Asn1_module
Description
Data Structures |
|
struct | mbedtls_asn1_buf |
Type-length-value structure that allows for ASN1 using DER.
|
|
struct | mbedtls_asn1_bitstring |
Container for ASN1 bit strings.
|
|
struct | mbedtls_asn1_sequence |
Container for a sequence of ASN.1 items.
|
|
struct | mbedtls_asn1_named_data |
Container for a sequence or list of 'named' ASN.1 data items.
|
|
Macros |
|
#define | MBEDTLS_OID_SIZE (x) (sizeof(x) - 1) |
Returns the size of the binary string, without the trailing \0.
|
|
#define | MBEDTLS_OID_CMP (oid_str, oid_buf) |
Compares an
mbedtls_asn1_buf
structure to a reference OID.
|
|
#define | MBEDTLS_OID_CMP_RAW (oid_str, oid_buf, oid_buf_len) |
ASN1 Error codes |
|
These error codes are OR'ed to X509 error codes for higher error granularity. ASN1 is a standard to specify data structures. |
|
#define | MBEDTLS_ERR_ASN1_OUT_OF_DATA -0x0060 |
Out of data when parsing an ASN1 data structure.
|
|
#define | MBEDTLS_ERR_ASN1_UNEXPECTED_TAG -0x0062 |
ASN1 tag was of an unexpected value.
|
|
#define | MBEDTLS_ERR_ASN1_INVALID_LENGTH -0x0064 |
Error when trying to determine the length or invalid length.
|
|
#define | MBEDTLS_ERR_ASN1_LENGTH_MISMATCH -0x0066 |
Actual length differs from expected length.
|
|
#define | MBEDTLS_ERR_ASN1_INVALID_DATA -0x0068 |
Data is invalid.
|
|
#define | MBEDTLS_ERR_ASN1_ALLOC_FAILED -0x006A |
Memory allocation failed.
|
|
#define | MBEDTLS_ERR_ASN1_BUF_TOO_SMALL -0x006C |
Buffer too small when writing ASN.1 data structure.
|
|
DER constants |
|
These constants comply with the DER encoded ASN.1 type tags.
DER encoding uses hexadecimal representation. An example DER sequence is:
|
|
#define | MBEDTLS_ASN1_BOOLEAN 0x01 |
#define | MBEDTLS_ASN1_INTEGER 0x02 |
#define | MBEDTLS_ASN1_BIT_STRING 0x03 |
#define | MBEDTLS_ASN1_OCTET_STRING 0x04 |
#define | MBEDTLS_ASN1_NULL 0x05 |
#define | MBEDTLS_ASN1_OID 0x06 |
#define | MBEDTLS_ASN1_ENUMERATED 0x0A |
#define | MBEDTLS_ASN1_UTF8_STRING 0x0C |
#define | MBEDTLS_ASN1_SEQUENCE 0x10 |
#define | MBEDTLS_ASN1_SET 0x11 |
#define | MBEDTLS_ASN1_PRINTABLE_STRING 0x13 |
#define | MBEDTLS_ASN1_T61_STRING 0x14 |
#define | MBEDTLS_ASN1_IA5_STRING 0x16 |
#define | MBEDTLS_ASN1_UTC_TIME 0x17 |
#define | MBEDTLS_ASN1_GENERALIZED_TIME 0x18 |
#define | MBEDTLS_ASN1_UNIVERSAL_STRING 0x1C |
#define | MBEDTLS_ASN1_BMP_STRING 0x1E |
#define | MBEDTLS_ASN1_PRIMITIVE 0x00 |
#define | MBEDTLS_ASN1_CONSTRUCTED 0x20 |
#define | MBEDTLS_ASN1_CONTEXT_SPECIFIC 0x80 |
#define | MBEDTLS_ASN1_IS_STRING_TAG (tag) |
#define | MBEDTLS_ASN1_TAG_CLASS_MASK 0xC0 |
#define | MBEDTLS_ASN1_TAG_PC_MASK 0x20 |
#define | MBEDTLS_ASN1_TAG_VALUE_MASK 0x1F |
Functions to parse ASN.1 data structures |
|
int | mbedtls_asn1_get_len (unsigned char **p, const unsigned char *end, size_t *len) |
Get the length of an ASN.1 element.
|
|
int | mbedtls_asn1_get_tag (unsigned char **p, const unsigned char *end, size_t *len, int tag) |
Get the tag and length of the element.
|
|
int | mbedtls_asn1_get_bool (unsigned char **p, const unsigned char *end, int *val) |
Retrieve a boolean ASN.1 tag and its value.
