1SMIME_READ_CMS(3ossl)               OpenSSL              SMIME_READ_CMS(3ossl)
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NAME

6       SMIME_read_CMS_ex, SMIME_read_CMS - parse S/MIME message
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SYNOPSIS

9        #include <openssl/cms.h>
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11        CMS_ContentInfo *SMIME_read_CMS_ex(BIO *bio, int flags, BIO **bcont,
12                                           CMS_ContentInfo **cms);
13        CMS_ContentInfo *SMIME_read_CMS(BIO *in, BIO **bcont);
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DESCRIPTION

16       SMIME_read_CMS() parses a message in S/MIME format.
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18       in is a BIO to read the message from.
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20       If cleartext signing is used then the content is saved in a memory bio
21       which is written to *bcont, otherwise *bcont is set to NULL.
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23       The parsed CMS_ContentInfo structure is returned or NULL if an error
24       occurred.
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26       SMIME_read_CMS_ex() is similar to SMIME_read_CMS() but optionally a
27       previously created cms CMS_ContentInfo object can be supplied as well
28       as some flags.  To create a cms object use CMS_ContentInfo_new_ex(3).
29       If the flags argument contains CMS_BINARY then the input is assumed to
30       be in binary format and is not translated to canonical form.  If in
31       addition SMIME_ASCIICRLF is set then the binary input is assumed to be
32       followed by CR and LF characters, else only by an LF character.  If
33       flags is 0 and cms is NULL then it is identical to SMIME_read_CMS().
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NOTES

36       If *bcont is not NULL then the message is clear text signed. *bcont can
37       then be passed to CMS_verify() with the CMS_DETACHED flag set.
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39       Otherwise the type of the returned structure can be determined using
40       CMS_get0_type().
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42       To support future functionality if bcont is not NULL *bcont should be
43       initialized to NULL. For example:
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45        BIO *cont = NULL;
46        CMS_ContentInfo *cms;
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48        cms = SMIME_read_CMS(in, &cont);
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BUGS

51       The MIME parser used by SMIME_read_CMS() is somewhat primitive.  While
52       it will handle most S/MIME messages more complex compound formats may
53       not work.
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55       The parser assumes that the CMS_ContentInfo structure is always base64
56       encoded and will not handle the case where it is in binary format or
57       uses quoted printable format.
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59       The use of a memory BIO to hold the signed content limits the size of
60       message which can be processed due to memory restraints: a streaming
61       single pass option should be available.
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RETURN VALUES

64       SMIME_read_CMS_ex() and SMIME_read_CMS() return a valid CMS_ContentInfo
65       structure or NULL if an error occurred. The error can be obtained from
66       ERR_get_error(3).
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SEE ALSO

69       ERR_get_error(3), CMS_sign(3), CMS_verify(3), CMS_encrypt(3),
70       CMS_decrypt(3)
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HISTORY

73       The function SMIME_read_CMS_ex() was added in OpenSSL 3.0.
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76       Copyright 2008-2021 The OpenSSL Project Authors. All Rights Reserved.
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78       Licensed under the Apache License 2.0 (the "License").  You may not use
79       this file except in compliance with the License.  You can obtain a copy
80       in the file LICENSE in the source distribution or at
81       <https://www.openssl.org/source/license.html>.
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853.0.5                             2022-07-05             SMIME_READ_CMS(3ossl)
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