diff --git a/crypto/asn1/a_verify.c b/crypto/asn1/a_verify.c
index 3ffd934..23271be 100644
--- a/crypto/asn1/a_verify.c
+++ b/crypto/asn1/a_verify.c
@@ -56,6 +56,9 @@
  * [including the GNU Public Licence.]
  */
 
+/* for secure_getenv */
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <time.h>
 
@@ -133,6 +136,30 @@ int ASN1_verify(i2d_of_void *i2d, X509_ALGOR *a, ASN1_BIT_STRING *signature,
 
 #endif
 
+static int legacy_mds[] = { NID_md5, NID_sha, NID_md4, NID_md2, 0 };
+extern int private_ossl_allowed_legacy_mds[];
+
+static int is_md_legacy_disallowed(int mdnid)
+{
+    int i;
+
+    if (mdnid == NID_md5 && secure_getenv("OPENSSL_ENABLE_MD5_VERIFY") != NULL)
+        return 0;
+
+    for (i = 0; legacy_mds[i] != 0; ++i) {
+         if (mdnid == legacy_mds[i]) {
+            int j;
+
+            for (j = 0; private_ossl_allowed_legacy_mds[j] != 0; ++j) {
+                 if (mdnid == private_ossl_allowed_legacy_mds[j])
+                     return 0;
+            }
+            return 1;
+        }
+     }
+     return 0;
+}
+
 int ASN1_item_verify(const ASN1_ITEM *it, X509_ALGOR *a,
                      ASN1_BIT_STRING *signature, void *asn, EVP_PKEY *pkey)
 {
@@ -174,6 +201,10 @@ int ASN1_item_verify(const ASN1_ITEM *it, X509_ALGOR *a,
         if (ret != 2)
             goto err;
         ret = -1;
+    } else if (is_md_legacy_disallowed(mdnid)) {
+        ASN1err(ASN1_F_ASN1_ITEM_VERIFY,
+                ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);
+        goto err;
     } else {
         const EVP_MD *type;
         type = EVP_get_digestbynid(mdnid);
diff --git a/crypto/o_init.c b/crypto/o_init.c
index 2f754ef..59439c2 100644
--- a/crypto/o_init.c
+++ b/crypto/o_init.c
@@ -55,6 +55,12 @@
 
 #include <e_os.h>
 #include <openssl/err.h>
+# include <stdio.h>
+# include <string.h>
+# include <strings.h>
+# include <ctype.h>
+# include <openssl/dh.h>
+# include <openssl/objects.h>
 #ifdef OPENSSL_FIPS
 # include <sys/types.h>
 # include <sys/stat.h>
@@ -89,6 +95,121 @@ static void init_fips_mode(void)
 }
 #endif
 
+# define LEGACY_SETTINGS_FILE "/etc/pki/tls/legacy-settings"
+
+# define NUM_MAX_LEGACY_MDS 8
+
+int private_ossl_allowed_legacy_mds[NUM_MAX_LEGACY_MDS + 1]; /* zero terminated */
+
+int private_ossl_minimum_dh_bits;
+
+#if !defined(_WIN32)
+static void parse_legacy_mds(char *p)
+{
+    int idx = 0;
+    char *e = p;
+
+    while (p[0] != '\0') {
+        while (e[0] != '\0' && !isspace(e[0]) && e[0] != ',') {
+            ++e;
+        }
+        if (e[0] != '\0') {
+            e[0] = '\0';
+            ++e;
+        }
+
+        if (strcasecmp(p, "md5") == 0) {
+            private_ossl_allowed_legacy_mds[idx++] = NID_md5;
+        } else if (strcasecmp(p, "md4") == 0) {
+            private_ossl_allowed_legacy_mds[idx++] = NID_md4;
+        } else if (strcasecmp(p, "sha") == 0) {
+            private_ossl_allowed_legacy_mds[idx++] = NID_sha;
+        } else if (strcasecmp(p, "md2") == 0) {
+            private_ossl_allowed_legacy_mds[idx++] = NID_md2;
+        }
+
+        if (idx >=
+            sizeof(private_ossl_allowed_legacy_mds) /
+            sizeof(private_ossl_allowed_legacy_mds[0])) {
+            break;
+        }
+
+        while (e[0] == ',' || isspace(e[0])) {
+            ++e;
+        }
+
+        p = e;
+    }
+}
+
+static void parse_minimum_dh_bits(char *p)
+{
+    private_ossl_minimum_dh_bits = strtol(p, NULL, 10);
+    if (private_ossl_minimum_dh_bits < 512
+        || private_ossl_minimum_dh_bits > OPENSSL_DH_MAX_MODULUS_BITS) {
+        /* use default */
+        private_ossl_minimum_dh_bits = 0;
+    }
+}
+
+static void load_legacy_settings(void)
+{
+    FILE *f;
+    char *line = NULL;
+    size_t len = 0;
+
+    if ((f = fopen(LEGACY_SETTINGS_FILE, "r")) == NULL) {
+        return;
+    }
+
+    while (getline(&line, &len, f) > 0) {
+        char *p = line, *e, *val;
+
+        /* skip initial whitespace */
+        while (isspace(p[0])) {
+            ++p;
+        }
+
+        e = p;
+
+        while (e[0] != '\0' && !isspace(e[0])) {
+            ++e;
+        }
+
+        /* terminate name, skip whitespace between name and value */
+        if (e[0] != '\0') {
+            e[0] = '\0';
+            ++e;
+            while (isspace(e[0])) {
+                ++e;
+            }
+        }
+
+        val = e;
+
+        e = e + strlen(val);
+
+        /* trim terminating whitespace */
+        while (e > val) {
+            --e;
+            if (isspace(e[0])) {
+                e[0] = '\0';
+            } else {
+                break;
+            }
+        }
+
+        if (strcasecmp(p, "LegacySigningMDs") == 0) {
+            parse_legacy_mds(val);
+        } else if (strcasecmp(line, "MinimumDHBits") == 0) {
+            parse_minimum_dh_bits(val);
+        }
+        /* simply skip other unrecognized lines */
+    }
+    (void)fclose(f);
+}
+#endif
+
 /*
  * Perform any essential OpenSSL initialization operations. Currently only
  * sets FIPS callbacks
@@ -100,6 +221,10 @@ void OPENSSL_init_library(void)
     if (done)
         return;
     done = 1;
+
+#if !defined(_WIN32)
+    load_legacy_settings();
+#endif
 #ifdef OPENSSL_FIPS
     RAND_init_fips();
     init_fips_mode();
diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 32f2f1a..6734e8a 100644
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -3500,6 +3500,8 @@ int ssl3_send_client_certificate(SSL *s)
 
 #define has_bits(i,m)   (((i)&(m)) == (m))
 
+extern int private_ossl_minimum_dh_bits;
+
 int ssl3_check_cert_and_algorithm(SSL *s)
 {
     int i, idx;
@@ -3630,8 +3632,7 @@ int ssl3_check_cert_and_algorithm(SSL *s)
             DH_free(dh_srvr);
         }
 
-        if ((!SSL_C_IS_EXPORT(s->s3->tmp.new_cipher) && dh_size < 1024)
-            || (SSL_C_IS_EXPORT(s->s3->tmp.new_cipher) && dh_size < 512)) {
+        if (dh_size < (private_ossl_minimum_dh_bits ? private_ossl_minimum_dh_bits : 1024)) {
             SSLerr(SSL_F_SSL3_CHECK_CERT_AND_ALGORITHM, SSL_R_DH_KEY_TOO_SMALL);
             goto f_err;
         }