merge-cryptohash-ctx-and-state-structs.patch

diff --git a/src/common/cryptohash.c b/src/common/cryptohash.c
index cf4588bad72..d3fa32888f0 100644
--- a/src/common/cryptohash.c
+++ b/src/common/cryptohash.c
@@ -39,6 +39,20 @@
 #define FREE(ptr) free(ptr)
 #endif
 
+struct pg_cryptohash_ctx
+{
+	pg_cryptohash_type type;
+
+	union
+	{
+		pg_md5_ctx		md5;
+		pg_sha224_ctx	sha224;
+		pg_sha256_ctx	sha256;
+		pg_sha384_ctx	sha384;
+		pg_sha512_ctx	sha512;
+	} data;
+};
+
 /*
  * pg_cryptohash_create
  *
@@ -50,38 +64,15 @@ pg_cryptohash_create(pg_cryptohash_type type)
 {
 	pg_cryptohash_ctx *ctx;
 
+	/*
+	 * FIXME: this always allocates enough space for the largest hash.
+	 * A smaller allocation would be enough for md5, sha224 and sha256.
+	 */
 	ctx = ALLOC(sizeof(pg_cryptohash_ctx));
 	if (ctx == NULL)
 		return NULL;
-
 	ctx->type = type;
 
-	switch (type)
-	{
-		case PG_MD5:
-			ctx->data = ALLOC(sizeof(pg_md5_ctx));
-			break;
-		case PG_SHA224:
-			ctx->data = ALLOC(sizeof(pg_sha224_ctx));
-			break;
-		case PG_SHA256:
-			ctx->data = ALLOC(sizeof(pg_sha256_ctx));
-			break;
-		case PG_SHA384:
-			ctx->data = ALLOC(sizeof(pg_sha384_ctx));
-			break;
-		case PG_SHA512:
-			ctx->data = ALLOC(sizeof(pg_sha512_ctx));
-			break;
-	}
-
-	if (ctx->data == NULL)
-	{
-		explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
-		FREE(ctx);
-		return NULL;
-	}
-
 	return ctx;
 }
 
@@ -100,19 +91,19 @@ pg_cryptohash_init(pg_cryptohash_ctx *ctx)
 	switch (ctx->type)
 	{
 		case PG_MD5:
-			pg_md5_init((pg_md5_ctx *) ctx->data);
+			pg_md5_init(&ctx->data.md5);
 			break;
 		case PG_SHA224:
-			pg_sha224_init((pg_sha224_ctx *) ctx->data);
+			pg_sha224_init(&ctx->data.sha224);
 			break;
 		case PG_SHA256:
-			pg_sha256_init((pg_sha256_ctx *) ctx->data);
+			pg_sha256_init(&ctx->data.sha256);
 			break;
 		case PG_SHA384:
-			pg_sha384_init((pg_sha384_ctx *) ctx->data);
+			pg_sha384_init(&ctx->data.sha384);
 			break;
 		case PG_SHA512:
-			pg_sha512_init((pg_sha512_ctx *) ctx->data);
+			pg_sha512_init(&ctx->data.sha512);
 			break;
 	}
 
@@ -134,19 +125,19 @@ pg_cryptohash_update(pg_cryptohash_ctx *ctx, const uint8 *data, size_t len)
 	switch (ctx->type)
 	{
 		case PG_MD5:
-			pg_md5_update((pg_md5_ctx *) ctx->data, data, len);
+			pg_md5_update(&ctx->data.md5, data, len);
 			break;
 		case PG_SHA224:
-			pg_sha224_update((pg_sha224_ctx *) ctx->data, data, len);
+			pg_sha224_update(&ctx->data.sha224, data, len);
 			break;
 		case PG_SHA256:
-			pg_sha256_update((pg_sha256_ctx *) ctx->data, data, len);
+			pg_sha256_update(&ctx->data.sha256, data, len);
 			break;
 		case PG_SHA384:
-			pg_sha384_update((pg_sha384_ctx *) ctx->data, data, len);
+			pg_sha384_update(&ctx->data.sha384, data, len);
 			break;
 		case PG_SHA512:
-			pg_sha512_update((pg_sha512_ctx *) ctx->data, data, len);
+			pg_sha512_update(&ctx->data.sha512, data, len);
 			break;
 	}
 
@@ -168,19 +159,19 @@ pg_cryptohash_final(pg_cryptohash_ctx *ctx, uint8 *dest)
 	switch (ctx->type)
 	{
 		case PG_MD5:
-			pg_md5_final((pg_md5_ctx *) ctx->data, dest);
+			pg_md5_final(&ctx->data.md5, dest);
 			break;
 		case PG_SHA224:
-			pg_sha224_final((pg_sha224_ctx *) ctx->data, dest);
+			pg_sha224_final(&ctx->data.sha224, dest);
 			break;
 		case PG_SHA256:
-			pg_sha256_final((pg_sha256_ctx *) ctx->data, dest);
+			pg_sha256_final(&ctx->data.sha256, dest);
 			break;
 		case PG_SHA384:
-			pg_sha384_final((pg_sha384_ctx *) ctx->data, dest);
+			pg_sha384_final(&ctx->data.sha384, dest);
 			break;
 		case PG_SHA512:
-			pg_sha512_final((pg_sha512_ctx *) ctx->data, dest);
+			pg_sha512_final(&ctx->data.sha512, dest);
 			break;
 	}
 
