diff --git a/include/mbedtls/asn1.h b/include/mbedtls/asn1.h index ab947ab7ef..6891bb9c31 100644 --- a/include/mbedtls/asn1.h +++ b/include/mbedtls/asn1.h @@ -176,119 +176,203 @@ mbedtls_asn1_named_data; * \brief Get the length of an ASN.1 element. * Updates the pointer to immediately behind the length. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param len The variable that will receive the value + * \param p On entry, \c *p points to the first byte of the length, + * i.e. immediately after the tag. + * On successful completion, \c *p points to the first byte + * after the length, i.e. the first byte of the content. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param len On successful completion, \c *len contains the lengtth + * read from the ASN.1 input. * - * \return 0 if successful, MBEDTLS_ERR_ASN1_OUT_OF_DATA on reaching - * end of data, MBEDTLS_ERR_ASN1_INVALID_LENGTH if length is - * unparseable. + * \return 0 if successful. + * \return #MBEDTLS_ERR_ASN1_OUT_OF_DATA if the ASN.1 element + * would end beyond \p end. + * \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the length is unparseable. */ int mbedtls_asn1_get_len( unsigned char **p, - const unsigned char *end, - size_t *len ); + const unsigned char *end, + size_t *len ); /** - * \brief Get the tag and length of the tag. Check for the requested tag. + * \brief Get the tag and length of the element. + * Check for the requested tag. * Updates the pointer to immediately behind the tag and length. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param len The variable that will receive the length - * \param tag The expected tag + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p points to the first byte + * after the length, i.e. the first byte of the content. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param len On successful completion, \c *len contains the lengtth + * read from the ASN.1 input. + * \param tag The expected tag. * - * \return 0 if successful, MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if tag did - * not match requested tag, or another specific ASN.1 error code. + * \return 0 if successful. + * \return #MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if the data does not start + * with the requested tag. + * \return #MBEDTLS_ERR_ASN1_OUT_OF_DATA if the ASN.1 element + * would end beyond \p end. + * \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the length is unparseable. */ int mbedtls_asn1_get_tag( unsigned char **p, - const unsigned char *end, - size_t *len, int tag ); + const unsigned char *end, + size_t *len, int tag ); /** * \brief Retrieve a boolean ASN.1 tag and its value. * Updates the pointer to immediately behind the full tag. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param val The variable that will receive the value + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p points to the first byte + * beyond the ASN.1 element. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param val On success, the parsed value (\c 0 or \c 1). * - * \return 0 if successful or a specific ASN.1 error code. + * \return 0 if successful. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 BOOLEAN. */ int mbedtls_asn1_get_bool( unsigned char **p, - const unsigned char *end, - int *val ); + const unsigned char *end, + int *val ); /** * \brief Retrieve an integer ASN.1 tag and its value. * Updates the pointer to immediately behind the full tag. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param val The variable that will receive the value + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p points to the first byte + * beyond the ASN.1 element. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param val On success, the parsed value. * - * \return 0 if successful or a specific ASN.1 error code. + * \return 0 if successful. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 INTEGER. + * \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the parsed value does + * not fit in an \c int. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 INTEGER. */ int mbedtls_asn1_get_int( unsigned char **p, - const unsigned char *end, - int *val ); + const unsigned char *end, + int *val ); /** * \brief Retrieve a bitstring ASN.1 tag and its value. * Updates the pointer to immediately behind the full tag. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param bs The variable that will receive the value + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p is equal to \p end. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param bs On success, ::mbedtls_asn1_bitstring information about + * the parsed value. * - * \return 0 if successful or a specific ASN.1 error code. + * \return 0 if successful. + * \return #MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input contains + * extra data after a valid BIT STRING. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 BIT STRING. */ int mbedtls_asn1_get_bitstring( unsigned char **p, const unsigned char *end, - mbedtls_asn1_bitstring *bs); + mbedtls_asn1_bitstring *bs ); /** * \brief Retrieve a bitstring ASN.1 tag without unused bits and its * value. * Updates the pointer to the beginning of the bit/octet string. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param len Length of the actual bit/octect string in bytes + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p points to the first byte + * of the content of the BIT STRING. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param len On success, \c *len is the length of the content in bytes. * - * \return 0 if successful or a specific ASN.1 error code. + * \return 0 if successful. + * \return #MBEDTLS_ERR_ASN1_INVALID_DATA if the input starts with + * a valid BIT STRING with a nonzero number of unused bits. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 BIT STRING. */ -int mbedtls_asn1_get_bitstring_null( unsigned char **p, const unsigned char *end, - size_t *len ); +int mbedtls_asn1_get_bitstring_null( unsigned char **p, + const unsigned char *end, + size_t *len ); /** * \brief Parses and splits an ASN.1 "SEQUENCE OF " * Updated the pointer to immediately behind the full sequence tag. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param cur First variable in the chain to fill - * \param tag Type of sequence + * \note On error, this function may return a partial list in \p cur. + * You must set `cur->next = NULL` before calling this function! + * Otherwise it is impossible to distinguish a previously non-null + * pointer from a pointer to an object allocated by this function. * - * \return 0 if successful or a specific ASN.1 error code. + * \note If the sequence is empty, this function does not modify + * \c *cur. If the sequence is valid and non-empty, this + * function sets `cur->buf.tag` to \p tag. This allows + * callers to distinguish between an empty sequence and + * a one-element sequence. + * + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p is equal to \p end. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param cur A ::mbedtls_asn1_sequence which this function fills. + * When this function returns, \c *cur is the head of a linked + * list. Each node in this list is allocated with + * mbedtls_calloc() apart from \p cur itself, and should + * therefore be freed with mbedtls_free(). + * The list describes the content of the sequence. + * The head of the list (i.e. \c *cur itself) describes the + * first element, `*cur->next` describes the second element, etc. + * For each element, `buf.tag == tag`, `buf.len` is the length + * of the content of the content of the element, and `buf.p` + * points to the first byte of the content (i.e. immediately + * past the length of the element). + * Note that list elements may be allocated even on error. + * \param tag Each element of the sequence must have this tag. + * + * \return 0 if successful. + * \return #MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input contains + * extra data after a valid SEQUENCE OF \p tag. + * \return #MBEDTLS_ERR_ASN1_ALLOC_FAILED if a memory allocation failed. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 BIT STRING. */ int mbedtls_asn1_get_sequence_of( unsigned char **p, - const unsigned char *end, - mbedtls_asn1_sequence *cur, - int tag); + const unsigned char *end, + mbedtls_asn1_sequence *cur, + int tag ); #if defined(MBEDTLS_BIGNUM_C) /** - * \brief Retrieve a MPI value from an integer ASN.1 tag. + * \brief Retrieve an integer ASN.1 tag and its value. * Updates the pointer to immediately behind the full tag. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param X The MPI that will receive the value + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p points to the first byte + * beyond the ASN.1 element. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param X On success, the parsed value. * - * \return 0 if successful or a specific ASN.1 or MPI error code. + * \return 0 if successful. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 INTEGER. + * \return #MBEDTLS_ERR_ASN1_INVALID_LENGTH if the parsed value does + * not fit in an \c int. + * \return An MPI error code if the parsed value is too large. + * \return An ASN.1 error code if the input does not start with + * a valid ASN.1 INTEGER. */ int mbedtls_asn1_get_mpi( unsigned char **p, - const unsigned char *end, - mbedtls_mpi *X ); + const unsigned char *end, + mbedtls_mpi *X ); #endif /* MBEDTLS_BIGNUM_C */ /** @@ -296,10 +380,14 @@ int mbedtls_asn1_get_mpi( unsigned char **p, * Updates the pointer to immediately behind the full * AlgorithmIdentifier. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param alg The buffer to receive the OID - * \param params The buffer to receive the params (if any) + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p points to the first byte + * beyond the AlgorithmIdentifier element. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param alg The buffer to receive the OID. + * \param params The buffer to receive the parameters. + * This is zeroized if there are no parameters. * * \return 0 if successful or a specific ASN.1 or MPI error code. */ @@ -313,9 +401,12 @@ int mbedtls_asn1_get_alg( unsigned char **p, * Updates the pointer to immediately behind the full * AlgorithmIdentifier. * - * \param p The position in the ASN.1 data - * \param end End of data - * \param alg The buffer to receive the OID + * \param p On entry, \c *p points to the start of the ASN.1 element. + * On successful completion, \c *p points to the first byte + * beyond the AlgorithmIdentifier element. + * On error, the value of \c *p is undefined. + * \param end End of data. + * \param alg The buffer to receive the OID. * * \return 0 if successful or a specific ASN.1 or MPI error code. */ @@ -339,15 +430,19 @@ mbedtls_asn1_named_data *mbedtls_asn1_find_named_data( mbedtls_asn1_named_data * /** * \brief Free a mbedtls_asn1_named_data entry * - * \param entry The named data entry to free + * \param entry The named data entry to free. + * This function calls mbedtls_free() on + * `entry->oid.p` and `entry->val.p`. */ void mbedtls_asn1_free_named_data( mbedtls_asn1_named_data *entry ); /** - * \brief Free all entries in a mbedtls_asn1_named_data list - * Head will be set to NULL + * \brief Free all entries in a mbedtls_asn1_named_data list. * - * \param head Pointer to the head of the list of named data entries to free + * \param head Pointer to the head of the list of named data entries to free. + * This function calls mbedtls_asn1_free_named_data() and + * mbedtls_free() on each list element and + * sets \c *head to \c NULL. */ void mbedtls_asn1_free_named_data_list( mbedtls_asn1_named_data **head );