From 30c7b4dd01734b6ba20bfc7790b9fe8bc0500214 Mon Sep 17 00:00:00 2001

From: Daniel Stenberg <daniel@haxx.se>

Date: Sat, 19 Jun 2021 00:42:28 +0200

Subject: [PATCH] vtls: fix connection reuse checks for issuer cert and case

 sensitivity

CVE-2021-22924

Reported-by: Harry Sintonen

Bug: https://curl.se/docs/CVE-2021-22924.html

Upstream-commit: 5ea3145850ebff1dc2b13d17440300a01ca38161

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 lib/url.c          | 10 ++++++----

 lib/urldata.h      |  4 ++--

 lib/vtls/gtls.c    | 10 +++++-----

 lib/vtls/nss.c     |  4 ++--

 lib/vtls/openssl.c | 18 +++++++++---------

 lib/vtls/vtls.c    | 26 +++++++++++++++++++++-----

 6 files changed, 45 insertions(+), 27 deletions(-)

diff --git a/lib/url.c b/lib/url.c

index 9f2c9f2..bdcb095 100644

--- a/lib/url.c

+++ b/lib/url.c

@@ -3723,6 +3723,8 @@ static CURLcode create_conn(struct Curl_easy *data,

   */

   data->set.ssl.primary.CApath = data->set.str[STRING_SSL_CAPATH];

   data->set.ssl.primary.CAfile = data->set.str[STRING_SSL_CAFILE];

+  data->set.ssl.primary.issuercert = data->set.str[STRING_SSL_ISSUERCERT];

+  data->set.ssl.primary.issuercert_blob = data->set.blobs[BLOB_SSL_ISSUERCERT];

   data->set.ssl.primary.random_file = data->set.str[STRING_SSL_RANDOM_FILE];

   data->set.ssl.primary.egdsocket = data->set.str[STRING_SSL_EGDSOCKET];

   data->set.ssl.primary.cipher_list =

@@ -3747,8 +3749,11 @@ static CURLcode create_conn(struct Curl_easy *data,

   data->set.proxy_ssl.primary.pinned_key =

     data->set.str[STRING_SSL_PINNEDPUBLICKEY_PROXY];

   data->set.proxy_ssl.primary.cert_blob = data->set.blobs[BLOB_CERT_PROXY];

+  data->set.proxy_ssl.primary.issuercert =

+    data->set.str[STRING_SSL_ISSUERCERT_PROXY];

+  data->set.proxy_ssl.primary.issuercert_blob =

+    data->set.blobs[BLOB_SSL_ISSUERCERT_PROXY];

   data->set.proxy_ssl.CRLfile = data->set.str[STRING_SSL_CRLFILE_PROXY];

-  data->set.proxy_ssl.issuercert = data->set.str[STRING_SSL_ISSUERCERT_PROXY];

   data->set.proxy_ssl.cert_type = data->set.str[STRING_CERT_TYPE_PROXY];

   data->set.proxy_ssl.key = data->set.str[STRING_KEY_PROXY];

   data->set.proxy_ssl.key_type = data->set.str[STRING_KEY_TYPE_PROXY];

@@ -3757,7 +3762,6 @@ static CURLcode create_conn(struct Curl_easy *data,

   data->set.proxy_ssl.key_blob = data->set.blobs[BLOB_KEY_PROXY];

 #endif

   data->set.ssl.CRLfile = data->set.str[STRING_SSL_CRLFILE];

-  data->set.ssl.issuercert = data->set.str[STRING_SSL_ISSUERCERT];

   data->set.ssl.cert_type = data->set.str[STRING_CERT_TYPE];

   data->set.ssl.key = data->set.str[STRING_KEY];

   data->set.ssl.key_type = data->set.str[STRING_KEY_TYPE];

@@ -3771,9 +3775,7 @@ static CURLcode create_conn(struct Curl_easy *data,

   data->set.proxy_ssl.password = data->set.str[STRING_TLSAUTH_PASSWORD_PROXY];

