dhcp-network: adjust sockaddr length for addresses longer than 8 bytes (#6527)

An infiniband hardware address is 20 bytes, but sockaddr_ll.sll_addr is only 8
bytes. Explicitly ensure that sockaddr_union has enough space for infiniband
addresses, even if they run over sockaddr_ll and add a macro to compute the
proper size to pass to kernel.

diff --git a/src/basic/socket-util.h b/src/basic/socket-util.h
index 73c3a339fc61a493d56c5b4ad875c657003c3726..43edc05c635f0dc48036969b5296341425537170 100644 (file)
--- a/src/basic/socket-util.h
+++ b/src/basic/socket-util.h
@@ -27,6 +27,7 @@
 #include <sys/types.h>
 #include <sys/un.h>
 #include <linux/netlink.h>
+#include <linux/if_infiniband.h>
 #include <linux/if_packet.h>
 
 #include "macro.h"
@@ -42,6 +43,8 @@ union sockaddr_union {
         struct sockaddr_storage storage;
         struct sockaddr_ll ll;
         struct sockaddr_vm vm;
+        /* Ensure there is enough space to store Infiniband addresses */
+        uint8_t ll_buffer[offsetof(struct sockaddr_ll, sll_addr) + CONST_MAX(ETH_ALEN, INFINIBAND_ALEN)];
 };
 
 typedef struct SocketAddress {
@@ -147,6 +150,23 @@ int flush_accept(int fd);
 
 struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t length);
 
+/*
+ * Certain hardware address types (e.g Infiniband) do not fit into sll_addr
+ * (8 bytes) and run over the structure. This macro returns the correct size that
+ * must be passed to kernel.
+ */
+#define SOCKADDR_LL_LEN(sa)                                             \
+        ({                                                              \
+                const struct sockaddr_ll *_sa = &(sa);                  \
+                size_t _mac_len = sizeof(_sa->sll_addr);                \
+                assert(_sa->sll_family == AF_PACKET);                   \
+                if (be16toh(_sa->sll_hatype) == ARPHRD_ETHER)           \
+                        _mac_len = MAX(_mac_len, (size_t) ETH_ALEN);    \
+                if (be16toh(_sa->sll_hatype) == ARPHRD_INFINIBAND)      \
+                        _mac_len = MAX(_mac_len, (size_t) INFINIBAND_ALEN); \
+                offsetof(struct sockaddr_ll, sll_addr) + _mac_len;      \
+        })
+
 /* Covers only file system and abstract AF_UNIX socket addresses, but not unnamed socket addresses. */
 #define SOCKADDR_UN_LEN(sa)                                             \
         ({                                                              \

diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c
index 65405dcce07cddd8c95f5935f01f5f1f4b09e1df..a440a20f96d99211d51b10e5ea9a0659aed4d870 100644 (file)
--- a/src/libsystemd-network/dhcp-network.c
+++ b/src/libsystemd-network/dhcp-network.c
@@ -108,14 +108,16 @@ static int _bind_raw_socket(int ifindex, union sockaddr_union *link,
         if (r < 0)
                 return -errno;
 
-        link->ll.sll_family = AF_PACKET;
-        link->ll.sll_protocol = htobe16(ETH_P_IP);
-        link->ll.sll_ifindex = ifindex;
-        link->ll.sll_hatype = htobe16(arp_type);
-        link->ll.sll_halen = mac_addr_len;
+        link->ll = (struct sockaddr_ll) {
+                .sll_family = AF_PACKET,
+                .sll_protocol = htobe16(ETH_P_IP),
+                .sll_ifindex = ifindex,
+                .sll_hatype = htobe16(arp_type),
+                .sll_halen = mac_addr_len,
+        };
         memcpy(link->ll.sll_addr, bcast_addr, mac_addr_len);
 
-        r = bind(s, &link->sa, sizeof(link->ll));
+        r = bind(s, &link->sa, SOCKADDR_LL_LEN(link->ll));
         if (r < 0)
                 return -errno;
 
@@ -221,7 +223,7 @@ int dhcp_network_send_raw_socket(int s, const union sockaddr_union *link,
         assert(packet);
         assert(len);
 
-        r = sendto(s, packet, len, 0, &link->sa, sizeof(link->ll));
+        r = sendto(s, packet, len, 0, &link->sa, SOCKADDR_LL_LEN(link->ll));
         if (r < 0)
                 return -errno;