IN QUERY CACHE CODE
DESCRIPTION:
MySQL Server crashes sporadically when Query Caching is on and
the server has high contention among clients.
ANALYSIS :
Scenario 1:
In Query_cache::move_by_type() when handling RESULT or its related blocks,
Write Lock is acquired on its parent Query block. However the next and prev
pointers are cached in local variables before lock acquisition. In an extremely
high contention scenario there exists a possibility that
Query_cache::append_result_data() is operating on the same query block
and as a consequence might append a new Result block to the end of Result
blocks Linked List of the Query. This would manipulate the next, prev pointers
of the Block being processed in move_by_type(), however the local pointers
still point to previous nodes there by causing Data Corruption leading to crash.
Scenario 2:
In Windows SDK "BOOL" is typedefed as "int" and BOOLEAN is typedefed as
"usigned char". The function pointer definition "srw_bool_func" mistakenly uses
BOOL instead of BOOLEAN thereby virtually making the function
my_TryAcquireSRWLockExclusive() always succeed because only the LSB of EAX
has the actual result of the call, however due to type mismatch all bytes of EAX
are used for evaluation. Again during high contention scenarios in
Query_cache::free_old_query() calls try_lock_writing() on a Query, this call
always succeeds and the query is freed, even though it is used by some other
thread, in this case Query_cache::send_result_to_client() was using it and the
code causes a crash because it accessed free or reallocated memory.
FIX :
Scenario 1:
The next, prev pointers are now accessed only after Lock acquisition in
Query_cache::move_by_type().
Scenario 2:
In the definition of "srw_bool_func" BOOL has been replaced with "BOOLEAN"
IN QUERY CACHE CODE
DESCRIPTION:
MySQL Server crashes sporadically when Query Caching is on and
the server has high contention among clients.
ANALYSIS :
Scenario 1:
In Query_cache::move_by_type() when handling RESULT or its related blocks,
Write Lock is acquired on its parent Query block. However the next and prev
pointers are cached in local variables before lock acquisition. In an extremely
high contention scenario there exists a possibility that
Query_cache::append_result_data() is operating on the same query block
and as a consequence might append a new Result block to the end of Result
blocks Linked List of the Query. This would manipulate the next, prev pointers
of the Block being processed in move_by_type(), however the local pointers
still point to previous nodes there by causing Data Corruption leading to crash.
FIX :
Scenario 1:
The next, prev pointers are now accessed only after Lock acquisition in
Query_cache::move_by_type().
SAME VERSION NUMBER 1.0.17
Now that InnoDB/InnoDB Plugin is no longer separately developed and
distributed from the MySQL server it does not need its own version number.
Thus use the MySQL version instead.
"Removing" the version altogether is not feasible because the config
variable 'innodb_version' cannot be removed in GA branches.
Reviewed by: Marko (rb#1751)
Problem: tag's buffer overflow leads to a problem.
Fix: bound check added.
sql/item_xmlfunc.cc:
Fix for BUG#15948580 UPDATE_XML() CRASHES THE SERVER.
- XML tag/attribute level shouldn't exceed MAX_LEVEL as we use a
static buffer to store them in the MY_XML_USER_DATA.
BUF_PAGE_GET_GEN REDUNDANT?
rb://1711
approved by: Marko Makela
When decompressing a compressed page that had already been accessed
in the buffer pool, do not attempt to merge buffered changes.
File names with colon are being disallowed because of the Alternate Data
Stream (ADS) feature of NTFS that could be misused. ADS allows data to be
written to alternate streams of a normal file. The data in alternate
streams cannot be seen by normal tools on Windows (explorer, cmd.exe). As
a result someone can use this feature to hide large amount of data in
alternate streams and admins will have no easy way of figuring out the
files that are using that disk space. The fix also disallows ADS in the
scenarios where file name is passed as some dynamic variable.
An important thing about the fix is that it DOES NOT disallow ADS file
names if they are not dynamic (i.e. if the file is created by using some
option that needs local access to the MySQL server, for example error log
file). The reasoning is that if some MySQL option related to files
requires access to the local machine (it is not dynamic), then user can very
well create data in ADS by some other means. This fixes only those scenarios
which can allow users to create data in ADS over the wire.
