SMIME_read_CMS.pod 2.8 KB

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  1. =pod
  2. =head1 NAME
  3. SMIME_read_CMS_ex, SMIME_read_CMS - parse S/MIME message
  4. =head1 SYNOPSIS
  5. #include <openssl/cms.h>
  6. CMS_ContentInfo *SMIME_read_CMS_ex(BIO *bio, int flags, BIO **bcont,
  7. CMS_ContentInfo **cms);
  8. CMS_ContentInfo *SMIME_read_CMS(BIO *in, BIO **bcont);
  9. =head1 DESCRIPTION
  10. SMIME_read_CMS() parses a message in S/MIME format.
  11. B<in> is a BIO to read the message from.
  12. If cleartext signing is used then the content is saved in a memory bio which is
  13. written to B<*bcont>, otherwise B<*bcont> is set to NULL.
  14. The parsed CMS_ContentInfo structure is returned or NULL if an
  15. error occurred.
  16. SMIME_read_CMS_ex() is similar to SMIME_read_CMS() but optionally a previously
  17. created I<cms> CMS_ContentInfo object can be supplied as well as some I<flags>.
  18. To create a I<cms> object use L<CMS_ContentInfo_new_ex(3)>.
  19. If the I<flags> argument contains B<CMS_BINARY> then the input is assumed to be
  20. in binary format and is not translated to canonical form.
  21. If in addition B<SMIME_ASCIICRLF> is set then the binary input is assumed
  22. to be followed by B<CR> and B<LF> characters, else only by an B<LF> character.
  23. If I<flags> is 0 and I<cms> is NULL then it is identical to SMIME_read_CMS().
  24. =head1 NOTES
  25. If B<*bcont> is not NULL then the message is clear text signed. B<*bcont> can
  26. then be passed to CMS_verify() with the B<CMS_DETACHED> flag set.
  27. Otherwise the type of the returned structure can be determined
  28. using CMS_get0_type().
  29. To support future functionality if B<bcont> is not NULL B<*bcont> should be
  30. initialized to NULL. For example:
  31. BIO *cont = NULL;
  32. CMS_ContentInfo *cms;
  33. cms = SMIME_read_CMS(in, &cont);
  34. =head1 BUGS
  35. The MIME parser used by SMIME_read_CMS() is somewhat primitive. While it will
  36. handle most S/MIME messages more complex compound formats may not work.
  37. The parser assumes that the CMS_ContentInfo structure is always base64 encoded
  38. and will not handle the case where it is in binary format or uses quoted
  39. printable format.
  40. The use of a memory BIO to hold the signed content limits the size of message
  41. which can be processed due to memory restraints: a streaming single pass option
  42. should be available.
  43. =head1 RETURN VALUES
  44. SMIME_read_CMS_ex() and SMIME_read_CMS() return a valid B<CMS_ContentInfo>
  45. structure or B<NULL> if an error occurred. The error can be obtained from
  46. ERR_get_error(3).
  47. =head1 SEE ALSO
  48. L<ERR_get_error(3)>,
  49. L<CMS_sign(3)>,
  50. L<CMS_verify(3)>,
  51. L<CMS_encrypt(3)>,
  52. L<CMS_decrypt(3)>
  53. =head1 HISTORY
  54. The function SMIME_read_CMS_ex() was added in OpenSSL 3.0.
  55. =head1 COPYRIGHT
  56. Copyright 2008-2021 The OpenSSL Project Authors. All Rights Reserved.
  57. Licensed under the Apache License 2.0 (the "License"). You may not use
  58. this file except in compliance with the License. You can obtain a copy
  59. in the file LICENSE in the source distribution or at
  60. L<https://www.openssl.org/source/license.html>.
  61. =cut