document the very quirky behaviour of the SMIME_OLDMIME flag

1 files changed, 39 insertions, 3 deletions

diff --git a/src/lib/libcrypto/man/SMIME_write_PKCS7.3 b/src/lib/libcrypto/man/SMIME_write_PKCS7.3
index 4257a89018..c1a9f051d0 100644
--- a/src/lib/libcrypto/man/SMIME_write_PKCS7.3
+++ b/src/lib/libcrypto/man/SMIME_write_PKCS7.3
@@ -1,7 +1,24 @@
-.\" $OpenBSD: SMIME_write_PKCS7.3,v 1.8 2021/12/13 17:24:39 schwarze Exp $
+.\" $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 was written by Dr. Stephen Henson <steve@openssl.org>.
+.\" This file is a derived work.
+.\" The changes are covered by the following Copyright and license:
+.\"
+.\" Copyright (c) 2021 Ingo Schwarze <schwarze@openbsd.org>
+.\"
+.\" 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. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
+.\" The original file was written by Dr. Stephen Henson <steve@openssl.org>.
 .\" Copyright (c) 2002, 2003, 2006, 2007, 2015 The OpenSSL Project.
 .\" All rights reserved.
 .\"
@@ -49,7 +66,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 .\" OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: December 13 2021 $
+.Dd $Mdocdate: December 14 2021 $
 .Dt SMIME_WRITE_PKCS7 3
 .Os
 .Sh NAME
@@ -115,6 +132,25 @@ was also set in the previous call to
 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