1 files changed, 161 insertions, 0 deletions
diff --git a/src/backend/utils/adt/cryptohashfuncs.c b/src/backend/utils/adt/cryptohashfuncs.c
new file mode 100644
index 0000000..6a0f025
--- /dev/null
+++ b/src/backend/utils/adt/cryptohashfuncs.c
@@ -0,0 +1,161 @@
+/*-------------------------------------------------------------------------
+ *
+ * cryptohashfuncs.c
+ *	  Cryptographic hash functions
+ *
+ * Portions Copyright (c) 2018-2021, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/utils/adt/cryptohashfuncs.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "common/cryptohash.h"
+#include "common/md5.h"
+#include "common/sha2.h"
+#include "utils/builtins.h"
+
+
+/*
+ * MD5
+ */
+
+/* MD5 produces a 16 byte (128 bit) hash; double it for hex */
+#define MD5_HASH_LEN  32
+
+/*
+ * Create an MD5 hash of a text value and return it as hex string.
+ */
+Datum
+md5_text(PG_FUNCTION_ARGS)
+{
+	text	   *in_text = PG_GETARG_TEXT_PP(0);
+	size_t		len;
+	char		hexsum[MD5_HASH_LEN + 1];
+
+	/* Calculate the length of the buffer using varlena metadata */
+	len = VARSIZE_ANY_EXHDR(in_text);
+
+	/* get the hash result */
+	if (pg_md5_hash(VARDATA_ANY(in_text), len, hexsum) == false)
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of memory")));
+
+	/* convert to text and return it */
+	PG_RETURN_TEXT_P(cstring_to_text(hexsum));
+}
+
+/*
+ * Create an MD5 hash of a bytea value and return it as a hex string.
+ */
+Datum
+md5_bytea(PG_FUNCTION_ARGS)
+{
+	bytea	   *in = PG_GETARG_BYTEA_PP(0);
+	size_t		len;
+	char		hexsum[MD5_HASH_LEN + 1];
+
+	len = VARSIZE_ANY_EXHDR(in);
+	if (pg_md5_hash(VARDATA_ANY(in), len, hexsum) == false)
+		ereport(ERROR,
+				(errcode(ERRCODE_OUT_OF_MEMORY),
+				 errmsg("out of memory")));
+
+	PG_RETURN_TEXT_P(cstring_to_text(hexsum));
+}
+
+/*
+ * Internal routine to compute a cryptohash with the given bytea input.
+ */
+static inline bytea *
+cryptohash_internal(pg_cryptohash_type type, bytea *input)
+{
+	const uint8 *data;
+	const char *typestr = NULL;
+	int			digest_len = 0;
+	size_t		len;
+	pg_cryptohash_ctx *ctx;
+	bytea	   *result;
+
+	switch (type)
+	{
+		case PG_SHA224:
+			typestr = "SHA224";
+			digest_len = PG_SHA224_DIGEST_LENGTH;
+			break;
+		case PG_SHA256:
+			typestr = "SHA256";
+			digest_len = PG_SHA256_DIGEST_LENGTH;
+			break;
+		case PG_SHA384:
+			typestr = "SHA384";
+			digest_len = PG_SHA384_DIGEST_LENGTH;
+			break;
+		case PG_SHA512:
+			typestr = "SHA512";
+			digest_len = PG_SHA512_DIGEST_LENGTH;
+			break;
+		case PG_MD5:
+		case PG_SHA1:
+			elog(ERROR, "unsupported cryptohash type %d", type);
+			break;
+	}
+
+	result = palloc0(digest_len + VARHDRSZ);
+	len = VARSIZE_ANY_EXHDR(input);
+	data = (unsigned char *) VARDATA_ANY(input);
+
+	ctx = pg_cryptohash_create(type);
+	if (pg_cryptohash_init(ctx) < 0)
+		elog(ERROR, "could not initialize %s context", typestr);
+	if (pg_cryptohash_update(ctx, data, len) < 0)
+		elog(ERROR, "could not update %s context", typestr);
+	if (pg_cryptohash_final(ctx, (unsigned char *) VARDATA(result),
+							digest_len) < 0)
+		elog(ERROR, "could not finalize %s context", typestr);
+	pg_cryptohash_free(ctx);
+
+	SET_VARSIZE(result, digest_len + VARHDRSZ);
+
+	return result;
+}
+
+/*
+ * SHA-2 variants
+ */
+
+Datum
+sha224_bytea(PG_FUNCTION_ARGS)
+{
+	bytea	   *result = cryptohash_internal(PG_SHA224, PG_GETARG_BYTEA_PP(0));
+
+	PG_RETURN_BYTEA_P(result);
+}
+
+Datum
+sha256_bytea(PG_FUNCTION_ARGS)
+{
+	bytea	   *result = cryptohash_internal(PG_SHA256, PG_GETARG_BYTEA_PP(0));
+
+	PG_RETURN_BYTEA_P(result);
+}
+
+Datum
+sha384_bytea(PG_FUNCTION_ARGS)
+{
+	bytea	   *result = cryptohash_internal(PG_SHA384, PG_GETARG_BYTEA_PP(0));
+
+	PG_RETURN_BYTEA_P(result);
+}
+
+Datum
+sha512_bytea(PG_FUNCTION_ARGS)
+{
+	bytea	   *result = cryptohash_internal(PG_SHA512, PG_GETARG_BYTEA_PP(0));
+
+	PG_RETURN_BYTEA_P(result);
+}