File names with colon are being disallowed only on Windows. UNIX
(Linux in particular) supports NTFS, but it will not be a common
scenario for someone to configure a NTFS file system to store MySQL
data on Linux.
Changes in file bug11761752-master.opt are needed due to
bug number 15937938.
The error code returned from Merge file/Temp file creation functions are
ignored.
Use the return codes of the row_merge_file_create() and innobase_mysql_tmpfile()
to return the error to caller if file creation fails.
Approved by Marko. rb#1618
DOPROCESSREPLY()
Description: Function DoProcessReply() calls function
decrypt_message() in a while loop without
performing a check on available buffer
space. This can cause buffer overflow and
crash the server. This patch is fix provided
by Sawtooth to resolve the issue.
ROBUST AGAINST BUGS IN CALLERS".
Both MDL subsystems and Table Definition Cache code assume
that callers ensure that names of objects passed to them are
not longer than NAME_LEN bytes. Unfortunately due to bugs in
callers this assumption might be broken in some cases. As
result we get nasty bugs causing buffer overruns when we
construct MDL key or TDC key from object names.
This patch makes TDC code more robust against such bugs by
ensuring that we always checking size of result buffer when
constructing TDC keys. This doesn't free its callers from
ensuring that both db and table names are shorter than
NAME_LEN bytes. But at least this steps prevents buffer
overruns in case of bug in caller, replacing them with less
harmful behavior.
This is 5.1-only version of patch.
This patch introduces new version of create_table_def_key()
helper function which constructs TDC key without risk of
result buffer overrun. Places in code that construct TDC keys
were changed to use this function.
Also changed rm_temporary_table() and open_new_frm() functions
to avoid use of "unsafe" strmov() and strxmov() functions and
use safer strnxmov() instead.
Problem:
Before the ALTER TABLE statement, the array
dict_index_t::stat_n_diff_key_vals had proper values calculated
and updated. But after the ALTER TABLE statement, all the values
of this array is 0.
Because of this statistics returned by innodb_rec_per_key() is
different before and after the ALTER TABLE statement. Running the
ANALYZE TABLE command populates the statistics correctly.
Solution:
After ALTER TABLE statement, set the flag dict_table_t::stat_initialized
correctly so that the table statistics will be recalculated properly when
the table is next loaded. But note that we still don't choose the loose
index scans. This fix only ensures that an ALTER TABLE does not change
the optimizer plan.
rb://1639 approved by Marko and Jimmy.
IN A SQL STATEMENT
While processing each lines entered at the prompt,
mysql client appends a '\n' to all the lines except
for delimiter commands. However the same logic must
not apply if 'delimiter' is part of a string or a
comment, for which a '\n' should be added.
Fixed by adding appropriate checks.
Added a test case.
ROBUST AGAINST BUGS IN CALLERS".
Both MDL subsystems and Table Definition Cache code assume
that callers ensure that names of objects passed to them are
not longer than NAME_LEN bytes. Unfortunately due to bugs in
callers this assumption might be broken in some cases. As
result we get nasty bugs causing buffer overruns when we
construct MDL key or TDC key from object names.
This patch makes MDL and TDC code more robust against such
bugs by ensuring that we always checking size of result
buffer when constructing MDL and TDC keys. This doesn't
free its callers from ensuring that both db and table names
are shorter than NAME_LEN bytes. But at least these steps
prevents buffer overruns in case of bug in caller, replacing
them with less harmful behavior.
This is 5.5-only version of patch.
Changed code of MDL_key::mdl_key_init() to take into account
size of buffer for the key.
Introduced new version of create_table_def_key() helper function
which constructs TDC key without risk of result buffer overrun.
Places in code that construct TDC keys were changed to use this
function.
Also changed rm_temporary_table() and open_new_frm() functions
to avoid use of "unsafe" strmov() and strxmov() functions and
use safer strnxmov() instead.
Bug #15972480
This is the change for 5.5:
a cleanup in the way "libmysqld.so" is created.
