Fix crash after TLS channel shutdown

[exim.git] / src / src / tls-openssl.c

diff --git a/src/src/tls-openssl.c b/src/src/tls-openssl.c
index 8a1fec6a9be7f5284f065c1cdb64a4f6a5e395b0..e751edd9a234858cf420c54ba8dad829b6a74896 100644 (file)
--- a/src/src/tls-openssl.c
+++ b/src/src/tls-openssl.c
@@ -274,6 +274,7 @@ Server:
 typedef struct {
   SSL_CTX *    ctx;
   SSL *                ssl;
+  gstring *    corked;
 } exim_openssl_client_tls_ctx;
 
 static SSL_CTX *server_ctx = NULL;
@@ -2281,6 +2282,8 @@ if (rc <= 0)
   }
 
 DEBUG(D_tls) debug_printf("SSL_accept was successful\n");
+ERR_clear_error();     /* Even success can leave errors in the stack. Seen with
+                       anon-authentication ciphersuite negociated. */
 
 /* TLS has been set up. Adjust the input functions to read via TLS,
 and initialize things. */
@@ -2471,6 +2474,7 @@ BOOL require_ocsp = FALSE;
 rc = store_pool;
 store_pool = POOL_PERM;
 exim_client_ctx = store_get(sizeof(exim_openssl_client_tls_ctx));
+exim_client_ctx->corked = NULL;
 store_pool = rc;
 
 #ifdef SUPPORT_DANE
@@ -2723,32 +2727,10 @@ switch(error)
   case SSL_ERROR_ZERO_RETURN:
     DEBUG(D_tls) debug_printf("Got SSL_ERROR_ZERO_RETURN\n");
 
-    receive_getc = smtp_getc;
-    receive_getbuf = smtp_getbuf;
-    receive_get_cache = smtp_get_cache;
-    receive_ungetc = smtp_ungetc;
-    receive_feof = smtp_feof;
-    receive_ferror = smtp_ferror;
-    receive_smtp_buffered = smtp_buffered;
-
     if (SSL_get_shutdown(server_ssl) == SSL_RECEIVED_SHUTDOWN)
          SSL_shutdown(server_ssl);
 
-#ifndef DISABLE_OCSP
-    sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free);
-    server_static_cbinfo->verify_stack = NULL;
-#endif
-    SSL_free(server_ssl);
-    SSL_CTX_free(server_ctx);
-    server_ctx = NULL;
-    server_ssl = NULL;
-    tls_in.active.sock = -1;
-    tls_in.active.tls_ctx = NULL;
-    tls_in.bits = 0;
-    tls_in.cipher = NULL;
-    tls_in.peerdn = NULL;
-    tls_in.sni = NULL;
-
+    tls_close(NULL, TLS_NO_SHUTDOWN);
     return FALSE;
 
   /* Handle genuine errors */
@@ -2906,8 +2888,12 @@ int
 tls_write(void * ct_ctx, const uschar *buff, size_t len, BOOL more)
 {
 int outbytes, error, left;
-SSL * ssl = ct_ctx ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl;
-static gstring * corked = NULL;
+SSL * ssl = ct_ctx
+  ? ((exim_openssl_client_tls_ctx *)ct_ctx)->ssl : server_ssl;
+static gstring * server_corked = NULL;
+gstring ** corkedp = ct_ctx
+  ? &((exim_openssl_client_tls_ctx *)ct_ctx)->corked : &server_corked;
+gstring * corked = *corkedp;
 
 DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__,
   buff, (unsigned long)len, more ? ", more" : "");
@@ -2915,9 +2901,12 @@ DEBUG(D_tls) debug_printf("%s(%p, %lu%s)\n", __FUNCTION__,
 /* Lacking a CORK or MSG_MORE facility (such as GnuTLS has) we copy data when
 "more" is notified.  This hack is only ok if small amounts are involved AND only
 one stream does it, in one context (i.e. no store reset).  Currently it is used
-for the responses to the received SMTP MAIL , RCPT, DATA sequence, only. */
-/*XXX + if PIPE_COMMAND, banner & ehlo-resp for smmtp-on-connect. Suspect there's
-a store reset there. */
+for the responses to the received SMTP MAIL , RCPT, DATA sequence, only.
+We support callouts done by the server process by using a separate client
+context for the stashed information. */
+/* + if PIPE_COMMAND, banner & ehlo-resp for smmtp-on-connect. Suspect there's
+a store reset there, so use POOL_PERM. */
+/* + if CHUNKING, cmds EHLO,MAIL,RCPT(s),BDAT */
 
 if (!ct_ctx && (more || corked))
   {
@@ -2933,10 +2922,13 @@ if (!ct_ctx && (more || corked))
 #endif
 
   if (more)
+    {
+    *corkedp = corked;
     return len;
+    }
   buff = CUS corked->s;
   len = corked->ptr;
-  corked = NULL;
+  *corkedp = NULL;
   }
 
 for (left = len; left > 0;)
@@ -3026,14 +3018,25 @@ if (shutdown)
     }
   }
 
-#ifndef DISABLE_OCSP
 if (!o_ctx)            /* server side */
   {
+#ifndef DISABLE_OCSP
   sk_X509_pop_free(server_static_cbinfo->verify_stack, X509_free);
   server_static_cbinfo->verify_stack = NULL;
-  }
 #endif
 
+  receive_getc =       smtp_getc;
+  receive_getbuf =     smtp_getbuf;
+  receive_get_cache =  smtp_get_cache;
+  receive_ungetc =     smtp_ungetc;
+  receive_feof =       smtp_feof;
+  receive_ferror =     smtp_ferror;
+  receive_smtp_buffered = smtp_buffered;
+  tls_in.active.tls_ctx = NULL;
+  tls_in.sni = NULL;
+  /* Leave bits, peercert, cipher, peerdn, certificate_verified set, for logging */
+  }
+
 SSL_CTX_free(*ctxp);
 SSL_free(*sslp);
 *ctxp = NULL;