NAME
SMIME_read_PKCS7 —
extract a PKCS#7 object from an S/MIME
message
SYNOPSIS
#include
<openssl/pkcs7.h>
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.
If *bcont is not
NULL, then the message is clear text signed.
*bcont can then be passed to
PKCS7_verify(3) with the
PKCS7_DETACHED flag set.
Otherwise the type of the returned structure
can be determined using the
PKCS7_type_is_*()
macros defined in
<openssl/pkcs7.h>.
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);
RETURN VALUES
SMIME_read_PKCS7() returns a valid
PKCS7 structure or NULL if an
error occurred. The error can be obtained from
ERR_get_error(3).
SEE ALSO
HISTORY
SMIME_read_PKCS7() first appeared in
OpenSSL 0.9.5 and has been available since OpenBSD
2.7.
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 it 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 the message which can be processed due to memory restraints: a streaming single pass option should be available.