MDEV-18025 Mariabackup fails to detect corrupted page_compressed=1 tables

Problem:
=======
Mariabackup seems to fail to verify the pages of compressed tables.
The reason is that both fil_space_verify_crypt_checksum() and
buf_page_is_corrupted() will skip the validation for compressed pages.

Fix:
====
Mariabackup should call fil_page_decompress() for compressed and encrypted
compressed page. After that, call buf_page_is_corrupted() to
check the page corruption.

extra/mariabackup/fil_cur.cc

@@ -31,6 +31,7 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 
 #include "fil_cur.h"
 #include "fil0crypt.h"
+#include "fil0pagecompress.h"
 #include "common.h"
 #include "read_filt.h"
 #include "xtrabackup.h"
@@ -346,6 +347,7 @@ xb_fil_cur_read(
 	for (page = cursor->buf, i = 0; i < npages;
 	     page += cursor->page_size, i++) {
 		ulint page_no = cursor->buf_page_no + i;
+		ulint page_type = mach_read_from_2(page + FIL_PAGE_TYPE);
 
 		if (cursor->space_id == TRX_SYS_SPACE
 		    && page_no >= FSP_EXTENT_SIZE
@@ -367,12 +369,31 @@ xb_fil_cur_read(
 			memcpy(tmp_page, page, cursor->page_size);
 
 			if (!fil_space_decrypt(space, tmp_frame,
-					       tmp_page, &decrypted)
-			    || buf_page_is_corrupted(true, tmp_page,
-						     cursor->zip_size,
-						     space)) {
+					       tmp_page, &decrypted)) {
 				goto corrupted;
 			}
+
+			if (page_type == FIL_PAGE_PAGE_COMPRESSED_ENCRYPTED) {
+				goto page_decomp;
+			}
+
+			if (buf_page_is_corrupted(
+				true, tmp_page, cursor->zip_size, space)) {
+				goto corrupted;
+			}
+
+		} else if (page_type == FIL_PAGE_PAGE_COMPRESSED) {
+			memcpy(tmp_page, page, cursor->page_size);
+page_decomp:
+			ulint decomp = fil_page_decompress(tmp_frame, tmp_page);
+
+			if (!decomp
+			    || (decomp != srv_page_size && cursor->zip_size)
+			    || buf_page_is_corrupted(
+					true, tmp_page, cursor->zip_size, space)) {
+				goto corrupted;
+			}
+
 		} else if (buf_page_is_corrupted(true, page, cursor->zip_size,
 						 space)) {
 corrupted:

mysql-test/suite/mariabackup/encrypted_page_compressed.opt

+--innodb-encryption-rotate-key-age=2
+--innodb-encryption-threads=4
+--innodb-tablespaces-encryption
+--plugin-load-add=$FILE_KEY_MANAGEMENT_SO
+--loose-file-key-management
+--loose-file-key-management-filename=$MYSQL_TEST_DIR/std_data/logkey.txt

mysql-test/suite/mariabackup/encrypted_page_compressed.result

+CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY, b TEXT, c char(200)) ENGINE=InnoDB page_compressed=yes encrypted=yes;
+insert into t1(b, c) values("mariadb", "mariabackup");
+# Corrupt the table
+# xtrabackup backup
+FOUND /Database page corruption detected/ in backup.log
+drop table t1;

mysql-test/suite/mariabackup/encrypted_page_compressed.test

+source include/have_file_key_management.inc;
+CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY, b TEXT, c char(200)) ENGINE=InnoDB page_compressed=yes encrypted=yes;
+insert into t1(b, c) values("mariadb", "mariabackup");
+
+let $MYSQLD_DATADIR=`select @@datadir`;
+let t1_IBD = $MYSQLD_DATADIR/test/t1.ibd;
+let INNODB_PAGE_SIZE=`select @@innodb_page_size`;
+
+--source include/shutdown_mysqld.inc
+
+--echo # Corrupt the table
+
+perl;
+use strict;
+use warnings;
+use Fcntl qw(:DEFAULT :seek);
+
+my $ibd_file = $ENV{'t1_IBD'};
+
+my $chunk;
+my $page_size = $ENV{'INNODB_PAGE_SIZE'};
+
+sysopen IBD_FILE, $ibd_file, O_RDWR || die "Unable to open $ibd_file";
+sysseek IBD_FILE,  $page_size * 3 + 75, SEEK_CUR;
+$chunk = '\xAA\xAA\xAA\xAA';
+syswrite IBD_FILE, $chunk, 4;
+
+close IBD_FILE;
+EOF
+
+--source include/start_mysqld.inc
+
+echo # xtrabackup backup;
+--disable_result_log
+let $targetdir=$MYSQLTEST_VARDIR/tmp/backup;
+let $backuplog=$MYSQLTEST_VARDIR/tmp/backup.log;
+--error 1
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir > $backuplog;
+--enable_result_log
+
+--let SEARCH_PATTERN=Database page corruption detected
+--let SEARCH_FILE=$backuplog
+--source include/search_pattern_in_file.inc
+remove_file $backuplog;
+
+drop table t1;
+rmdir $targetdir;

