diff --git a/ChangeLog.d/check-return.txt b/ChangeLog.d/check-return.txt
new file mode 100644
index 0000000..045b180
--- /dev/null
+++ b/ChangeLog.d/check-return.txt
@@ -0,0 +1,17 @@
+Bugfix
+   * Failures of alternative implementations of AES or DES single-block
+     functions enabled with MBEDTLS_AES_ENCRYPT_ALT, MBEDTLS_AES_DECRYPT_ALT,
+     MBEDTLS_DES_CRYPT_ECB_ALT or MBEDTLS_DES3_CRYPT_ECB_ALT were ignored.
+     This does not concern the implementation provided with Mbed TLS,
+     where this function cannot fail, or full-module replacements with
+     MBEDTLS_AES_ALT or MBEDTLS_DES_ALT. Reported by Armelle Duboc in #1092.
+
+Features
+   * Warn if errors from certain functions are ignored. This is currently
+     supported on GCC-like compilers and on MSVC and can be configured through
+     the macro MBEDTLS_CHECK_RETURN. The warnings are always enabled
+     (where supported) for critical functions where ignoring the return
+     value is almost always a bug. Enable the new configuration option
+     MBEDTLS_CHECK_RETURN_WARNING to get warnings for other functions. This
+     is currently implemented in the AES and DES modules, and will be extended
+     to other modules in the future.
diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index ab8793c..94ee58a 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -45,6 +45,7 @@
 #else
 #include MBEDTLS_CONFIG_FILE
 #endif
+#include "mbedtls/platform_util.h"
 
 #include <stddef.h>
 #include <stdint.h>
@@ -174,6 +175,7 @@
  * \return         \c 0 on success.
  * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
                     unsigned int keybits );
 
@@ -192,6 +194,7 @@
  * \return         \c 0 on success.
  * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_setkey_dec( mbedtls_aes_context *ctx, const unsigned char *key,
                     unsigned int keybits );
 
@@ -212,6 +215,7 @@
  * \return         \c 0 on success.
  * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_xts_setkey_enc( mbedtls_aes_xts_context *ctx,
                                 const unsigned char *key,
                                 unsigned int keybits );
@@ -232,6 +236,7 @@
  * \return         \c 0 on success.
  * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_xts_setkey_dec( mbedtls_aes_xts_context *ctx,
                                 const unsigned char *key,
                                 unsigned int keybits );
@@ -260,6 +265,7 @@
 
  * \return         \c 0 on success.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_crypt_ecb( mbedtls_aes_context *ctx,
                     int mode,
                     const unsigned char input[16],
@@ -307,6 +313,7 @@
  * \return         #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH
  *                 on failure.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_crypt_cbc( mbedtls_aes_context *ctx,
                     int mode,
                     size_t length,
@@ -351,6 +358,7 @@
  *                     smaller than an AES block in size (16 Bytes) or if \p
  *                     length is larger than 2^20 blocks (16 MiB).
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_crypt_xts( mbedtls_aes_xts_context *ctx,
                            int mode,
                            size_t length,
@@ -399,6 +407,7 @@
  *
  * \return         \c 0 on success.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_crypt_cfb128( mbedtls_aes_context *ctx,
                        int mode,
                        size_t length,
@@ -443,6 +452,7 @@
  *
  * \return         \c 0 on success.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_crypt_cfb8( mbedtls_aes_context *ctx,
                     int mode,
                     size_t length,
@@ -497,6 +507,7 @@
  *
  * \return         \c 0 on success.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_crypt_ofb( mbedtls_aes_context *ctx,
                        size_t length,
                        size_t *iv_off,
@@ -583,6 +594,7 @@
  *
  * \return                 \c 0 on success.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_aes_crypt_ctr( mbedtls_aes_context *ctx,
                        size_t length,
                        size_t *nc_off,
@@ -603,6 +615,7 @@
  *
  * \return          \c 0 on success.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
                                   const unsigned char input[16],
                                   unsigned char output[16] );
@@ -618,6 +631,7 @@
  *
  * \return          \c 0 on success.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
                                   const unsigned char input[16],
                                   unsigned char output[16] );
@@ -667,6 +681,7 @@
  * \return         \c 0 on success.
  * \return         \c 1 on failure.
  */
+MBEDTLS_CHECK_RETURN_CRITICAL
 int mbedtls_aes_self_test( int verbose );
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 2730967..87b4e91 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -617,6 +617,29 @@
 //#define MBEDTLS_CAMELLIA_SMALL_MEMORY
 
