diff --git a/crypto/x509/x509_test.cc b/crypto/x509/x509_test.cc
index 56d800c..4020665 100644
--- a/crypto/x509/x509_test.cc
+++ b/crypto/x509/x509_test.cc
@@ -2813,3 +2813,182 @@
   EXPECT_EQ(ERR_LIB_X509, ERR_GET_LIB(err));
   EXPECT_EQ(X509_R_INVALID_PARAMETER, ERR_GET_REASON(err));
 }
+
+TEST(X509Test, GeneralName)  {
+  const std::vector<uint8_t> kNames[] = {
+      // [0] {
+      //   OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2.1 }
+      //   [0] {
+      //     SEQUENCE {}
+      //   }
+      // }
+      {0xa0, 0x13, 0x06, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04,
+       0x01, 0x84, 0xb7, 0x09, 0x02, 0x01, 0xa0, 0x02, 0x30, 0x00},
+      // [0] {
+      //   OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2.1 }
+      //   [0] {
+      //     [APPLICATION 0] {}
+      //   }
+      // }
+      {0xa0, 0x13, 0x06, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04,
+       0x01, 0x84, 0xb7, 0x09, 0x02, 0x01, 0xa0, 0x02, 0x60, 0x00},
+      // [0] {
+      //   OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2.1 }
+      //   [0] {
+      //     UTF8String { "a" }
+      //   }
+      // }
+      {0xa0, 0x14, 0x06, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04,
+       0x01, 0x84, 0xb7, 0x09, 0x02, 0x01, 0xa0, 0x03, 0x0c, 0x01, 0x61},
+      // [0] {
+      //   OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2.2 }
+      //   [0] {
+      //     UTF8String { "a" }
+      //   }
+      // }
+      {0xa0, 0x14, 0x06, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04,
+       0x01, 0x84, 0xb7, 0x09, 0x02, 0x02, 0xa0, 0x03, 0x0c, 0x01, 0x61},
+      // [0] {
+      //   OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2.1 }
+      //   [0] {
+      //     UTF8String { "b" }
+      //   }
+      // }
+      {0xa0, 0x14, 0x06, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04,
+       0x01, 0x84, 0xb7, 0x09, 0x02, 0x01, 0xa0, 0x03, 0x0c, 0x01, 0x62},
+      // [0] {
+      //   OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2.1 }
+      //   [0] {
+      //     BOOLEAN { TRUE }
+      //   }
+      // }
+      {0xa0, 0x14, 0x06, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04,
+       0x01, 0x84, 0xb7, 0x09, 0x02, 0x01, 0xa0, 0x03, 0x01, 0x01, 0xff},
+      // [0] {
+      //   OBJECT_IDENTIFIER { 1.2.840.113554.4.1.72585.2.1 }
+      //   [0] {
+      //     BOOLEAN { FALSE }
+      //   }
+      // }
+      {0xa0, 0x14, 0x06, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04,
+       0x01, 0x84, 0xb7, 0x09, 0x02, 0x01, 0xa0, 0x03, 0x01, 0x01, 0x00},
+      // [1 PRIMITIVE] { "a" }
+      {0x81, 0x01, 0x61},
+      // [1 PRIMITIVE] { "b" }
+      {0x81, 0x01, 0x62},
+      // [2 PRIMITIVE] { "a" }
+      {0x82, 0x01, 0x61},
+      // [2 PRIMITIVE] { "b" }
+      {0x82, 0x01, 0x62},
+      // [4] {
+      //   SEQUENCE {
+      //     SET {
+      //       SEQUENCE {
+      //         # commonName
+      //         OBJECT_IDENTIFIER { 2.5.4.3 }
+      //         UTF8String { "a" }
+      //       }
+      //     }
+      //   }
+      // }
+      {0xa4, 0x0e, 0x30, 0x0c, 0x31, 0x0a, 0x30, 0x08, 0x06, 0x03, 0x55, 0x04,
+       0x03, 0x0c, 0x01, 0x61},
+      // [4] {
+      //   SEQUENCE {
+      //     SET {
+      //       SEQUENCE {
