dhcp-identifier: un-inline dhcp_validate_duid_len

After all it is used in more than one place and is not that short.
Also tweak the test a bit:
- do not check that duid_len > 0, because we want to allow unknown
  duid types, and there might be some which are fine with 0 length data,
  (also assert should not be called from library code),
- always check that duid_len <= MAX_DUID_LEN, because we could overwrite
  available buffer space otherwise.

2 files changed, 37 insertions, 35 deletions

diff --git a/src/libsystemd-network/dhcp-identifier.c b/src/libsystemd-network/dhcp-identifier.c
index 4f7d4d8bf2..a21efc4d06 100644
--- a/src/libsystemd-network/dhcp-identifier.c
+++ b/src/libsystemd-network/dhcp-identifier.c
@@ -31,6 +31,37 @@
 #define SYSTEMD_PEN 43793
 #define HASH_KEY SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
 
+int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len) {
+        struct duid d;
+
+        assert_cc(sizeof(d.raw) >= MAX_DUID_LEN);
+        if (duid_len > MAX_DUID_LEN)
+                return -EINVAL;
+
+        switch (duid_type) {
+        case DUID_TYPE_LLT:
+                if (duid_len <= sizeof(d.llt))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_EN:
+                if (duid_len != sizeof(d.en))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_LL:
+                if (duid_len <= sizeof(d.ll))
+                        return -EINVAL;
+                break;
+        case DUID_TYPE_UUID:
+                if (duid_len != sizeof(d.uuid))
+                        return -EINVAL;
+                break;
+        default:
+                /* accept unknown type in order to be forward compatible */
+                break;
+        }
+        return 0;
+}
+
 int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len) {
         sd_id128_t machine_id;
         uint64_t hash;
diff --git a/src/libsystemd-network/dhcp-identifier.h b/src/libsystemd-network/dhcp-identifier.h
index e6486b78f8..dd0f926f90 100644
--- a/src/libsystemd-network/dhcp-identifier.h
+++ b/src/libsystemd-network/dhcp-identifier.h
@@ -40,27 +40,28 @@ typedef enum DUIDType {
  */
 #define MAX_DUID_LEN 128
 
+/* https://tools.ietf.org/html/rfc3315#section-9.1 */
 struct duid {
         be16_t type;
         union {
                 struct {
-                        /* DHCP6_DUID_LLT */
+                        /* DUID_TYPE_LLT */
                         uint16_t htype;
                         uint32_t time;
                         uint8_t haddr[0];
                 } _packed_ llt;
                 struct {
-                        /* DHCP6_DUID_EN */
+                        /* DUID_TYPE_EN */
                         uint32_t pen;
                         uint8_t id[8];
                 } _packed_ en;
                 struct {
-                        /* DHCP6_DUID_LL */
+                        /* DUID_TYPE_LL */
                         int16_t htype;
                         uint8_t haddr[0];
                 } _packed_ ll;
                 struct {
-                        /* DHCP6_DUID_UUID */
+                        /* DUID_TYPE_UUID */
                         sd_id128_t uuid;
                 } _packed_ uuid;
                 struct {
@@ -69,36 +70,6 @@ struct duid {
         };
 } _packed_;
 
+int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len);
 int dhcp_identifier_set_duid_en(struct duid *duid, size_t *len);
 int dhcp_identifier_set_iaid(int ifindex, uint8_t *mac, size_t mac_len, void *_id);
-
-static inline int dhcp_validate_duid_len(uint16_t duid_type, size_t duid_len) {
-        struct duid d;
-
-        assert(duid_len > 0);
-
-        switch (duid_type) {
-        case DUID_TYPE_LLT:
-                if (duid_len <= sizeof(d.llt))
-                        return -EINVAL;
-                break;
-        case DUID_TYPE_EN:
-                if (duid_len != sizeof(d.en))
-                        return -EINVAL;
-                break;
-        case DUID_TYPE_LL:
-                if (duid_len <= sizeof(d.ll))
-                        return -EINVAL;
-                break;
-        case DUID_TYPE_UUID:
-                if (duid_len != sizeof(d.uuid))
-                        return -EINVAL;
-                break;
-        default:
-                if (duid_len > sizeof(d.raw))
-                        return -EINVAL;
-                /* accept unknown type in order to be forward compatible */
-                break;
-        }
-        return 0;
-}