Fix the warnings issued by GCC 8 -Wstringop-truncation
and -Wstringop-overflow in InnoDB and XtraDB.
This work is motivated by Jan Lindström. The patch mainly differs
from his original one as follows:
(1) We remove explicit initialization of stack-allocated string buffers.
The minimum amount of initialization that is needed is a terminating
NUL character.
(2) GCC issues a warning for invoking strncpy(dest, src, sizeof dest)
because if strlen(src) >= sizeof dest, there would be no terminating
NUL byte in dest. We avoid this problem by invoking strncpy() with
a limit that is 1 less than the buffer size, and by always writing
NUL to the last byte of the buffer.
(3) We replace strncpy() with memcpy() or strcpy() in those cases
when the result is functionally equivalent.
Note: fts_fetch_index_words() never deals with len==UNIV_SQL_NULL.
This was enforced by an assertion that limits the maximum length
to FTS_MAX_WORD_LEN. Also, the encoding that InnoDB uses for
the compressed fulltext index is not byte-order agnostic, that is,
InnoDB data files that use FULLTEXT INDEX are not portable between
big-endian and little-endian systems.
log_group_read_log_seg(): Always return false when returning
before reading end_lsn.
xtrabackup_copy_logfile(): On error, indicate whether
a corrupt log record was encountered.
Only xtrabackup_copy_logfile() in Mariabackup cared about the
return value of the function. InnoDB crash recovery was not
affected by this bug.
The variable is obsolete.
In mariabackup --backup, encryption plugin loading code sets the value
this parameter to the same as in server.
In mariabackup --prepare, no new redo log is generated,
and xtrabackup_logfile is removed after it anyway.
Fix one more bug in "DDL redo" phase in prepare
If table was renamed, and then new table was created with the old name,
prepare can be confused, and .ibd can end up with wrong name.
Fix the order of how DDL fixup is applied , once again - ".new" files
should be processed after renames.
If, during backup
1) Innodb table is dropped (after being copied to backup) and then
2) Before backup finished, another Innodb table is renamed, and new name
is the name of the dropped table in 1)
then, --prepare fails with assertion, as DDL fixup code in prepare
did not handle this specific case.
The fix is to process drops before renames, in prepare DDL-"redo" phase.
If an encrypted table is created during backup, then
mariabackup --backup could wrongly fail.
This caused a failure of the test mariabackup.huge_lsn once on buildbot.
This is due to the way how InnoDB creates .ibd files. It would first
write a dummy page 0 with no encryption information. Due to this,
xb_fil_cur_open() could wrongly interpret that the table is not encrypted.
Subsequently, page_is_corrupted() would compare the computed page
checksum to the wrong checksum. (There are both "before" and "after"
checksums for encrypted pages.)
To work around this problem, we introduce a Boolean option
--backup-encrypted that is enabled by default. With this option,
Mariabackup will assume that a nonzero key_version implies that the
page is encrypted. We need this option in order to be able to copy
encrypted tables from MariaDB 10.1 or 10.2, because unencrypted pages
that were originally created before MySQL 5.1.48 could contain nonzero
garbage in the fields that were repurposed for encryption.
Later, MDEV-18128 would clean up the way how .ibd files are created,
to remove the need for this option.
page_is_corrupted(): Add missing const qualifiers, and do not check
space->crypt_data unless --skip-backup-encrypted has been specified.
xb_fil_cur_read(): After a failed page read, output a page dump.
would not hide more interesting information, like invalid memory accesses.
some "leaks" are expected
- partly this is due to weird options parsing, that runs twice, and
does not free memory after the first run.
- also we do not mind to exit() whenever it makes sense, without full
cleanup.
- Refactor code to isolate page validation in page_is_corrupted() function.
- Introduce --extended-validation parameter(default OFF) for mariabackup
--backup to enable decryption of encrypted uncompressed pages during
backup.
