diff --git a/ChangeLog b/ChangeLog
index f2488a2..4be7ec4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -34,6 +34,8 @@
      ECPrivateKey structure. Found by jethrogb, fixed in #1379.
    * Return plaintext data sooner on unpadded CBC decryption, as stated in
      the mbedtls_cipher_update() documentation. Contributed by Andy Leiserson.
+   * Fix overriding and ignoring return values when parsing and writing to
+     a file in pk_sign program. Found by kevlut in #1142.
    * Fix buffer length assertions in the ssl_parse_certificate_request()
      function which leads to a potential one byte overread of the message
      buffer.
@@ -59,6 +61,12 @@
      Alex Hixon.
    * Allow configuring the shared library extension by setting the DLEXT
      environment variable when using the project makefiles.
+   * In the SSL module, when f_send, f_recv or f_recv_timeout report
+     transmitting more than the required length, return an error. Raised by
+     Sam O'Connor in #1245.
+   * Improve robustness of mbedtls_ssl_derive_keys against the use of
+     HMAC functions with non-HMAC ciphersuites. Independently contributed
+     by Jiayuan Chen in #1377. Fixes #1437.
 
 = mbed TLS 2.7.2 branch released 2018-03-16
 
diff --git a/doxygen/mbedtls.doxyfile b/doxygen/mbedtls.doxyfile
index c07cdde..8143d59 100644
--- a/doxygen/mbedtls.doxyfile
+++ b/doxygen/mbedtls.doxyfile
@@ -702,7 +702,7 @@
 # directories that are symbolic links (a Unix file system feature) are excluded
 # from the input.
 
-EXCLUDE_SYMLINKS       = NO
+EXCLUDE_SYMLINKS       = YES
 
 # If the value of the INPUT tag contains directories, you can use the
 # EXCLUDE_PATTERNS tag to specify one or more wildcard patterns to exclude
diff --git a/include/mbedtls/ecdsa.h b/include/mbedtls/ecdsa.h
index aa23d67..ff6efbc 100644
--- a/include/mbedtls/ecdsa.h
+++ b/include/mbedtls/ecdsa.h
@@ -272,8 +272,8 @@
  *
  * \return          \c 0 on success,
  *                  #MBEDTLS_ERR_ECP_BAD_INPUT_DATA if signature is invalid,
- *                  #MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH if the signature is
- *                  valid but its actual length is less than \p siglen,
+ *                  #MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH if there is a valid
+ *                  signature in sig but its length is less than \p siglen,
  *                  or an \c MBEDTLS_ERR_ECP_XXX or \c MBEDTLS_ERR_MPI_XXX
  *                  error code on failure for any other reason.
  *
diff --git a/include/mbedtls/ecp.h b/include/mbedtls/ecp.h
index b00ba4d..7b8ffff 100644
--- a/include/mbedtls/ecp.h
+++ b/include/mbedtls/ecp.h
@@ -36,7 +36,7 @@
 #define MBEDTLS_ERR_ECP_ALLOC_FAILED                      -0x4D80  /**< Memory allocation failed. */
 #define MBEDTLS_ERR_ECP_RANDOM_FAILED                     -0x4D00  /**< Generation of random value, such as (ephemeral) key, failed. */
 #define MBEDTLS_ERR_ECP_INVALID_KEY                       -0x4C80  /**< Invalid private or public key. */
-#define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH                  -0x4C00  /**< Signature is valid but shorter than the user-supplied length. */
+#define MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH                  -0x4C00  /**< The buffer contains a valid signature followed by more data. */
 #define MBEDTLS_ERR_ECP_HW_ACCEL_FAILED                   -0x4B80  /**< ECP hardware accelerator failed. */
 