mysql-test/suite/mariabackup/unencrypted_page_compressed.result

+CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY, b TEXT, c char(200)) ENGINE=InnoDB page_compressed=yes;
+insert into t1(b, c) values("mariadb", "mariabackup");
+# Corrupt the table
+# xtrabackup backup
+FOUND /Database page corruption detected/ in backup.log
+drop table t1;

mysql-test/suite/mariabackup/unencrypted_page_compressed.test

+CREATE TABLE t1 (a INT AUTO_INCREMENT PRIMARY KEY, b TEXT, c char(200)) ENGINE=InnoDB page_compressed=yes;
+insert into t1(b, c) values("mariadb", "mariabackup");
+
+let $MYSQLD_DATADIR=`select @@datadir`;
+let t1_IBD = $MYSQLD_DATADIR/test/t1.ibd;
+let INNODB_PAGE_SIZE=`select @@innodb_page_size`;
+
+--source include/shutdown_mysqld.inc
+
+--echo # Corrupt the table
+
+perl;
+use strict;
+use warnings;
+use Fcntl qw(:DEFAULT :seek);
+
+my $ibd_file = $ENV{'t1_IBD'};
+
+my $chunk;
+my $page_size = $ENV{'INNODB_PAGE_SIZE'};
+
+sysopen IBD_FILE, $ibd_file, O_RDWR || die "Unable to open $ibd_file";
+sysseek IBD_FILE, 16384 * 3 + 75, SEEK_CUR;
+$chunk = '\xAA\xAA\xAA\xAA';
+syswrite IBD_FILE, $chunk, 4;
+
+close IBD_FILE;
+EOF
+
+--source include/start_mysqld.inc
+
+echo # xtrabackup backup;
+--disable_result_log
+let $targetdir=$MYSQLTEST_VARDIR/tmp/backup;
+let $backuplog=$MYSQLTEST_VARDIR/tmp/backup.log;
+--error 1
+exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir > $backuplog;
+--enable_result_log
+
+--let SEARCH_PATTERN=Database page corruption detected
+--let SEARCH_FILE=$backuplog
+--source include/search_pattern_in_file.inc
+remove_file $backuplog;
+
+drop table t1;
+rmdir $targetdir;

storage/innobase/buf/buf0buf.cc

@@ -452,6 +452,8 @@ static bool buf_page_decrypt_after_read(buf_page_t* bpage, fil_space_t* space)
 		decrypt. */
 		if (!fil_space_verify_crypt_checksum(
 			    dst_frame, buf_page_get_zip_size(bpage))) {
+
+decrypt_failed:
 			ib_logf(IB_LOG_LEVEL_ERROR,
 				"Encrypted page %u:%u in file %s"
 				" looks corrupted; key_version=" ULINTPF,
@@ -460,7 +462,7 @@ static bool buf_page_decrypt_after_read(buf_page_t* bpage, fil_space_t* space)
 				mach_read_from_4(
 					FIL_PAGE_FILE_FLUSH_LSN_OR_KEY_VERSION
 					+ dst_frame));
-decrypt_failed:
+
 			/* Mark page encrypted in case it should be. */
 			if (space->crypt_data->type
 			    != CRYPT_SCHEME_UNENCRYPTED) {
@@ -4769,7 +4771,6 @@ static dberr_t buf_page_check_corrupt(buf_page_t* bpage, fil_space_t* space)
 		not anymore encrypted. */
 		corrupted = buf_page_is_corrupted(true, dst_frame, zip_size,
 						  space);
-
 		if (!corrupted) {
 			bpage->encrypted = false;
 		} else {