 /**
+ * \def MBEDTLS_CHECK_RETURN_WARNING
+ *
+ * If this macro is defined, emit a compile-time warning if application code
+ * calls a function without checking its return value, but the return value
+ * should generally be checked in portable applications.
+ *
+ * This is only supported on platforms where #MBEDTLS_CHECK_RETURN is
+ * implemented. Otherwise this option has no effect.
+ *
+ * Uncomment to get warnings on using fallible functions without checking
+ * their return value.
+ *
+ * \note  This feature is a work in progress.
+ *        Warnings will be added to more functions in the future.
+ *
+ * \note  A few functions are considered critical, and ignoring the return
+ *        value of these functions will trigger a warning even if this
+ *        macro is not defined. To completely disable return value check
+ *        warnings, define #MBEDTLS_CHECK_RETURN with an empty expansion.
+ */
+//#define MBEDTLS_CHECK_RETURN_WARNING
+
+/**
  * \def MBEDTLS_CIPHER_MODE_CBC
  *
  * Enable Cipher Block Chaining mode (CBC) for symmetric ciphers.
@@ -3689,6 +3712,29 @@
  */
 //#define MBEDTLS_PARAM_FAILED( cond )               assert( cond )
 
+/** \def MBEDTLS_CHECK_RETURN
+ *
+ * This macro is used at the beginning of the declaration of a function
+ * to indicate that its return value should be checked. It should
+ * instruct the compiler to emit a warning or an error if the function
+ * is called without checking its return value.
+ *
+ * There is a default implementation for popular compilers in platform_util.h.
+ * You can override the default implementation by defining your own here.
+ *
+ * If the implementation here is empty, this will effectively disable the
+ * checking of functions' return values.
+ */
+//#define MBEDTLS_CHECK_RETURN __attribute__((__warn_unused_result__))
+
+/** \def MBEDTLS_IGNORE_RETURN
+ *
+ * This macro requires one argument, which should be a C function call.
+ * If that function call would cause a #MBEDTLS_CHECK_RETURN warning, this
+ * warning is suppressed.
+ */
+//#define MBEDTLS_IGNORE_RETURN( result ) ((void) !(result))
+
 /* PSA options */
 /**
  * Use HMAC_DRBG with the specified hash algorithm for HMAC_DRBG for the
diff --git a/include/mbedtls/des.h b/include/mbedtls/des.h
index 6bfe654..325aab5 100644
--- a/include/mbedtls/des.h
+++ b/include/mbedtls/des.h
@@ -32,6 +32,7 @@
 #else
 #include MBEDTLS_CONFIG_FILE
 #endif
+#include "mbedtls/platform_util.h"
 
 #include <stddef.h>
 #include <stdint.h>
@@ -146,6 +147,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des_key_check_key_parity( const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -159,6 +161,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des_key_check_weak( const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -173,6 +176,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des_setkey_enc( mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -187,6 +191,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des_setkey_dec( mbedtls_des_context *ctx, const unsigned char key[MBEDTLS_DES_KEY_SIZE] );
 
 /**
@@ -197,6 +202,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des3_set2key_enc( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2] );
 
@@ -208,6 +214,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des3_set2key_dec( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 2] );
 
@@ -219,6 +226,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des3_set3key_enc( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3] );
 
@@ -230,6 +238,7 @@
  *
  * \return         0
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des3_set3key_dec( mbedtls_des3_context *ctx,
                       const unsigned char key[MBEDTLS_DES_KEY_SIZE * 3] );
 
@@ -246,6 +255,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des_crypt_ecb( mbedtls_des_context *ctx,
                     const unsigned char input[8],
                     unsigned char output[8] );
@@ -273,6 +283,7 @@
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des_crypt_cbc( mbedtls_des_context *ctx,
                     int mode,
                     size_t length,
@@ -290,6 +301,7 @@
  *
  * \return         0 if successful
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des3_crypt_ecb( mbedtls_des3_context *ctx,
                      const unsigned char input[8],
                      unsigned char output[8] );
@@ -315,6 +327,7 @@
  *
  * \return         0 if successful, or MBEDTLS_ERR_DES_INVALID_INPUT_LENGTH
  */
+MBEDTLS_CHECK_RETURN_TYPICAL
 int mbedtls_des3_crypt_cbc( mbedtls_des3_context *ctx,
                      int mode,
                      size_t length,
@@ -345,6 +358,7 @@
  *
  * \return         0 if successful, or 1 if the test failed
  */
+MBEDTLS_CHECK_RETURN_CRITICAL
 int mbedtls_des_self_test( int verbose );
 
 #endif /* MBEDTLS_SELF_TEST */
diff --git a/include/mbedtls/platform_util.h b/include/mbedtls/platform_util.h
index fbc2a0d..f982db8 100644
--- a/include/mbedtls/platform_util.h
+++ b/include/mbedtls/platform_util.h
@@ -132,6 +132,95 @@
 #endif /* MBEDTLS_DEPRECATED_WARNING */
 #endif /* MBEDTLS_DEPRECATED_REMOVED */
 