 #if !defined(MBEDTLS_ECP_ALT)
diff --git a/include/mbedtls/pk.h b/include/mbedtls/pk.h
index 1059bda..ee06b2f 100644
--- a/include/mbedtls/pk.h
+++ b/include/mbedtls/pk.h
@@ -63,7 +63,7 @@
 #define MBEDTLS_ERR_PK_INVALID_ALG         -0x3A80  /**< The algorithm tag or value is invalid. */
 #define MBEDTLS_ERR_PK_UNKNOWN_NAMED_CURVE -0x3A00  /**< Elliptic curve is unsupported (only NIST curves are supported). */
 #define MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE -0x3980  /**< Unavailable feature, e.g. RSA disabled for RSA key. */
-#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH    -0x3900  /**< The signature is valid but its length is less than expected. */
+#define MBEDTLS_ERR_PK_SIG_LEN_MISMATCH    -0x3900  /**< The buffer contains a valid signature followed by more data. */
 #define MBEDTLS_ERR_PK_HW_ACCEL_FAILED     -0x3880  /**< PK hardware accelerator failed. */
 
 #ifdef __cplusplus
@@ -269,8 +269,8 @@
  * \param sig_len   Signature length
  *
  * \return          0 on success (signature is valid),
- *                  MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if the signature is
- *                  valid but its actual length is less than sig_len,
+ *                  #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid
+ *                  signature in sig but its length is less than \p siglen,
  *                  or a specific error code.
  *
  * \note            For RSA keys, the default padding type is PKCS#1 v1.5.
@@ -300,10 +300,10 @@
  * \param sig_len   Signature length
  *
  * \return          0 on success (signature is valid),
- *                  MBEDTLS_ERR_PK_TYPE_MISMATCH if the PK context can't be
+ *                  #MBEDTLS_ERR_PK_TYPE_MISMATCH if the PK context can't be
  *                  used for this type of signatures,
- *                  MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if the signature is
- *                  valid but its actual length is less than sig_len,
+ *                  #MBEDTLS_ERR_PK_SIG_LEN_MISMATCH if there is a valid
+ *                  signature in sig but its length is less than \p siglen,
  *                  or a specific error code.
  *
  * \note            If hash_len is 0, then the length associated with md_alg
diff --git a/include/mbedtls/rsa_internal.h b/include/mbedtls/rsa_internal.h
index 12e0f6b..53abd3c 100644
--- a/include/mbedtls/rsa_internal.h
+++ b/include/mbedtls/rsa_internal.h
@@ -2,6 +2,37 @@
  * \file rsa_internal.h
  *
  * \brief Context-independent RSA helper functions
+ *
+ *  This module declares some RSA-related helper functions useful when
+ *  implementing the RSA interface. These functions are provided in a separate
+ *  compilation unit in order to make it easy for designers of alternative RSA
+ *  implementations to use them in their own code, as it is conceived that the
+ *  functionality they provide will be necessary for most complete
+ *  implementations.
+ *
+ *  End-users of Mbed TLS who are not providing their own alternative RSA
+ *  implementations should not use these functions directly, and should instead
+ *  use only the functions declared in rsa.h.
+ *
+ *  The interface provided by this module will be maintained through LTS (Long
+ *  Term Support) branches of Mbed TLS, but may otherwise be subject to change,
+ *  and must be considered an internal interface of the library.
+ *
+ *  There are two classes of helper functions:
+ *
+ *  (1) Parameter-generating helpers. These are:
+ *      - mbedtls_rsa_deduce_primes
+ *      - mbedtls_rsa_deduce_private_exponent
+ *      - mbedtls_rsa_deduce_crt
+ *       Each of these functions takes a set of core RSA parameters and
+ *       generates some other, or CRT related parameters.
+ *
+ *  (2) Parameter-checking helpers. These are:
+ *      - mbedtls_rsa_validate_params
+ *      - mbedtls_rsa_validate_crt
+ *      They take a set of core or CRT related RSA parameters and check their
+ *      validity.
+ *
  */
 /*
  *  Copyright (C) 2006-2017, ARM Limited, All Rights Reserved
@@ -21,31 +52,6 @@
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
  *
- *
- *  This file declares some RSA-related helper functions useful when
- *  implementing the RSA interface. They are public and provided in a
- *  separate compilation unit in order to make it easy for designers of
- *  alternative RSA implementations to use them in their code, as it is
- *  conceived that the functionality they provide will be necessary
- *  for most complete implementations.
- *
- *  End-users of Mbed TLS not intending to re-implement the RSA functionality
- *  are not expected to get into the need of making use of these functions directly,
- *  but instead should be able to use the functions declared in rsa.h.
- *
- *  There are two classes of helper functions:
- *  (1) Parameter-generating helpers. These are:
- *      - mbedtls_rsa_deduce_primes
- *      - mbedtls_rsa_deduce_private_exponent
- *      - mbedtls_rsa_deduce_crt
- *       Each of these functions takes a set of core RSA parameters
- *       and generates some other, or CRT related parameters.
- *  (2) Parameter-checking helpers. These are:
- *      - mbedtls_rsa_validate_params
- *      - mbedtls_rsa_validate_crt
- *      They take a set of core or CRT related RSA parameters
- *      and check their validity.
- *
  */
 
