.\" $OpenBSD: SMIME_write_PKCS7.3,v 1.9 2021/12/14 15:46:48 schwarze Exp $ .\" full merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 .\" .\" This file is a derived work. .\" The changes are covered by the following Copyright and license: .\" .\" Copyright (c) 2021 Ingo Schwarze .\" .\" Permission to use, copy, modify, and distribute this software for any .\" purpose with or without fee is hereby granted, provided that the above .\" copyright notice and this permission notice appear in all copies. .\" .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF .\" MERCHANTABILITY AND FITNESS. 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IN NO EVENT SHALL THE OpenSSL PROJECT OR .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED .\" OF THE POSSIBILITY OF SUCH DAMAGE. .\" .Dd $Mdocdate: December 14 2021 $ .Dt SMIME_WRITE_PKCS7 3 .Os .Sh NAME .Nm SMIME_write_PKCS7 .Nd convert PKCS#7 structure to S/MIME format .Sh SYNOPSIS .In openssl/pkcs7.h .Ft int .Fo SMIME_write_PKCS7 .Fa "BIO *out" .Fa "PKCS7 *p7" .Fa "BIO *data" .Fa "int flags" .Fc .Sh DESCRIPTION .Fn SMIME_write_PKCS7 adds the appropriate MIME headers to a PKCS#7 structure to produce an S/MIME message. .Pp .Fa out is the .Vt BIO to write the data to. .Fa p7 is the appropriate .Vt PKCS7 structure. If streaming is enabled, then the content must be supplied in the .Fa data argument. .Fa flags is an optional set of flags. .Pp The following flags can be passed in the .Fa flags parameter. .Pp If .Dv PKCS7_DETACHED is set, then cleartext signing will be used. This option only makes sense for signedData where .Dv PKCS7_DETACHED is also set when .Xr PKCS7_sign 3 is also called. .Pp If the .Dv PKCS7_TEXT flag is set, MIME headers for type .Sy text/plain are added to the content. This only makes sense if .Dv PKCS7_DETACHED is also set. .Pp If the .Dv PKCS7_STREAM flag is set, streaming is performed. This flag should only be set if .Dv PKCS7_STREAM was also set in the previous call to .Xr PKCS7_sign 3 or .Xr PKCS7_encrypt 3 . .Pp The bit .Dv SMIME_OLDMIME is inverted before passing on the .Fa flags to .Xr SMIME_write_ASN1 3 . Consequently, if this bit is set in the .Fa flags argument, .Qq application/pkcs7-mime or .Qq application/pkcs7-signature is used in Content-Type headers. Otherwise, .Qq application/x-pkcs7-mime or .Qq application/x-pkcs7-signature is used. .Pp If cleartext signing is being used and .Dv PKCS7_STREAM is not set, then the data must be read twice: once to compute the signature in .Xr PKCS7_sign 3 and once to output the S/MIME message. .Pp If streaming is performed, the content is output in BER format using indefinite length constructed encoding except in the case of signed data with detached content where the content is absent and DER format is used. .Sh RETURN VALUES Upon successful completion, 1 is returned; otherwise 0 is returned and an error code can be retrieved with .Xr ERR_get_error 3 . .Sh SEE ALSO .Xr i2d_PKCS7_bio_stream 3 , .Xr PEM_write_bio_PKCS7_stream 3 , .Xr PEM_write_PKCS7 3 , .Xr PKCS7_final 3 , .Xr PKCS7_new 3 , .Xr SMIME_read_PKCS7 3 , .Xr SMIME_write_ASN1 3 .Sh HISTORY .Fn SMIME_write_PKCS7 first appeared in OpenSSL 0.9.5 and has been available since .Ox 2.7 . .Sh BUGS .Fn SMIME_write_PKCS7 always base64 encodes PKCS#7 structures. There should be an option to disable this.