Increase HKDF_MAXBUF from 1024 to 2048

We've encountered some scenarios that need to use more than 1 kB of
data as the HKDF-Expand() "info" argument (which, per RFC 5869,
contains "optional context and application specific information").

Since HKDF_MAXBUF is used to size an array in the HKDF_PKEY_CTX
structure, this adds 1 kB of memory footprint to each EVP_PKEY_CTX
used for HKDF.

Reviewed-by: Shane Lontis <>
Reviewed-by: Paul Dale <>
(Merged from
Benjamin Kaduk 2 years ago committed by Benjamin Kaduk
parent c6b09ea0fe
commit 20c2876f24

@ -30,7 +30,7 @@
#include "prov/provider_util.h"
#include "e_os.h"
#define HKDF_MAXBUF 1024
#define HKDF_MAXBUF 2048
static OSSL_FUNC_kdf_newctx_fn kdf_hkdf_new;
static OSSL_FUNC_kdf_freectx_fn kdf_hkdf_free;