Remove alignment constraint from the sha*_read_ctx functions.

* lib/sha256.c (set_uint32): New function.
(sha256_read_ctx, sha224_read_ctx): Use it.
* lib/sha512.c (set_uint64): New function.
(sha512_read_ctx, sha384_read_ctx): Use it.
* lib/sha256.h: Remove warning about alignment constraint.
* lib/sha512.h: Likewise.
Prompted by similar changes in gnulib's sha1 and md[45] modules.

1 files changed, 16 insertions, 11 deletions

diff --git a/lib/sha256.c b/lib/sha256.c
index 8f4bb9580..4a632c9fb 100644
--- a/lib/sha256.c
+++ b/lib/sha256.c
@@ -1,7 +1,7 @@
 /* sha256.c - Functions to compute SHA256 and SHA224 message digest of files or
    memory blocks according to the NIST specification FIPS-180-2.
 
-   Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2005, 2006, 2008 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -85,18 +85,25 @@ sha224_init_ctx (struct sha256_ctx *ctx)
   ctx->buflen = 0;
 }
 
-/* Put result from CTX in first 32 bytes following RESBUF.  The result
-   must be in little endian byte order.
+/* Copy the value from v into the memory location pointed to by *cp,
+   If your architecture allows unaligned access this is equivalent to
+   * (uint32_t *) cp = v  */
+static inline void
+set_uint32 (char *cp, uint32_t v)
+{
+  memcpy (cp, &v, sizeof v);
+}
 
-   IMPORTANT: On some systems it is required that RESBUF is correctly
-   aligned for a 32-bit value.  */
+/* Put result from CTX in first 32 bytes following RESBUF.  The result
+   must be in little endian byte order.  */
 void *
 sha256_read_ctx (const struct sha256_ctx *ctx, void *resbuf)
 {
   int i;
+  char *r = resbuf;
 
   for (i = 0; i < 8; i++)
-    ((uint32_t *) resbuf)[i] = SWAP (ctx->state[i]);
+    set_uint32 (r + i * sizeof ctx->state[0], SWAP (ctx->state[i]));
 
   return resbuf;
 }
@@ -105,18 +112,16 @@ void *
 sha224_read_ctx (const struct sha256_ctx *ctx, void *resbuf)
 {
   int i;
+  char *r = resbuf;
 
   for (i = 0; i < 7; i++)
-    ((uint32_t *) resbuf)[i] = SWAP (ctx->state[i]);
+    set_uint32 (r + i * sizeof ctx->state[0], SWAP (ctx->state[i]));
 
   return resbuf;
 }
 
 /* Process the remaining bytes in the internal buffer and the usual
-   prolog according to the standard and write the result to RESBUF.
-
-   IMPORTANT: On some systems it is required that RESBUF is correctly
-   aligned for a 32-bit value.  */
+   prolog according to the standard and write the result to RESBUF.  */
 static void
 sha256_conclude_ctx (struct sha256_ctx *ctx)
 {