+/* Implementation of the check-return facility.
+ * See the user documentation in config.h.
+ *
+ * Do not use this macro directly to annotate function: instead,
+ * use one of MBEDTLS_CHECK_RETURN_CRITICAL or MBEDTLS_CHECK_RETURN_TYPICAL
+ * depending on how important it is to check the return value.
+ */
+#if !defined(MBEDTLS_CHECK_RETURN)
+#if defined(__GNUC__)
+#define MBEDTLS_CHECK_RETURN __attribute__((__warn_unused_result__))
+#elif defined(_MSC_VER) && _MSC_VER >= 1700
+#include <sal.h>
+#define MBEDTLS_CHECK_RETURN _Check_return_
+#else
+#define MBEDTLS_CHECK_RETURN
+#endif
+#endif
+
+/** Critical-failure function
+ *
+ * This macro appearing at the beginning of the declaration of a function
+ * indicates that its return value should be checked in all applications.
+ * Omitting the check is very likely to indicate a bug in the application
+ * and will result in a compile-time warning if #MBEDTLS_CHECK_RETURN
+ * is implemented for the compiler in use.
+ *
+ * \note  The use of this macro is a work in progress.
+ *        This macro may be added to more functions in the future.
+ *        Such an extension is not considered an API break, provided that
+ *        there are near-unavoidable circumstances under which the function
+ *        can fail. For example, signature/MAC/AEAD verification functions,
+ *        and functions that require a random generator, are considered
+ *        return-check-critical.
+ */
+#define MBEDTLS_CHECK_RETURN_CRITICAL MBEDTLS_CHECK_RETURN
+
+/** Ordinary-failure function
+ *
+ * This macro appearing at the beginning of the declaration of a function
+ * indicates that its return value should be generally be checked in portable
+ * applications. Omitting the check will result in a compile-time warning if
+ * #MBEDTLS_CHECK_RETURN is implemented for the compiler in use and
+ * #MBEDTLS_CHECK_RETURN_WARNING is enabled in the compile-time configuration.
+ *
+ * You can use #MBEDTLS_IGNORE_RETURN to explicitly ignore the return value
+ * of a function that is annotated with #MBEDTLS_CHECK_RETURN.
+ *
+ * \note  The use of this macro is a work in progress.
+ *        This macro will be added to more functions in the future.
+ *        Eventually this should appear before most functions returning
+ *        an error code (as \c int in the \c mbedtls_xxx API or
+ *        as ::psa_status_t in the \c psa_xxx API).
+ */
+#if defined(MBEDTLS_CHECK_RETURN_WARNING)
+#define MBEDTLS_CHECK_RETURN_TYPICAL MBEDTLS_CHECK_RETURN
+#else
+#define MBEDTLS_CHECK_RETURN_TYPICAL
+#endif
+
+/** Benign-failure function
+ *
+ * This macro appearing at the beginning of the declaration of a function
+ * indicates that it is rarely useful to check its return value.
+ *
+ * This macro has an empty expansion. It exists for documentation purposes:
+ * a #MBEDTLS_CHECK_RETURN_OPTIONAL annotation indicates that the function
+ * has been analyzed for return-check usefuless, whereas the lack of
+ * an annotation indicates that the function has not been analyzed and its
+ * return-check usefulness is unknown.
+ */
+#define MBEDTLS_CHECK_RETURN_OPTIONAL
+
+/** \def MBEDTLS_IGNORE_RETURN
+ *
+ * Call this macro with one argument, a function call, to suppress a warning
+ * from #MBEDTLS_CHECK_RETURN due to that function call.
+ */
+#if !defined(MBEDTLS_IGNORE_RETURN)
+/* GCC doesn't silence the warning with just (void)(result).
+ * (void)!(result) is known to work up at least up to GCC 10, as well
+ * as with Clang and MSVC.
+ *
+ * https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Non_002dbugs.html
+ * https://stackoverflow.com/questions/40576003/ignoring-warning-wunused-result
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425#c34
+ */
+#define MBEDTLS_IGNORE_RETURN(result) ( (void) !( result ) )
+#endif
+
 /**
  * \brief       Securely zeroize a buffer
  *
diff --git a/library/aes.c b/library/aes.c
index 544b583..31824e7 100644
--- a/library/aes.c
+++ b/library/aes.c
@@ -903,7 +903,7 @@
                           const unsigned char input[16],
                           unsigned char output[16] )
 {
-    mbedtls_internal_aes_encrypt( ctx, input, output );
+    MBEDTLS_IGNORE_RETURN( mbedtls_internal_aes_encrypt( ctx, input, output ) );
 }
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
@@ -976,7 +976,7 @@
                           const unsigned char input[16],
                           unsigned char output[16] )
 {
-    mbedtls_internal_aes_decrypt( ctx, input, output );
+    MBEDTLS_IGNORE_RETURN( mbedtls_internal_aes_decrypt( ctx, input, output ) );
 }
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
@@ -1029,6 +1029,7 @@
                     unsigned char *output )
 {
     int i;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char temp[16];
 
     AES_VALIDATE_RET( ctx != NULL );
@@ -1058,7 +1059,9 @@
         while( length > 0 )
         {
             memcpy( temp, input, 16 );
-            mbedtls_aes_crypt_ecb( ctx, mode, input, output );
+            ret = mbedtls_aes_crypt_ecb( ctx, mode, input, output );
+            if( ret != 0 )
+                goto exit;
 
             for( i = 0; i < 16; i++ )
                 output[i] = (unsigned char)( output[i] ^ iv[i] );
@@ -1077,7 +1080,9 @@
             for( i = 0; i < 16; i++ )
                 output[i] = (unsigned char)( input[i] ^ iv[i] );
 
-            mbedtls_aes_crypt_ecb( ctx, mode, output, output );
+            ret = mbedtls_aes_crypt_ecb( ctx, mode, output, output );
+            if( ret != 0 )
+                goto exit;
             memcpy( iv, output, 16 );
 
             input  += 16;
@@ -1085,8 +1090,10 @@
             length -= 16;
         }
     }
+    ret = 0;
 
-    return( 0 );
+exit:
+    return( ret );
 }
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
 
@@ -1240,6 +1247,7 @@
                        unsigned char *output )
 {
     int c;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t n;
 
     AES_VALIDATE_RET( ctx != NULL );
@@ -1260,7 +1268,11 @@
         while( length-- )
         {
             if( n == 0 )
-                mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
+            {
+                ret = mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
+                if( ret != 0 )
+                    goto exit;
+            }
 
             c = *input++;
             *output++ = (unsigned char)( c ^ iv[n] );
@@ -1274,7 +1286,11 @@
         while( length-- )
         {
             if( n == 0 )
-                mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
+            {
+                ret = mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
+                if( ret != 0 )
+                    goto exit;
+            }
 
             iv[n] = *output++ = (unsigned char)( iv[n] ^ *input++ );
 
@@ -1283,8 +1299,10 @@
     }
 
     *iv_off = n;
+    ret = 0;
 
-    return( 0 );
+exit:
+    return( ret );
 }
 
 /*
@@ -1297,6 +1315,7 @@
                             const unsigned char *input,
                             unsigned char *output )
 {
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char c;
     unsigned char ov[17];
 
@@ -1309,7 +1328,9 @@
     while( length-- )
     {
         memcpy( ov, iv, 16 );
-        mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
+        ret = mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, iv, iv );
+        if( ret != 0 )
+            goto exit;
 
         if( mode == MBEDTLS_AES_DECRYPT )
             ov[16] = *input;
@@ -1321,8 +1342,10 @@
 
         memcpy( iv, ov + 1, 16 );
     }
+    ret = 0;
 
-    return( 0 );
+exit:
+    return( ret );
 }
 #endif /* MBEDTLS_CIPHER_MODE_CFB */
 
@@ -1384,6 +1407,7 @@
                        unsigned char *output )
 {
     int c, i;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     size_t n;
 
     AES_VALIDATE_RET( ctx != NULL );
@@ -1401,7 +1425,9 @@
     while( length-- )
     {
         if( n == 0 ) {
-            mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, nonce_counter, stream_block );
+            ret = mbedtls_aes_crypt_ecb( ctx, MBEDTLS_AES_ENCRYPT, nonce_counter, stream_block );
+            if( ret != 0 )
+                goto exit;
 
             for( i = 16; i > 0; i-- )
                 if( ++nonce_counter[i - 1] != 0 )
@@ -1414,8 +1440,10 @@
     }
 
     *nc_off = n;
+    ret = 0;
 
-    return( 0 );
+exit:
+    return( ret );
 }
 #endif /* MBEDTLS_CIPHER_MODE_CTR */
 
diff --git a/library/des.c b/library/des.c
index 7f90faa..91d22b5 100644
--- a/library/des.c
+++ b/library/des.c
@@ -28,6 +28,7 @@
 #if defined(MBEDTLS_DES_C)
 
 #include "mbedtls/des.h"
+#include "mbedtls/error.h"
 #include "mbedtls/platform_util.h"
 
 #include <string.h>
@@ -642,6 +643,7 @@
                     unsigned char *output )
 {
     int i;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char temp[8];
 
     if( length % 8 )
@@ -654,7 +656,9 @@
             for( i = 0; i < 8; i++ )
                 output[i] = (unsigned char)( input[i] ^ iv[i] );
 
-            mbedtls_des_crypt_ecb( ctx, output, output );
+            ret = mbedtls_des_crypt_ecb( ctx, output, output );
+            if( ret != 0 )
+                goto exit;
             memcpy( iv, output, 8 );
 
             input  += 8;
@@ -667,7 +671,9 @@
         while( length > 0 )
         {
             memcpy( temp, input, 8 );
-            mbedtls_des_crypt_ecb( ctx, input, output );
+            ret = mbedtls_des_crypt_ecb( ctx, input, output );
+            if( ret != 0 )
+                goto exit;
 
             for( i = 0; i < 8; i++ )
                 output[i] = (unsigned char)( output[i] ^ iv[i] );
@@ -679,8 +685,10 @@
             length -= 8;
         }
     }
+    ret = 0;
 
-    return( 0 );
+exit:
+    return( ret );
 }
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
 
@@ -741,6 +749,7 @@
                      unsigned char *output )
 {
     int i;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
     unsigned char temp[8];
 
     if( length % 8 )
@@ -753,7 +762,9 @@
             for( i = 0; i < 8; i++ )
                 output[i] = (unsigned char)( input[i] ^ iv[i] );
 
-            mbedtls_des3_crypt_ecb( ctx, output, output );
+            ret = mbedtls_des3_crypt_ecb( ctx, output, output );
+            if( ret != 0 )
+                goto exit;
             memcpy( iv, output, 8 );
 
             input  += 8;
@@ -766,7 +777,9 @@
         while( length > 0 )
         {
             memcpy( temp, input, 8 );
-            mbedtls_des3_crypt_ecb( ctx, input, output );
+            ret = mbedtls_des3_crypt_ecb( ctx, input, output );
+            if( ret != 0 )
+                goto exit;
 
             for( i = 0; i < 8; i++ )
                 output[i] = (unsigned char)( output[i] ^ iv[i] );
@@ -778,8 +791,10 @@
             length -= 8;
         }
     }
+    ret = 0;
 
-    return( 0 );
+exit:
+    return( ret );
 }
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
 
@@ -872,39 +887,43 @@
         switch( i )
         {
         case 0:
-            mbedtls_des_setkey_dec( &ctx, des3_test_keys );
+            ret = mbedtls_des_setkey_dec( &ctx, des3_test_keys );
             break;
 
         case 1:
-            mbedtls_des_setkey_enc( &ctx, des3_test_keys );
+            ret = mbedtls_des_setkey_enc( &ctx, des3_test_keys );
             break;
 
         case 2:
-            mbedtls_des3_set2key_dec( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set2key_dec( &ctx3, des3_test_keys );
             break;
 
         case 3:
-            mbedtls_des3_set2key_enc( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set2key_enc( &ctx3, des3_test_keys );
             break;
 
         case 4:
-            mbedtls_des3_set3key_dec( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set3key_dec( &ctx3, des3_test_keys );
             break;
 
         case 5:
-            mbedtls_des3_set3key_enc( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set3key_enc( &ctx3, des3_test_keys );
             break;
 
         default:
             return( 1 );
         }
+        if( ret != 0 )
+            goto exit;
 
         for( j = 0; j < 100; j++ )
         {
             if( u == 0 )
-                mbedtls_des_crypt_ecb( &ctx, buf, buf );
+                ret = mbedtls_des_crypt_ecb( &ctx, buf, buf );
             else
-                mbedtls_des3_crypt_ecb( &ctx3, buf, buf );
+                ret = mbedtls_des3_crypt_ecb( &ctx3, buf, buf );
+            if( ret != 0 )
+                goto exit;
         }
 
         if( ( v == MBEDTLS_DES_DECRYPT &&
@@ -947,41 +966,45 @@
         switch( i )
         {
         case 0:
-            mbedtls_des_setkey_dec( &ctx, des3_test_keys );
+            ret = mbedtls_des_setkey_dec( &ctx, des3_test_keys );
             break;
 
         case 1:
-            mbedtls_des_setkey_enc( &ctx, des3_test_keys );
+            ret = mbedtls_des_setkey_enc( &ctx, des3_test_keys );
             break;
 
         case 2:
-            mbedtls_des3_set2key_dec( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set2key_dec( &ctx3, des3_test_keys );
             break;
 
         case 3:
-            mbedtls_des3_set2key_enc( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set2key_enc( &ctx3, des3_test_keys );
             break;
 
         case 4:
-            mbedtls_des3_set3key_dec( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set3key_dec( &ctx3, des3_test_keys );
             break;
 
         case 5:
-            mbedtls_des3_set3key_enc( &ctx3, des3_test_keys );
+            ret = mbedtls_des3_set3key_enc( &ctx3, des3_test_keys );
             break;
 
         default:
             return( 1 );
         }
+        if( ret != 0 )
+            goto exit;
 
         if( v == MBEDTLS_DES_DECRYPT )
         {
             for( j = 0; j < 100; j++ )
             {
                 if( u == 0 )
-                    mbedtls_des_crypt_cbc( &ctx, v, 8, iv, buf, buf );
+                    ret = mbedtls_des_crypt_cbc( &ctx, v, 8, iv, buf, buf );
                 else
-                    mbedtls_des3_crypt_cbc( &ctx3, v, 8, iv, buf, buf );
+                    ret = mbedtls_des3_crypt_cbc( &ctx3, v, 8, iv, buf, buf );
+                if( ret != 0 )
+                    goto exit;
             }
         }
         else
@@ -991,9 +1014,11 @@
                 unsigned char tmp[8];
 
                 if( u == 0 )
-                    mbedtls_des_crypt_cbc( &ctx, v, 8, iv, buf, buf );
+                    ret = mbedtls_des_crypt_cbc( &ctx, v, 8, iv, buf, buf );
                 else
-                    mbedtls_des3_crypt_cbc( &ctx3, v, 8, iv, buf, buf );
+                    ret = mbedtls_des3_crypt_cbc( &ctx3, v, 8, iv, buf, buf );
+                if( ret != 0 )
+                    goto exit;
 
                 memcpy( tmp, prv, 8 );
                 memcpy( prv, buf, 8 );
@@ -1027,6 +1052,8 @@
     mbedtls_des_free( &ctx );
     mbedtls_des3_free( &ctx3 );
 
+    if( ret != 0 )
+        ret = 1;
     return( ret );
 }
 
diff --git a/library/version_features.c b/library/version_features.c
index f665a23..40c9520 100644
--- a/library/version_features.c
+++ b/library/version_features.c
@@ -267,6 +267,9 @@
 #if defined(MBEDTLS_CAMELLIA_SMALL_MEMORY)
     "MBEDTLS_CAMELLIA_SMALL_MEMORY",
 #endif /* MBEDTLS_CAMELLIA_SMALL_MEMORY */
+#if defined(MBEDTLS_CHECK_RETURN_WARNING)
+    "MBEDTLS_CHECK_RETURN_WARNING",
+#endif /* MBEDTLS_CHECK_RETURN_WARNING */
 #if defined(MBEDTLS_CIPHER_MODE_CBC)
     "MBEDTLS_CIPHER_MODE_CBC",
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
diff --git a/programs/pkey/dh_client.c b/programs/pkey/dh_client.c
index d6e4990..f6c6226 100644
--- a/programs/pkey/dh_client.c
+++ b/programs/pkey/dh_client.c
@@ -274,7 +274,9 @@
     mbedtls_printf( "...\n  . Receiving and decrypting the ciphertext" );
     fflush( stdout );
 
-    mbedtls_aes_setkey_dec( &aes, buf, 256 );
+    ret = mbedtls_aes_setkey_dec( &aes, buf, 256 );
+    if( ret != 0 )
+        goto exit;
 
     memset( buf, 0, sizeof( buf ) );
 
@@ -284,7 +286,9 @@
         goto exit;
     }
 
-    mbedtls_aes_crypt_ecb( &aes, MBEDTLS_AES_DECRYPT, buf, buf );
+    ret = mbedtls_aes_crypt_ecb( &aes, MBEDTLS_AES_DECRYPT, buf, buf );
+    if( ret != 0 )
+        goto exit;
     buf[16] = '\0';
     mbedtls_printf( "\n  . Plaintext is \"%s\"\n\n", (char *) buf );
 
diff --git a/programs/pkey/dh_server.c b/programs/pkey/dh_server.c
index dccf095..8f032a3 100644
--- a/programs/pkey/dh_server.c
+++ b/programs/pkey/dh_server.c
@@ -295,9 +295,13 @@
     mbedtls_printf( "...\n  . Encrypting and sending the ciphertext" );
     fflush( stdout );
 
-    mbedtls_aes_setkey_enc( &aes, buf, 256 );
+    ret = mbedtls_aes_setkey_enc( &aes, buf, 256 );
+    if( ret != 0 )
+        goto exit;
     memcpy( buf, PLAINTEXT, 16 );
-    mbedtls_aes_crypt_ecb( &aes, MBEDTLS_AES_ENCRYPT, buf, buf );
+    ret = mbedtls_aes_crypt_ecb( &aes, MBEDTLS_AES_ENCRYPT, buf, buf );
+    if( ret != 0 )
+        goto exit;
 
     if( ( ret = mbedtls_net_send( &client_fd, buf, 16 ) ) != 16 )
     {
diff --git a/programs/test/benchmark.c b/programs/test/benchmark.c
index 9c5911b..88c9e65 100644
--- a/programs/test/benchmark.c
+++ b/programs/test/benchmark.c
@@ -449,7 +449,8 @@
     {
         mbedtls_des3_context des3;
         mbedtls_des3_init( &des3 );
-        mbedtls_des3_set3key_enc( &des3, tmp );
+        if( mbedtls_des3_set3key_enc( &des3, tmp ) != 0 )
+            mbedtls_exit( 1 );
         TIME_AND_TSC( "3DES",
                 mbedtls_des3_crypt_cbc( &des3, MBEDTLS_DES_ENCRYPT, BUFSIZE, tmp, buf, buf ) );
         mbedtls_des3_free( &des3 );
@@ -459,7 +460,8 @@
     {
         mbedtls_des_context des;
         mbedtls_des_init( &des );
-        mbedtls_des_setkey_enc( &des, tmp );
+        if( mbedtls_des_setkey_enc( &des, tmp ) != 0 )
+            mbedtls_exit( 1 );
         TIME_AND_TSC( "DES",
                 mbedtls_des_crypt_cbc( &des, MBEDTLS_DES_ENCRYPT, BUFSIZE, tmp, buf, buf ) );
         mbedtls_des_free( &des );
@@ -497,7 +499,7 @@
 
             memset( buf, 0, sizeof( buf ) );
             memset( tmp, 0, sizeof( tmp ) );
-            mbedtls_aes_setkey_enc( &aes, tmp, keysize );
+            CHECK_AND_CONTINUE( mbedtls_aes_setkey_enc( &aes, tmp, keysize ) );
 
