Use hash transform function return type for passing burn stack depth

* cipher/gostr4311-94.c (transform): Return stack burn depth.
* cipher/hash-common.c (_gcry_md_block_write): Use stack burn depth
returned by 'hd->bwrite'.
* cipher/hash-common.h (_gcry_md_block_write_t): Change return type to
'unsigned int'.
(gry_md_block_ctx_t): Remove 'stack_burn'.
* cipher/md4.c (transform): Return stack burn depth.
(md4_final): Use stack burn depth from transform.
* cipher/md5.c (transform): Return stack burn depth.
(md5_final): Use stack burn depth from transform.
* cipher/rmd160.c (transform): Return stack burn depth.
(rmd160_final): Use stack burn depth from transform.
* cipher/sha1.c (transform): Return stack burn depth.
(sha1_final): Use stack burn depth from transform.
* cipher/sha256.c (transform): Return stack burn depth.
(sha256_final): Use stack burn depth from transform.
* cipher/sha512.c (__transform, transform): Return stack burn depth.
(sha512_final): Use stack burn depth from transform.
* cipher/stribog.c (transform64): Return stack burn depth.
* cipher/tiger.c (transform): Return stack burn depth.
(tiger_final): Use stack burn depth from transform.
--

Transform function might want different depth of stack burn depending on
detected CPU features (like in SHA-512 on ARM with NEON). So return
stack burn depth from transform functions as a request or a hint to
calling function.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>

1 files changed, 8 insertions, 6 deletions

diff --git a/cipher/sha256.c b/cipher/sha256.c
index 17856994..cf23f2f4 100644
--- a/cipher/sha256.c
+++ b/cipher/sha256.c
@@ -50,9 +50,10 @@ typedef struct {
   u32  h0,h1,h2,h3,h4,h5,h6,h7;
 } SHA256_CONTEXT;
 
-static void
+static unsigned int
 transform (void *c, const unsigned char *data);
 
+
 static void
 sha256_init (void *context)
 {
@@ -70,7 +71,6 @@ sha256_init (void *context)
   hd->bctx.nblocks = 0;
   hd->bctx.count = 0;
   hd->bctx.blocksize = 64;
-  hd->bctx.stack_burn = 74*4+32;
   hd->bctx.bwrite = transform;
 }
 
@@ -92,7 +92,6 @@ sha224_init (void *context)
   hd->bctx.nblocks = 0;
   hd->bctx.count = 0;
   hd->bctx.blocksize = 64;
-  hd->bctx.stack_burn = 74*4+32;
   hd->bctx.bwrite = transform;
 }
 
@@ -145,7 +144,7 @@ Sum1 (u32 x)
 }
 
 
-static void
+static unsigned int
 transform (void *ctx, const unsigned char *data)
 {
   SHA256_CONTEXT *hd = ctx;
@@ -261,6 +260,8 @@ transform (void *ctx, const unsigned char *data)
   hd->h5 += f;
   hd->h6 += g;
   hd->h7 += h;
+
+  return /*burn_stack*/ 74*4+32;
 }
 #undef S0
 #undef S1
@@ -278,6 +279,7 @@ sha256_final(void *context)
   SHA256_CONTEXT *hd = context;
   u32 t, msb, lsb;
   byte *p;
+  unsigned int burn;
 
   _gcry_md_block_write (hd, NULL, 0); /* flush */;
 
@@ -318,8 +320,8 @@ sha256_final(void *context)
   hd->bctx.buf[61] = lsb >> 16;
   hd->bctx.buf[62] = lsb >>  8;
   hd->bctx.buf[63] = lsb;
-  transform (hd, hd->bctx.buf);
-  _gcry_burn_stack (74*4+32);
+  burn = transform (hd, hd->bctx.buf);
+  _gcry_burn_stack (burn);
 
   p = hd->bctx.buf;
 #ifdef WORDS_BIGENDIAN