (arp_type == ARPHRD_ETHER) + assert_return(addr_len == ETH_ALEN, -EINVAL); + else if (arp_type == ARPHRD_INFINIBAND) + assert_return(addr_len == INFINIBAND_ALEN, -EINVAL); + else + return -EINVAL; + + unaligned_write_be16(&duid->type, DUID_TYPE_LL); + unaligned_write_be16(&duid->ll.htype, arp_type); + memcpy(duid->ll.haddr, addr, addr_len); + + *len = sizeof(duid->type) + sizeof(duid->ll.htype) + addr_len; + + return 0; +} + +int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len) { + sd_id128_t machine_id; + uint64_t hash; + int r; + + assert(duid); + assert(len); + + r = sd_id128_get_machine(&machine_id); + if (r < 0) { +#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION + machine_id = SD_ID128_MAKE(01, 02, 03, 04, 05, 06, 07, 08, 09, 0a, 0b, 0c, 0d, 0e, 0f, 10); +#else + return r; +#endif + } + + unaligned_write_be16(&duid->type, DUID_TYPE_EN); + unaligned_write_be32(&duid->en.pen, SYSTEMD_PEN); + + *len = sizeof(duid->type) + sizeof(duid->en); + + /* a bit of snake-oil perhaps, but no need to expose the machine-id + * directly; duid->en.id might not be aligned, so we need to copy */ + hash = htole64(siphash24(&machine_id, sizeof(machine_id), HASH_KEY.bytes)); + memcpy(duid->en.id, &hash, sizeof(duid->en.id)); + + return 0; +} + +int dhcp_identifier_set_duid_uuid(struct duid *duid, size_t *len) { + sd_id128_t machine_id; + int r; + + assert(duid); + assert(len); + + r = sd_id128_get_machine_app_specific(APPLICATION_ID, &machine_id); + if (r < 0) + return r; + + unaligned_write_be16(&duid->type, DUID_TYPE_UUID); + memcpy(&duid->raw.data, &machine_id, sizeof(machine_id)); + + *len = sizeof(duid->type) + sizeof(machine_id); + + return 0; +} + +int dhcp_identifier_set_iaid( + int ifindex, + const uint8_t *mac, + size_t mac_len, + bool legacy_unstable_byteorder, + void *_id) { + /* name is a pointer to memory in the sd_device struct, so must + * have the same scope */ + _cleanup_(sd_device_unrefp) sd_device *device = NULL; + const char *name = NULL; + uint64_t id; + uint32_t id32; + + if (detect_container() <= 0) { + /* not in a container, udev will be around */ + char ifindex_str[1 + DECIMAL_STR_MAX(int)]; + int r; + + xsprintf(ifindex_str, "n%d", ifindex); + if (sd_device_new_from_device_id(&device, ifindex_str) >= 0) { + r = sd_device_get_is_initialized(device); + if (r < 0) + return r; + if (r == 0) + /* not yet ready */ + return -EBUSY; + + name = net_get_name(device); + } + } + + if (name) + id = siphash24(name, strlen(name), HASH_KEY.bytes); + else + /* fall back to MAC address if no predictable name available */ + id = siphash24(mac, mac_len, HASH_KEY.bytes); + + id32 = (id & 0xffffffff) ^ (id >> 32); + + if (legacy_unstable_byteorder) + /* for historical reasons (a bug), the bits were swapped and thus + * the result was endianness dependent. Preserve that behavior. */ + id32 = __bswap_32(id32); + else + /* the fixed behavior returns a stable byte order. Since LE is expected + * to be more common, swap the bytes on LE to give the same as legacy + * behavior. */ + id32 = be32toh(id32); + + unaligned_write_ne32(_id, id32); + return 0; +} |