|
|
int | mbedtls_asn1_get_int (unsigned char **p, const unsigned char *end, int *val) |
Retrieve an integer ASN.1 tag and its value.
|
|
int | mbedtls_asn1_get_enum (unsigned char **p, const unsigned char *end, int *val) |
Retrieve an enumerated ASN.1 tag and its value.
|
|
int | mbedtls_asn1_get_bitstring (unsigned char **p, const unsigned char *end, mbedtls_asn1_bitstring *bs) |
Retrieve a bitstring ASN.1 tag and its value.
|
|
int | mbedtls_asn1_get_bitstring_null (unsigned char **p, const unsigned char *end, size_t *len) |
Retrieve a bitstring ASN.1 tag without unused bits and its value.
|
|
int | mbedtls_asn1_get_sequence_of (unsigned char **p, const unsigned char *end, mbedtls_asn1_sequence *cur, int tag) |
Parses and splits an ASN.1 "SEQUENCE OF <tag>".
|
|
void | mbedtls_asn1_sequence_free ( mbedtls_asn1_sequence *seq) |
Free a heap-allocated linked list presentation of an ASN.1 sequence, including the first element.
|
|
int | mbedtls_asn1_traverse_sequence_of (unsigned char **p, const unsigned char *end, unsigned char tag_must_mask, unsigned char tag_must_val, unsigned char tag_may_mask, unsigned char tag_may_val, int(*cb)(void *ctx, int tag, unsigned char *start, size_t len), void *ctx) |
Traverse an ASN.1 SEQUENCE container and call a callback for each entry.
|
|
int | mbedtls_asn1_get_alg (unsigned char **p, const unsigned char *end, mbedtls_asn1_buf *alg, mbedtls_asn1_buf *params) |
Retrieve an AlgorithmIdentifier ASN.1 sequence.
|
|
int | mbedtls_asn1_get_alg_null (unsigned char **p, const unsigned char *end, mbedtls_asn1_buf *alg) |
Retrieve an AlgorithmIdentifier ASN.1 sequence with NULL or no params.
|
|
const mbedtls_asn1_named_data * | mbedtls_asn1_find_named_data (const mbedtls_asn1_named_data *list, const char *oid, size_t len) |
Find a specific named_data entry in a sequence or list based on the OID.
|
|
void | mbedtls_asn1_free_named_data ( mbedtls_asn1_named_data *entry) |
Free a
mbedtls_asn1_named_data
entry.
|
|
void | mbedtls_asn1_free_named_data_list ( mbedtls_asn1_named_data **head) |
Free all entries in a
mbedtls_asn1_named_data
list.
|
|
Function Documentation
◆ mbedtls_asn1_get_len()
int mbedtls_asn1_get_len | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
size_t * |
len
|
||
) |
Get the length of an ASN.1 element.
Updates the pointer to immediately behind the length.
- Parameters
-
p
On entry, *p
points to the first byte of the length, i.e. immediately after the tag. On successful completion,*p
points to the first byte after the length, i.e. the first byte of the content. On error, the value of*p
is undefined.end
End of data. len
On successful completion, *len
contains the length read from the ASN.1 input.
- Returns
- 0 if successful.
-
MBEDTLS_ERR_ASN1_OUT_OF_DATA
if the ASN.1 element would end beyond
end
. - MBEDTLS_ERR_ASN1_INVALID_LENGTH if the length is unparsable.
◆ mbedtls_asn1_get_tag()
int mbedtls_asn1_get_tag | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
size_t * |
len,
|
||
int |
tag
|
||
) |
Get the tag and length of the element.
Check for the requested tag. Updates the pointer to immediately behind the tag and length.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
points to the first byte after the length, i.e. the first byte of the content. On error, the value of*p
is undefined.end
End of data. len
On successful completion, *len
contains the length read from the ASN.1 input.tag
The expected tag.
- Returns
- 0 if successful.
- MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if the data does not start with the requested tag.
-
MBEDTLS_ERR_ASN1_OUT_OF_DATA
if the ASN.1 element would end beyond
end
. - MBEDTLS_ERR_ASN1_INVALID_LENGTH if the length is unparsable.
◆ mbedtls_asn1_get_bool()
int mbedtls_asn1_get_bool | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
int * |
val
|
||
) |
Retrieve a boolean ASN.1 tag and its value.
Updates the pointer to immediately behind the full tag.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
points to the first byte beyond the ASN.1 element. On error, the value of*p
is undefined.end
End of data. val
On success, the parsed value ( 0
or1
).
