ASAN heap-use-after-free in Field_blob::pack / THD::binlog_update_row upon DML on table with virtual column

--source include/have_binlog_format_row.inc

# BLOB → TEXT is also affected; STORED is not affected

CREATE TABLE t (a TEXT, v BLOB AS (a) VIRTUAL) WITH SYSTEM VERSIONING AS

  SELECT 'foo' AS a;

UPDATE t SET a='bar'; # or REPLACE

# Cleanup

DROP TABLE t;

==26818==ERROR: AddressSanitizer: heap-use-after-free on address 0x6d1a52937e68 at pc 0x70ea5491fdbb bp 0x6cea44316c80 sp 0x6cea44316428

READ of size 3 at 0x6d1a52937e68 thread T7

    #0 0x70ea5491fdba in memcpy path/to/libsanitizer/sanitizer_common/sanitizer_common_interceptors_memintrinsics.inc:115

    #1 0x5e3fea57c9f1 in Field_blob::pack(unsigned char*, unsigned char const*, unsigned int) path/to/src/sql/field.cc:9248

    #2 0x5e3fea98ab87 in pack_row(TABLE*, st_bitmap const*, unsigned char*, unsigned char const*) path/to/src/sql/rpl_record.cc:106

    #3 0x5e3fe9cd769a in THD::binlog_update_row(TABLE*, bool, unsigned char const*, unsigned char const*) path/to/src/sql/sql_class.cc:7443

    #4 0x5e3fea612505 in Update_rows_log_event::binlog_row_logging_function(THD*, TABLE*, bool, unsigned char const*, unsigned char const*) path/to/src/sql/log_event.h:5575

    #5 0x5e3fea603c4f in handler::binlog_log_row(TABLE*, unsigned char const*, unsigned char const*, bool (*)(THD*, TABLE*, bool, unsigned char const*, unsigned char const*)) path/to/src/sql/handler.cc:7274

    #6 0x5e3fea60a2e0 in handler::ha_update_row(unsigned char const*, unsigned char const*) path/to/src/sql/handler.cc:7905

    #7 0x5e3fea0f94b0 in mysql_update(THD*, TABLE_LIST*, List<Item>&, List<Item>&, Item*, unsigned int, st_order*, unsigned long long, bool, unsigned long long*, unsigned long long*) path/to/src/sql/sql_update.cc:1137

    #8 0x5e3fe9deb144 in mysql_execute_command(THD*, bool) path/to/src/sql/sql_parse.cc:4503

    #9 0x5e3fe9df68dd in mysql_parse(THD*, char*, unsigned int, Parser_state*) path/to/src/sql/sql_parse.cc:8221

    #10 0x5e3fe9dfa9a0 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool) path/to/src/sql/sql_parse.cc:1924

    #11 0x5e3fe9dff2cf in do_command(THD*, bool) path/to/src/sql/sql_parse.cc:1434

    #12 0x5e3fea201b66 in do_handle_one_connection(CONNECT*, bool) path/to/src/sql/sql_connect.cc:1475

    #13 0x5e3fea202040 in handle_one_connection path/to/src/sql/sql_connect.cc:1387

    #14 0x5e3feac6a285 in pfs_spawn_thread path/to/src/storage/perfschema/pfs.cc:2201

    #15 0x70ea5485f802 in asan_thread_start path/to/libsanitizer/asan/asan_interceptors.cpp:239

    #16 0x70ea536a3d63  (/lib/x86_64-linux-gnu/libc.so.6+0xa3d63) (BuildId: a5b27db7ef3036c1dacf2e4ddc2e052767129439)

    #17 0x70ea537373fb  (/lib/x86_64-linux-gnu/libc.so.6+0x1373fb) (BuildId: a5b27db7ef3036c1dacf2e4ddc2e052767129439)

0x6d1a52937e68 is located 24 bytes inside of 32-byte region [0x6d1a52937e50,0x6d1a52937e70)

freed by thread T7 here:

    #0 0x70ea5492114b in free path/to/libsanitizer/asan/asan_malloc_linux.cpp:51

    #1 0x5e3feb753841 in my_free path/to/src/mysys/my_malloc.c:217

previously allocated by thread T7 here:

    #0 0x70ea5492261b in malloc path/to/libsanitizer/asan/asan_malloc_linux.cpp:67

    #1 0x5e3feb7532d8 in my_malloc path/to/src/mysys/my_malloc.c:92

Thread T7 created by T0 here:

    #0 0x70ea549196aa in pthread_create path/to/libsanitizer/asan/asan_interceptors.cpp:250

    #1 0x5e3feac6a4f4 in my_thread_create path/to/src/storage/perfschema/my_thread.h:52

    #2 0x5e3feac6a4f4 in pfs_spawn_thread_v1 path/to/src/storage/perfschema/pfs.cc:2252

SUMMARY: AddressSanitizer: heap-use-after-free path/to/src/sql/field.cc:9248 in Field_blob::pack(unsigned char*, unsigned char const*, unsigned int)

Shadow bytes around the buggy address:

  0x6d1a52937b80: fd fd fd fd fa fa fd fd fd fd fa fa fd fd fd fd

  0x6d1a52937c00: fa fa fd fd fd fd fa fa fd fd fd fd fa fa fd fd

  0x6d1a52937c80: fd fd fa fa fd fd fd fd fa fa fd fd fd fd fa fa

  0x6d1a52937d00: 00 00 00 00 fa fa fd fd fd fd fa fa 00 00 00 00

  0x6d1a52937d80: fa fa 00 00 00 00 fa fa fd fd fd fd fa fa fd fd

=>0x6d1a52937e00: fd fd fa fa fd fd fd fd fa fa fd fd fd[fd]fa fa

  0x6d1a52937e80: 00 00 00 00 fa fa 00 00 00 00 fa fa fd fd fd fd

  0x6d1a52937f00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

  0x6d1a52937f80: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

  0x6d1a52938000: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

  0x6d1a52938080: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa

Shadow byte legend (one shadow byte represents 8 application bytes):

  Addressable:           00

  Partially addressable: 01 02 03 04 05 06 07 

  Heap left redzone:       fa

  Freed heap region:       fd

  Stack left redzone:      f1

  Stack mid redzone:       f2

  Stack right redzone:     f3

  Stack after return:      f5

  Stack use after scope:   f8

  Global redzone:          f9

  Global init order:       f6

  Poisoned by user:        f7

  Container overflow:      fc

  Array cookie:            ac

  Intra object redzone:    bb

  ASan internal:           fe

  Left alloca redzone:     ca

  Right alloca redzone:    cb

==26818==ABORTING