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SMIME_read_PKCS7(3)                 OpenSSL                SMIME_read_PKCS7(3)



NAME
       SMIME_read_PKCS7_ex, SMIME_read_PKCS7 - parse S/MIME message

LIBRARY
       libcrypto, -lcrypto

SYNOPSIS
        #include <openssl/pkcs7.h>

        PKCS7 *SMIME_read_PKCS7_ex(BIO *bio, BIO **bcont, PKCS7 **p7);
        PKCS7 *SMIME_read_PKCS7(BIO *in, BIO **bcont);

DESCRIPTION
       SMIME_read_PKCS7() parses a message in S/MIME format.

       in is a BIO to read the message from.

       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 PKCS#7 structure is returned or NULL if an error occurred.

       SMIME_read_PKCS7_ex() is similar to SMIME_read_PKCS7() but can
       optionally supply a previously created p7 PKCS#7 object. If p7 is NULL
       then it is identical to SMIME_read_PKCS7().  To create a p7 object use
       PKCS7_new_ex(3).

NOTES
       If *bcont is not NULL then the message is clear text signed. *bcont can
       then be passed to PKCS7_verify() with the PKCS7_DETACHED flag set.

       Otherwise the type of the returned structure can be determined using
       PKCS7_type_is_enveloped(), etc.

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

        BIO *cont = NULL;
        PKCS7 *p7;

        p7 = SMIME_read_PKCS7(in, &cont);

BUGS
       The MIME parser used by SMIME_read_PKCS7() is somewhat primitive.
       While it will handle most S/MIME messages more complex compound formats
       may not work.

       The parser assumes that the PKCS7 structure is always base64 encoded
       and will not handle the case where it is in binary format or uses
       quoted printable format.

       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_PKCS7_ex() and SMIME_read_PKCS7() return a valid PKCS7
       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_PKCS7(3), PKCS7_sign(3), PKCS7_verify(3),
       PKCS7_encrypt(3) PKCS7_decrypt(3)

HISTORY
       The function SMIME_read_PKCS7_ex() was added in OpenSSL 3.0.

COPYRIGHT
       Copyright 2002-2020 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_PKCS7(3)