KTLS: Check for unprocessed receive records in ktls_configure_crypto.

KTLS implementations currently assume that the start of the in-kernel
socket buffer is aligned with the start of a TLS record for the
receive side.  The socket option to enable KTLS specifies the TLS
sequence number of this initial record.

When read ahead is enabled, data can be pending in the SSL read buffer
after negotiating session keys.  This pending data must be examined to
ensurs that the kernel's socket buffer does not contain a partial TLS
record as well as to determine the correct sequence number of the
first TLS record to be processed by the kernel.

In preparation for enabling receive kernel offload for TLS 1.3, move
the existing logic to handle read ahead from t1_enc.c into ktls.c and
invoke it from ktls_configure_crypto().

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/17942)

diff --git a/ssl/ktls.c b/ssl/ktls.c
index fd0a9038785534bc21b9080cd43e311e8dbd18c7..e343d382cc984513e8467f1b65860f76be345378 100644 (file)
--- a/ssl/ktls.c
+++ b/ssl/ktls.c
@@ -10,6 +10,67 @@
 #include "ssl_local.h"
 #include "internal/ktls.h"
 
+#ifndef OPENSSL_NO_KTLS_RX
+ /*
+  * Count the number of records that were not processed yet from record boundary.
+  *
+  * This function assumes that there are only fully formed records read in the
+  * record layer. If read_ahead is enabled, then this might be false and this
+  * function will fail.
+  */
+static int count_unprocessed_records(SSL *s)
+{
+    SSL3_BUFFER *rbuf = RECORD_LAYER_get_rbuf(&s->rlayer);
+    PACKET pkt, subpkt;
+    int count = 0;
+
+    if (!PACKET_buf_init(&pkt, rbuf->buf + rbuf->offset, rbuf->left))
+        return -1;
+
+    while (PACKET_remaining(&pkt) > 0) {
+        /* Skip record type and version */
+        if (!PACKET_forward(&pkt, 3))
+            return -1;
+
+        /* Read until next record */
+        if (!PACKET_get_length_prefixed_2(&pkt, &subpkt))
+            return -1;
+
+        count += 1;
+    }
+
+    return count;
+}
+
+/*
+ * The kernel cannot offload receive if a partial TLS record has been read.
+ * Check the read buffer for unprocessed records.  If the buffer contains a
+ * partial record, fail and return 0.  Otherwise, update the sequence
+ * number at *rec_seq for the count of unprocessed records and return 1.
+ */
+static int check_rx_read_ahead(SSL *s, unsigned char *rec_seq)
+{
+    int bit, count_unprocessed;
+
+    count_unprocessed = count_unprocessed_records(s);
+    if (count_unprocessed < 0)
+        return 0;
+
+    /* increment the crypto_info record sequence */
+    while (count_unprocessed) {
+        for (bit = 7; bit >= 0; bit--) { /* increment */
+            ++rec_seq[bit];
+            if (rec_seq[bit] != 0)
+                break;
+        }
+        count_unprocessed--;
+
+    }
+
+    return 1;
+}
+#endif
+
 #if defined(__FreeBSD__)
 # include "crypto/cryptodev.h"
 
@@ -59,9 +120,9 @@ int ktls_check_supported_cipher(const SSL *s, const EVP_CIPHER *c,
 }
 
 /* Function to configure kernel TLS structure */
-int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
+int ktls_configure_crypto(SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
                           void *rl_sequence, ktls_crypto_info_t *crypto_info,
-                          unsigned char **rec_seq, unsigned char *iv,
+                          int is_tx, unsigned char *iv,
                           unsigned char *key, unsigned char *mac_key,
                           size_t mac_secret_size)
 {
@@ -111,11 +172,11 @@ int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
     crypto_info->tls_vminor = (s->version & 0x000000ff);
 # ifdef TCP_RXTLS_ENABLE
     memcpy(crypto_info->rec_seq, rl_sequence, sizeof(crypto_info->rec_seq));
-    if (rec_seq != NULL)
-        *rec_seq = crypto_info->rec_seq;
+    if (!is_tx && !check_rx_read_ahead(s, crypto_info->rec_seq))
+        return 0;
 # else
-    if (rec_seq != NULL)
-        *rec_seq = NULL;
+    if (!is_tx)
+        return 0;
 # endif
     return 1;
 };
@@ -164,15 +225,20 @@ int ktls_check_supported_cipher(const SSL *s, const EVP_CIPHER *c,
 }
 