+      //         # commonName
+      //         OBJECT_IDENTIFIER { 2.5.4.3 }
+      //         UTF8String { "b" }
+      //       }
+      //     }
+      //   }
+      // }
+      {0xa4, 0x0e, 0x30, 0x0c, 0x31, 0x0a, 0x30, 0x08, 0x06, 0x03, 0x55, 0x04,
+       0x03, 0x0c, 0x01, 0x62},
+      // [5] {
+      //   [1] {
+      //     UTF8String { "a" }
+      //   }
+      // }
+      {0xa5, 0x05, 0xa1, 0x03, 0x0c, 0x01, 0x61},
+      // [5] {
+      //   [1] {
+      //     UTF8String { "b" }
+      //   }
+      // }
+      {0xa5, 0x05, 0xa1, 0x03, 0x0c, 0x01, 0x62},
+      // [5] {
+      //   [0] {
+      //     UTF8String {}
+      //   }
+      //   [1] {
+      //     UTF8String { "a" }
+      //   }
+      // }
+      {0xa5, 0x09, 0xa0, 0x02, 0x0c, 0x00, 0xa1, 0x03, 0x0c, 0x01, 0x61},
+      // [5] {
+      //   [0] {
+      //     UTF8String { "a" }
+      //   }
+      //   [1] {
+      //     UTF8String { "a" }
+      //   }
+      // }
+      {0xa5, 0x0a, 0xa0, 0x03, 0x0c, 0x01, 0x61, 0xa1, 0x03, 0x0c, 0x01, 0x61},
+      // [5] {
+      //   [0] {
+      //     UTF8String { "b" }
+      //   }
+      //   [1] {
+      //     UTF8String { "a" }
+      //   }
+      // }
+      {0xa5, 0x0a, 0xa0, 0x03, 0x0c, 0x01, 0x62, 0xa1, 0x03, 0x0c, 0x01, 0x61},
+      // [6 PRIMITIVE] { "a" }
+      {0x86, 0x01, 0x61},
+      // [6 PRIMITIVE] { "b" }
+      {0x86, 0x01, 0x62},
+      // [7 PRIMITIVE] { `11111111` }
+      {0x87, 0x04, 0x11, 0x11, 0x11, 0x11},
+      // [7 PRIMITIVE] { `22222222`}
+      {0x87, 0x04, 0x22, 0x22, 0x22, 0x22},
+      // [7 PRIMITIVE] { `11111111111111111111111111111111` }
+      {0x87, 0x10, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11, 0x11,
+       0x11, 0x11, 0x11, 0x11, 0x11, 0x11},
+      // [7 PRIMITIVE] { `22222222222222222222222222222222` }
+      {0x87, 0x10, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
+       0x22, 0x22, 0x22, 0x22, 0x22, 0x22},
+      // [8 PRIMITIVE] { 1.2.840.113554.4.1.72585.2.1 }
+      {0x88, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04, 0x01, 0x84, 0xb7,
+       0x09, 0x02, 0x01},
+      // [8 PRIMITIVE] { 1.2.840.113554.4.1.72585.2.2 }
+      {0x88, 0x0d, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x04, 0x01, 0x84, 0xb7,
+       0x09, 0x02, 0x02},
+  };
+
+  // Every name should be equal to itself and not equal to any others.
+  for (size_t i = 0; i < OPENSSL_ARRAY_SIZE(kNames); i++) {
+    SCOPED_TRACE(Bytes(kNames[i]));
+
+    const uint8_t *ptr = kNames[i].data();
+    bssl::UniquePtr<GENERAL_NAME> a(
+        d2i_GENERAL_NAME(nullptr, &ptr, kNames[i].size()));
+    ASSERT_TRUE(a);
+
+    for (size_t j = 0; j < OPENSSL_ARRAY_SIZE(kNames); j++) {
+      SCOPED_TRACE(Bytes(kNames[j]));
+
+      ptr = kNames[j].data();
+      bssl::UniquePtr<GENERAL_NAME> b(
+          d2i_GENERAL_NAME(nullptr, &ptr, kNames[j].size()));
+      ASSERT_TRUE(b);
+
+      if (i == j) {
+        EXPECT_EQ(GENERAL_NAME_cmp(a.get(), b.get()), 0);
+      } else {
+        EXPECT_NE(GENERAL_NAME_cmp(a.get(), b.get()), 0);
+      }
+    }
+  }
+}
diff --git a/crypto/x509v3/v3_genn.c b/crypto/x509v3/v3_genn.c
index 57223b4..af7e4e1 100644
--- a/crypto/x509v3/v3_genn.c
+++ b/crypto/x509v3/v3_genn.c
@@ -72,8 +72,9 @@
 IMPLEMENT_ASN1_FUNCTIONS(OTHERNAME)
 