 #endif

 #endif

-

   data->set.ssl.key_blob = data->set.blobs[BLOB_KEY];

-  data->set.ssl.issuercert_blob = data->set.blobs[BLOB_SSL_ISSUERCERT];

   if(!Curl_clone_primary_ssl_config(&data->set.ssl.primary,

                                     &conn->ssl_config)) {

diff --git a/lib/urldata.h b/lib/urldata.h

index 2bb7d81..7cf63d0 100644

--- a/lib/urldata.h

+++ b/lib/urldata.h

@@ -246,6 +246,7 @@ struct ssl_primary_config {

   long version_max;      /* max supported version the client wants to use*/

   char *CApath;          /* certificate dir (doesn't work on windows) */

   char *CAfile;          /* certificate to verify peer against */

+  char *issuercert;      /* optional issuer certificate filename */

   char *clientcert;

   char *random_file;     /* path to file containing "random" data */

   char *egdsocket;       /* path to file containing the EGD daemon socket */

@@ -253,6 +254,7 @@ struct ssl_primary_config {

   char *cipher_list13;   /* list of TLS 1.3 cipher suites to use */

   char *pinned_key;

   struct curl_blob *cert_blob;

+  struct curl_blob *issuercert_blob;

   char *curves;          /* list of curves to use */

   BIT(verifypeer);       /* set TRUE if this is desired */

   BIT(verifyhost);       /* set TRUE if CN/SAN must match hostname */

@@ -264,8 +266,6 @@ struct ssl_config_data {

   struct ssl_primary_config primary;

   long certverifyresult; /* result from the certificate verification */

   char *CRLfile;   /* CRL to check certificate revocation */

-  char *issuercert;/* optional issuer certificate filename */

-  struct curl_blob *issuercert_blob;

   curl_ssl_ctx_callback fsslctx; /* function to initialize ssl ctx */

   void *fsslctxp;        /* parameter for call back */

   char *cert_type; /* format for certificate (default: PEM)*/

diff --git a/lib/vtls/gtls.c b/lib/vtls/gtls.c

index ea54fe3..ccc5ce8 100644

--- a/lib/vtls/gtls.c

+++ b/lib/vtls/gtls.c

@@ -849,7 +849,7 @@ gtls_connect_step3(struct Curl_easy *data,

   if(!chainp) {

     if(SSL_CONN_CONFIG(verifypeer) ||

        SSL_CONN_CONFIG(verifyhost) ||

-       SSL_SET_OPTION(issuercert)) {

+       SSL_CONN_CONFIG(issuercert)) {

 #ifdef HAVE_GNUTLS_SRP

       if(SSL_SET_OPTION(authtype) == CURL_TLSAUTH_SRP

          && SSL_SET_OPTION(username) != NULL

@@ -1033,21 +1033,21 @@ gtls_connect_step3(struct Curl_easy *data,

        gnutls_x509_crt_t format */

     gnutls_x509_crt_import(x509_cert, chainp, GNUTLS_X509_FMT_DER);

-  if(SSL_SET_OPTION(issuercert)) {

+  if(SSL_CONN_CONFIG(issuercert)) {

     gnutls_x509_crt_init(&x509_issuer);

-    issuerp = load_file(SSL_SET_OPTION(issuercert));

+    issuerp = load_file(SSL_CONN_CONFIG(issuercert));

     gnutls_x509_crt_import(x509_issuer, &issuerp, GNUTLS_X509_FMT_PEM);

     rc = gnutls_x509_crt_check_issuer(x509_cert, x509_issuer);

     gnutls_x509_crt_deinit(x509_issuer);

     unload_file(issuerp);

     if(rc <= 0) {

       failf(data, "server certificate issuer check failed (IssuerCert: %s)",

-            SSL_SET_OPTION(issuercert)?SSL_SET_OPTION(issuercert):"none");

