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SMIME_read_ASN1(3)                  OpenSSL                 SMIME_read_ASN1(3)



NAME
       SMIME_read_ASN1_ex, SMIME_read_ASN1 - parse S/MIME message

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/asn1.h>

        ASN1_VALUE *SMIME_read_ASN1_ex(BIO *in, int flags, BIO **bcont,
                                       const ASN1_ITEM *it, ASN1_VALUE **x,
                                       OSSL_LIB_CTX *libctx, const char *propq);
        ASN1_VALUE *SMIME_read_ASN1(BIO *in, BIO **bcont, const ASN1_ITEM *it);

DESCRIPTION
       SMIME_read_ASN1_ex() parses a message in S/MIME format.

       in is a BIO to read the message from.  If the flags argument contains
       CMS_BINARY then the input is assumed to be in binary format and is not
       translated to canonical form.  If in addition SMIME_ASCIICRLF is set
       then the binary input is assumed to be followed by CR and LF
       characters, else only by an LF character.  x can be used to optionally
       supply a previously created it ASN1_VALUE object (such as
       CMS_ContentInfo or PKCS7), it can be set to NULL. Valid values that can
       be used by ASN.1 structure it are ASN1_ITEM_rptr(PKCS7) or
       ASN1_ITEM_rptr(CMS_ContentInfo). Any algorithm fetches that occur
       during the operation will use the OSSL_LIB_CTX supplied in the libctx
       parameter, and use the property query string propq See "ALGORITHM
       FETCHING" in crypto(7) for further details about algorithm fetching.

       If cleartext signing is used then the content is saved in a memory bio
       which is written to *bcont, otherwise *bcont is set to NULL.

       The parsed ASN1_VALUE structure is returned or NULL if an error
       occurred.

       SMIME_read_ASN1() is similar to SMIME_read_ASN1_ex() but sets the value
       of x to NULL and the value of flags to 0.

NOTES
       The higher level functions SMIME_read_CMS_ex(3) and
       SMIME_read_PKCS7_ex(3) should be used instead of SMIME_read_ASN1_ex().

       To support future functionality if bcont is not NULL *bcont should be
       initialized to NULL.

BUGS
       The MIME parser used by SMIME_read_ASN1_ex() is somewhat primitive.
       While it will handle most S/MIME messages more complex compound formats
       may not work.

       The use of a memory BIO to hold the signed content limits the size of
       message which can be processed due to memory restraints: a streaming
       single pass option should be available.

RETURN VALUES
       SMIME_read_ASN1_ex() and SMIME_read_ASN1() return a valid ASN1_VALUE
       structure or NULL if an error occurred. The error can be obtained from
       ERR_get_error(3).

SEE ALSO
       ERR_get_error(3), SMIME_read_CMS_ex(3), SMIME_read_PKCS7_ex(3),
       SMIME_write_ASN1(3), SMIME_write_ASN1_ex(3)

HISTORY
       The function SMIME_read_ASN1_ex() was added in OpenSSL 3.0.

COPYRIGHT
       Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.



3.0.12                            2023-05-07                SMIME_read_ASN1(3)