 /* Function to configure kernel TLS structure */
-int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
+int ktls_configure_crypto(SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
                           void *rl_sequence, ktls_crypto_info_t *crypto_info,
-                          unsigned char **rec_seq, unsigned char *iv,
+                          int is_tx, unsigned char *iv,
                           unsigned char *key, unsigned char *mac_key,
                           size_t mac_secret_size)
 {
     unsigned char geniv[12];
     unsigned char *iiv = iv;
 
+# ifdef OPENSSL_NO_KTLS_RX
+    if (!is_tx)
+        return 0;
+# endif
+
     if (s->version == TLS1_2_VERSION &&
         EVP_CIPHER_get_mode(c) == EVP_CIPH_GCM_MODE) {
         if (!EVP_CIPHER_CTX_get_updated_iv(dd, geniv,
@@ -196,8 +262,8 @@ int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
         memcpy(crypto_info->gcm128.key, key, EVP_CIPHER_get_key_length(c));
         memcpy(crypto_info->gcm128.rec_seq, rl_sequence,
                TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE);
-        if (rec_seq != NULL)
-            *rec_seq = crypto_info->gcm128.rec_seq;
+        if (!is_tx && !check_rx_read_ahead(s, crypto_info->gcm128.rec_seq))
+            return 0;
         return 1;
 # endif
 # ifdef OPENSSL_KTLS_AES_GCM_256
@@ -211,8 +277,8 @@ int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
         memcpy(crypto_info->gcm256.key, key, EVP_CIPHER_get_key_length(c));
         memcpy(crypto_info->gcm256.rec_seq, rl_sequence,
                TLS_CIPHER_AES_GCM_256_REC_SEQ_SIZE);
-        if (rec_seq != NULL)
-            *rec_seq = crypto_info->gcm256.rec_seq;
+        if (!is_tx && !check_rx_read_ahead(s, crypto_info->gcm256.rec_seq))
+            return 0;
         return 1;
 # endif
 # ifdef OPENSSL_KTLS_AES_CCM_128
@@ -226,8 +292,8 @@ int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
         memcpy(crypto_info->ccm128.key, key, EVP_CIPHER_get_key_length(c));
         memcpy(crypto_info->ccm128.rec_seq, rl_sequence,
                TLS_CIPHER_AES_CCM_128_REC_SEQ_SIZE);
-        if (rec_seq != NULL)
-            *rec_seq = crypto_info->ccm128.rec_seq;
+        if (!is_tx && !check_rx_read_ahead(s, crypto_info->ccm128.rec_seq))
+            return 0;
         return 1;
 # endif
 # ifdef OPENSSL_KTLS_CHACHA20_POLY1305
@@ -241,8 +307,10 @@ int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
                EVP_CIPHER_get_key_length(c));
         memcpy(crypto_info->chacha20poly1305.rec_seq, rl_sequence,
                TLS_CIPHER_CHACHA20_POLY1305_REC_SEQ_SIZE);
-        if (rec_seq != NULL)
-            *rec_seq = crypto_info->chacha20poly1305.rec_seq;
+        if (!is_tx
+                && !check_rx_read_ahead(s,
+                                        crypto_info->chacha20poly1305.rec_seq))
+            return 0;
         return 1;
 # endif
     default:

diff --git a/ssl/ssl_local.h b/ssl/ssl_local.h
index aee8f9272f7fadd89c6a62bc7aa46beb370895c6..5e3c908cd28ce72dabd0977f850493b0196d0945 100644 (file)
--- a/ssl/ssl_local.h
+++ b/ssl/ssl_local.h
@@ -2764,9 +2764,9 @@ __owur int ssl_log_secret(SSL *ssl, const char *label,
 /* ktls.c */
 int ktls_check_supported_cipher(const SSL *s, const EVP_CIPHER *c,
                                 const EVP_CIPHER_CTX *dd);
-int ktls_configure_crypto(const SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
+int ktls_configure_crypto(SSL *s, const EVP_CIPHER *c, EVP_CIPHER_CTX *dd,
                           void *rl_sequence, ktls_crypto_info_t *crypto_info,
-                          unsigned char **rec_seq, unsigned char *iv,
+                          int is_tx, unsigned char *iv,
                           unsigned char *key, unsigned char *mac_key,
                           size_t mac_secret_size);
 #  endif

diff --git a/ssl/t1_enc.c b/ssl/t1_enc.c
index 101cba6490935a29ca9d2217a59e9b9a1123c654..11c663e16da56553f0aa70c3490890e340201a2c 100644 (file)
--- a/ssl/t1_enc.c
+++ b/ssl/t1_enc.c
@@ -98,42 +98,6 @@ static int tls1_generate_key_block(SSL *s, unsigned char *km, size_t num)
     return ret;
 }
 
-#ifndef OPENSSL_NO_KTLS
- /*
-  * Count the number of records that were not processed yet from record boundary.
-  *
-  * This function assumes that there are only fully formed records read in the
-  * record layer. If read_ahead is enabled, then this might be false and this
-  * function will fail.
-  */
-# ifndef OPENSSL_NO_KTLS_RX
-static int count_unprocessed_records(SSL *s)
-{
-    SSL3_BUFFER *rbuf = RECORD_LAYER_get_rbuf(&s->rlayer);
-    PACKET pkt, subpkt;
-    int count = 0;
-
-    if (!PACKET_buf_init(&pkt, rbuf->buf + rbuf->offset, rbuf->left))
-        return -1;
-
-    while (PACKET_remaining(&pkt) > 0) {
-        /* Skip record type and version */
-        if (!PACKET_forward(&pkt, 3))
-            return -1;
-
-        /* Read until next record */
-        if (!PACKET_get_length_prefixed_2(&pkt, &subpkt))
-            return -1;
-
-        count += 1;
-    }
-
-    return count;
-}
-# endif
-#endif
-
-
 int tls_provider_set_tls_params(SSL *s, EVP_CIPHER_CTX *ctx,
                                 const EVP_CIPHER *ciph,
                                 const EVP_MD *md)
@@ -201,12 +165,7 @@ int tls1_change_cipher_state(SSL *s, int which)
     int reuse_dd = 0;
 #ifndef OPENSSL_NO_KTLS
     ktls_crypto_info_t crypto_info;
-    unsigned char *rec_seq;
     void *rl_sequence;
-# ifndef OPENSSL_NO_KTLS_RX
-    int count_unprocessed;
-    int bit;
-# endif
     BIO *bio;
 #endif
 
@@ -473,30 +432,11 @@ int tls1_change_cipher_state(SSL *s, int which)
     else
         rl_sequence = RECORD_LAYER_get_read_sequence(&s->rlayer);
 
-    if (!ktls_configure_crypto(s, c, dd, rl_sequence, &crypto_info, &rec_seq,
-                               iv, key, ms, *mac_secret_size))
+    if (!ktls_configure_crypto(s, c, dd, rl_sequence, &crypto_info,
+                               which & SSL3_CC_WRITE, iv, key, ms,
+                               *mac_secret_size))
         goto skip_ktls;
 
-    if (which & SSL3_CC_READ) {
-# ifndef OPENSSL_NO_KTLS_RX
-        count_unprocessed = count_unprocessed_records(s);
-        if (count_unprocessed < 0)
-            goto skip_ktls;
-
-        /* increment the crypto_info record sequence */
-        while (count_unprocessed) {
-            for (bit = 7; bit >= 0; bit--) { /* increment */
-                ++rec_seq[bit];
-                if (rec_seq[bit] != 0)
-                    break;
-            }
-            count_unprocessed--;
-        }
-# else
-        goto skip_ktls;
-# endif
-    }
-
     /* ktls works with user provided buffers directly */
     if (BIO_set_ktls(bio, &crypto_info, which & SSL3_CC_WRITE)) {
         if (which & SSL3_CC_WRITE)

diff --git a/ssl/tls13_enc.c b/ssl/tls13_enc.c
index a9fcf12e93e52d745f77954ceb4500a19094b83b..32ce92f57245a03f0a0d8b0d339f07737a16bac8 100644 (file)
--- a/ssl/tls13_enc.c
+++ b/ssl/tls13_enc.c
@@ -719,7 +719,8 @@ int tls13_change_cipher_state(SSL *s, int which)
     /* configure kernel crypto structure */
     if (!ktls_configure_crypto(s, cipher, ciph_ctx,
                                RECORD_LAYER_get_write_sequence(&s->rlayer),
-                               &crypto_info, NULL, iv, key, NULL, 0))
+                               &crypto_info, which & SSL3_CC_WRITE, iv, key,
+                               NULL, 0))
         goto skip_ktls;
 
     /* ktls works with user provided buffers directly */