 #ifndef MBEDTLS_RSA_INTERNAL_H
diff --git a/library/ecdsa.c b/library/ecdsa.c
index 826fefe..17a88bd 100644
--- a/library/ecdsa.c
+++ b/library/ecdsa.c
@@ -400,6 +400,9 @@
                               &ctx->Q, &r, &s ) ) != 0 )
         goto cleanup;
 
+    /* At this point we know that the buffer starts with a valid signature.
+     * Return 0 if the buffer just contains the signature, and a specific
+     * error code if the valid signature is followed by more data. */
     if( p != end )
         ret = MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH;
 
diff --git a/library/error.c b/library/error.c
index 0292480..b173c7e 100644
--- a/library/error.c
+++ b/library/error.c
@@ -266,7 +266,7 @@
         if( use_ret == -(MBEDTLS_ERR_ECP_INVALID_KEY) )
             mbedtls_snprintf( buf, buflen, "ECP - Invalid private or public key" );
         if( use_ret == -(MBEDTLS_ERR_ECP_SIG_LEN_MISMATCH) )
-            mbedtls_snprintf( buf, buflen, "ECP - Signature is valid but shorter than the user-supplied length" );
+            mbedtls_snprintf( buf, buflen, "ECP - The buffer contains a valid signature followed by more data" );
         if( use_ret == -(MBEDTLS_ERR_ECP_HW_ACCEL_FAILED) )
             mbedtls_snprintf( buf, buflen, "ECP - ECP hardware accelerator failed" );
 #endif /* MBEDTLS_ECP_C */
@@ -333,7 +333,7 @@
         if( use_ret == -(MBEDTLS_ERR_PK_FEATURE_UNAVAILABLE) )
             mbedtls_snprintf( buf, buflen, "PK - Unavailable feature, e.g. RSA disabled for RSA key" );
         if( use_ret == -(MBEDTLS_ERR_PK_SIG_LEN_MISMATCH) )
-            mbedtls_snprintf( buf, buflen, "PK - The signature is valid but its length is less than expected" );
+            mbedtls_snprintf( buf, buflen, "PK - The buffer contains a valid signature followed by more data" );
         if( use_ret == -(MBEDTLS_ERR_PK_HW_ACCEL_FAILED) )
             mbedtls_snprintf( buf, buflen, "PK - PK hardware accelerator failed" );
 #endif /* MBEDTLS_PK_C */
diff --git a/library/pk_wrap.c b/library/pk_wrap.c
index a4bb35f..5446e23 100644
--- a/library/pk_wrap.c
+++ b/library/pk_wrap.c
@@ -93,6 +93,11 @@
                                   (unsigned int) hash_len, hash, sig ) ) != 0 )
         return( ret );
 
+    /* The buffer contains a valid signature followed by extra data.
+     * We have a special error code for that so that so that callers can
+     * use mbedtls_pk_verify() to check "Does the buffer start with a
+     * valid signature?" and not just "Does the buffer contain a valid
+     * signature?". */
     if( sig_len > rsa_len )
         return( MBEDTLS_ERR_PK_SIG_LEN_MISMATCH );
 
