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libsystemd-network: fix unaligned loads (issue #7654)

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should fix https://github.com/systemd/systemd/issues/7654

Also fix up mistaken endianness swap. BPF is native endianness.
This commit is contained in:
Shawn Landden 2017-12-16 21:41:37 -08:00
parent e51292485a
commit f11cba7479
2 changed files with 6 additions and 4 deletions
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5
src/libsystemd-network/arp-util.c
View File

@ -24,6 +24,7 @@
#include "arp-util.h"
#include "fd-util.h"
#include "unaligned.h"
#include "util.h"
int arp_network_bind_raw_socket(int ifindex, be32_t address, const struct ether_addr *eth_mac) {
@ -48,12 +49,12 @@ int arp_network_bind_raw_socket(int ifindex, be32_t address, const struct ether_
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, ARPOP_REPLY, 1, 0), /* protocol == reply ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
/* Sender Hardware Address must be different from our own */
BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((uint32_t *) eth_mac))), /* A <- 4 bytes of client's MAC */
BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_ne32(&eth_mac->ether_addr_octet[0])),/* A <- 4 bytes of client's MAC */
BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(struct ether_arp, arp_sha)), /* A <- 4 bytes of SHA */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 0, 6), /* A == 0 ? */
BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((uint16_t *) (((char *) eth_mac) + 4)))), /* A <- remainder of client's MAC */
BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_ne16(&eth_mac->ether_addr_octet[4])),/* A <- remainder of client's MAC */
BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(struct ether_arp, arp_sha) + 4), /* A <- remainder of SHA */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */

5
src/libsystemd-network/dhcp-network.c
View File

@ -32,6 +32,7 @@
#include "dhcp-internal.h"
#include "fd-util.h"
#include "socket-util.h"
#include "unaligned.h"
static int _bind_raw_socket(int ifindex, union sockaddr_union *link,
uint32_t xid, const uint8_t *mac_addr,
@ -70,13 +71,13 @@ static int _bind_raw_socket(int ifindex, union sockaddr_union *link,
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.xid)), /* A <- client identifier */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, xid, 1, 0), /* client identifier == xid ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((unsigned int *) eth_mac))), /* A <- 4 bytes of client's MAC */
BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be32(&eth_mac->ether_addr_octet[0])), /* A <- 4 bytes of client's MAC */
BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
BPF_STMT(BPF_LD + BPF_W + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr)), /* A <- 4 bytes of MAC from dhcp.chaddr */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */
BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, 0, 1, 0), /* A == 0 ? */
BPF_STMT(BPF_RET + BPF_K, 0), /* ignore */
BPF_STMT(BPF_LD + BPF_IMM, htobe16(*((unsigned short *) (((char *) eth_mac) + 4)))), /* A <- remainder of client's MAC */
BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be16(&eth_mac->ether_addr_octet[4])), /* A <- remainder of client's MAC */
BPF_STMT(BPF_MISC + BPF_TAX, 0), /* X <- A */
BPF_STMT(BPF_LD + BPF_H + BPF_ABS, offsetof(DHCPPacket, dhcp.chaddr) + 4), /* A <- remainder of MAC from dhcp.chaddr */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */