1 files changed, 58 insertions, 57 deletions

diff --git a/src/lib/libssl/ssl_pkt.c b/src/lib/libssl/ssl_pkt.c
index 157dd9895b..02282778a2 100644
--- a/src/lib/libssl/ssl_pkt.c
+++ b/src/lib/libssl/ssl_pkt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_pkt.c,v 1.24 2020/03/16 15:25:14 tb Exp $ */
+/* $OpenBSD: ssl_pkt.c,v 1.25 2020/07/30 16:53:01 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -622,18 +622,15 @@ ssl3_create_record(SSL *s, unsigned char *p, int type, const unsigned char *buf,
 {
         SSL3_RECORD_INTERNAL *wr = &(S3I(s)->wrec);
         SSL_SESSION *sess = s->session;
-        int eivlen, mac_size;
+        int eivlen, mac_size = 0;
         uint16_t version;
         CBB cbb;
 
         memset(&cbb, 0, sizeof(cbb));
 
-        if ((sess == NULL) || (s->internal->enc_write_ctx == NULL) ||
-            (EVP_MD_CTX_md(s->internal->write_hash) == NULL)) {
-                mac_size = 0;
-        } else {
-                mac_size = EVP_MD_CTX_size(s->internal->write_hash);
-                if (mac_size < 0)
+        if (sess != NULL && s->internal->enc_write_ctx != NULL &&
+            EVP_MD_CTX_md(s->internal->write_hash) != NULL) {
+                if ((mac_size = EVP_MD_CTX_size(s->internal->write_hash)) < 0)
                         goto err;
         }
 
@@ -682,9 +679,11 @@ ssl3_create_record(SSL *s, unsigned char *p, int type, const unsigned char *buf,
         memcpy(wr->data, wr->input, wr->length);
         wr->input = wr->data;
 
-        /* we should still have the output to wr->data and the input
+        /*
+         * We should still have the output to wr->data and the input
          * from wr->input.  Length should be wr->length.
-         * wr->data still points in the wb->buf */
+         * wr->data still points in the wb->buf.
+         */
 
         if (mac_size != 0) {
                 if (tls1_mac(s, &(p[wr->length + eivlen]), 1) < 0)
@@ -732,26 +731,29 @@ do_ssl3_write(SSL *s, int type, const unsigned char *buf, unsigned int len)
         SSL3_BUFFER_INTERNAL *wb = &(S3I(s)->wbuf);
         SSL_SESSION *sess = s->session;
         unsigned char *p;
-        int i, clear = 0;
+        int need_empty_fragment = 0;
         int prefix_len = 0;
         size_t align;
+        int ret;
 
         if (wb->buf == NULL)
                 if (!ssl3_setup_write_buffer(s))
                         return -1;
 
-        /* first check if there is a SSL3_BUFFER_INTERNAL still being written
-         * out.  This will happen with non blocking IO */
+        /*
+         * First check if there is a SSL3_BUFFER_INTERNAL still being written
+         * out.  This will happen with non blocking IO.
+         */
         if (wb->left != 0)
                 return (ssl3_write_pending(s, type, buf, len));
 
-        /* If we have an alert to send, lets send it */
+        /* If we have an alert to send, let's send it. */
         if (S3I(s)->alert_dispatch) {
-                i = s->method->ssl_dispatch_alert(s);
-                if (i <= 0)
-                        return (i);
-                /* if it went, fall through and send more stuff */
-                /* we may have released our buffer, so get it again */
+                if ((ret = s->method->ssl_dispatch_alert(s)) <= 0)
+                        return (ret);
+                /* If it went, fall through and send more stuff. */
+
+                /* We may have released our buffer, if so get it again. */
                 if (wb->buf == NULL)
                         if (!ssl3_setup_write_buffer(s))
                                 return -1;
@@ -760,47 +762,44 @@ do_ssl3_write(SSL *s, int type, const unsigned char *buf, unsigned int len)
         if (len == 0)
                 return 0;
 
+        /*
+         * Countermeasure against known-IV weakness in CBC ciphersuites
+         * (see http://www.openssl.org/~bodo/tls-cbc.txt). Note that this
+         * is unnecessary for AEAD.
+         */
+        if (sess != NULL && s->internal->enc_write_ctx != NULL &&
+            EVP_MD_CTX_md(s->internal->write_hash) != NULL) {
+                if (S3I(s)->need_empty_fragments &&
+                    !S3I(s)->empty_fragment_done &&
+                    type == SSL3_RT_APPLICATION_DATA)
+                        need_empty_fragment = 1;
+        }
+
+        /*
+         * An extra fragment would be a couple of cipher blocks, which would
+         * be a multiple of SSL3_ALIGN_PAYLOAD, so if we want to align the real
+         * payload, then we can just simply pretend we have two headers.
+         */
         align = (size_t)wb->buf + SSL3_RT_HEADER_LENGTH;
+        if (need_empty_fragment)
+                align += SSL3_RT_HEADER_LENGTH;
         align = (-align) & (SSL3_ALIGN_PAYLOAD - 1);
 
         p = wb->buf + align;
         wb->offset = align;
 
-        if ((sess == NULL) || (s->internal->enc_write_ctx == NULL) ||
-            (EVP_MD_CTX_md(s->internal->write_hash) == NULL)) {
-                clear = s->internal->enc_write_ctx ? 0 : 1; /* must be AEAD cipher */
-        }
-
-        if (!clear && !S3I(s)->empty_fragment_done) {
-                /*
-                 * Countermeasure against known-IV weakness in CBC ciphersuites
-                 * (see http://www.openssl.org/~bodo/tls-cbc.txt)
-                 */
-                if (S3I(s)->need_empty_fragments &&
-                    type == SSL3_RT_APPLICATION_DATA) {
-                        /* extra fragment would be couple of cipher blocks,
-                         * which would be multiple of SSL3_ALIGN_PAYLOAD, so
-                         * if we want to align the real payload, then we can
-                         * just pretent we simply have two headers. */
-                        align = (size_t)wb->buf + 2 * SSL3_RT_HEADER_LENGTH;
-                        align = (-align) & (SSL3_ALIGN_PAYLOAD - 1);
-
-                        p = wb->buf + align;
-                        wb->offset = align;
-
-                        if (!ssl3_create_record(s, p, type, buf, 0))
-                                goto err;
-
-                        prefix_len = wr->length;
-                        if (prefix_len > (SSL3_RT_HEADER_LENGTH +
-                            SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD)) {
-                                /* insufficient space */
-                                SSLerror(s, ERR_R_INTERNAL_ERROR);
-                                goto err;
-                        }
+        if (need_empty_fragment) {
+                if (!ssl3_create_record(s, p, type, buf, 0))
+                        goto err;
 
-                        p = wb->buf + wb->offset + prefix_len;
+                prefix_len = wr->length;
+                if (prefix_len > (SSL3_RT_HEADER_LENGTH +
+                    SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD)) {
+                        /* insufficient space */
+                        SSLerror(s, ERR_R_INTERNAL_ERROR);
+                        goto err;
                 }
+                p = wb->buf + wb->offset + prefix_len;
 
                 S3I(s)->empty_fragment_done = 1;
         }
@@ -808,19 +807,21 @@ do_ssl3_write(SSL *s, int type, const unsigned char *buf, unsigned int len)
         if (!ssl3_create_record(s, p, type, buf, len))
                 goto err;
 
-        /* now let's set up wb */
         wb->left = prefix_len + wr->length;
 
-        /* memorize arguments so that ssl3_write_pending can detect
-         * bad write retries later */
+        /*
+         * Memorize arguments so that ssl3_write_pending can detect
+         * bad write retries later.
+         */
         S3I(s)->wpend_tot = len;
         S3I(s)->wpend_buf = buf;
         S3I(s)->wpend_type = type;
         S3I(s)->wpend_ret = len;
 
-        /* we now just need to write the buffer */
+        /* We now just need to write the buffer. */
         return ssl3_write_pending(s, type, buf, len);
-err:
+
+ err:
         return -1;
 }