Add parameter validation for the GCM module
diff --git a/include/mbedtls/gcm.h b/include/mbedtls/gcm.h
index 93d15ee..f68643d 100644
--- a/include/mbedtls/gcm.h
+++ b/include/mbedtls/gcm.h
@@ -85,7 +85,7 @@
* cipher, nor set the key. For this purpose, use
* mbedtls_gcm_setkey().
*
- * \param ctx The GCM context to initialize.
+ * \param ctx The GCM context to initialize. This must not be \c NULL.
*/
void mbedtls_gcm_init( mbedtls_gcm_context *ctx );
@@ -93,9 +93,10 @@
* \brief This function associates a GCM context with a
* cipher algorithm and a key.
*
- * \param ctx The GCM context to initialize.
+ * \param ctx The GCM context. This must be initialized.
* \param cipher The 128-bit block cipher to use.
- * \param key The encryption key.
+ * \param key The encryption key. This must be a readable buffer of at
+ * least \p keybits bits.
* \param keybits The key size in bits. Valid options are:
* <ul><li>128 bits</li>
* <li>192 bits</li>
@@ -122,7 +123,8 @@
* authentic. You should use this function to perform encryption
* only. For decryption, use mbedtls_gcm_auth_decrypt() instead.
*
- * \param ctx The GCM context to use for encryption or decryption.
+ * \param ctx The GCM context to use for encryption or decryption. This
+ * must be initialized.
* \param mode The operation to perform:
* - #MBEDTLS_GCM_ENCRYPT to perform authenticated encryption.
* The ciphertext is written to \p output and the
@@ -136,21 +138,28 @@
* calling this function in decryption mode.
* \param length The length of the input data, which is equal to the length
* of the output data.
- * \param iv The initialization vector.
+ * \param iv The initialization vector. This must be a readable buffer of
+ * at least \p iv_len Bytes.
* \param iv_len The length of the IV.
- * \param add The buffer holding the additional data.
+ * \param add The buffer holding the additional data. If \p add_len is
+ * greater than zero, this must be of at least that size in
+ * Bytes.
* \param add_len The length of the additional data.
- * \param input The buffer holding the input data. Its size is \b length.
- * \param output The buffer for holding the output data. It must have room
- * for \b length bytes.
+ * \param input The buffer holding the input data. If \p length is greater
+ * than zero, this must be a readable buffer of at least that
+ * size in Bytes.
+ * \param output The buffer for holding the output data. If \p length is greater
+ * than zero, this must be a writable buffer of at least that
+ * size in Bytes.
* \param tag_len The length of the tag to generate.
- * \param tag The buffer for holding the tag.
+ * \param tag The buffer for holding the tag. This must be a readable
+ * buffer of at least \p tag_len Bytes.
*
* \return \c 0 if the encryption or decryption was performed
* successfully. Note that in #MBEDTLS_GCM_DECRYPT mode,
* this does not indicate that the data is authentic.
- * \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths are not valid or
- * a cipher-specific error code if the encryption
+ * \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths or pointers are
+ * not valid or a cipher-specific error code if the encryption
* or decryption failed.
*/
int mbedtls_gcm_crypt_and_tag( mbedtls_gcm_context *ctx,
@@ -173,23 +182,31 @@
* input buffer. If the buffers overlap, the output buffer
* must trail at least 8 Bytes behind the input buffer.
*
- * \param ctx The GCM context.
+ * \param ctx The GCM context. This must be initialized.
* \param length The length of the ciphertext to decrypt, which is also
* the length of the decrypted plaintext.
- * \param iv The initialization vector.
+ * \param iv The initialization vector. This must be a readable buffer
+ * of at least \p iv_len Bytes.
* \param iv_len The length of the IV.
- * \param add The buffer holding the additional data.
+ * \param add The buffer holding the additional data. If \p add_len is
+ * greater than zero, this must be of at least that size in
+ * Bytes.
* \param add_len The length of the additional data.
- * \param tag The buffer holding the tag to verify.
+ * \param tag The buffer holding the tag to verify. This must be a
+ * readable buffer of at least \p tag_len Bytes.
* \param tag_len The length of the tag to verify.
- * \param input The buffer holding the ciphertext. Its size is \b length.
- * \param output The buffer for holding the decrypted plaintext. It must
- * have room for \b length bytes.
+ * \param input The buffer holding the ciphertext. If \p length is greater
+ * than zero, this must be a readable buffer of at least that
+ * size.
+ * \param output The buffer for holding the decrypted plaintext. If \p length
+ * is greater than zero, this must be a writable buffer of at
+ * least that size.
*
* \return \c 0 if successful and authenticated.
* \return #MBEDTLS_ERR_GCM_AUTH_FAILED if the tag does not match.
- * \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths are not valid or
- * a cipher-specific error code if the decryption failed.
+ * \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths or pointers are
+ * not valid or a cipher-specific error code if the decryption
+ * failed.
*/
int mbedtls_gcm_auth_decrypt( mbedtls_gcm_context *ctx,
size_t length,
@@ -206,15 +223,16 @@
* \brief This function starts a GCM encryption or decryption
* operation.
*
- * \param ctx The GCM context.
+ * \param ctx The GCM context. This must be initialized.
* \param mode The operation to perform: #MBEDTLS_GCM_ENCRYPT or
* #MBEDTLS_GCM_DECRYPT.
- * \param iv The initialization vector.
+ * \param iv The initialization vector. This must be a readable buffer of
+ * at least \p iv_len Bytes.
* \param iv_len The length of the IV.
* \param add The buffer holding the additional data, or NULL
* if \p add_len is 0.
* \param add_len The length of the additional data. If 0,
- * \p add is NULL.
+ * \p add may be NULL.
*
* \return \c 0 on success.
*/
@@ -237,11 +255,15 @@
* input buffer. If the buffers overlap, the output buffer
* must trail at least 8 Bytes behind the input buffer.
*
- * \param ctx The GCM context.
+ * \param ctx The GCM context. This must be initialized.
* \param length The length of the input data. This must be a multiple of
* 16 except in the last call before mbedtls_gcm_finish().
- * \param input The buffer holding the input data.
- * \param output The buffer for holding the output data.
+ * \param input The buffer holding the input data. If \p length is greater
+ * than zero, this must be a readable buffer of at least that
+ * size in Bytes.
+ * \param output The buffer for holding the output data. If \p length is
+ * greater than zero, this must be a writable buffer of at
+ * least that size in Bytes.
*
* \return \c 0 on success.
* \return #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
@@ -258,9 +280,11 @@
* It wraps up the GCM stream, and generates the
* tag. The tag can have a maximum length of 16 Bytes.
*
- * \param ctx The GCM context.
- * \param tag The buffer for holding the tag.
- * \param tag_len The length of the tag to generate. Must be at least four.
+ * \param ctx The GCM context. This must be initialized.
+ * \param tag The buffer for 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 generate. This must be at least
+ * four.
*
* \return \c 0 on success.
* \return #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
@@ -273,7 +297,8 @@
* \brief This function clears a GCM context and the underlying
* cipher sub-context.
*
- * \param ctx The GCM context to clear.
+ * \param ctx The GCM context to clear. If this is \c NULL, the call has
+ * no effect.
*/
void mbedtls_gcm_free( mbedtls_gcm_context *ctx );