Fix issue with EVENT TRIGGERS and ALTER PUBLICATIONorigin/REL_16_STABLE

When processing the "publish" options of an ALTER PUBLICATION command,
we call SplitIdentifierString() to split the options into a List of
strings.  Since SplitIdentifierString() modifies the delimiter
character and puts NULs in their place, this would overwrite the memory
of the AlterPublicationStmt.  Later in AlterPublicationOptions(), the
modified AlterPublicationStmt is copied for event triggers, which would
result in the event trigger only seeing the first "publish" option
rather than all options that were specified in the command.

To fix this, make a copy of the string before passing to
SplitIdentifierString().

Here we also adjust a similar case in the pgoutput plugin.  There's no
known issues caused by SplitIdentifierString() here, so this is being
done out of paranoia.

Thanks to Henson Choi for putting together an example case showing the
ALTER PUBLICATION issue.

Author: sunil s <sunilfeb26@gmail.com>
Reviewed-by: Henson Choi <assam258@gmail.com>
Reviewed-by: zengman <zengman@halodbtech.com>
Backpatch-through: 14

2 files changed, 11 insertions, 2 deletions

diff --git a/src/backend/commands/publicationcmds.c b/src/backend/commands/publicationcmds.c
index f4ba572697a..874a8ce6e14 100644
--- a/src/backend/commands/publicationcmds.c
+++ b/src/backend/commands/publicationcmds.c
@@ -123,7 +123,12 @@ parse_publication_options(ParseState *pstate,
 			pubactions->pubtruncate = false;
 
 			*publish_given = true;
-			publish = defGetString(defel);
+
+			/*
+			 * SplitIdentifierString destructively modifies its input, so make
+			 * a copy so we don't modify the memory of the executing statement
+			 */
+			publish = pstrdup(defGetString(defel));
 
 			if (!SplitIdentifierString(publish, ',', &publish_list))
 				ereport(ERROR,
diff --git a/src/backend/replication/pgoutput/pgoutput.c b/src/backend/replication/pgoutput/pgoutput.c
index 62e584a2cd1..210d49a2228 100644
--- a/src/backend/replication/pgoutput/pgoutput.c
+++ b/src/backend/replication/pgoutput/pgoutput.c
@@ -340,7 +340,11 @@ parse_output_parameters(List *options, PGOutputData *data)
 						 errmsg("conflicting or redundant options")));
 			publication_names_given = true;
 
-			if (!SplitIdentifierString(strVal(defel->arg), ',',
+			/*
+			 * Pass a copy of the DefElem->arg since SplitIdentifierString
+			 * modifies its input.
+			 */
+			if (!SplitIdentifierString(pstrdup(strVal(defel->arg)), ',',
 									   &data->publication_names))
 				ereport(ERROR,
 						(errcode(ERRCODE_INVALID_NAME),