Fix string literal length for compressed_data_info

The function `compressed_data_info` returns a record containing `name`
but copies the data from string literal. Since `heap_form_tuple`
expects a `name` value as source as well, it will copy too much data
from the source, leading to ASAN complaining about copying outside the
allocated range of data.

The problem is fixed by using `NameData` for each source string,
ensuring that each of the string literals has sufficient data for being
copied as names.

.unreleased/pr_7187

@@ -0,0 +1 @@
+Fixes: #7187 Fix string literal length for compressed_data_info

tsl/src/compression/compression.c

@@ -46,16 +46,18 @@ static const CompressionAlgorithmDefinition definitions[_END_COMPRESSION_ALGORIT
 	[COMPRESSION_ALGORITHM_DELTADELTA] = DELTA_DELTA_ALGORITHM_DEFINITION,
 };
 
-static const char *compression_algorithm_name[] = {
-	[_INVALID_COMPRESSION_ALGORITHM] = "INVALID",	   [COMPRESSION_ALGORITHM_ARRAY] = "ARRAY",
-	[COMPRESSION_ALGORITHM_DICTIONARY] = "DICTIONARY", [COMPRESSION_ALGORITHM_GORILLA] = "GORILLA",
-	[COMPRESSION_ALGORITHM_DELTADELTA] = "DELTADELTA",
+static NameData compression_algorithm_name[] = {
+	[_INVALID_COMPRESSION_ALGORITHM] = { "INVALID" },
+	[COMPRESSION_ALGORITHM_ARRAY] = { "ARRAY" },
+	[COMPRESSION_ALGORITHM_DICTIONARY] = { "DICTIONARY" },
+	[COMPRESSION_ALGORITHM_GORILLA] = { "GORILLA" },
+	[COMPRESSION_ALGORITHM_DELTADELTA] = { "DELTADELTA" },
 };
 
-const char *
+Name
 compression_get_algorithm_name(CompressionAlgorithm alg)
 {
-	return compression_algorithm_name[alg];
+	return &compression_algorithm_name[alg];
 }
 
 static Compressor *
@@ -2041,7 +2043,7 @@ tsl_compressed_data_info(PG_FUNCTION_ARGS)
 	bool nulls[Natts_compressed_info] = { false };
 
 	values[AttrNumberGetAttrOffset(Anum_compressed_info_algorithm)] =
-		CStringGetDatum(compression_get_algorithm_name(header->compression_algorithm));
+		NameGetDatum(compression_get_algorithm_name(header->compression_algorithm));
 	values[AttrNumberGetAttrOffset(Anum_compressed_info_has_nulls)] = BoolGetDatum(has_nulls);
 	tuple = heap_form_tuple(tupdesc, values, nulls);
 

tsl/src/compression/compression.h

@@ -321,7 +321,7 @@ pg_attribute_unused() assert_num_compression_algorithms_sane(void)
 					 "number of algorithms have changed, the asserts should be updated");
 }
 
-extern const char *compression_get_algorithm_name(CompressionAlgorithm alg);
+extern Name compression_get_algorithm_name(CompressionAlgorithm alg);
 extern CompressionStorage compression_get_toast_storage(CompressionAlgorithm algo);
 extern CompressionAlgorithm compression_get_default_algorithm(Oid typeoid);