             TIME_AND_TSC( title,
                 mbedtls_aes_crypt_cbc( &aes, MBEDTLS_AES_ENCRYPT, BUFSIZE, tmp, buf, buf ) );
@@ -518,7 +520,7 @@
 
             memset( buf, 0, sizeof( buf ) );
             memset( tmp, 0, sizeof( tmp ) );
-            mbedtls_aes_xts_setkey_enc( &ctx, tmp, keysize * 2 );
+            CHECK_AND_CONTINUE( mbedtls_aes_xts_setkey_enc( &ctx, tmp, keysize * 2 ) );
 
             TIME_AND_TSC( title,
                     mbedtls_aes_crypt_xts( &ctx, MBEDTLS_AES_ENCRYPT, BUFSIZE,
diff --git a/programs/test/query_config.c b/programs/test/query_config.c
index 9b9d0c0..5dfe383 100644
--- a/programs/test/query_config.c
+++ b/programs/test/query_config.c
@@ -770,6 +770,14 @@
     }
 #endif /* MBEDTLS_CAMELLIA_SMALL_MEMORY */
 
+#if defined(MBEDTLS_CHECK_RETURN_WARNING)
+    if( strcmp( "MBEDTLS_CHECK_RETURN_WARNING", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_CHECK_RETURN_WARNING );
+        return( 0 );
+    }
+#endif /* MBEDTLS_CHECK_RETURN_WARNING */
+
 #if defined(MBEDTLS_CIPHER_MODE_CBC)
     if( strcmp( "MBEDTLS_CIPHER_MODE_CBC", config ) == 0 )
     {
@@ -2642,6 +2650,22 @@
     }
 #endif /* MBEDTLS_PLATFORM_NV_SEED_WRITE_MACRO */
 
+#if defined(MBEDTLS_CHECK_RETURN)
+    if( strcmp( "MBEDTLS_CHECK_RETURN", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_CHECK_RETURN );
+        return( 0 );
+    }
+#endif /* MBEDTLS_CHECK_RETURN */
+
+#if defined(MBEDTLS_IGNORE_RETURN)
+    if( strcmp( "MBEDTLS_IGNORE_RETURN", config ) == 0 )
+    {
+        MACRO_EXPANSION_TO_STR( MBEDTLS_IGNORE_RETURN );
+        return( 0 );
+    }
+#endif /* MBEDTLS_IGNORE_RETURN */
+
 #if defined(MBEDTLS_PSA_HMAC_DRBG_MD_TYPE)
     if( strcmp( "MBEDTLS_PSA_HMAC_DRBG_MD_TYPE", config ) == 0 )
     {
diff --git a/tests/suites/test_suite_aes.function b/tests/suites/test_suite_aes.function
index a90277d..5a64099 100644
--- a/tests/suites/test_suite_aes.function
+++ b/tests/suites/test_suite_aes.function
@@ -67,7 +67,7 @@
 
     mbedtls_aes_init( &ctx );
 
-    mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 );
+    TEST_ASSERT( mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 ) == 0 );
     TEST_ASSERT( mbedtls_aes_crypt_cbc( &ctx, MBEDTLS_AES_ENCRYPT, src_str->len, iv_str->x, src_str->x, output ) == cbc_result );
     if( cbc_result == 0 )
     {
@@ -92,7 +92,7 @@
     memset(output, 0x00, 100);
     mbedtls_aes_init( &ctx );
 
-    mbedtls_aes_setkey_dec( &ctx, key_str->x, key_str->len * 8 );
+    TEST_ASSERT( mbedtls_aes_setkey_dec( &ctx, key_str->x, key_str->len * 8 ) == 0 );
     TEST_ASSERT( mbedtls_aes_crypt_cbc( &ctx, MBEDTLS_AES_DECRYPT, src_str->len, iv_str->x, src_str->x, output ) == cbc_result );
     if( cbc_result == 0)
     {
@@ -244,7 +244,7 @@
     mbedtls_aes_init( &ctx );
 
 
-    mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 );
+    TEST_ASSERT( mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 ) == 0 );
     TEST_ASSERT( mbedtls_aes_crypt_cfb128( &ctx, MBEDTLS_AES_ENCRYPT, 16, &iv_offset, iv_str->x, src_str->x, output ) == 0 );
 
     TEST_ASSERT( mbedtls_test_hexcmp( output, dst->x, 16, dst->len ) == 0 );
@@ -266,7 +266,7 @@
     mbedtls_aes_init( &ctx );
 
 
-    mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 );
+    TEST_ASSERT( mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 ) == 0 );
     TEST_ASSERT( mbedtls_aes_crypt_cfb128( &ctx, MBEDTLS_AES_DECRYPT, 16, &iv_offset, iv_str->x, src_str->x, output ) == 0 );
 
