PKCS7_DATAFINAL(3) | Library Functions Manual | PKCS7_DATAFINAL(3)

# NAME

`PKCS7_dataFinal` — move data from a BIO chain to a ContentInfo object

# SYNOPSIS

library “libcrypto”
`#include <openssl/pkcs7.h>`

int
`PKCS7_dataFinal`(PKCS7 *p7, BIO *chain);

# DESCRIPTION

`PKCS7_dataFinal`() transfers the data from the memory BIO at the end of the given chain into the appropriate content field of p7 itself or of its appropriate substructure. It is typically used as the final step of populating p7, after creating the chain with PKCS7_dataInit(3) and after writing the data into it.

After calling `PKCS7_dataFinal`(), the program can call BIO_free_all(3) on the chain because such chains are not designed for reuse.

Depending on the contentType of p7, `PKCS7_dataFinal`() sets the following fields:

for SignedData or DigestedData:
  in substructures of the content field of p7: the content field in the ContentInfo structure (unless p7 is configured to store a detached signature) and the encryptedDigest fields in all the SignerInfo structures
for EnvelopedData or SignedAndEnvelopedData:
  the encryptedContent field in the EncryptedContentInfo structure contained in the content field of p7
for arbitrary data:
  the content field of p7 itself

# RETURN VALUES

`PKCS7_dataFinal`() returns 1 on success or 0 on failure.

Possible reasons for failure include:

- p7 is `NULL`.
- The content field of p7 is empty.
- The contentType of p7 is unsupported.
- The chain does not contain the expected memory BIO.
- Signing or digesting is requested and p7 is not configured to store a detached signature, but does not contain the required field to store the content either.
- At least one signer lacks a usable digest algorithm.
- Signing or digesting fails.
- Memory allocation fails.

Signers lacking private keys do not cause failure but are silently skipped.

# SEE ALSO

BIO_new(3), PKCS7_dataInit(3), PKCS7_final(3), PKCS7_new(3), PKCS7_sign(3)

# HISTORY

`PKCS7_dataFinal`() first appeared in SSLeay 0.9.1 and has been available since OpenBSD 2.6.

# CAVEATS

This function does not support EncryptedData.

Even though this function is typically used after PKCS7_dataInit(3) and even though PKCS7_dataInit(3) also supports reading from ContentInfo structures that are already fully populated, do not use `PKCS7_dataFinal`() on fully populated structures. It is only intended for putting data into new structures and it is neither needed nor suitable for reading.

June 8, 2025 | Debian