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| author | Beniamino Galvani <b.galvani@gmail.com> | 2018-02-22 18:09:33 +0100 |
|---|---|---|
| committer | Lennart Poettering <lennart@poettering.net> | 2018-02-22 18:09:33 +0100 |
| commit | 6afe9046d570fd86dbc04526b5685c64d7958086 (patch) | |
| tree | c9463728c39ba2200ca70fe75f3c6f6dafce9c58 | |
| parent | d156d1d2c9afcc501f7f888623914ea497ceb8ce (diff) | |
| download | systemd-6afe9046d570fd86dbc04526b5685c64d7958086.tar.gz | |
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
| -rw-r--r-- | src/libsystemd-network/arp-util.c | 4 |
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(ð_mac->ether_addr_octet[0])),/* A <- 4 bytes of client's MAC */ + BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be32(ð_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(ð_mac->ether_addr_octet[4])),/* A <- remainder of client's MAC */ + BPF_STMT(BPF_LD + BPF_IMM, unaligned_read_be16(ð_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 */ |