Document that OPENSSL_free() is required in some circumstances

BoringSSL uses the common trick of storing malloc metadata in a prefix
and then returning a pointer with an offset. Therefore callers must not
call free() but OPENSSL_free().

Reported by dropk1ck via tobhe

ok beck jsing

1 files changed, 6 insertions, 2 deletions

diff --git a/src/lib/libcrypto/man/OPENSSL_malloc.3 b/src/lib/libcrypto/man/OPENSSL_malloc.3
index e6dba165f8..87f8d81ed1 100644
--- a/src/lib/libcrypto/man/OPENSSL_malloc.3
+++ b/src/lib/libcrypto/man/OPENSSL_malloc.3
@@ -1,4 +1,4 @@
-.\"     $OpenBSD: OPENSSL_malloc.3,v 1.9 2019/06/10 09:49:48 schwarze Exp $
+.\"     $OpenBSD: OPENSSL_malloc.3,v 1.10 2022/11/06 18:31:15 tb Exp $
 .\"
 .\" Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
 .\"
@@ -14,7 +14,7 @@
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
-.Dd $Mdocdate: June 10 2019 $
+.Dd $Mdocdate: November 6 2022 $
 .Dt OPENSSL_MALLOC 3
 .Os
 .Sh NAME
@@ -108,3 +108,7 @@ and
 .Fn OPENSSL_strdup
 first appeared in OpenSSL 0.9.8j and have been available since
 .Ox 4.5 .
+.Sh CAVEATS
+If interoperability with other implementations is required,
+memory returned by the library as bare pointers must be freed with
+.Fn OPENSSL_free .