Fix RETURN VALUES for EVP_CIPHER_CTX_ctrl(3)HEADmaster

The current documentation was clearly incorrect since a return of -1 from
the methods is explicitly intercepted and translated to 0. schwarze and I
both audited the tree and concluded that only 0 and 1 is possible.

OpenSSL 3 broke this API contract and now has explicit return -1 in the
convoluted 200-line maze this simple function has become with recent
provider improvements. So add a small sentence hinting at that. Nobody
will be surprised to read that with OpenSSL's characteristic penchant
for needless inconsistency the return value checks in their tree are all
over the place and sometimes incorrect.

ok schwarze (with two tweaks)

1 files changed, 4 insertions, 9 deletions

diff --git a/src/lib/libcrypto/man/EVP_CIPHER_CTX_ctrl.3 b/src/lib/libcrypto/man/EVP_CIPHER_CTX_ctrl.3
index a75b722cd4..d7ab36e711 100644
--- a/src/lib/libcrypto/man/EVP_CIPHER_CTX_ctrl.3
+++ b/src/lib/libcrypto/man/EVP_CIPHER_CTX_ctrl.3
@@ -1,4 +1,4 @@
-.\" $OpenBSD: EVP_CIPHER_CTX_ctrl.3,v 1.3 2024/12/08 17:41:23 schwarze Exp $
+.\" $OpenBSD: EVP_CIPHER_CTX_ctrl.3,v 1.4 2025/03/25 11:54:34 tb Exp $
 .\" full merge up to: OpenSSL 5211e094 Nov 11 14:39:11 2014 -0800
 .\"
 .\" This file is a derived work.
@@ -67,7 +67,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 .\" OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: December 8 2024 $
+.Dd $Mdocdate: March 25 2025 $
 .Dt EVP_CIPHER_CTX_CTRL 3
 .Os
 .Sh NAME
@@ -198,13 +198,8 @@ IV length for the context as returned by
 .Fn EVP_CIPHER_CTX_iv_length .
 .Sh RETURN VALUES
 .Fn EVP_CIPHER_CTX_ctrl
-usually returns 1 for success, 0 for failure, or \-1 if the
-.Fa type
-is not supported by the
-.Fa ctx ,
-but there may be exceptions for some
-.Fa type
-arguments.
+returns 1 for success or 0 for failure.
+Some implementations may return negative values for some errors.
 .Pp
 .Fn EVP_CIPHER_CTX_set_padding
 always returns 1.