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-rw-r--r--src/udev/net/link-config.c38
1 files changed, 21 insertions, 17 deletions
diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c
index 9b91d9d145..e6618b8cbf 100644
--- a/src/udev/net/link-config.c
+++ b/src/udev/net/link-config.c
@@ -39,6 +39,7 @@
#include "hashmap.h"
#include "rtnl-util.h"
#include "net-util.h"
+#include "siphash24.h"
struct link_config_ctx {
LIST_HEAD(link_config, links);
@@ -301,17 +302,18 @@ static bool mac_is_permanent(struct udev_device *device) {
return type == 0;
}
+#define HASH_KEY SD_ID128_MAKE(d3,1e,48,fa,90,fe,4b,4c,9d,af,d5,d7,a1,b1,2e,8a)
+
static int get_mac(struct udev_device *device, bool want_random, struct ether_addr *mac) {
- unsigned int seed;
- int r, i;
+ int r;
if (want_random)
- seed = random_u();
+ random_bytes(mac->ether_addr_octet, ETH_ALEN);
else {
const char *name;
- sd_id128_t machine;
- char machineid_buf[33];
- const char *seed_str;
+ uint8_t result[8];
+ size_t l, sz;
+ uint8_t *v;
/* fetch some persistent data unique (on this machine) to this device */
name = udev_device_get_property_value(device, "ID_NET_NAME_ONBOARD");
@@ -323,22 +325,24 @@ static int get_mac(struct udev_device *device, bool want_random, struct ether_ad
return -ENOENT;
}
}
+
+ l = strlen(name);
+ sz = sizeof(sd_id128_t) + l;
+ v = alloca(sz);
+
/* fetch some persistent data unique to this machine */
- r = sd_id128_get_machine(&machine);
+ r = sd_id128_get_machine((sd_id128_t*) v);
if (r < 0)
return r;
+ memcpy(v + sizeof(sd_id128_t), name, l);
- /* combine the data */
- seed_str = strappenda(name, sd_id128_to_string(machine, machineid_buf));
-
- /* hash to get seed */
- seed = string_hash_func(seed_str);
- }
-
- srandom(seed);
+ /* Let's hash the machine ID plus the device name. We
+ * use a fixed, but originally randomly created hash
+ * key here. */
+ siphash24(result, v, sz, HASH_KEY.bytes);
- for (i = 0; i < ETH_ALEN; i++) {
- mac->ether_addr_octet[i] = random();
+ assert_cc(ETH_ALEN <= sizeof(result));
+ memcpy(mac->ether_addr_octet, result, ETH_ALEN);
}
/* see eth_random_addr in the kernel */