From d55241af705667d4503638e3f77d3689fd6be31d Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Fri, 19 Oct 2018 22:44:12 +0900
Subject: [PATCH] Use whitelist to choose files scanned with
pg_verify_checksums
The original implementation of pg_verify_checksums used a blacklist to
decide which files should be skipped for scanning as they do not include
data checksums, like pg_internal.init or pg_control. However, this
missed two things:
- Some files are created within builds of EXEC_BACKEND and these were
not listed, causing failures on Windows.
- Extensions may create custom files in data folders, causing the tool
to equally fail.
This commit switches to a whitelist-like method instead by checking if
the files to scan are authorized relation files. This is close to a
reverse-engineering of what is defined in relpath.c in charge of
building the relation paths, and we could consider refactoring what this
patch does so as all routines are in a single place. This is left for
later.
This is based on a suggestion from Andres Freund. TAP tests are updated
so as multiple file patterns are tested. The bug has been spotted by
various buildfarm members as a result of b34e84f which has introduced
the TAP tests of pg_verify_checksums.
Author: Michael Paquier
Reviewed-by: Andrew Dunstan, Michael Banck
Discussion: https://postgr.es/m/20181012005614.GC26424@paquier.xyz
Backpatch-through: 11
---
.../pg_verify_checksums/pg_verify_checksums.c | 79 ++++++++++++++-----
src/bin/pg_verify_checksums/t/002_actions.pl | 56 ++++++++++++-
2 files changed, 116 insertions(+), 19 deletions(-)
diff --git a/src/bin/pg_verify_checksums/pg_verify_checksums.c b/src/bin/pg_verify_checksums/pg_verify_checksums.c
index 1bc020ab6c..f0e09bea20 100644
--- a/src/bin/pg_verify_checksums/pg_verify_checksums.c
+++ b/src/bin/pg_verify_checksums/pg_verify_checksums.c
@@ -15,6 +15,7 @@
#include "catalog/pg_control.h"
#include "common/controldata_utils.h"
+#include "common/relpath.h"
#include "getopt_long.h"
#include "pg_getopt.h"
#include "storage/bufpage.h"
@@ -49,27 +50,69 @@ usage(void)
printf(_("Report bugs to <pgsql-bugs@postgresql.org>.\n"));
}
-static const char *const skip[] = {
- "pg_control",
- "pg_filenode.map",
- "pg_internal.init",
- "PG_VERSION",
- NULL,
-};
-
+/*
+ * isRelFileName
+ *
+ * Check if the given file name is authorized for checksum verification.
+ */
static bool
-skipfile(const char *fn)
+isRelFileName(const char *fn)
{
- const char *const *f;
-
- if (strcmp(fn, ".") == 0 ||
- strcmp(fn, "..") == 0)
+ int pos;
+
+ /*----------
+ * Only files including data checksums are authorized for verification.
+ * This is guessed based on the file name by reverse-engineering
+ * GetRelationPath() so make sure to update both code paths if any
+ * updates are done. The following file name formats are allowed:
+ * <digits>
+ * <digits>.<segment>
+ * <digits>_<forkname>
+ * <digits>_<forkname>.<segment>
+ *
+ * Note that temporary files, beginning with 't', are also skipped.
+ *
+ *----------
+ */
+
+ /* A non-empty string of digits should follow */
+ for (pos = 0; isdigit((unsigned char) fn[pos]); ++pos)
+ ;
+ /* leave if no digits */
+ if (pos == 0)
+ return false;
+ /* good to go if only digits */
+ if (fn[pos] == '\0')
return true;
- for (f = skip; *f; f++)
- if (strcmp(*f, fn) == 0)
- return true;
- return false;
+ /* Authorized fork files can be scanned */
+ if (fn[pos] == '_')
+ {
+ int forkchar = forkname_chars(&fn[pos + 1], NULL);
+
+ if (forkchar <= 0)
+ return false;
+
+ pos += forkchar + 1;
+ }
+
+ /* Check for an optional segment number */
+ if (fn[pos] == '.')
