Problem:
Item_func_date_format::val_str() and make_date_time() did not take into
account that the format string and the result string
(separately or at the same time) can be of a tricky character set
like UCS2, UTF16, UTF32. As a result, DATE_FORMAT() could generate
an ill-formed result which crashed on DBUG_ASSERTs testing well-formedness
in other parts of the code.
Fix:
1. class String changes
Removing String::append_with_prefill(). It was not compatible with
tricky character sets. Also it was inconvenient to use and required
too much duplicate code on the caller side.
Adding String::append_zerofill() instead. It's compatible with tricky
character sets and is easier to use.
Adding helper methods Static_binary_string::q_append_wc() and
String::append_wc(), to append a single wide character
(a Unicode code point in my_wc_t).
2. storage/spider changes
Removing spider_string::append_with_prefill().
It used String::append_with_prefix() inside, but it was unused itself.
3. Changing tricky charset incompatible code pieces in make_date_time()
to compatible replacements:
- Fixing the loop scanning the format string to iterate in terms
of Unicode code points (using mb_wc()) rather than in terms
of "char" items.
- Using append_wc(my_wc_t) instead of append(char) to append
a single character to the result string.
- Using append_zerofill() instead of append_with_prefill() to
append date/time numeric components to the result string.
The easiest way to compile and test the server with UBSAN is to run:
./BUILD/compile-pentium64-ubsan
and then run mysql-test-run.
After this commit, one should be able to run this without any UBSAN
warnings. There is still a few compiler warnings that should be fixed
at some point, but these do not expose any real bugs.
The 'special' cases where we disable, suppress or circumvent UBSAN are:
- ref10 source (as here we intentionally do some shifts that UBSAN
complains about.
- x86 version of optimized int#korr() methods. UBSAN do not like unaligned
memory access of integers. Fixed by using byte_order_generic.h when
compiling with UBSAN
- We use smaller thread stack with ASAN and UBSAN, which forced me to
disable a few tests that prints the thread stack size.
- Verifying class types does not work for shared libraries. I added
suppression in mysql-test-run.pl for this case.
- Added '#ifdef WITH_UBSAN' when using integer arithmetic where it is
safe to have overflows (two cases, in item_func.cc).
Things fixed:
- Don't left shift signed values
(byte_order_generic.h, mysqltest.c, item_sum.cc and many more)
- Don't assign not non existing values to enum variables.
- Ensure that bool and enum values are properly initialized in
constructors. This was needed as UBSAN checks that these types has
correct values when one copies an object.
(gcalc_tools.h, ha_partition.cc, item_sum.cc, partition_element.h ...)
- Ensure we do not called handler functions on unallocated objects or
deleted objects.
(events.cc, sql_acl.cc).
- Fixed bugs in Item_sp::Item_sp() where we did not call constructor
on Query_arena object.
- Fixed several cast of objects to an incompatible class!
(Item.cc, Item_buff.cc, item_timefunc.cc, opt_subselect.cc, sql_acl.cc,
sql_select.cc ...)
- Ensure we do not do integer arithmetic that causes over or underflows.
This includes also ++ and -- of integers.
(Item_func.cc, Item_strfunc.cc, item_timefunc.cc, sql_base.cc ...)
- Added JSON_VALUE_UNITIALIZED to json_value_types and ensure that
value_type is initialized to this instead of to -1, which is not a valid
enum value for json_value_types.
- Ensure we do not call memcpy() when second argument could be null.
- Fixed that Item_func_str::make_empty_result() creates an empty string
instead of a null string (safer as it ensures we do not do arithmetic
on null strings).
Other things:
- Changed struct st_position to an OBJECT and added an initialization
function to it to ensure that we do not copy or use uninitialized
members. The change to a class was also motived that we used "struct
st_position" and POSITION randomly trough the code which was
confusing.
- Notably big rewrite in sql_acl.cc to avoid using deleted objects.
- Changed in sql_partition to use '^' instead of '-'. This is safe as
the operator is either 0 or 0x8000000000000000ULL.
- Added check for select_nr < INT_MAX in JOIN::build_explain() to
avoid bug when get_select() could return NULL.
- Reordered elements in POSITION for better alignment.
- Changed sql_test.cc::print_plan() to use pointers instead of objects.
- Fixed bug in find_set() where could could execute '1 << -1'.
- Added variable have_sanitizer, used by mtr. (This variable was before
only in 10.5 and up). It can now have one of two values:
ASAN or UBSAN.
- Moved ~Archive_share() from ha_archive.cc to ha_archive.h and marked
it virtual. This was an effort to get UBSAN to work with loaded storage
engines. I kept the change as the new place is better.
- Added in CONNECT engine COLBLK::SetName(), to get around a wrong cast
in tabutil.cpp.
- Added HAVE_REPLICATION around usage of rgi_slave, to get embedded
server to compile with UBSAN. (Patch from Marko).
- Added #ifdef for powerpc64 to avoid a bug in old gcc versions related
to integer arithmetic.
Changes that should not be needed but had to be done to suppress warnings
from UBSAN:
- Added static_cast<<uint16_t>> around shift to get rid of a LOT of
compiler warnings when using UBSAN.
- Had to change some '/' of 2 base integers to shift to get rid of
some compile time warnings.
Reviewed by:
- Json changes: Alexey Botchkov
- Charset changes in ctype-uca.c: Alexander Barkov
- InnoDB changes & Embedded server: Marko Mäkelä
- sql_acl.cc changes: Vicențiu Ciorbaru
- build_explain() changes: Sergey Petrunia
and
MDEV-23414 Assertion `res->charset() == item->collation.collation' failed in Type_handler_string_result::make_packed_sort_key_part
pack_sort_string() *must* take a collation from the Item, not from the
String value. Because when casting a string to _binary the original
String is not copied for performance reasons, it's reused but its
collation does not match Item's collation anymore.
Note, that String's collation cannot be simply changed to _binary,
because for an Item_string literal the original String must stay
unchanged for the duration of the query.
this partially reverts 61c15ebe32
- Better to use 'String *' directly.
- Added String::get_value(LEX_STRING*) for the few cases where we want to
convert a String to LEX_CSTRING.
Other things:
- Use StringBuffer for some functions to avoid mallocs
- Making classes Field_time, Field_datetime, Field_timestamp abstract
- Adding instantiable Field_time0, Field_datetime0, Field_timestamp0 classes
- Removing redundant cast in field_conv.cc, item_timefunc.cc, sp.cc in calls for set_time() and get_timestamp()
- Replacing store_TIME() to store_timestamp() in log.cc and removing redundant cast
The patch for `MDEV-20795 CAST(inet6 AS BINARY) returns wrong result`
unintentionally changed what Item_char_typecast::type_handler()
returns. This broke UNIONs with the BINARY() function, as the Aria
engine started to get columns of unexpected data types.
Restoring previous behaviour, to return
Type_handler::string_type_handler(max_length).
The prototype for Item_handed_func::return_type_handler() has changed
from:
const Type_handler *return_type_handler() const
to:
const Type_handler *return_type_handler(const Item_handled_func *) const
