On Tue, Jun 24, 2014 at 12:58 PM, Michal Sekletar <msekl...@redhat.com> wrote: > On Thu, Jun 19, 2014 at 12:02:39PM -0500, Dan Williams wrote: >> On Thu, 2014-06-19 at 18:59 +0200, Michal Sekletar wrote: >> > Check that received DHCP packets actually include our MAC address in >> > chaddr field. BPF interpreter has 32 bit wide registers but MAC address >> > is 48 bits long so we have to do check in two steps. >> >> And if the MAC address is not 48 bits (Infiniband) or the interface type >> doesn't really have a MAC address (PPP/PPPoE)? DHCP can be used in both >> cases... If anything, the code that uses the MAC address should be >> if-ed so it only executes when a MAC address is provided. > > I reconsidered. In filter code I can very easily find out type of device to > which > filter is attached and skip ethernet specific bits or fallback to something > else. However filter already assumes ethernet data-link type moreover there > is a ton of > code in networkd which does likewise. > > I think we should merge patch as is right now. If somebody will hack up > patches > for supporting various data-link types I will be happy to patch filter > accordingly.
Ok. I'm fine with that. Please push. Just to make clear: I'd be happy if anyone wanted to turn all our libs to work also on non-ethernet (and test it!), and would merge such patches. Cheers, Tom >> > src/libsystemd-network/dhcp-internal.h | 3 ++- >> > src/libsystemd-network/dhcp-network.c | 15 +++++++++++++-- >> > src/libsystemd-network/sd-dhcp-client.c | 4 ++-- >> > src/libsystemd-network/test-dhcp-client.c | 2 +- >> > 4 files changed, 18 insertions(+), 6 deletions(-) >> > >> > diff --git a/src/libsystemd-network/dhcp-internal.h >> > b/src/libsystemd-network/dhcp-internal.h >> > index 03cc824..fd86a70 100644 >> > --- a/src/libsystemd-network/dhcp-internal.h >> > +++ b/src/libsystemd-network/dhcp-internal.h >> > @@ -24,12 +24,13 @@ >> > >> > #include <stdint.h> >> > #include <linux/if_packet.h> >> > +#include <net/ethernet.h> >> > >> > #include "socket-util.h" >> > >> > #include "dhcp-protocol.h" >> > >> > -int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, >> > uint32_t xid); >> > +int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, >> > uint32_t xid, struct ether_addr mac_addr); >> > int dhcp_network_bind_udp_socket(be32_t address, uint16_t port); >> > int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link, >> > const void *packet, size_t len); >> > diff --git a/src/libsystemd-network/dhcp-network.c >> > b/src/libsystemd-network/dhcp-network.c >> > index d7ba0ef..e5fd6a8 100644 >> > --- a/src/libsystemd-network/dhcp-network.c >> > +++ b/src/libsystemd-network/dhcp-network.c >> > @@ -33,7 +33,7 @@ >> > #include "dhcp-internal.h" >> > >> > int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, >> > - uint32_t xid) { >> > + uint32_t xid, struct ether_addr >> > mac_addr) { >> > struct sock_filter filter[] = { >> > BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), >> > /* A <- packet length */ >> > BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(DHCPPacket), 1, >> > 0), /* packet >= DHCPPacket ? */ >> > @@ -56,7 +56,18 @@ int dhcp_network_bind_raw_socket(int index, 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 */ >> > - /* TODO: match chaddr */ >> > + BPF_STMT(BPF_LD + BPF_IMM, htobe32(*((unsigned int *) >> > &mac_addr))), /* 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 *) &mac_addr) + 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 */ >> > + 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_W + BPF_ABS, offsetof(DHCPPacket, >> > dhcp.magic)), /* A <- DHCP magic cookie */ >> > BPF_JUMP(BPF_JMP + BPF_JEQ + BPF_K, DHCP_MAGIC_COOKIE, 1, 0), >> > /* cookie == DHCP magic cookie ? */ >> > BPF_STMT(BPF_RET + BPF_K, 0), >> > /* ignore */ >> > diff --git a/src/libsystemd-network/sd-dhcp-client.c >> > b/src/libsystemd-network/sd-dhcp-client.c >> > index c1af6df..d44cad2 100644 >> > --- a/src/libsystemd-network/sd-dhcp-client.c >> > +++ b/src/libsystemd-network/sd-dhcp-client.c >> > @@ -719,7 +719,7 @@ static int client_start(sd_dhcp_client *client) { >> > >> > client->xid = random_u32(); >> > >> > - r = dhcp_network_bind_raw_socket(client->index, &client->link, >> > client->xid); >> > + r = dhcp_network_bind_raw_socket(client->index, &client->link, >> > client->xid, client->client_id.mac_addr); >> > if (r < 0) { >> > client_stop(client, r); >> > return r; >> > @@ -761,7 +761,7 @@ static int client_timeout_t2(sd_event_source *s, >> > uint64_t usec, void *userdata) >> > client->state = DHCP_STATE_REBINDING; >> > client->attempt = 1; >> > >> > - r = dhcp_network_bind_raw_socket(client->index, &client->link, >> > client->xid); >> > + r = dhcp_network_bind_raw_socket(client->index, &client->link, >> > client->xid, client->client_id.mac_addr); >> > if (r < 0) { >> > client_stop(client, r); >> > return 0; >> > diff --git a/src/libsystemd-network/test-dhcp-client.c >> > b/src/libsystemd-network/test-dhcp-client.c >> > index 450b6d4..7cbe10d 100644 >> > --- a/src/libsystemd-network/test-dhcp-client.c >> > +++ b/src/libsystemd-network/test-dhcp-client.c >> > @@ -196,7 +196,7 @@ int dhcp_network_send_raw_socket(int s, const union >> > sockaddr_union *link, >> > return 575; >> > } >> > >> > -int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, >> > uint32_t id) >> > +int dhcp_network_bind_raw_socket(int index, union sockaddr_union *link, >> > uint32_t id, struct ether_addr mac) >> > { >> > if (socketpair(AF_UNIX, SOCK_STREAM, 0, test_fd) < 0) >> > return -errno; >> >> _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel