Add Cipher module parameter validation
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index 58a5d63..4df10e8 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -336,11 +336,12 @@
  * \brief               This function retrieves the cipher-information
  *                      structure associated with the given cipher name.
  *
- * \param cipher_name   Name of the cipher to search for.
+ * \param cipher_name   Name of the cipher to search for. This can be \c NULL.
  *
  * \return              The cipher information structure associated with the
  *                      given \p cipher_name.
- * \return              NULL if the associated cipher information is not found.
+ * \return              \c NULL if the associated cipher information is not found
+ *                      or if \p cipher_name is \c NULL.
  */
 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string( const char *cipher_name );
 
@@ -352,7 +353,7 @@
  *
  * \return              The cipher information structure associated with the
  *                      given \p cipher_type.
- * \return              NULL if the associated cipher information is not found.
+ * \return              \c NULL if the associated cipher information is not found.
  */
 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type( const mbedtls_cipher_type_t cipher_type );
 
@@ -368,7 +369,7 @@
  *
  * \return              The cipher information structure associated with the
  *                      given \p cipher_id.
- * \return              NULL if the associated cipher information is not found.
+ * \return              \c NULL if the associated cipher information is not found.
  */
 const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values( const mbedtls_cipher_id_t cipher_id,
                                               int key_bitlen,
@@ -376,6 +377,8 @@
 
 /**
  * \brief               This function initializes a \p cipher_context as NONE.
+ *
+ * \param ctx           The context to be initialized. This must not be \c NULL.
  */
 void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx );
 
@@ -383,6 +386,9 @@
  * \brief               This function frees and clears the cipher-specific
  *                      context of \p ctx. Freeing \p ctx itself remains the
  *                      responsibility of the caller.
+ *
+ * \param ctx           The context to be freed. If this is \c NULL, the
+ *                      function has no effect.
  */
 void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx );
 
@@ -392,8 +398,8 @@
  *                      structure with the appropriate values. It also clears
  *                      the structure.
  *
- * \param ctx           The context to initialize. May not be NULL.
- * \param cipher_info   The cipher to use.
+ * \param ctx           The context to initialize. This must be initialized.
+ * \param cipher_info   The cipher to use. This may not be \c NULL.
  *
  * \return              \c 0 on success.
  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
@@ -405,17 +411,19 @@
  * In future versions, the caller will be required to call
  * mbedtls_cipher_init() on the structure first.
  */
-int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info );
+int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx,
+                          const mbedtls_cipher_info_t *cipher_info );
 
 /**
  * \brief        This function returns the block size of the given cipher.
  *
- * \param ctx    The context of the cipher. Must be initialized.
+ * \param ctx    The context of the cipher. This must be initialized.
  *
  * \return       The size of the blocks of the cipher.
  * \return       0 if \p ctx has not been initialized.
  */
-static inline unsigned int mbedtls_cipher_get_block_size( const mbedtls_cipher_context_t *ctx )
+static inline unsigned int mbedtls_cipher_get_block_size(
+    const mbedtls_cipher_context_t *ctx )
 {
     if( NULL == ctx || NULL == ctx->cipher_info )
         return 0;
@@ -427,12 +435,13 @@
  * \brief        This function returns the mode of operation for
  *               the cipher. For example, MBEDTLS_MODE_CBC.
  *
- * \param ctx    The context of the cipher. Must be initialized.
+ * \param ctx    The context of the cipher. This must be initialized.
  *
  * \return       The mode of operation.
  * \return       #MBEDTLS_MODE_NONE if \p ctx has not been initialized.
  */
-static inline mbedtls_cipher_mode_t mbedtls_cipher_get_cipher_mode( const mbedtls_cipher_context_t *ctx )
+static inline mbedtls_cipher_mode_t mbedtls_cipher_get_cipher_mode(
+    const mbedtls_cipher_context_t *ctx )
 {
     if( NULL == ctx || NULL == ctx->cipher_info )
         return MBEDTLS_MODE_NONE;
@@ -444,13 +453,14 @@
  * \brief       This function returns the size of the IV or nonce
  *              of the cipher, in Bytes.
  *
- * \param ctx   The context of the cipher. Must be initialized.
+ * \param ctx   The context of the cipher. This must be initialized.
  *
  * \return      The recommended IV size if no IV has been set.
  * \return      \c 0 for ciphers not using an IV or a nonce.
  * \return      The actual size if an IV has been set.
  */
-static inline int mbedtls_cipher_get_iv_size( const mbedtls_cipher_context_t *ctx )
+static inline int mbedtls_cipher_get_iv_size(
+    const mbedtls_cipher_context_t *ctx )
 {
     if( NULL == ctx || NULL == ctx->cipher_info )
         return 0;
@@ -464,12 +474,13 @@
 /**
  * \brief               This function returns the type of the given cipher.
  *
- * \param ctx           The context of the cipher. Must be initialized.
+ * \param ctx           The context of the cipher. This must be initialized.
  *
  * \return              The type of the cipher.
  * \return              #MBEDTLS_CIPHER_NONE if \p ctx has not been initialized.
  */
-static inline mbedtls_cipher_type_t mbedtls_cipher_get_type( const mbedtls_cipher_context_t *ctx )
+static inline mbedtls_cipher_type_t mbedtls_cipher_get_type(
+    const mbedtls_cipher_context_t *ctx )
 {
     if( NULL == ctx || NULL == ctx->cipher_info )
         return MBEDTLS_CIPHER_NONE;
@@ -481,12 +492,13 @@
  * \brief               This function returns the name of the given cipher
  *                      as a string.
  *
- * \param ctx           The context of the cipher. Must be initialized.
+ * \param ctx           The context of the cipher. This must be initialized.
  *
  * \return              The name of the cipher.
  * \return              NULL if \p ctx has not been not initialized.
  */
-static inline const char *mbedtls_cipher_get_name( const mbedtls_cipher_context_t *ctx )
+static inline const char *mbedtls_cipher_get_name(
+    const mbedtls_cipher_context_t *ctx )
 {
     if( NULL == ctx || NULL == ctx->cipher_info )
         return 0;
@@ -497,13 +509,14 @@
 /**
  * \brief               This function returns the key length of the cipher.
  *
- * \param ctx           The context of the cipher. Must be initialized.
+ * \param ctx           The context of the cipher. This must be initialized.
  *
  * \return              The key length of the cipher in bits.
  * \return              #MBEDTLS_KEY_LENGTH_NONE if ctx \p has not been
  *                      initialized.
  */
-static inline int mbedtls_cipher_get_key_bitlen( const mbedtls_cipher_context_t *ctx )
+static inline int mbedtls_cipher_get_key_bitlen(
+    const mbedtls_cipher_context_t *ctx )
 {
     if( NULL == ctx || NULL == ctx->cipher_info )
         return MBEDTLS_KEY_LENGTH_NONE;
@@ -514,12 +527,13 @@
 /**
  * \brief          This function returns the operation of the given cipher.
  *
- * \param ctx      The context of the cipher. Must be initialized.
+ * \param ctx      The context of the cipher. This must be initialized.
  *
  * \return         The type of operation: #MBEDTLS_ENCRYPT or #MBEDTLS_DECRYPT.
  * \return         #MBEDTLS_OPERATION_NONE if \p ctx has not been initialized.
  */
-static inline mbedtls_operation_t mbedtls_cipher_get_operation( const mbedtls_cipher_context_t *ctx )
+static inline mbedtls_operation_t mbedtls_cipher_get_operation(
+    const mbedtls_cipher_context_t *ctx )
 {
     if( NULL == ctx || NULL == ctx->cipher_info )
         return MBEDTLS_OPERATION_NONE;
@@ -530,11 +544,12 @@
 /**
  * \brief               This function sets the key to use with the given context.
  *
- * \param ctx           The generic cipher context. May not be NULL. Must have
- *                      been initialized using mbedtls_cipher_info_from_type()
- *                      or mbedtls_cipher_info_from_string().
- * \param key           The key to use.
- * \param key_bitlen    The key length to use, in bits.
+ * \param ctx           The generic cipher context. This must be initialized
+ *                      using mbedtls_cipher_info_from_type() or
+ *                      mbedtls_cipher_info_from_string().
+ * \param key           The key to use. This must be a readable buffer of at
+ *                      least \p key_bitlen Bits.
+ * \param key_bitlen    The key length to use, in Bits.
  * \param operation     The operation that the key will be used for:
  *                      #MBEDTLS_ENCRYPT or #MBEDTLS_DECRYPT.
  *
@@ -543,8 +558,10 @@
  *                      parameter-verification failure.
  * \return              A cipher-specific error code on failure.
  */
-int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, const unsigned char *key,
-                   int key_bitlen, const mbedtls_operation_t operation );
+int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx,
+                           const unsigned char *key,
+                           int key_bitlen,
+                           const mbedtls_operation_t operation );
 