- Returns
- 0 if successful.
- An ASN.1 error code if the input does not start with a valid ASN.1 BOOLEAN.
◆ mbedtls_asn1_get_int()
int mbedtls_asn1_get_int | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
int * |
val
|
||
) |
Retrieve an integer ASN.1 tag and its value.
Updates the pointer to immediately behind the full tag.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
points to the first byte beyond the ASN.1 element. On error, the value of*p
is undefined.end
End of data. val
On success, the parsed value.
- Returns
- 0 if successful.
- An ASN.1 error code if the input does not start with a valid ASN.1 INTEGER.
-
MBEDTLS_ERR_ASN1_INVALID_LENGTH
if the parsed value does not fit in an
int
.
◆ mbedtls_asn1_get_enum()
int mbedtls_asn1_get_enum | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
int * |
val
|
||
) |
Retrieve an enumerated ASN.1 tag and its value.
Updates the pointer to immediately behind the full tag.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
points to the first byte beyond the ASN.1 element. On error, the value of*p
is undefined.end
End of data. val
On success, the parsed value.
- Returns
- 0 if successful.
- An ASN.1 error code if the input does not start with a valid ASN.1 ENUMERATED.
-
MBEDTLS_ERR_ASN1_INVALID_LENGTH
if the parsed value does not fit in an
int
.
◆ mbedtls_asn1_get_bitstring()
int mbedtls_asn1_get_bitstring | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
mbedtls_asn1_bitstring * |
bs
|
||
) |
Retrieve a bitstring ASN.1 tag and its value.
Updates the pointer to immediately behind the full tag.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
is equal toend
. On error, the value of*p
is undefined.end
End of data. bs
On success, mbedtls_asn1_bitstring information about the parsed value.
- Returns
- 0 if successful.
- MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input contains extra data after a valid BIT STRING.
- An ASN.1 error code if the input does not start with a valid ASN.1 BIT STRING.
◆ mbedtls_asn1_get_bitstring_null()
int mbedtls_asn1_get_bitstring_null | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
size_t * |
len
|
||
) |
Retrieve a bitstring ASN.1 tag without unused bits and its value.
Updates the pointer to the beginning of the bit/octet string.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
points to the first byte of the content of the BIT STRING. On error, the value of*p
is undefined.end
End of data. len
On success, *len
is the length of the content in bytes.
- Returns
- 0 if successful.
- MBEDTLS_ERR_ASN1_INVALID_DATA if the input starts with a valid BIT STRING with a nonzero number of unused bits.
- An ASN.1 error code if the input does not start with a valid ASN.1 BIT STRING.
◆ mbedtls_asn1_get_sequence_of()
int mbedtls_asn1_get_sequence_of | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
mbedtls_asn1_sequence * |
cur,
|
||
int |
tag
|
||
) |
Parses and splits an ASN.1 "SEQUENCE OF <tag>".
Updates the pointer to immediately behind the full sequence tag.
This function allocates memory for the sequence elements. You can free the allocated memory with mbedtls_asn1_sequence_free() .
- Note
-
On error, this function may return a partial list in
cur
. You must setcur->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. -
If the sequence is empty, this function does not modify
*cur
. If the sequence is valid and non-empty, this function setscur->buf.tag
totag
. This allows callers to distinguish between an empty sequence and a one-element sequence.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
is equal toend
. On error, the value of*p
is undefined.end
End of data. cur
A mbedtls_asn1_sequence which this function fills. When this function returns, *cur
is the head of a linked list. Each node in this list is allocated with mbedtls_calloc() apart fromcur
itself, and should therefore be freed with mbedtls_free(). The list describes the content of the sequence. The head of the list (i.e.*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, andbuf.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.tag
Each element of the sequence must have this tag.
- Returns
- 0 if successful.
-
MBEDTLS_ERR_ASN1_LENGTH_MISMATCH
if the input contains extra data after a valid SEQUENCE OF
tag
. -
MBEDTLS_ERR_ASN1_UNEXPECTED_TAG
if the input starts with an ASN.1 SEQUENCE in which an element has a tag that is different from
tag
. - MBEDTLS_ERR_ASN1_ALLOC_FAILED if a memory allocation failed.
- An ASN.1 error code if the input does not start with a valid ASN.1 SEQUENCE.
◆ mbedtls_asn1_sequence_free()
void mbedtls_asn1_sequence_free | ( | mbedtls_asn1_sequence * |
seq
|
) |
Free a heap-allocated linked list presentation of an ASN.1 sequence, including the first element.
