PKCS#7: Introduce pkcs7_get_digest()

IMA will need to access the digest of the PKCS7 message (as calculated by
the kernel) before the signature is verified, so introduce
pkcs7_get_digest() for that purpose.

Also, modify pkcs7_digest() to detect when the digest was already
calculated so that it doesn't have to do redundant work. Verifying that
sinfo->sig->digest isn't NULL is sufficient because both places which
allocate sinfo->sig (pkcs7_parse_message() and pkcs7_note_signed_info())
use kzalloc() so sig->digest is always initialized to zero.

Signed-off-by: Thiago Jung Bauermann <[email protected]>
Reviewed-by: Mimi Zohar <[email protected]>
Cc: David Howells <[email protected]>
Cc: David Woodhouse <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: "David S. Miller" <[email protected]>
Signed-off-by: Mimi Zohar <[email protected]>

0 files changed, 0 insertions, 0 deletions