From fca2eb3d43226cb119b682fda7716c5a4c28a841 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 23 May 2016 14:16:41 -0400
Subject: [PATCH] Fix latent crash in do_text_output_multiline().
do_text_output_multiline() would fail (typically with a null pointer
dereference crash) if its input string did not end with a newline. Such
cases do not arise in our current sources; but it certainly could happen
in future, or in extension code's usage of the function, so we should fix
it. To fix, replace "eol += len" with "eol = text + len".
While at it, make two cosmetic improvements: mark the input string const,
and rename the argument from "text" to "txt" to dodge pgindent strangeness
(since "text" is a typedef name).
Even though this problem is only latent at present, it seems like a good
idea to back-patch the fix, since it's a very simple/safe patch and it's
not out of the realm of possibility that we might in future back-patch
something that expects sane behavior from do_text_output_multiline().
Per report from Hao Lee.
Report: <CAGoxFiFPAGyPAJLcFxTB5cGhTW2yOVBDYeqDugYwV4dEd1L_Ag@mail.gmail.com>
---
src/backend/executor/execTuples.c | 19 +++++++++----------
src/include/executor/executor.h | 2 +-
2 files changed, 10 insertions(+), 11 deletions(-)
diff --git a/src/backend/executor/execTuples.c b/src/backend/executor/execTuples.c
index 227e01c6191..d0a982a4a3a 100644
--- a/src/backend/executor/execTuples.c
+++ b/src/backend/executor/execTuples.c
@@ -1282,33 +1282,32 @@ do_tup_output(TupOutputState *tstate, Datum *values, bool *isnull)
* Should only be used with a single-TEXT-attribute tupdesc.
*/
void
-do_text_output_multiline(TupOutputState *tstate, char *text)
+do_text_output_multiline(TupOutputState *tstate, const char *txt)
{
Datum values[1];
bool isnull[1] = {false};
- while (*text)
+ while (*txt)
{
- char *eol;
+ const char *eol;
int len;
- eol = strchr(text, '\n');
+ eol = strchr(txt, '\n');
if (eol)
{
- len = eol - text;
-
+ len = eol - txt;
eol++;
}
else
{
- len = strlen(text);
- eol += len;
+ len = strlen(txt);
+ eol = txt + len;
}
- values[0] = PointerGetDatum(cstring_to_text_with_len(text, len));
+ values[0] = PointerGetDatum(cstring_to_text_with_len(txt, len));
do_tup_output(tstate, values, isnull);
pfree(DatumGetPointer(values[0]));
- text = eol;
+ txt = eol;
}
}
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index f60d809bc98..ba3cfc8d738 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -275,7 +275,7 @@ typedef struct TupOutputState
extern TupOutputState *begin_tup_output_tupdesc(DestReceiver *dest,
TupleDesc tupdesc);
extern void do_tup_output(TupOutputState *tstate, Datum *values, bool *isnull);
-extern void do_text_output_multiline(TupOutputState *tstate, char *text);
+extern void do_text_output_multiline(TupOutputState *tstate, const char *txt);
extern void end_tup_output(TupOutputState *tstate);
/*
--
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