(Patches were adapted for 5.5 previously.)
Originally, the ".so" was created by taking all modules in
"libmysqld.a", after removing some few which caused unresolved
references.
This is no good idea, rather "ld" should be used to follow all
references from some few start modules.
At the same time, the ".so" version needed to be corrected:
The original "0.0.1" is both wrong and risky.
Rather, the server version is used to identify the ".so" file,
but for linkage the first two levels are sufficient (so upgrades
are possible without re-building the embedded application).
Using too long table aliases in stored routines might
have caused server crashes.
Code in sp_head::merge_table_list() which is responsible
for collecting information about tables used in stored
routine was not aware of the fact that table alias might
have arbitrary length. I.e. it assumed that table alias
can't be longer than NAME_LEN bytes and allocated buffer
for a key identifying table accordingly.
This patch fixes the issue by ensuring that we use
dynamically allocated buffer for table key when table
alias is too long. By default stack based buffer is used
in which NAME_LEN bytes are reserved for table alias.
patch to fix post push falures in pb2
BUG#15872504 - REMOVE MYSQL-TEST/INCLUDE/GET_BINLOG_DUMP_THREAD_ID.INC
=== Problem ===
The file named "mysql-test/include/get_binlog_dump_thread_id.inc" is not
used anywhere. In any case, this file does wrong things in the wrong way:
1) The file seems to assume there is only one dump thread, but there may
be many.
2) you can get this information in a much easier way using the command:
"select thread_id from threads where processlist_command="Binlog Dump";"
=== Fix ===
removed file 'mysql-test/include/get_binlog_dump_thread_id.inc'
RPL_ROW_UNTIL TIMES OUT
patch to fix post push falures in pb2
mysql-test/suite/rpl/r/rpl_row_until.result:
changes to account for the changes made in
corresponding test file.
mysql-test/suite/rpl/t/disabled.def:
disabled test in macosx
mysql-test/suite/rpl/t/rpl_row_until.test:
replaced static relayy log file by an mtr variable
which saves the name of relay log file.
taking a change done to main 5.1 by Dmitri Lenev.
This is the original comment:
> committer: Dmitry Lenev <Dmitry.Lenev@oracle.com>
> branch nick: mysql-5.1-15954896
> timestamp: Wed 2012-12-05 19:26:56 +0400
> message:
> Bug #15954896 "SP, MULTI-TABLE DELETE AND LONG ALIAS".
Using too long table aliases in stored routines might
have caused server crashes.
Code in sp_head::merge_table_list() which is responsible
for collecting information about tables used in stored
routine was not aware of the fact that table alias might
have arbitrary length. I.e. it assumed that table alias
can't be longer than NAME_LEN bytes and allocated buffer
for a key identifying table accordingly.
This patch fixes the issue by ensuring that we use
dynamically allocated buffer for table key when table
alias is too long. By default stack based buffer is used
in which NAME_LEN bytes are reserved for table alias.
Description: A very large database name causes buffer
overflow in functions acl_get() and
check_grant_db() in sql_acl.cc. It happens
due to an unguarded string copy operation.
This puts required sanity checks before
copying db string to destination buffer.
Description: A very large database name causes buffer
overflow in functions acl_get() and
check_grant_db() in sql_acl.cc. It happens
due to an unguarded string copy operation.
This puts required sanity checks before
copying db string to destination buffer.
XID_STATE->XID.KEY(),
XID_STATE->XID.KEY_LENGTH())==0
This bug is a regression of bug#11759534 - 51855: RACE CONDITION
IN XA START.
The reason for regression is that the changes that fixes the original
bug wasn't merged from mysql-5.1 into mysql-5.5 and mysql-trunk.
Only null-merge was done for the patch changeset.
To incorporate lost changes the manual merge have been done.
Additionally the call of trans_rolback() was added into trans_xa_start()
in case if xid_cache_insert is failed() after transaction has been started.
If we don't call trans_rollback() we would never reset the flag
SERVER_STATUS_IN_TRANS in THD::server_status and therefore all subsequent
attempts to execute XA START in the connection where the error was occurred
will be failed since thd->in_active_multi_stmt_transaction() will return
the true every time when trans_xa_start is called.
The latest changes were absent in patch for mysql-5.1
Using too long table aliases in stored routines might
have caused server crashes.
Code in sp_head::merge_table_list() which is responsible
for collecting information about tables used in stored
routine was not aware of the fact that table alias might
have arbitrary length. I.e. it assumed that table alias
can't be longer than NAME_LEN bytes and allocated buffer
for a key identifying table accordingly.
This patch fixes the issue by ensuring that we use
dynamically allocated buffer for table key when table
alias is too long. By default stack based buffer is used
in which NAME_LEN bytes are reserved for table alias.
Code in MDL subsystem assumes that identifiers of objects can't
be longer than NAME_LEN characters. This assumption was broken
when one tried to construct MDL_key based on table alias, which
can have arbitrary length. Since MDL_key's (and MDL locks) are
not really used for table aliases this patch changes code to
not initialize MDL_key object for table list element representing
aliases.
Code in MDL subsystem assumes that identifiers of objects can't
be longer than NAME_LEN characters. This assumption was broken
when one tried to construct MDL_key based on table alias, which
can have arbitrary length. Since MDL_key's (and MDL locks) are
not really used for table aliases this patch changes code to
not initialize MDL_key object for table list element representing
aliases.
=== Problem ===
The test is dependent on binlog positions and checks
to see if the command 'START SLAVE' functions correctly
with the 'UNTIL' clause added to it. The 'UNTIL' clause
is added to specify that the slave should start and run
until the SQL thread reaches a given point in the master
binary log or in the slave relay log.
The test uses hard coded values for MASTER_LOG_POS and
RELAY_LOG_POS, instead of extracting it using
query_get_value() function. There is a test
'rpl.rpl_row_until' which does the similar thing but uses
query_get_value() function to set the values of
MASTER_LOG_POS/ RELAY_LOG_POS. To be precise,
rpl.rpl_row_until is a modified version of
engines/func.rpl_row_until.test.
The use of hard coded values may lead the slave to stop at a position
which may differ from the expected position in the binlog file,
an example being the failure of engines/funcs.rpl_row_until in
mysql-5.1 given as:
"query 'select * from t2' failed. Table 'test.t2' doesn't exist".
In this case, the slave actually ran a couple of extra commands
as a result of which the slave first deleted the table and then
ran a select query on table, leading to the above mentioned failure.
=== Fix ===
1) Fixed the code for failure seen in rpl.rpl_row_until.
This test was also failing although the symptoms of
failure were different.
2) Copied the contents from rpl.rpl_row_until into
into engines/funcs.rpl.rpl_row_until.
3) Updated engines/funcs.rpl_row_until.result accordingly.
mysql-test/suite/engines/funcs/r/rpl_row_until.result:
modified to accomodate the changes in corresponding
test file.
mysql-test/suite/engines/funcs/t/disabled.def:
removed from the list of disabled tests.
mysql-test/suite/engines/funcs/t/rpl_row_until.test:
fixed rpl.rpl_row_until and copied its content to
engines/funcs.rpl_row_until. The reason being both
are same tests but rpl.rpl_row_until is an
updated version.
mysql-test/suite/rpl/t/disabled.def:
removed from the list of disabled tests.
sql/sql_repl.cc:
Added a check to catch an improper combination
of arguements passed to 'START SLAVE UNTIL'. Earlier,
START SLAVE UNTIL MASTER_LOG_FILE='master-bin.000001',
MASTER_LOG_POS=561, RELAY_LOG_POS=12;
passed. It is now detected and an error is reported.
RPL_ROTATE_LOGS has been failing sporadically in what seems a
problem related to routines that update the coordinates. However,
the test lacks proper assert statments and because of this the
debug information upon failure simply points to the content
mismatch between the test and the result file.
Not as a solution, but as a improvement to the test to better
debug this failure, new assert statments were added to the test.
@rpl_rotate_logs.test
Added new assert statments reducing the
dependency on the result file.
@rpl_rotate_logs.result
Added new content to the result file to
match the test changes
