NAME

SMIME_read_CMS - parse S/MIME message.

SYNOPSIS

#include <openssl/cms.h>

CMS_ContentInfo *SMIME_read_CMS(BIO *in, BIO **bcont);

DESCRIPTION

SMIME_read_CMS() 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 CMS_ContentInfo structure is returned or NULL if an error occurred.

NOTES

If *bcont is not NULL then the message is clear text signed. *bcont can then be passed to CMS_verify() with the CMS_DETACHED flag set. Otherwise the type of the returned structure can be determined using CMS_get0_type(). To support future functionality if bcont is not NULL *bcont should be initialized to NULL. For example:
BIO *cont = NULL;
CMS_ContentInfo *cms;

cms = SMIME_read_CMS(in, &cont);

BUGS

The MIME parser used by SMIME_read_CMS() is somewhat primitive. While it will handle most S/MIME messages more complex compound formats may not work. The parser assumes that the CMS_ContentInfo structure is always base64 encoded and 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 message which can be processed due to memory restraints: a streaming single pass option should be available.

RETURN VALUES

SMIME_read_CMS() returns a valid CMS_ContentInfo structure or NULL if an error occurred. The error can be obtained from ERR_get_error(3).

SEE ALSO

ERR_get_error(3), CMS_type(3) SMIME_read_CMS(3), CMS_sign(3), CMS_verify(3), CMS_encrypt(3) CMS_decrypt(3)

HISTORY

SMIME_read_CMS() was added to OpenSSL 0.9.8