From cf22e851b6ae8737f3e767dffcadf1722fbb36a7 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 10 Nov 2011 16:08:14 -0500
Subject: [PATCH] Avoid platform-dependent infinite loop in pg_dump.
If malloc(0) returns NULL, the binary search in findSecLabels() will
probably go into an infinite loop when there are no security labels,
because NULL-1 is greater than NULL after wraparound.
(We've seen this pathology before ... I wonder whether there's a way to
detect the class of bugs automatically?)
Diagnosis and patch by Steve Singer, cosmetic adjustments by me
---
src/bin/pg_dump/pg_dump.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 88a867fe8e3..973f0b335d7 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -645,9 +645,10 @@ main(int argc, char **argv)
do_sql_command(g_conn, "SET quote_all_identifiers = true");
/*
- * Disables security label support if server version < v9.1.x
+ * Disable security label support if server version < v9.1.x (prevents
+ * access to nonexistent pg_seclabel catalog)
*/
- if (!no_security_labels && g_fout->remoteVersion < 90100)
+ if (g_fout->remoteVersion < 90100)
no_security_labels = 1;
/*
@@ -11993,6 +11994,12 @@ findSecLabels(Archive *fout, Oid classoid, Oid objoid, SecLabelItem **items)
if (nlabels < 0)
nlabels = collectSecLabels(fout, &labels);
+ if (nlabels <= 0) /* no labels, so no match is possible */
+ {
+ *items = NULL;
+ return 0;
+ }
+
/*
* Do binary search to find some item matching the object.
*/
--
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