+            SSL_CONN_CONFIG(issuercert)?SSL_CONN_CONFIG(issuercert):"none");

       gnutls_x509_crt_deinit(x509_cert);

       return CURLE_SSL_ISSUER_ERROR;

     }

     infof(data, "\t server certificate issuer check OK (Issuer Cert: %s)\n",

-          SSL_SET_OPTION(issuercert)?SSL_SET_OPTION(issuercert):"none");

+          SSL_CONN_CONFIG(issuercert)?SSL_CONN_CONFIG(issuercert):"none");

   }

   size = sizeof(certname);

diff --git a/lib/vtls/nss.c b/lib/vtls/nss.c

index ae3945c..b0b1e8c 100644

--- a/lib/vtls/nss.c

+++ b/lib/vtls/nss.c

@@ -2156,9 +2156,9 @@ static CURLcode nss_do_connect(struct Curl_easy *data,

   if(result)

     goto error;

-  if(SSL_SET_OPTION(issuercert)) {

+  if(SSL_CONN_CONFIG(issuercert)) {

     SECStatus ret = SECFailure;

-    char *nickname = dup_nickname(data, SSL_SET_OPTION(issuercert));

+    char *nickname = dup_nickname(data, SSL_CONN_CONFIG(issuercert));

     if(nickname) {

       /* we support only nicknames in case of issuercert for now */

       ret = check_issuer_cert(backend->handle, nickname);

diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c

index 2404393..be7b811 100644

--- a/lib/vtls/openssl.c

+++ b/lib/vtls/openssl.c

@@ -3872,10 +3872,10 @@ static CURLcode servercert(struct Curl_easy *data,

        deallocating the certificate. */

     /* e.g. match issuer name with provided issuer certificate */

-    if(SSL_SET_OPTION(issuercert) || SSL_SET_OPTION(issuercert_blob)) {

-      if(SSL_SET_OPTION(issuercert_blob))

-        fp = BIO_new_mem_buf(SSL_SET_OPTION(issuercert_blob)->data,

-                             (int)SSL_SET_OPTION(issuercert_blob)->len);

+    if(SSL_CONN_CONFIG(issuercert) || SSL_CONN_CONFIG(issuercert_blob)) {

+      if(SSL_CONN_CONFIG(issuercert_blob))

+        fp = BIO_new_mem_buf(SSL_CONN_CONFIG(issuercert_blob)->data,

+                             (int)SSL_CONN_CONFIG(issuercert_blob)->len);

       else {

         fp = BIO_new(BIO_s_file());

         if(fp == NULL) {

@@ -3889,10 +3889,10 @@ static CURLcode servercert(struct Curl_easy *data,

           return CURLE_OUT_OF_MEMORY;

         }

-        if(BIO_read_filename(fp, SSL_SET_OPTION(issuercert)) <= 0) {

+        if(BIO_read_filename(fp, SSL_CONN_CONFIG(issuercert)) <= 0) {

           if(strict)

             failf(data, "SSL: Unable to open issuer cert (%s)",

-                  SSL_SET_OPTION(issuercert));

+                  SSL_CONN_CONFIG(issuercert));

           BIO_free(fp);

           X509_free(backend->server_cert);

           backend->server_cert = NULL;

@@ -3904,7 +3904,7 @@ static CURLcode servercert(struct Curl_easy *data,

       if(!issuer) {

         if(strict)

           failf(data, "SSL: Unable to read issuer cert (%s)",

-                SSL_SET_OPTION(issuercert));

+                SSL_CONN_CONFIG(issuercert));

         BIO_free(fp);

         X509_free(issuer);

         X509_free(backend->server_cert);

@@ -3915,7 +3915,7 @@ static CURLcode servercert(struct Curl_easy *data,

       if(X509_check_issued(issuer, backend->server_cert) != X509_V_OK) {

         if(strict)

           failf(data, "SSL: Certificate issuer check failed (%s)",

-                SSL_SET_OPTION(issuercert));

+                SSL_CONN_CONFIG(issuercert));

         BIO_free(fp);

         X509_free(issuer);

         X509_free(backend->server_cert);

@@ -3924,7 +3924,7 @@ static CURLcode servercert(struct Curl_easy *data,

       }

       infof(data, " SSL certificate issuer check ok (%s)\n",

-            SSL_SET_OPTION(issuercert));

+            SSL_CONN_CONFIG(issuercert));

       BIO_free(fp);

       X509_free(issuer);

     }

diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c

index fa8a6fa..1aa6fc8 100644

--- a/lib/vtls/vtls.c

+++ b/lib/vtls/vtls.c

@@ -125,6 +125,16 @@ static bool blobcmp(struct curl_blob *first, struct curl_blob *second)

   return !memcmp(first->data, second->data, first->len); /* same data */

 }

+static bool safecmp(char *a, char *b)

+{

+  if(a && b)

+    return !strcmp(a, b);

+  else if(!a && !b)

+    return TRUE; /* match */

+  return FALSE; /* no match */

+}

+

+

 bool

 Curl_ssl_config_matches(struct ssl_primary_config *data,

                         struct ssl_primary_config *needle)

@@ -135,11 +145,13 @@ Curl_ssl_config_matches(struct ssl_primary_config *data,

      (data->verifyhost == needle->verifyhost) &&

      (data->verifystatus == needle->verifystatus) &&

      blobcmp(data->cert_blob, needle->cert_blob) &&

-     Curl_safe_strcasecompare(data->CApath, needle->CApath) &&

-     Curl_safe_strcasecompare(data->CAfile, needle->CAfile) &&

-     Curl_safe_strcasecompare(data->clientcert, needle->clientcert) &&

-     Curl_safe_strcasecompare(data->random_file, needle->random_file) &&

-     Curl_safe_strcasecompare(data->egdsocket, needle->egdsocket) &&

+     blobcmp(data->issuercert_blob, needle->issuercert_blob) &&

+     safecmp(data->CApath, needle->CApath) &&

+     safecmp(data->CAfile, needle->CAfile) &&

+     safecmp(data->issuercert, needle->issuercert) &&

+     safecmp(data->clientcert, needle->clientcert) &&

+     safecmp(data->random_file, needle->random_file) &&

+     safecmp(data->egdsocket, needle->egdsocket) &&

      Curl_safe_strcasecompare(data->cipher_list, needle->cipher_list) &&

      Curl_safe_strcasecompare(data->cipher_list13, needle->cipher_list13) &&

      Curl_safe_strcasecompare(data->curves, needle->curves) &&

@@ -161,8 +173,10 @@ Curl_clone_primary_ssl_config(struct ssl_primary_config *source,

   dest->sessionid = source->sessionid;

   CLONE_BLOB(cert_blob);

+  CLONE_BLOB(issuercert_blob);

   CLONE_STRING(CApath);

   CLONE_STRING(CAfile);

+  CLONE_STRING(issuercert);

   CLONE_STRING(clientcert);

   CLONE_STRING(random_file);

   CLONE_STRING(egdsocket);

@@ -178,6 +192,7 @@ void Curl_free_primary_ssl_config(struct ssl_primary_config *sslc)

 {

   Curl_safefree(sslc->CApath);

   Curl_safefree(sslc->CAfile);

+  Curl_safefree(sslc->issuercert);

   Curl_safefree(sslc->clientcert);

   Curl_safefree(sslc->random_file);

   Curl_safefree(sslc->egdsocket);

@@ -185,6 +200,7 @@ void Curl_free_primary_ssl_config(struct ssl_primary_config *sslc)

   Curl_safefree(sslc->cipher_list13);

   Curl_safefree(sslc->pinned_key);

   Curl_safefree(sslc->cert_blob);

+  Curl_safefree(sslc->issuercert_blob);

   Curl_safefree(sslc->curves);

 }

-- 

2.31.1