 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
 /**
@@ -553,7 +570,7 @@
  *
  *                      The default passing mode is PKCS7 padding.
  *
- * \param ctx           The generic cipher context.
+ * \param ctx           The generic cipher context. This must be initialized.
  * \param mode          The padding mode.
  *
  * \return              \c 0 on success.
@@ -562,7 +579,8 @@
  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode
  *                      does not support padding.
  */
-int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t mode );
+int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx,
+                                     mbedtls_cipher_padding_t mode );
 #endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
 
 /**
@@ -572,8 +590,9 @@
  * \note            Some ciphers do not use IVs nor nonce. For these
  *                  ciphers, this function has no effect.
  *
- * \param ctx       The generic cipher context.
- * \param iv        The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ * \param ctx       The generic cipher context. This must be initialized.
+ * \param iv        The IV to use, or NONCE_COUNTER for CTR-mode ciphers. This
+ *                  must be a readable buffer of at least \p iv_len Bytes.
  * \param iv_len    The IV length for ciphers with variable-size IV.
  *                  This parameter is discarded by ciphers with fixed-size IV.
  *
@@ -582,12 +601,13 @@
  *                  parameter-verification failure.
  */
 int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx,
-                   const unsigned char *iv, size_t iv_len );
+                           const unsigned char *iv,
+                           size_t iv_len );
 
 /**
  * \brief         This function resets the cipher state.
  *
- * \param ctx     The generic cipher context.
+ * \param ctx     The generic cipher context. This must be initialized.
  *
  * \return        \c 0 on success.
  * \return        #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
@@ -599,10 +619,12 @@
 /**
  * \brief               This function adds additional data for AEAD ciphers.
  *                      Currently supported with GCM and ChaCha20+Poly1305.
- *                      Must be called exactly once, after mbedtls_cipher_reset().
+ *                      This must be called exactly once, after
+ *                      mbedtls_cipher_reset().
  *
- * \param ctx           The generic cipher context.
- * \param ad            The additional data to use.
+ * \param ctx           The generic cipher context. This must be initialized.
+ * \param ad            The additional data to use. If `ad_len > 0`, then this
+ *                      must be a readable buffer of at least \p ad_len Bytes.
  * \param ad_len        the Length of \p ad.
  *
  * \return              \c 0 on success.
@@ -627,14 +649,16 @@
  *                      mbedtls_cipher_finish(), must have \p ilen as a
  *                      multiple of the block size of the cipher.
  *
- * \param ctx           The generic cipher context.
- * \param input         The buffer holding the input data.
+ * \param ctx           The generic cipher context. This must be initialized.
+ * \param input         The buffer holding the input data. This must be a
+ *                      readable buffer of at least \p ilen Bytes.
  * \param ilen          The length of the input data.
- * \param output        The buffer for the output data. Must be able to hold at
- *                      least \p ilen + block_size. Must not be the same buffer
- *                      as input.
+ * \param output        The buffer for the output data. This must be able to
+ *                      hold at least \p ilen + block_size. This must not be the
+ *                      same buffer as \p input.
  * \param olen          The length of the output data, to be updated with the
- *                      actual number of Bytes written.
+ *                      actual number of Bytes written. This must not be
+ *                      \c NULL.
  *
  * \return              \c 0 on success.
  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
@@ -652,9 +676,11 @@
  *                      contained in it is padded to the size of
  *                      the last block, and written to the \p output buffer.
  *
- * \param ctx           The generic cipher context.
- * \param output        The buffer to write data to. Needs block_size available.
+ * \param ctx           The generic cipher context. This must be initialized.
+ * \param output        The buffer to write data to. This needs to be a writable
+ *                      buffer of at least \p block_size Bytes.
  * \param olen          The length of the data written to the \p output buffer.
+ *                      This may not be \c NULL.
  *
  * \return              \c 0 on success.
  * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
@@ -672,10 +698,11 @@
 /**
  * \brief               This function writes a tag for AEAD ciphers.
  *                      Currently supported with GCM and ChaCha20+Poly1305.
- *                      Must be called after mbedtls_cipher_finish().
+ *                      This must be called after mbedtls_cipher_finish().
  *
- * \param ctx           The generic cipher context.
- * \param tag           The buffer to write the tag to.
+ * \param ctx           The generic cipher context. This must be initialized.
+ * \param tag           The buffer to write the tag to. This must be a readable
+ *                      boffer of at least \p tag_len Bytes.
  * \param tag_len       The length of the tag to write.
  *
  * \return              \c 0 on success.
@@ -687,10 +714,11 @@
 /**
  * \brief               This function checks the tag for AEAD ciphers.
  *                      Currently supported with GCM and ChaCha20+Poly1305.
- *                      Must be called after mbedtls_cipher_finish().
+ *                      This must be called after mbedtls_cipher_finish().
  *
- * \param ctx           The generic cipher context.
- * \param tag           The buffer holding the tag.
+ * \param ctx           The generic cipher context. This must be initialized.
+ * \param tag           The buffer holding the tag. This must be a readable
+ *                      buffer of at least \p tag_len Bytes.
  * \param tag_len       The length of the tag to check.
  *
  * \return              \c 0 on success.
@@ -704,18 +732,22 @@
  * \brief               The generic all-in-one encryption/decryption function,
  *                      for all ciphers except AEAD constructs.
  *
- * \param ctx           The generic cipher context.
+ * \param ctx           The generic cipher context. This must be initialized.
  * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ *                      If `iv_len > 0`, this must be a readable buffer of at
+ *                      least \p Bytes.
  * \param iv_len        The IV length for ciphers with variable-size IV.
  *                      This parameter is discarded by ciphers with fixed-size
  *                      IV.
- * \param input         The buffer holding the input data.
+ * \param input         The buffer holding the input data. This must be a
+ *                      readable buffer of at least \p ilen Bytes.
  * \param ilen          The length of the input data.
- * \param output        The buffer for the output data. Must be able to hold at
- *                      least \p ilen + block_size. Must not be the same buffer
- *                      as input.
+ * \param output        The buffer for the output data. This must be able to
+ *                      hold at least \p ilen + block_size. This must not be the
+ *                      same buffer as \p input.
  * \param olen          The length of the output data, to be updated with the
- *                      actual number of Bytes written.
+ *                      actual number of Bytes written. This must not be
+ *                      \c NULL.
  *
  * \note                Some ciphers do not use IVs nor nonce. For these
  *                      ciphers, use \p iv = NULL and \p iv_len = 0.
@@ -738,19 +770,26 @@
 /**
  * \brief               The generic autenticated encryption (AEAD) function.
  *
- * \param ctx           The generic cipher context.
+ * \param ctx           The generic cipher context. This must be initialized.
  * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ *                      This must be a readable buffer of at least \p iv_len
+ *                      Bytes.
  * \param iv_len        The IV length for ciphers with variable-size IV.
  *                      This parameter is discarded by ciphers with fixed-size IV.
- * \param ad            The additional data to authenticate.
+ * \param ad            The additional data to authenticate. If `ad_len > 0`,
+ *                      this must be a readable buffer of at least \p ad_len
+ *                      Bytes.
  * \param ad_len        The length of \p ad.
- * \param input         The buffer holding the input data.
+ * \param input         The buffer holding the input data. This must be a
+ *                      readable buffer of at least \p ilen Bytes.
  * \param ilen          The length of the input data.
- * \param output        The buffer for the output data.
- *                      Must be able to hold at least \p ilen.
+ * \param output        The buffer for the output data. This must be able to
+ *                      hold at least \p ilen.
  * \param olen          The length of the output data, to be updated with the
- *                      actual number of Bytes written.
- * \param tag           The buffer for the authentication tag.
+ *                      actual number of Bytes written. This must not be
+ *                      \c NULL.
+ * \param tag           The buffer for the authentication tag. This must be a
+ *                      writable buffer of at least \p tag_len Bytes.
  * \param tag_len       The desired length of the authentication tag.
  *
  * \return              \c 0 on success.
@@ -772,19 +811,26 @@
  *                      is zeroed out to prevent the unauthentic plaintext being
  *                      used, making this interface safer.
  *
- * \param ctx           The generic cipher context.
+ * \param ctx           The generic cipher context. This must be initialized.
  * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
+ *                      This must be a readable buffer of at least \p iv_len
+ *                      Bytes.
  * \param iv_len        The IV length for ciphers with variable-size IV.
  *                      This parameter is discarded by ciphers with fixed-size IV.
- * \param ad            The additional data to be authenticated.
+ * \param ad            The additional data to be authenticated. If `ad_len > 0`,
+ *                      this must be a readable buffer of at least \p ad_len
+ *                      Bytes.
  * \param ad_len        The length of \p ad.
- * \param input         The buffer holding the input data.
+ * \param input         The buffer holding the input data. This must be a
+ *                      readable buffer of at least \p ilen Bytes.
  * \param ilen          The length of the input data.
  * \param output        The buffer for the output data.
- *                      Must be able to hold at least \p ilen.
+ *                      This must be able to hold at least \p ilen Bytes.
  * \param olen          The length of the output data, to be updated with the
- *                      actual number of Bytes written.
- * \param tag           The buffer holding the authentication tag.
+ *                      actual number of Bytes written. This must not be
+ *                      \c NULL.
+ * \param tag           The buffer holding the authentication tag. This must be
+ *                      a readable buffer of at least \p tag_len Bytes.
  * \param tag_len       The length of the authentication tag.
  *
  * \return              \c 0 on success.
diff --git a/library/cipher.c b/library/cipher.c
index d7acf34..d2078f6 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -65,6 +65,11 @@
 #define mbedtls_free   free
 #endif
 
+#define CIPHER_VALIDATE_RET( cond )    \
+    MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA )
+#define CIPHER_VALIDATE( cond )        \
+    MBEDTLS_INTERNAL_VALIDATE( cond )
+
 #if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CHACHAPOLY_C)
 /* Compare the contents of two buffers in constant time.
  * Returns 0 if the contents are bitwise identical, otherwise returns
@@ -150,6 +155,7 @@
 
 void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx )
 {
+    CIPHER_VALIDATE( ctx != NULL );
     memset( ctx, 0, sizeof( mbedtls_cipher_context_t ) );
 }
 
@@ -199,9 +205,14 @@
     return( 0 );
 }
 
-int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, const unsigned char *key,
-        int key_bitlen, const mbedtls_operation_t operation )
+int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx,
+                           const unsigned char *key,
+                           int key_bitlen,
+                           const mbedtls_operation_t operation )
 {
+    CIPHER_VALIDATE_RET( operation == MBEDTLS_ENCRYPT ||
+                         operation == MBEDTLS_DECRYPT );
+
     if( NULL == ctx || NULL == ctx->cipher_info )
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
@@ -234,9 +245,11 @@
 }
 
 int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx,
-                   const unsigned char *iv, size_t iv_len )
+                           const unsigned char *iv,
+                           size_t iv_len )
 {
     size_t actual_iv_size;
+
     if( NULL == ctx || NULL == ctx->cipher_info )
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
     else if( NULL == iv && iv_len != 0  )
@@ -295,6 +308,8 @@
 int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx,
                       const unsigned char *ad, size_t ad_len )
 {
+    CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL );
+
     if( NULL == ctx || NULL == ctx->cipher_info )
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
@@ -335,9 +350,13 @@
                    size_t ilen, unsigned char *output, size_t *olen )
 {
     int ret;
-    size_t block_size = 0;
+    size_t block_size;
 
-    if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
+    CIPHER_VALIDATE_RET( input != NULL );
+    CIPHER_VALIDATE_RET( output != NULL );
+    CIPHER_VALIDATE_RET( olen != NULL );
+
+    if( NULL == ctx || NULL == ctx->cipher_info )
     {
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
     }
@@ -745,7 +764,10 @@
 int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx,
                    unsigned char *output, size_t *olen )
 {
-    if( NULL == ctx || NULL == ctx->cipher_info || NULL == olen )
+    CIPHER_VALIDATE_RET( output != NULL );
+    CIPHER_VALIDATE_RET( olen != NULL );
+
+    if( NULL == ctx || NULL == ctx->cipher_info )
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     *olen = 0;
@@ -830,10 +852,13 @@
 }
 
 #if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
-int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t mode )
+int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx,
+                                     mbedtls_cipher_padding_t mode )
 {
-    if( NULL == ctx ||
-        MBEDTLS_MODE_CBC != ctx->cipher_info->mode )
+    CIPHER_VALIDATE_RET( ctx != NULL );
+    CIPHER_VALIDATE_RET( ctx->cipher_info != NULL );
+
+    if( MBEDTLS_MODE_CBC != ctx->cipher_info->mode )
     {
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
     }
@@ -881,7 +906,9 @@
 int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx,
                       unsigned char *tag, size_t tag_len )
 {
-    if( NULL == ctx || NULL == ctx->cipher_info || NULL == tag )
+    CIPHER_VALIDATE_RET( tag != NULL );
+
+    if( NULL == ctx || NULL == ctx->cipher_info )
         return( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA );
 
     if( MBEDTLS_ENCRYPT != ctx->operation )
@@ -913,6 +940,8 @@
     unsigned char check_tag[16];
     int ret;
 
+    CIPHER_VALIDATE_RET( tag != NULL );
+
     if( NULL == ctx || NULL == ctx->cipher_info ||
         MBEDTLS_DECRYPT != ctx->operation )
     {
@@ -976,6 +1005,13 @@
     int ret;
     size_t finish_olen;
 
+    CIPHER_VALIDATE_RET( ctx != NULL );
+    CIPHER_VALIDATE_RET( ctx->cipher_info != NULL );
+    CIPHER_VALIDATE_RET( iv_len == 0 || iv != NULL );
+    CIPHER_VALIDATE_RET( input != NULL );
+    CIPHER_VALIDATE_RET( output != NULL );
+    CIPHER_VALIDATE_RET( olen != NULL );
+
     if( ( ret = mbedtls_cipher_set_iv( ctx, iv, iv_len ) ) != 0 )
         return( ret );
 
@@ -1004,6 +1040,15 @@
                          unsigned char *output, size_t *olen,
                          unsigned char *tag, size_t tag_len )
 {
+    CIPHER_VALIDATE_RET( ctx != NULL );
+    CIPHER_VALIDATE_RET( ctx->cipher_info != NULL );
+    CIPHER_VALIDATE_RET( iv != NULL );
+    CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL );
+    CIPHER_VALIDATE_RET( input != NULL );
+    CIPHER_VALIDATE_RET( output != NULL );
+    CIPHER_VALIDATE_RET( olen != NULL );
+    CIPHER_VALIDATE_RET( tag != NULL );
+
 #if defined(MBEDTLS_GCM_C)
     if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
     {
@@ -1051,6 +1096,15 @@
                          unsigned char *output, size_t *olen,
                          const unsigned char *tag, size_t tag_len )
 {
+    CIPHER_VALIDATE_RET( ctx != NULL );
+    CIPHER_VALIDATE_RET( ctx->cipher_info != NULL );
+    CIPHER_VALIDATE_RET( iv != NULL );
+    CIPHER_VALIDATE_RET( ad_len == 0 || ad != NULL );
+    CIPHER_VALIDATE_RET( input != NULL );
+    CIPHER_VALIDATE_RET( output != NULL );
+    CIPHER_VALIDATE_RET( olen != NULL );
+    CIPHER_VALIDATE_RET( tag != NULL );
+
 #if defined(MBEDTLS_GCM_C)
     if( MBEDTLS_MODE_GCM == ctx->cipher_info->mode )
     {
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 58126be..d7a1442 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -72,6 +72,7 @@
 add_test_suite(cipher cipher.chachapoly)
 add_test_suite(cipher cipher.des)
 add_test_suite(cipher cipher.gcm)
+add_test_suite(cipher cipher.misc)
 add_test_suite(cipher cipher.null)
 add_test_suite(cipher cipher.padding)
 add_test_suite(cmac)
diff --git a/tests/suites/test_suite_cipher.function b/tests/suites/test_suite_cipher.function
index c5bce7e..3d559a3 100644
--- a/tests/suites/test_suite_cipher.function
+++ b/tests/suites/test_suite_cipher.function
@@ -91,6 +91,264 @@
 }
 /* END_CASE */
 