- mariabackup would still always check checksum on encrypted data,
it is needed to detect partially written pages.
Write a test case that computes valid crc32 checksums for
an encrypted page, but zeroes out the payload area, so
that the checksum after decryption fails.
xb_fil_cur_read(): Validate the page number before trying
any checksum calculation or decrypting or decompression.
Also, skip zero-filled pages. For page_compressed pages,
ensure that the FIL_PAGE_TYPE was changed. Also, reject
FIL_PAGE_PAGE_COMPRESSED_ENCRYPTED if no decryption was attempted.
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.
The initial fix only covered a part of Mariabackup.
This fix hardens InnoDB and XtraDB in a similar way, in order
to reduce the probability of mistaking a corrupted encrypted page
for a valid unencrypted one.
This is based on work by Thirunarayanan Balathandayuthapani.
fil_space_verify_crypt_checksum(): Assert that key_version!=0.
Let the callers guarantee that. Now that we have this assertion,
we also know that buf_page_is_zeroes() cannot hold.
Also, remove all diagnostic output and related parameters,
and let the relevant callers emit such messages.
Last but not least, validate the post-encryption checksum
according to the innodb_checksum_algorithm (only accepting
one checksum for the strict variants), and no longer
try to validate the page as if it was unencrypted.
buf_page_is_zeroes(): Move to the compilation unit of the only callers,
and declare static.
xb_fil_cur_read(), buf_page_check_corrupt(): Add a condition before
calling fil_space_verify_crypt_checksum(). This is a non-functional
change.
buf_dblwr_process(): Validate the page only as encrypted or unencrypted,
but not both.
ported privilege checking from xtrabackup.
Now, mariabackup would terminate early if either RELOAD or PROCESS privilege
is not held, not at the very end of backup
The behavior can be disabled with nre setting --check-privileges=0.
Also , --no-lock does not need all of these privileges, since it skips
FTWRL and SHOW ENGINE STATUS INNODB.
After validating the post-encryption checksum on an encrypted page,
Mariabackup should decrypt the page and validate the pre-encryption
checksum as well. This should reduce the probability of accepting
invalid pages as valid ones.
This is a backport and refactoring of a patch that was
originally written by Thirunarayanan Balathandayuthapani
for the 10.2 branch.
Innochecksum was being built as if WITH_INNODB_BUG_ENDIAN_CRC32:BOOL=OFF
had been specified.
Also, clean up tests:
innodb.innochecksum: Useless; superceded by innodb_zip.innochecksum.
innodb.innodb_zip_innochecksum: Remove; duplicated innodb_zip.innochecksum.
innodb.innodb_zip_innochecksum2: Remove; duplicated innodb_zip.innochecksum_2.
innodb.innodb_zip_innochecksum3: Remove; duplicated innodb_zip.innochecksum_3.
No test case was added. I tested manually by adding debug instrumentation
to both innochecksum and buf_page_is_checksum_valid_crc32() to make
innochecksum write the buggy crc32, and to get warnings for falling back
to the buggy checksum. Automating this would require that tests be
adjusted depending on the build options.
fil_space_t::add(): Replaces fil_node_create(), fil_node_create_low().
Let the caller pass fil_node_t::handle, to avoid having to close and
re-open files.
fil_node_t::read_page0(): Refactored from fil_node_open_file().
Read the first page of a data file.
fil_node_open_file(): Open the file only once.
srv_undo_tablespace_open(): Set the file handle for the opened
undo tablespace. This should ensure that ut_ad(file->is_open())
no longer fails in recv_add_trim().
xtrabackup_backup_func(): Remove some dead code.
xb_fil_cur_open(): Open files only if needed. Undo tablespaces
should already have been opened.
Query INFORMATION_SCHEMA.INNODB_SYS_TABLES only once, and cache results.
As a small cleanup, remove mdl_lock_con_mutex, the MDL handling
connection is never accessed by multiple threads at the same time.
