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✏️ Editing: SMIME_read_PKCS7.3

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.\" ========================================================================
.\"
.IX Title "SMIME_READ_PKCS7 3"
.TH SMIME_READ_PKCS7 3 "2023-09-11" "1.1.1w" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
SMIME_read_PKCS7 \- parse S/MIME message
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\& #include <openssl/pkcs7.h>
\&
\& PKCS7 *SMIME_read_PKCS7(BIO *in, BIO **bcont);
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
\&\fBSMIME_read_PKCS7()\fR parses a message in S/MIME format.
.PP
\&\fBin\fR is a \s-1BIO\s0 to read the message from.
.PP
If cleartext signing is used then the content is saved in
a memory bio which is written to \fB*bcont\fR, otherwise
\&\fB*bcont\fR is set to \fB\s-1NULL\s0\fR.
.PP
The parsed PKCS#7 structure is returned or \fB\s-1NULL\s0\fR if an
error occurred.
.SH "NOTES"
.IX Header "NOTES"
If \fB*bcont\fR is not \fB\s-1NULL\s0\fR then the message is clear text
signed. \fB*bcont\fR can then be passed to \fBPKCS7_verify()\fR with
the \fB\s-1PKCS7_DETACHED\s0\fR flag set.
.PP
Otherwise the type of the returned structure can be determined
using \fBPKCS7_type_is_enveloped()\fR, etc.
.PP
To support future functionality if \fBbcont\fR is not \fB\s-1NULL\s0\fR
\&\fB*bcont\fR should be initialized to \fB\s-1NULL\s0\fR. For example:
.PP
.Vb 2
\& BIO *cont = NULL;
\& PKCS7 *p7;
\&
\& p7 = SMIME_read_PKCS7(in, &cont);
.Ve
.SH "BUGS"
.IX Header "BUGS"
The \s-1MIME\s0 parser used by \fBSMIME_read_PKCS7()\fR is somewhat primitive.
While it will handle most S/MIME messages more complex compound
formats may not work.
.PP
The parser assumes that the \s-1PKCS7\s0 structure is always base64
encoded and will not handle the case where it is in binary format
or uses quoted printable format.
.PP
The use of a memory \s-1BIO\s0 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.
.SH "RETURN VALUES"
.IX Header "RETURN VALUES"
\&\fBSMIME_read_PKCS7()\fR returns a valid \fB\s-1PKCS7\s0\fR structure or \fB\s-1NULL\s0\fR
if an error occurred. The error can be obtained from \fBERR_get_error\fR\|(3).
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBERR_get_error\fR\|(3),
\&\fBSMIME_read_PKCS7\fR\|(3), \fBPKCS7_sign\fR\|(3),
\&\fBPKCS7_verify\fR\|(3), \fBPKCS7_encrypt\fR\|(3)
\&\fBPKCS7_decrypt\fR\|(3)
.SH "COPYRIGHT"
.IX Header "COPYRIGHT"
Copyright 2002\-2018 The OpenSSL Project Authors. All Rights Reserved.
.PP
Licensed under the OpenSSL license (the \*(L"License\*(R").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file \s-1LICENSE\s0 in the source distribution or at
<https://www.openssl.org/source/license.html>.

MR SKB