@@ -198,26 +189,6 @@ pg_cryptohash_free(pg_cryptohash_ctx *ctx)
 	if (ctx == NULL)
 		return;
 
-	switch (ctx->type)
-	{
-		case PG_MD5:
-			explicit_bzero(ctx->data, sizeof(pg_md5_ctx));
-			break;
-		case PG_SHA224:
-			explicit_bzero(ctx->data, sizeof(pg_sha224_ctx));
-			break;
-		case PG_SHA256:
-			explicit_bzero(ctx->data, sizeof(pg_sha256_ctx));
-			break;
-		case PG_SHA384:
-			explicit_bzero(ctx->data, sizeof(pg_sha384_ctx));
-			break;
-		case PG_SHA512:
-			explicit_bzero(ctx->data, sizeof(pg_sha512_ctx));
-			break;
-	}
-
-	FREE(ctx->data);
 	explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
 	FREE(ctx);
 }
diff --git a/src/common/cryptohash_openssl.c b/src/common/cryptohash_openssl.c
index 118651c4153..24b9636d1ca 100644
--- a/src/common/cryptohash_openssl.c
+++ b/src/common/cryptohash_openssl.c
@@ -35,7 +35,7 @@
  * use malloc to be able to return a failure status back to the caller.
  */
 #ifndef FRONTEND
-#define ALLOC(size) palloc(size)
+#define ALLOC(size) MemoryContextAllocExtended(TopMemoryContext, size, MCXT_ALLOC_NO_OOM)
 #define FREE(ptr) pfree(ptr)
 #else
 #define ALLOC(size) malloc(size)
@@ -43,19 +43,21 @@
 #endif
 
 /*
- * Internal structure for pg_cryptohash_ctx->data.
+ * Internal pg_cryptohash_ctx structure.
  *
  * This tracks the resource owner associated to each EVP context data
  * for the backend.
  */
-typedef struct pg_cryptohash_state
+struct pg_cryptohash_ctx
 {
+	pg_cryptohash_type type;
+
 	EVP_MD_CTX *evpctx;
 
 #ifndef FRONTEND
 	ResourceOwner resowner;
 #endif
-} pg_cryptohash_state;
+};
 
 /*
  * pg_cryptohash_create
@@ -67,49 +69,41 @@ pg_cryptohash_ctx *
 pg_cryptohash_create(pg_cryptohash_type type)
 {
 	pg_cryptohash_ctx *ctx;
-	pg_cryptohash_state *state;
+
+	/*
+	 * Make sure that the resource owner has space to remember this
+	 * reference. This can error out with "out of memory", so do this
+	 * before any other allocation to avoid leaking.
+	 */
+#ifndef FRONTEND
+	ResourceOwnerEnlargeCryptoHash(CurrentResourceOwner);
+#endif
 
 	ctx = ALLOC(sizeof(pg_cryptohash_ctx));
 	if (ctx == NULL)
 		return NULL;
-
-	state = ALLOC(sizeof(pg_cryptohash_state));
-	if (state == NULL)
-	{
-		explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
-		FREE(ctx);
-		return NULL;
-	}
-
-	ctx->data = state;
 	ctx->type = type;
 
-#ifndef FRONTEND
-	ResourceOwnerEnlargeCryptoHash(CurrentResourceOwner);
-#endif
-
 	/*
 	 * Initialization takes care of assigning the correct type for OpenSSL.
 	 */
-	state->evpctx = EVP_MD_CTX_create();
+	ctx->evpctx = EVP_MD_CTX_create();
 
-	if (state->evpctx == NULL)
+	if (ctx->evpctx == NULL)
 	{
-		explicit_bzero(state, sizeof(pg_cryptohash_state));
 		explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
 #ifndef FRONTEND
 		ereport(ERROR,
 				(errcode(ERRCODE_OUT_OF_MEMORY),
 				 errmsg("out of memory")));
 #else
-		FREE(state);
 		FREE(ctx);
 		return NULL;
 #endif
 	}
 
 #ifndef FRONTEND
-	state->resowner = CurrentResourceOwner;
+	ctx->resowner = CurrentResourceOwner;
 	ResourceOwnerRememberCryptoHash(CurrentResourceOwner,
 									PointerGetDatum(ctx));
 #endif
@@ -126,33 +120,30 @@ int
 pg_cryptohash_init(pg_cryptohash_ctx *ctx)
 {
 	int			status = 0;
-	pg_cryptohash_state *state;
 
 	if (ctx == NULL)
 		return 0;
 