+/* BEGIN_CASE depends_on:MBEDTLS_CHECK_PARAMS:!MBEDTLS_PARAM_FAILED_ALT */
+void cipher_invalid_param( )
+{
+    mbedtls_cipher_context_t invalid_ctx;
+    mbedtls_cipher_context_t valid_ctx;
+
+    mbedtls_operation_t invalid_operation = 100;
+    mbedtls_cipher_padding_t valid_mode = MBEDTLS_PADDING_ZEROS;
+    unsigned char valid_buffer[] = { 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07 };
+    int valid_size = sizeof(valid_buffer);
+    int valid_bitlen = valid_size * 8;
+    size_t size_t_var;
+
+    /* mbedtls_cipher_init() */
+    TEST_VALID_PARAM( mbedtls_cipher_init( &invalid_ctx ) );
+    TEST_VALID_PARAM( mbedtls_cipher_init( &valid_ctx ) );
+
+    TEST_INVALID_PARAM( mbedtls_cipher_init( NULL ) );
+
+    /* mbedtls_cipher_setkey() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_setkey( &valid_ctx,
+                               valid_buffer,
+                               valid_bitlen,
+                               invalid_operation ) );
+
+    /* mbedtls_cipher_set_padding_mode() */
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+                            mbedtls_cipher_set_padding_mode( NULL, valid_mode ) );
+    TEST_INVALID_PARAM_RET( MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+                            mbedtls_cipher_set_padding_mode( &invalid_ctx,
+                                                             valid_mode ) );
+
+    /* mbedtls_cipher_update() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_update( &valid_ctx,
+                               NULL, valid_size,
+                               valid_buffer,
+                               &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_update( &valid_ctx,
+                               valid_buffer, valid_size,
+                               NULL,
+                               &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_update( &valid_ctx,
+                               valid_buffer, valid_size,
+                               valid_buffer,
+                               NULL ) );
+
+    /* mbedtls_cipher_finish() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_finish( &valid_ctx,
+                               NULL,
+                               &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_finish( &valid_ctx,
+                               valid_buffer,
+                               NULL ) );
+
+    /* mbedtls_cipher_write_tag() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_write_tag( &valid_ctx,
+                                  NULL,
+                                  valid_size ) );
+
+    /* mbedtls_cipher_check_tag() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_check_tag( &valid_ctx,
+                                  NULL,
+                                  valid_size ) );
+
+    /* mbedtls_cipher_crypt() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_crypt( NULL,
+                              valid_buffer, valid_size,
+                              valid_buffer, valid_size,
+                              valid_buffer, &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_crypt( &invalid_ctx,
+                              valid_buffer, valid_size,
+                              valid_buffer, valid_size,
+                              valid_buffer, &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_crypt( &valid_ctx,
+                              NULL, valid_size,
+                              valid_buffer, valid_size,
+                              valid_buffer, &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_crypt( &valid_ctx,
+                              valid_buffer, valid_size,
+                              NULL, valid_size,
+                              valid_buffer, &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_crypt( &valid_ctx,
+                              valid_buffer, valid_size,
+                              valid_buffer, valid_size,
+                              NULL, &size_t_var ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_crypt( &valid_ctx,
+                              valid_buffer, valid_size,
+                              valid_buffer, valid_size,
+                              valid_buffer, NULL ) );
+
+    /* mbedtls_cipher_auth_encrypt() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( NULL,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( &invalid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( &valid_ctx,
+                                     NULL, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     NULL, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     NULL, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     NULL, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, NULL,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_encrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     NULL, valid_size ) );
+
+    /* mbedtls_cipher_auth_decrypt() */
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( NULL,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( &invalid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( &valid_ctx,
+                                     NULL, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     NULL, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     NULL, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     NULL, &size_t_var,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, NULL,
+                                     valid_buffer, valid_size ) );
+    TEST_INVALID_PARAM_RET(
+        MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA,
+        mbedtls_cipher_auth_decrypt( &valid_ctx,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, valid_size,
+                                     valid_buffer, &size_t_var,
+                                     NULL, valid_size ) );
+
+    /* mbedtls_cipher_free() */
+    TEST_VALID_PARAM( mbedtls_cipher_free( NULL ) );
+exit:
+    TEST_VALID_PARAM( mbedtls_cipher_free( &invalid_ctx ) );
+    TEST_VALID_PARAM( mbedtls_cipher_free( &valid_ctx ) );
+}
+/* END_CASE */
+
 /* BEGIN_CASE depends_on:MBEDTLS_AES_C */
 void cipher_special_behaviours(  )
 {
diff --git a/tests/suites/test_suite_cipher.misc.data b/tests/suites/test_suite_cipher.misc.data
new file mode 100644
index 0000000..4ef257f
--- /dev/null
+++ b/tests/suites/test_suite_cipher.misc.data
@@ -0,0 +1,2 @@
+CIPHER - Invalid parameters
+cipher_invalid_param:
\ No newline at end of file