+ {
+ int segchar;
+
+ for (segchar = 1; isdigit((unsigned char) fn[pos + segchar]); ++segchar)
+ ;
+
+ if (segchar <= 1)
+ return false;
+ pos += segchar;
+ }
+
+ /* Now this should be the end */
+ if (fn[pos] != '\0')
+ return false;
+ return true;
}
static void
@@ -146,7 +189,7 @@ scan_directory(const char *basedir, const char *subdir)
char fn[MAXPGPATH];
struct stat st;
- if (skipfile(de->d_name))
+ if (!isRelFileName(de->d_name))
continue;
snprintf(fn, sizeof(fn), "%s/%s", path, de->d_name);
diff --git a/src/bin/pg_verify_checksums/t/002_actions.pl b/src/bin/pg_verify_checksums/t/002_actions.pl
index dc29da09af..a9003b14cc 100644
--- a/src/bin/pg_verify_checksums/t/002_actions.pl
+++ b/src/bin/pg_verify_checksums/t/002_actions.pl
@@ -5,7 +5,7 @@ use strict;
use warnings;
use PostgresNode;
use TestLib;
-use Test::More tests => 12;
+use Test::More tests => 36;
# Initialize node with checksums enabled.
my $node = get_new_node('node_checksum');
@@ -17,6 +17,31 @@ command_like(['pg_controldata', $pgdata],
qr/Data page checksum version:.*1/,
'checksums enabled in control file');
+# Add set of dummy files with some contents. These should not be scanned
+# by the tool.
+append_to_file "$pgdata/global/123.", "foo";
+append_to_file "$pgdata/global/123_", "foo";
+append_to_file "$pgdata/global/123_.", "foo";
+append_to_file "$pgdata/global/123.12t", "foo";
+append_to_file "$pgdata/global/foo", "foo2";
+append_to_file "$pgdata/global/t123", "bar";
+append_to_file "$pgdata/global/123a", "bar2";
+append_to_file "$pgdata/global/.123", "foobar";
+append_to_file "$pgdata/global/_fsm", "foobar2";
+append_to_file "$pgdata/global/_init", "foobar3";
+append_to_file "$pgdata/global/_vm.123", "foohoge";
+append_to_file "$pgdata/global/123_vm.123t", "foohoge2";
+
+# Those are correct but empty files, so they should pass through.
+append_to_file "$pgdata/global/99999", "";
+append_to_file "$pgdata/global/99999.123", "";
+append_to_file "$pgdata/global/99999_fsm", "";
+append_to_file "$pgdata/global/99999_init", "";
+append_to_file "$pgdata/global/99999_vm", "";
+append_to_file "$pgdata/global/99999_init.123", "";
+append_to_file "$pgdata/global/99999_fsm.123", "";
+append_to_file "$pgdata/global/99999_vm.123", "";
+
# Checksums pass on a newly-created cluster
command_ok(['pg_verify_checksums', '-D', $pgdata],
"succeeds with offline cluster");
@@ -67,3 +92,32 @@ $node->command_checks_all([ 'pg_verify_checksums', '-D', $pgdata, '-r',
[qr/Bad checksums:.*1/],
[qr/checksum verification failed/],
'fails for corrupted data on single relfilenode');
+
+# Utility routine to check that pg_verify_checksums is able to detect
+# correctly-named relation files filled with some corrupted data.
+sub fail_corrupt
+{
+ my $node = shift;
+ my $file = shift;
+ my $pgdata = $node->data_dir;
+
+ # Create the file with some dummy data in it.
+ append_to_file "$pgdata/global/$file", "foo";
+
+ $node->command_checks_all([ 'pg_verify_checksums', '-D', $pgdata],
+ 1,
+ [qr/^$/],
+ [qr/could not read block/],
+ "fails for corrupted data in $file");
+}
+
+# Authorized relation files filled with corrupted data cause the
+# checksum checks to fail.
+fail_corrupt($node, "99999");
+fail_corrupt($node, "99999.123");
+fail_corrupt($node, "99999_fsm");
+fail_corrupt($node, "99999_init");
+fail_corrupt($node, "99999_vm");
+fail_corrupt($node, "99999_init.123");
+fail_corrupt($node, "99999_fsm.123");
+fail_corrupt($node, "99999_vm.123");
--
2.50.0