 ASN1_SEQUENCE(EDIPARTYNAME) = {
-        ASN1_IMP_OPT(EDIPARTYNAME, nameAssigner, DIRECTORYSTRING, 0),
-        ASN1_IMP_OPT(EDIPARTYNAME, partyName, DIRECTORYSTRING, 1)
+        /* DirectoryString is a CHOICE type, so use explicit tagging. */
+        ASN1_EXP_OPT(EDIPARTYNAME, nameAssigner, DIRECTORYSTRING, 0),
+        ASN1_EXP(EDIPARTYNAME, partyName, DIRECTORYSTRING, 1)
 } ASN1_SEQUENCE_END(EDIPARTYNAME)
 
 IMPLEMENT_ASN1_FUNCTIONS(EDIPARTYNAME)
@@ -102,6 +103,24 @@
 
 IMPLEMENT_ASN1_DUP_FUNCTION(GENERAL_NAME)
 
+static int edipartyname_cmp(const EDIPARTYNAME *a, const EDIPARTYNAME *b)
+{
+    /* nameAssigner is optional and may be NULL. */
+    if (a->nameAssigner == NULL) {
+        if (b->nameAssigner != NULL) {
+            return -1;
+        }
+    } else {
+        if (b->nameAssigner == NULL ||
+            ASN1_STRING_cmp(a->nameAssigner, b->nameAssigner) != 0) {
+            return -1;
+        }
+    }
+
+    /* partyName may not be NULL. */
+    return ASN1_STRING_cmp(a->partyName, b->partyName);
+}
+
 /* Returns 0 if they are equal, != 0 otherwise. */
 int GENERAL_NAME_cmp(GENERAL_NAME *a, GENERAL_NAME *b)
 {
@@ -111,8 +130,11 @@
         return -1;
     switch (a->type) {
     case GEN_X400:
+        result = ASN1_TYPE_cmp(a->d.x400Address, b->d.x400Address);
+        break;
+
     case GEN_EDIPARTY:
-        result = ASN1_TYPE_cmp(a->d.other, b->d.other);
+        result = edipartyname_cmp(a->d.ediPartyName, b->d.ediPartyName);
         break;
 
     case GEN_OTHERNAME:
@@ -159,8 +181,11 @@
 {
     switch (type) {
     case GEN_X400:
+        a->d.x400Address = value;
+        break;
+
     case GEN_EDIPARTY:
-        a->d.other = value;
+        a->d.ediPartyName = value;
         break;
 
     case GEN_OTHERNAME:
@@ -194,8 +219,10 @@
         *ptype = a->type;
     switch (a->type) {
     case GEN_X400:
+        return a->d.x400Address;
+
     case GEN_EDIPARTY:
-        return a->d.other;
+        return a->d.ediPartyName;
 
     case GEN_OTHERNAME:
         return a->d.otherName;
diff --git a/include/openssl/x509v3.h b/include/openssl/x509v3.h
index a0b6bd8..09fc4ea 100644
--- a/include/openssl/x509v3.h
+++ b/include/openssl/x509v3.h
@@ -474,6 +474,12 @@
 
 DECLARE_ASN1_FUNCTIONS(GENERAL_NAME)
 OPENSSL_EXPORT GENERAL_NAME *GENERAL_NAME_dup(GENERAL_NAME *a);
+
+// GENERAL_NAME_cmp returns zero if |a| and |b| are equal and a non-zero
+// value otherwise. Note this function does not provide a comparison suitable
+// for sorting.
+//
+// TODO(davidben): Const-correct this function.
 OPENSSL_EXPORT int GENERAL_NAME_cmp(GENERAL_NAME *a, GENERAL_NAME *b);