ni...@lysator.liu.se (Niels Möller) writes:
> For now, I think I'll fix this, and add a TMP_ALIGN_DECL,
> TMP_ALIGN_ALLOC.
Below patch seems to work. Other options?
Regards,
/Niels
diff --git a/nettle-internal.h b/nettle-internal.h
index 38c8d2a8..b109e944 100644
--- a/nettle-internal.h
+++ b/nettle-internal.h
@@ -35,20 +35,41 @@
#ifndef NETTLE_INTERNAL_H_INCLUDED
#define NETTLE_INTERNAL_H_INCLUDED
+#include
+
#include "nettle-meta.h"
+/* For definition of NETTLE_MAX_HASH_CONTEXT_SIZE. */
+#include "sha3.h"
+
/* Temporary allocation, for systems that don't support alloca. Note
* that the allocation requests should always be reasonably small, so
* that they can fit on the stack. For non-alloca systems, we use a
- * fix maximum size, and abort if we ever need anything larger. */
+ * fix maximum size + an assert.
+ *
+ * TMP_DECL and TMP_ALLOC allocate an array of the given type, and
+ * take the array size (not byte size) as argument.
+ *
+ * TMP_DECL_ALIGN and TMP_ALLOC_ALIGN are intended for context
+ * structs, with void * pointer, size in bytes, and alignment
+ * requirements. On systems without alloca, implemented as an array of
+ * uint64_t, to ensure alignment. Since it is used as void * argument,
+ * no type casts are needed.
+ */
#if HAVE_ALLOCA
# define TMP_DECL(name, type, max) type *name
# define TMP_ALLOC(name, size) (name = alloca(sizeof (*name) * (size)))
+# define TMP_DECL_ALIGN(name, max) void *name
+# define TMP_ALLOC_ALIGN(name, size) (name = alloca(size))
#else /* !HAVE_ALLOCA */
# define TMP_DECL(name, type, max) type name[max]
# define TMP_ALLOC(name, size) \
- do { if ((size) > (sizeof(name) / sizeof(name[0]))) abort(); } while (0)
+ do { assert((size_t)(size) <= (sizeof(name) / sizeof(name[0]))); } while (0)
+# define TMP_DECL_ALIGN(name, max) \
+ uint64_t name[((max) + (sizeof(uint64_t) - 1))/ sizeof(uint64_t)]
+# define TMP_ALLOC_ALIGN(name, size) \
+ do { assert((size_t)(size) <= (sizeof(name))); } while (0)
#endif
/* Arbitrary limits which apply to systems that don't have alloca */
diff --git a/pss-mgf1.c b/pss-mgf1.c
index 67df5570..3f5e204b 100644
--- a/pss-mgf1.c
+++ b/pss-mgf1.c
@@ -48,12 +48,12 @@ pss_mgf1(const void *seed, const struct nettle_hash *hash,
size_t length, uint8_t *mask)
{
TMP_DECL(h, uint8_t, NETTLE_MAX_HASH_DIGEST_SIZE);
- TMP_DECL(state, uint8_t, NETTLE_MAX_HASH_CONTEXT_SIZE);
+ TMP_DECL_ALIGN(state, NETTLE_MAX_HASH_CONTEXT_SIZE);
size_t i;
uint8_t c[4];
TMP_ALLOC(h, hash->digest_size);
- TMP_ALLOC(state, hash->context_size);
+ TMP_ALLOC_ALIGN(state, hash->context_size);
for (i = 0;;
i++, mask += hash->digest_size, length -= hash->digest_size)
diff --git a/pss.c b/pss.c
index 88125c06..d28e7b13 100644
--- a/pss.c
+++ b/pss.c
@@ -67,12 +67,12 @@ pss_encode_mgf1(mpz_t m, size_t bits,
const uint8_t *digest)
{
TMP_GMP_DECL(em, uint8_t);
- TMP_DECL(state, uint8_t, NETTLE_MAX_HASH_CONTEXT_SIZE);
+ TMP_DECL_ALIGN(state, NETTLE_MAX_HASH_CONTEXT_SIZE);
size_t key_size = (bits + 7) / 8;
size_t j;
TMP_GMP_ALLOC(em, key_size);
- TMP_ALLOC(state, hash->context_size);
+ TMP_ALLOC_ALIGN(state, hash->context_size);
if (key_size < hash->digest_size + salt_length + 2)
{
@@ -127,7 +127,7 @@ pss_verify_mgf1(const mpz_t m, size_t bits,
{
TMP_GMP_DECL(em, uint8_t);
TMP_DECL(h2, uint8_t, NETTLE_MAX_HASH_DIGEST_SIZE);
- TMP_DECL(state, uint8_t, NETTLE_MAX_HASH_CONTEXT_SIZE);
+ TMP_DECL_ALIGN(state, NETTLE_MAX_HASH_CONTEXT_SIZE);
uint8_t *h, *db, *salt;
size_t key_size = (bits + 7) / 8;
size_t j;
@@ -138,7 +138,7 @@ pss_verify_mgf1(const mpz_t m, size_t bits,
TMP_GMP_ALLOC(em, key_size * 2);
TMP_ALLOC(h2, hash->digest_size);
- TMP_ALLOC(state, hash->context_size);
+ TMP_ALLOC_ALIGN(state, hash->context_size);
if (key_size < hash->digest_size + salt_length + 2)
goto cleanup;
--
Niels Möller. PGP-encrypted email is preferred. Keyid 368C6677.
Internet email is subject to wholesale government surveillance.
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