There are two common ways to manage the memory used for the representation of a parsed ASN.1 sequence:
-
Allocate a head node
mbedtls_asn1_sequence *head
with mbedtls_calloc(). Pass this node as thecur
argument to mbedtls_asn1_get_sequence_of() . When you have finished processing the sequence, call mbedtls_asn1_sequence_free() onhead
. -
Allocate a head node
mbedtls_asn1_sequence *head
in any manner, for example on the stack. Make sure thathead->next == NULL
. Passhead
as thecur
argument to mbedtls_asn1_get_sequence_of() . When you have finished processing the sequence, call mbedtls_asn1_sequence_free() onhead->cur
, then freehead
itself in the appropriate manner.
- Parameters
-
seq
The address of the first sequence component. This may be NULL
, in which case this functions returns immediately.
◆ mbedtls_asn1_traverse_sequence_of()
int mbedtls_asn1_traverse_sequence_of | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
unsigned char |
tag_must_mask,
|
||
unsigned char |
tag_must_val,
|
||
unsigned char |
tag_may_mask,
|
||
unsigned char |
tag_may_val,
|
||
int(*)(void *ctx, int tag, unsigned char *start, size_t len) |
cb,
|
||
void * |
ctx
|
||
) |
Traverse an ASN.1 SEQUENCE container and call a callback for each entry.
This function checks that the input is a SEQUENCE of elements that each have a "must" tag, and calls a callback function on the elements that have a "may" tag.
For example, to validate that the input is a SEQUENCE of
tag1
and call
cb
on each element, use
To validate that the input is a SEQUENCE of ANY and call
cb
on each element, use
To validate that the input is a SEQUENCE of CHOICE {NULL, OCTET STRING} and call
cb
on each element that is an OCTET STRING, use
The callback is called on the elements with a "may" tag from left to right. If the input is not a valid SEQUENCE of elements with a "must" tag, the callback is called on the elements up to the leftmost point where the input is invalid.
- Warning
- This function is still experimental and may change at any time.
- Parameters
-
p
The address of the pointer to the beginning of the ASN.1 SEQUENCE header. This is updated to point to the end of the ASN.1 SEQUENCE container on a successful invocation. end
The end of the ASN.1 SEQUENCE container. tag_must_mask
A mask to be applied to the ASN.1 tags found within the SEQUENCE before comparing to tag_must_value
.tag_must_val
The required value of each ASN.1 tag found in the SEQUENCE, after masking with tag_must_mask
. Mismatching tags lead to an error. For example, a value of0
for bothtag_must_mask
andtag_must_val
means that every tag is allowed, while a value of0xFF
fortag_must_mask
means thattag_must_val
is the only allowed tag.tag_may_mask
A mask to be applied to the ASN.1 tags found within the SEQUENCE before comparing to tag_may_value
.tag_may_val
The desired value of each ASN.1 tag found in the SEQUENCE, after masking with tag_may_mask
. Mismatching tags will be silently ignored. For example, a value of0
fortag_may_mask
andtag_may_val
means that any tag will be considered, while a value of0xFF
fortag_may_mask
means that all tags with value different fromtag_may_val
will be ignored.cb
The callback to trigger for each component in the ASN.1 SEQUENCE that matches tag_may_val
. The callback function is called with the following parameters:-
ctx
. - The tag of the current element.
- A pointer to the start of the current element's content inside the input.
- The length of the content of the current element. If the callback returns a non-zero value, the function stops immediately, forwarding the callback's return value.
ctx
The context to be passed to the callback cb
. -
- Returns
-
0
if successful the entire ASN.1 SEQUENCE was traversed without parsing or callback errors. - MBEDTLS_ERR_ASN1_LENGTH_MISMATCH if the input contains extra data after a valid SEQUENCE of elements with an accepted tag.
- MBEDTLS_ERR_ASN1_UNEXPECTED_TAG if the input starts with an ASN.1 SEQUENCE in which an element has a tag that is not accepted.
- An ASN.1 error code if the input does not start with a valid ASN.1 SEQUENCE.
-
A non-zero error code forwarded from the callback
cb
in case the latter returns a non-zero value.
◆ mbedtls_asn1_get_alg()
int mbedtls_asn1_get_alg | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
mbedtls_asn1_buf * |
alg,
|
||
mbedtls_asn1_buf * |
params
|
||
) |
Retrieve an AlgorithmIdentifier ASN.1 sequence.
