Handle unaligned keys in hash().

Reported by Christopher Ferris <cferris@google.com>.

2 files changed, 33 insertions, 4 deletions

diff --git a/include/jemalloc/internal/hash.h b/include/jemalloc/internal/hash.h
index bcead33..8b5fb03 100644
--- a/include/jemalloc/internal/hash.h
+++ b/include/jemalloc/internal/hash.h
@@ -1,6 +1,6 @@
 /*
  * The following hash function is based on MurmurHash3, placed into the public
- * domain by Austin Appleby.  See http://code.google.com/p/smhasher/ for
+ * domain by Austin Appleby.  See https://github.com/aappleby/smhasher for
  * details.
  */
 /******************************************************************************/
@@ -49,6 +49,14 @@ JEMALLOC_INLINE uint32_t
 hash_get_block_32(const uint32_t *p, int i)
 {
 
+	/* Handle unaligned read. */
+	if (unlikely((uintptr_t)p & (sizeof(uint32_t)-1)) != 0) {
+		uint32_t ret;
+
+		memcpy(&ret, &p[i], sizeof(uint32_t));
+		return (ret);
+	}
+
 	return (p[i]);
 }
 
@@ -56,6 +64,14 @@ JEMALLOC_INLINE uint64_t
 hash_get_block_64(const uint64_t *p, int i)
 {
 
+	/* Handle unaligned read. */
+	if (unlikely((uintptr_t)p & (sizeof(uint64_t)-1)) != 0) {
+		uint64_t ret;
+
+		memcpy(&ret, &p[i], sizeof(uint64_t));
+		return (ret);
+	}
+
 	return (p[i]);
 }
 
diff --git a/test/unit/hash.c b/test/unit/hash.c
index 77a8ced..ea73d70 100644
--- a/test/unit/hash.c
+++ b/test/unit/hash.c
@@ -59,17 +59,17 @@ hash_variant_string(hash_variant_t variant)
 	}
 }
 
+#define	KEY_SIZE	256
 static void
-hash_variant_verify(hash_variant_t variant)
+hash_variant_verify_key(hash_variant_t variant, uint8_t *key)
 {
 	const size_t hashbytes = hash_variant_bits(variant) / 8;
-	uint8_t key[256];
 	VARIABLE_ARRAY(uint8_t, hashes, hashbytes * 256);
 	VARIABLE_ARRAY(uint8_t, final, hashbytes);
 	unsigned i;
 	uint32_t computed, expected;
 
-	memset(key, 0, sizeof(key));
+	memset(key, 0, KEY_SIZE);
 	memset(hashes, 0, sizeof(hashes));
 	memset(final, 0, sizeof(final));
 
@@ -139,6 +139,19 @@ hash_variant_verify(hash_variant_t variant)
 	    hash_variant_string(variant), expected, computed);
 }
 
+static void
+hash_variant_verify(hash_variant_t variant)
+{
+#define	MAX_ALIGN	16
+	uint8_t key[KEY_SIZE + (MAX_ALIGN - 1)];
+	unsigned i;
+
+	for (i = 0; i < MAX_ALIGN; i++)
+		hash_variant_verify_key(variant, &key[i]);
+#undef MAX_ALIGN
+}
+#undef KEY_SIZE
+
 TEST_BEGIN(test_hash_x86_32)
 {