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authorBeniamino Galvani <b.galvani@gmail.com>2018-02-22 18:09:33 +0100
committerLennart Poettering <lennart@poettering.net>2018-02-22 18:09:33 +0100
commit6afe9046d570fd86dbc04526b5685c64d7958086 (patch)
treec9463728c39ba2200ca70fe75f3c6f6dafce9c58 /src/libsystemd-network/arp-util.c
parentMerge pull request #8251 from Shuangistan/pr_virt_qnx (diff)
downloadsystemd-6afe9046d570fd86dbc04526b5685c64d7958086.tar.xz
systemd-6afe9046d570fd86dbc04526b5685c64d7958086.zip
libsystemd-network: fix endianness in ARP BPF filter (#8255)
Commit f11cba7479fe ("libsystemd-network: fix unaligned loads (issue #7654)") changed the way in which the MAC address is read to use native endiannes: htobe32(*((uint32_t *)x) -> unaligned_read_ne32(x) This is wrong because loads done with BPF_LD + BPF_ABS are big-endian, as it can be seen for the ethertype and arp-operation loads above in the filter. Also, the same commit changed: htobe32(*((unsigned int *)x) -> unaligned_read_be32(x) in _bind_raw_socket(), which is the correct form. The commit broke IPv4LL in presence of loops, as the sender now considers its own packets as conflicting. Fixes: f11cba7479fe29a9dab9e3151bbca4302d173811
Diffstat (limited to 'src/libsystemd-network/arp-util.c')
-rw-r--r--src/libsystemd-network/arp-util.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/src/libsystemd-network/arp-util.c b/src/libsystemd-network/arp-util.c
index 89e68c7ac7..b8e9b2e496 100644
--- a/src/libsystemd-network/arp-util.c
+++ b/src/libsystemd-network/arp-util.c
@@ -49,12 +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, unaligned_read_ne32(&eth_mac->ether_addr_octet[0])),/* 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(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, unaligned_read_ne16(&eth_mac->ether_addr_octet[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(struct ether_arp, arp_sha) + 4), /* A <- remainder of SHA */
BPF_STMT(BPF_ALU + BPF_XOR + BPF_X, 0), /* A xor X */