-	state = (pg_cryptohash_state *) ctx->data;
-
 	switch (ctx->type)
 	{
 		case PG_MD5:
-			status = EVP_DigestInit_ex(state->evpctx, EVP_md5(), NULL);
+			status = EVP_DigestInit_ex(ctx->evpctx, EVP_md5(), NULL);
 			break;
 		case PG_SHA224:
-			status = EVP_DigestInit_ex(state->evpctx, EVP_sha224(), NULL);
+			status = EVP_DigestInit_ex(ctx->evpctx, EVP_sha224(), NULL);
 			break;
 		case PG_SHA256:
-			status = EVP_DigestInit_ex(state->evpctx, EVP_sha256(), NULL);
+			status = EVP_DigestInit_ex(ctx->evpctx, EVP_sha256(), NULL);
 			break;
 		case PG_SHA384:
-			status = EVP_DigestInit_ex(state->evpctx, EVP_sha384(), NULL);
+			status = EVP_DigestInit_ex(ctx->evpctx, EVP_sha384(), NULL);
 			break;
 		case PG_SHA512:
-			status = EVP_DigestInit_ex(state->evpctx, EVP_sha512(), NULL);
+			status = EVP_DigestInit_ex(ctx->evpctx, EVP_sha512(), NULL);
 			break;
 	}
 
-	/* OpenSSL internals return 1 on success, 0 on failure */
+	/* openssl internals return 1 on success, 0 on failure */
 	if (status <= 0)
 		return -1;
 	return 0;
@@ -161,21 +152,19 @@ pg_cryptohash_init(pg_cryptohash_ctx *ctx)
 /*
  * pg_cryptohash_update
  *
- * Update a hash context.  Returns 0 on success, and -1 on failure.
+ * update a hash context.  returns 0 on success, and -1 on failure.
  */
 int
 pg_cryptohash_update(pg_cryptohash_ctx *ctx, const uint8 *data, size_t len)
 {
 	int			status = 0;
-	pg_cryptohash_state *state;
 
 	if (ctx == NULL)
 		return 0;
 
-	state = (pg_cryptohash_state *) ctx->data;
-	status = EVP_DigestUpdate(state->evpctx, data, len);
+	status = EVP_DigestUpdate(ctx->evpctx, data, len);
 
-	/* OpenSSL internals return 1 on success, 0 on failure */
+	/* openssl internals return 1 on success, 0 on failure */
 	if (status <= 0)
 		return -1;
 	return 0;
@@ -184,19 +173,17 @@ pg_cryptohash_update(pg_cryptohash_ctx *ctx, const uint8 *data, size_t len)
 /*
  * pg_cryptohash_final
  *
- * Finalize a hash context.  Returns 0 on success, and -1 on failure.
+ * finalize a hash context.  returns 0 on success, and -1 on failure.
  */
 int
 pg_cryptohash_final(pg_cryptohash_ctx *ctx, uint8 *dest)
 {
 	int			status = 0;
-	pg_cryptohash_state *state;
 
 	if (ctx == NULL)
 		return 0;
 
-	state = (pg_cryptohash_state *) ctx->data;
-	status = EVP_DigestFinal_ex(state->evpctx, dest, 0);
+	status = EVP_DigestFinal_ex(ctx->evpctx, dest, 0);
 
 	/* OpenSSL internals return 1 on success, 0 on failure */
 	if (status <= 0)
@@ -207,26 +194,21 @@ pg_cryptohash_final(pg_cryptohash_ctx *ctx, uint8 *dest)
 /*
  * pg_cryptohash_free
  *
- * Free a hash context.
+ * free a hash context.
  */
 void
 pg_cryptohash_free(pg_cryptohash_ctx *ctx)
 {
-	pg_cryptohash_state *state;
-
 	if (ctx == NULL)
 		return;
 
-	state = (pg_cryptohash_state *) ctx->data;
-	EVP_MD_CTX_destroy(state->evpctx);
+	EVP_MD_CTX_destroy(ctx->evpctx);
 
 #ifndef FRONTEND
-	ResourceOwnerForgetCryptoHash(state->resowner,
+	ResourceOwnerForgetCryptoHash(ctx->resowner,
 								  PointerGetDatum(ctx));
 #endif
 
-	explicit_bzero(state, sizeof(pg_cryptohash_state));
 	explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
-	FREE(state);
 	FREE(ctx);
 }
diff --git a/src/include/common/cryptohash.h b/src/include/common/cryptohash.h
index 6ead1cb8e5b..69e69532d44 100644
--- a/src/include/common/cryptohash.h
+++ b/src/include/common/cryptohash.h
@@ -25,12 +25,8 @@ typedef enum
 	PG_SHA512
 } pg_cryptohash_type;
 
-typedef struct pg_cryptohash_ctx
-{
-	pg_cryptohash_type type;
-	/* private area used by each hash implementation */
-	void	   *data;
-} pg_cryptohash_ctx;
+/* opaque context, private to the cryptohash implementation */
+typedef struct pg_cryptohash_ctx pg_cryptohash_ctx;
 
 extern pg_cryptohash_ctx *pg_cryptohash_create(pg_cryptohash_type type);
 extern int	pg_cryptohash_init(pg_cryptohash_ctx *ctx);