Disallow "=" in names of reloptions and foreign-data options.

We store values for these options as array elements with the syntax
"name=value", hence a name containing "=" confuses matters when
it's time to read the array back in.  Since validation of the
options is often done (long) after this conversion to array format,
that leads to confusing and off-point error messages.  We can
improve matters by rejecting names containing "=" up-front.

(Probably a better design would have involved pairs of array
elements, but it's too late now --- and anyway, there's no
evident use-case for option names like this.  We already
reject such names in some other contexts such as GUCs.)

Reported-by: Chapman Flack <jcflack@acm.org>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Chapman Flack <jcflack@acm.org>
Discussion: https://postgr.es/m/6830EB30.8090904@acm.org
Backpatch-through: 13

4 files changed, 32 insertions, 6 deletions

diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index df8d43b3749..246e3d3e566 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -48,6 +48,10 @@ SET ROLE regress_file_fdw_superuser;
 CREATE USER MAPPING FOR regress_file_fdw_superuser SERVER file_server;
 CREATE USER MAPPING FOR regress_no_priv_user SERVER file_server;
 -- validator tests
+CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (foo 'bar');  -- ERROR
+ERROR:  invalid option "foo"
+CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS ("a=b" 'true');  -- ERROR
+ERROR:  invalid option name "a=b": must not contain "="
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'xml');  -- ERROR
 ERROR:  COPY format "xml" not recognized
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', quote ':');          -- ERROR
diff --git a/contrib/file_fdw/sql/file_fdw.sql b/contrib/file_fdw/sql/file_fdw.sql
index 2cdbe7a8a4c..1a397ad4bd1 100644
--- a/contrib/file_fdw/sql/file_fdw.sql
+++ b/contrib/file_fdw/sql/file_fdw.sql
@@ -55,6 +55,8 @@ CREATE USER MAPPING FOR regress_file_fdw_superuser SERVER file_server;
 CREATE USER MAPPING FOR regress_no_priv_user SERVER file_server;
 
 -- validator tests
+CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (foo 'bar');  -- ERROR
+CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS ("a=b" 'true');  -- ERROR
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'xml');  -- ERROR
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', quote ':');          -- ERROR
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (format 'text', escape ':');         -- ERROR
diff --git a/src/backend/access/common/reloptions.c b/src/backend/access/common/reloptions.c
index 46c1dce222d..50747c16396 100644
--- a/src/backend/access/common/reloptions.c
+++ b/src/backend/access/common/reloptions.c
@@ -1243,8 +1243,9 @@ transformRelOptions(Datum oldOptions, List *defList, const char *namspace,
 		}
 		else
 		{
-			text	   *t;
+			const char *name;
 			const char *value;
+			text	   *t;
 			Size		len;
 
 			/*
@@ -1291,11 +1292,19 @@ transformRelOptions(Datum oldOptions, List *defList, const char *namspace,
 			 * have just "name", assume "name=true" is meant.  Note: the
 			 * namespace is not output.
 			 */
+			name = def->defname;
 			if (def->arg != NULL)
 				value = defGetString(def);
 			else
 				value = "true";
 
+			/* Insist that name not contain "=", else "a=b=c" is ambiguous */
+			if (strchr(name, '=') != NULL)
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("invalid option name \"%s\": must not contain \"=\"",
+								name)));
+
 			/*
 			 * This is not a great place for this test, but there's no other
 			 * convenient place to filter the option out. As WITH (oids =
@@ -1303,7 +1312,7 @@ transformRelOptions(Datum oldOptions, List *defList, const char *namspace,
 			 * amount of ugly.
 			 */
 			if (acceptOidsOff && def->defnamespace == NULL &&
-				strcmp(def->defname, "oids") == 0)
+				strcmp(name, "oids") == 0)
 			{
 				if (defGetBoolean(def))
 					ereport(ERROR,
@@ -1313,11 +1322,11 @@ transformRelOptions(Datum oldOptions, List *defList, const char *namspace,
 				continue;
 			}
 
-			len = VARHDRSZ + strlen(def->defname) + 1 + strlen(value);
+			len = VARHDRSZ + strlen(name) + 1 + strlen(value);
 			/* +1 leaves room for sprintf's trailing null */
 			t = (text *) palloc(len + 1);
 			SET_VARSIZE(t, len);
-			sprintf(VARDATA(t), "%s=%s", def->defname, value);
+			sprintf(VARDATA(t), "%s=%s", name, value);
 
 			astate = accumArrayResult(astate, PointerGetDatum(t),
 									  false, TEXTOID,
diff --git a/src/backend/commands/foreigncmds.c b/src/backend/commands/foreigncmds.c
index c14e038d54f..8d2d7431544 100644
--- a/src/backend/commands/foreigncmds.c
+++ b/src/backend/commands/foreigncmds.c
@@ -71,15 +71,26 @@ optionListToArray(List *options)
 	foreach(cell, options)
 	{
 		DefElem    *def = lfirst(cell);
+		const char *name;
 		const char *value;
 		Size		len;
 		text	   *t;
 
+		name = def->defname;
 		value = defGetString(def);
-		len = VARHDRSZ + strlen(def->defname) + 1 + strlen(value);
+
+		/* Insist that name not contain "=", else "a=b=c" is ambiguous */
+		if (strchr(name, '=') != NULL)
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("invalid option name \"%s\": must not contain \"=\"",
+							name)));
+
+		len = VARHDRSZ + strlen(name) + 1 + strlen(value);
+		/* +1 leaves room for sprintf's trailing null */
 		t = palloc(len + 1);
 		SET_VARSIZE(t, len);
-		sprintf(VARDATA(t), "%s=%s", def->defname, value);
+		sprintf(VARDATA(t), "%s=%s", name, value);
 
 		astate = accumArrayResult(astate, PointerGetDatum(t),
 								  false, TEXTOID,