Updates the pointer to immediately behind the full AlgorithmIdentifier.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
points to the first byte beyond the AlgorithmIdentifier element. On error, the value of*p
is undefined.end
End of data. alg
The buffer to receive the OID. params
The buffer to receive the parameters. This is zeroized if there are no parameters.
- Returns
- 0 if successful or a specific ASN.1 or MPI error code.
◆ mbedtls_asn1_get_alg_null()
int mbedtls_asn1_get_alg_null | ( | unsigned char ** |
p,
|
const unsigned char * |
end,
|
||
mbedtls_asn1_buf * |
alg
|
||
) |
Retrieve an AlgorithmIdentifier ASN.1 sequence with NULL or no params.
Updates the pointer to immediately behind the full AlgorithmIdentifier.
- Parameters
-
p
On entry, *p
points to the start of the ASN.1 element. On successful completion,*p
points to the first byte beyond the AlgorithmIdentifier element. On error, the value of*p
is undefined.end
End of data. alg
The buffer to receive the OID.
- Returns
- 0 if successful or a specific ASN.1 or MPI error code.
◆ mbedtls_asn1_find_named_data()
const mbedtls_asn1_named_data * mbedtls_asn1_find_named_data | ( | const mbedtls_asn1_named_data * |
list,
|
const char * |
oid,
|
||
size_t |
len
|
||
) |
Find a specific named_data entry in a sequence or list based on the OID.
- Parameters
-
list
The list to seek through oid
The OID to look for len
Size of the OID
- Returns
- NULL if not found, or a pointer to the existing entry.
◆ mbedtls_asn1_free_named_data()
void mbedtls_asn1_free_named_data | ( | mbedtls_asn1_named_data * |
entry
|
) |
Free a mbedtls_asn1_named_data entry.
- Parameters
-
entry
The named data entry to free. This function calls mbedtls_free() on entry->oid.p
andentry->val.p
.
◆ mbedtls_asn1_free_named_data_list()
void mbedtls_asn1_free_named_data_list | ( | mbedtls_asn1_named_data ** |
head
|
) |
Free all entries in a mbedtls_asn1_named_data list.
- Parameters
-
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 *head
toNULL
.
Macro Definition Documentation
◆ MBEDTLS_ERR_ASN1_OUT_OF_DATA
#define MBEDTLS_ERR_ASN1_OUT_OF_DATA -0x0060 |
Out of data when parsing an ASN1 data structure.
◆ MBEDTLS_ERR_ASN1_UNEXPECTED_TAG
#define MBEDTLS_ERR_ASN1_UNEXPECTED_TAG -0x0062 |
ASN1 tag was of an unexpected value.
◆ MBEDTLS_ERR_ASN1_INVALID_LENGTH
#define MBEDTLS_ERR_ASN1_INVALID_LENGTH -0x0064 |
Error when trying to determine the length or invalid length.
◆ MBEDTLS_ERR_ASN1_LENGTH_MISMATCH
#define MBEDTLS_ERR_ASN1_LENGTH_MISMATCH -0x0066 |
Actual length differs from expected length.
◆ MBEDTLS_ERR_ASN1_INVALID_DATA
#define MBEDTLS_ERR_ASN1_INVALID_DATA -0x0068 |
Data is invalid.
◆ MBEDTLS_ERR_ASN1_ALLOC_FAILED
#define MBEDTLS_ERR_ASN1_ALLOC_FAILED -0x006A |
Memory allocation failed.
◆ MBEDTLS_ERR_ASN1_BUF_TOO_SMALL
#define MBEDTLS_ERR_ASN1_BUF_TOO_SMALL -0x006C |
Buffer too small when writing ASN.1 data structure.
◆ MBEDTLS_ASN1_IS_STRING_TAG
#define MBEDTLS_ASN1_IS_STRING_TAG | ( |
tag
|
) |
◆ MBEDTLS_OID_SIZE
#define MBEDTLS_OID_SIZE | ( |
x
|
) | (sizeof(x) - 1) |
Returns the size of the binary string, without the trailing \0.
◆ MBEDTLS_OID_CMP
#define MBEDTLS_OID_CMP | ( |
oid_str,
|
|
oid_buf
|
|||
) |
Compares an mbedtls_asn1_buf structure to a reference OID.
Only works for 'defined' oid_str values (MBEDTLS_OID_HMAC_SHA1), you cannot use a 'unsigned char *oid' here!
◆ MBEDTLS_OID_CMP_RAW
#define MBEDTLS_OID_CMP_RAW | ( |
oid_str,
|
|
oid_buf,
|
|||
oid_buf_len
|
|||
) |