commit db028d8: [Fix] Sigh, another try to fix brain-damaged openssl

[Vsevolod Stakhov]

Author: Vsevolod Stakhov
Date: 2019-11-03 11:26:49 +0000
URL: https://github.com/rspamd/rspamd/commit/db028d8757203f78bb3b6d54d7a707ad9f115030 (HEAD -> master)

[Fix] Sigh, another try to fix brain-damaged openssl

---
 src/libutil/ssl_util.c | 35 +++++++++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/libutil/ssl_util.c b/src/libutil/ssl_util.c
index f4fe3b31c..3e8f25910 100644
--- a/src/libutil/ssl_util.c
+++ b/src/libutil/ssl_util.c
@@ -433,14 +433,35 @@ rspamd_ssl_connection_dtor (struct rspamd_ssl_connection *conn)
 static void
 rspamd_ssl_shutdown (struct rspamd_ssl_connection *conn)
 {
-	gint ret;
+	gint ret = 0, retries;
+	static const gint max_retries = 5;
+
+	/*
+	 * Fucking openssl...
+	 * From the manual, 0 means: "The shutdown is not yet finished.
+	 * Call SSL_shutdown() for a second time,
+	 * if a bidirectional shutdown shall be performed.
+	 * The output of SSL_get_error(3) may be misleading,
+	 * as an erroneous SSL_ERROR_SYSCALL may be flagged
+	 * even though no error occurred."
+	 *
+	 * What is `second`, what if `second` also returns 0?
+	 * What a retarded behaviour!
+	 */
+	for (retries = 0; retries < max_retries; retries ++) {
+		ret = SSL_shutdown (conn->ssl);
+
+		if (ret != 0) {
+			break;
+		}
+	}
 
-	if ((ret = SSL_shutdown (conn->ssl)) == 1) {
+	if (ret == 1) {
 		/* All done */
 		msg_debug_ssl ("ssl shutdown: all done");
 		rspamd_ssl_connection_dtor (conn);
 	}
-	else {
+	else if (ret < 0) {
 		short what;
 
 		ret = SSL_get_error (conn->ssl, ret);
@@ -451,7 +472,7 @@ rspamd_ssl_shutdown (struct rspamd_ssl_connection *conn)
 			what = EV_READ;
 		}
 		else if (ret == SSL_ERROR_WANT_WRITE) {
-			msg_debug_ssl ("ssl shutdown: need read");
+			msg_debug_ssl ("ssl shutdown: need write");
 			what = EV_WRITE;
 		}
 		else {
@@ -480,6 +501,12 @@ rspamd_ssl_shutdown (struct rspamd_ssl_connection *conn)
 
 		conn->state = ssl_next_shutdown;
 	}
+	else if (ret == 0) {
+		/* What can we do here?? */
+		msg_debug_ssl ("ssl shutdown: openssl failed to initiate shutdown after "
+				 "%d attempts!", max_retries);
+		rspamd_ssl_connection_dtor (conn);
+	}
 }
 
 static void