     TEST_ASSERT( mbedtls_test_hexcmp( output, dst->x, 16, dst->len ) == 0 );
@@ -287,7 +287,7 @@
     mbedtls_aes_init( &ctx );
 
 
-    mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 );
+    TEST_ASSERT( mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 ) == 0 );
     TEST_ASSERT( mbedtls_aes_crypt_cfb8( &ctx, MBEDTLS_AES_ENCRYPT, src_str->len, iv_str->x, src_str->x, output ) == 0 );
 
     TEST_ASSERT( mbedtls_test_hexcmp( output, dst->x,
@@ -309,7 +309,7 @@
     mbedtls_aes_init( &ctx );
 
 
-    mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 );
+    TEST_ASSERT( mbedtls_aes_setkey_enc( &ctx, key_str->x, key_str->len * 8 ) == 0 );
     TEST_ASSERT( mbedtls_aes_crypt_cfb8( &ctx, MBEDTLS_AES_DECRYPT, src_str->len, iv_str->x, src_str->x, output ) == 0 );
 
     TEST_ASSERT( mbedtls_test_hexcmp( output, dst->x,
diff --git a/tests/suites/test_suite_des.function b/tests/suites/test_suite_des.function
index 5b24935..7256fb5 100644
--- a/tests/suites/test_suite_des.function
+++ b/tests/suites/test_suite_des.function
@@ -24,7 +24,7 @@
     mbedtls_des_init( &ctx );
 
 
-    mbedtls_des_setkey_enc( &ctx, key_str->x );
+    TEST_ASSERT( mbedtls_des_setkey_enc( &ctx, key_str->x ) == 0 );
     TEST_ASSERT( mbedtls_des_crypt_ecb( &ctx, src_str->x, output ) == 0 );
 
     TEST_ASSERT( mbedtls_test_hexcmp( output, dst->x, 8, dst->len ) == 0 );
@@ -44,7 +44,7 @@
     mbedtls_des_init( &ctx );
 
 
-    mbedtls_des_setkey_dec( &ctx, key_str->x );
+    TEST_ASSERT( mbedtls_des_setkey_dec( &ctx, key_str->x ) == 0 );
     TEST_ASSERT( mbedtls_des_crypt_ecb( &ctx, src_str->x, output ) == 0 );
 
     TEST_ASSERT( mbedtls_test_hexcmp( output, dst->x, 8, dst->len ) == 0 );
@@ -65,7 +65,7 @@
     mbedtls_des_init( &ctx );
 
 
-    mbedtls_des_setkey_enc( &ctx, key_str->x );
+    TEST_ASSERT( mbedtls_des_setkey_enc( &ctx, key_str->x ) == 0 );
     TEST_ASSERT( mbedtls_des_crypt_cbc( &ctx, MBEDTLS_DES_ENCRYPT, src_str->len, iv_str->x, src_str->x, output ) == cbc_result );
     if( cbc_result == 0 )
     {
@@ -91,7 +91,7 @@
     mbedtls_des_init( &ctx );
 
 
-    mbedtls_des_setkey_dec( &ctx, key_str->x );
+    TEST_ASSERT( mbedtls_des_setkey_dec( &ctx, key_str->x ) == 0 );
     TEST_ASSERT( mbedtls_des_crypt_cbc( &ctx, MBEDTLS_DES_DECRYPT, src_str->len, iv_str->x, src_str->x, output ) == cbc_result );
     if( cbc_result == 0 )
     {
@@ -117,9 +117,9 @@
 
 
     if( key_count == 2 )
-        mbedtls_des3_set2key_enc( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set2key_enc( &ctx, key_str->x ) == 0 );
     else if( key_count == 3 )
-        mbedtls_des3_set3key_enc( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set3key_enc( &ctx, key_str->x ) == 0 );
     else
         TEST_ASSERT( 0 );
 
@@ -144,9 +144,9 @@
 
 
     if( key_count == 2 )
-        mbedtls_des3_set2key_dec( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set2key_dec( &ctx, key_str->x ) == 0 );
     else if( key_count == 3 )
-        mbedtls_des3_set3key_dec( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set3key_dec( &ctx, key_str->x ) == 0 );
     else
         TEST_ASSERT( 0 );
 
@@ -172,9 +172,9 @@
 
 
     if( key_count == 2 )
-        mbedtls_des3_set2key_enc( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set2key_enc( &ctx, key_str->x ) == 0 );
     else if( key_count == 3 )
-        mbedtls_des3_set3key_enc( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set3key_enc( &ctx, key_str->x ) == 0 );
     else
         TEST_ASSERT( 0 );
 
@@ -205,9 +205,9 @@
 
 
     if( key_count == 2 )
-        mbedtls_des3_set2key_dec( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set2key_dec( &ctx, key_str->x ) == 0 );
     else if( key_count == 3 )
-        mbedtls_des3_set3key_dec( &ctx, key_str->x );
+        TEST_ASSERT( mbedtls_des3_set3key_dec( &ctx, key_str->x ) == 0 );
     else
         TEST_ASSERT( 0 );