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 236e52d..d386dfa 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -855,8 +855,13 @@
     defined(MBEDTLS_SSL_PROTO_TLS1_2)
     if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 )
     {
-        mbedtls_md_hmac_starts( &transform->md_ctx_enc, mac_enc, mac_key_len );
-        mbedtls_md_hmac_starts( &transform->md_ctx_dec, mac_dec, mac_key_len );
+        /* For HMAC-based ciphersuites, initialize the HMAC transforms.
+           For AEAD-based ciphersuites, there is nothing to do here. */
+        if( mac_key_len != 0 )
+        {
+            mbedtls_md_hmac_starts( &transform->md_ctx_enc, mac_enc, mac_key_len );
+            mbedtls_md_hmac_starts( &transform->md_ctx_dec, mac_dec, mac_key_len );
+        }
     }
     else
 #endif
@@ -2434,6 +2439,14 @@
             if( ret < 0 )
                 return( ret );
 
+            if ( (size_t)ret > len || ( INT_MAX > SIZE_MAX && ret > SIZE_MAX ) )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 1,
+                    ( "f_recv returned %d bytes but only %lu were requested",
+                    ret, (unsigned long)len ) );
+                return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+            }
+
             ssl->in_left += ret;
         }
     }
@@ -2481,6 +2494,14 @@
         if( ret <= 0 )
             return( ret );
 
+        if( (size_t)ret > ssl->out_left || ( INT_MAX > SIZE_MAX && ret > SIZE_MAX ) )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1,
+                ( "f_send returned %d bytes but only %lu bytes were sent",
+                ret, (unsigned long)ssl->out_left ) );
+            return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+        }
+
         ssl->out_left -= ret;
     }
 
diff --git a/programs/pkey/pk_sign.c b/programs/pkey/pk_sign.c
index daf08a9..55df95e 100644
--- a/programs/pkey/pk_sign.c
+++ b/programs/pkey/pk_sign.c
@@ -29,6 +29,7 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
+#include <stdlib.h>
 #define mbedtls_snprintf   snprintf
 #define mbedtls_printf     printf
 #endif
@@ -100,8 +101,7 @@
 
     if( ( ret = mbedtls_pk_parse_keyfile( &pk, argv[1], "" ) ) != 0 )
     {
-        ret = 1;
-        mbedtls_printf( " failed\n  ! Could not open '%s'\n", argv[1] );
+        mbedtls_printf( " failed\n  ! Could not parse '%s'\n", argv[1] );
         goto exit;
     }
 
@@ -141,6 +141,7 @@
 
     if( fwrite( buf, 1, olen, f ) != olen )
     {
+        ret = 1;
         mbedtls_printf( "failed\n  ! fwrite failed\n\n" );
         fclose( f );
         goto exit;
@@ -168,7 +169,7 @@
     fflush( stdout ); getchar();
 #endif
 
-    return( ret );
+    return( ret ? EXIT_FAILURE : EXIT_SUCCESS );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_SHA256_C && MBEDTLS_PK_PARSE_C && MBEDTLS_FS_IO &&
diff --git a/tests/compat.sh b/tests/compat.sh
index 672bdab..34e38f1 100755
--- a/tests/compat.sh
+++ b/tests/compat.sh
@@ -1087,7 +1087,7 @@
             cp $CLI_OUT c-cli-${TESTS}.log
             echo "  ! outputs saved to c-srv-${TESTS}.log, c-cli-${TESTS}.log"
 
-            if [ "X${USER:-}" = Xbuildbot -o "X${LOGNAME:-}" = Xbuildbot ]; then
+            if [ "X${USER:-}" = Xbuildbot -o "X${LOGNAME:-}" = Xbuildbot -o "${LOG_FAILURE_ON_STDOUT:-0}" != 0 ]; then
                 echo "  ! server output:"
                 cat c-srv-${TESTS}.log
                 echo "  ! ==================================================="
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 2d6b71a..9fde54a 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -231,7 +231,7 @@
     fi
     echo "  ! outputs saved to o-XXX-${TESTS}.log"
 
-    if [ "X${USER:-}" = Xbuildbot -o "X${LOGNAME:-}" = Xbuildbot ]; then
+    if [ "X${USER:-}" = Xbuildbot -o "X${LOGNAME:-}" = Xbuildbot -o "${LOG_FAILURE_ON_STDOUT:-0}" != 0 ]; then
         echo "  ! server output:"
         cat o-srv-${TESTS}.log
         echo "  ! ========================================================"