[MDEV-22337] Assertion `Alloced_length >= (str_length + length + net_length_size(length))' failed in Binary_string::q_net_store_data on long MULTIPOLYGON query with session_track_user_variables=1 (optimized builds) Created: 2020-04-22  Updated: 2020-05-04  Resolved: 2020-04-29

Status: Closed
Project: MariaDB Server
Component/s: Variables
Affects Version/s: 10.5.2, 10.5.3
Fix Version/s: 10.5.3

Type: Bug Priority: Blocker
Reporter: Roel Van de Paar Assignee: Alexey Botchkov
Resolution: Fixed Votes: 0
Labels: not-10.1, not-10.2, not-10.3, not-10.4, regression


 Description    

SET @@session.session_track_user_variables=1;
 
set @a='MULTIPOLYGON(((0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)))';

Leads to:

10.5.3 98003440c2f8d20164a191ced1b7d92b283bb68f

 
mysqld: /test/10.5_dbg/sql/sql_string.h:725: void Binary_string::q_net_store_data(const uchar*, size_t): Assertion `Alloced_length >= (str_length + length + net_length_size(length))' failed.

10.5.3 98003440c2f8d20164a191ced1b7d92b283bb68f

 
Core was generated by `/test/MD210420-mariadb-10.5.3-linux-x86_64-dbg/bin/mysqld --no-defaults --core-'.
 
Program terminated with signal SIGABRT, Aborted.
 
#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=6)
 
    at ../sysdeps/unix/sysv/linux/pthread_kill.c:57
 
[Current thread is 1 (Thread 0x7ff90f206700 (LWP 1139608))]
 
(gdb) bt
 
#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=6) at ../sysdeps/unix/sysv/linux/pthread_kill.c:57
 
#1  0x000055cf9881203d in my_write_core (sig=sig@entry=6) at /test/10.5_dbg/mysys/stacktrace.c:518
 
#2  0x000055cf97fb7d7b in handle_fatal_signal (sig=6) at /test/10.5_dbg/sql/signal_handler.cc:329
 
#3  <signal handler called>
 
#4  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
 
#5  0x00007ff90d94a801 in __GI_abort () at abort.c:79
 
#6  0x00007ff90d93a39a in __assert_fail_base (fmt=0x7ff90dac17d8 "%s%s%s:%u: %s%sAssertion `%s' failed.\n%n", assertion=assertion@entry=0x55cf98961a20 "Alloced_length >= (str_length + length + net_length_size(length))", file=file@entry=0x55cf98961658 "/test/10.5_dbg/sql/sql_string.h", line=line@entry=725, function=function@entry=0x55cf98963940 <_ZZN13Binary_string16q_net_store_dataEPKhmE19__PRETTY_FUNCTION__> "void Binary_string::q_net_store_data(const uchar*, size_t)") at assert.c:92
 
#7  0x00007ff90d93a412 in __GI___assert_fail (assertion=assertion@entry=0x55cf98961a20 "Alloced_length >= (str_length + length + net_length_size(length))", file=file@entry=0x55cf98961658 "/test/10.5_dbg/sql/sql_string.h", line=line@entry=725, function=function@entry=0x55cf98963940 <_ZZN13Binary_string16q_net_store_dataEPKhmE19__PRETTY_FUNCTION__> "void Binary_string::q_net_store_data(const uchar*, size_t)") at assert.c:101
 
#8  0x000055cf97c23514 in Binary_string::q_net_store_data (length=517, from=0x7ff8e1880688 "MULTIPOLYGON(((0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"..., this=0x7ff90f204e08) at /test/10.5_dbg/sql/sql_string.h:724
 
#9  User_variables_tracker::store (this=0x7ff8e181afb8, thd=<optimized out>, buf=0x7ff90f204e00) at /test/10.5_dbg/sql/session_tracker.cc:1211
 
#10 0x000055cf97c25112 in Session_tracker::store (this=this@entry=0x7ff8e181aec0, thd=thd@entry=0x7ff8e1815088, buf=buf@entry=0x7ff90f204e00) at /test/10.5_dbg/sql/session_tracker.cc:1251
 
#11 0x000055cf97c1b384 in net_send_ok (thd=0x7ff8e1815088, server_status=server_status@entry=16386, statement_warn_count=statement_warn_count@entry=0, affected_rows=affected_rows@entry=0, id=id@entry=0, message=<optimized out>, message@entry=0x7ff8e181aba3 "", is_eof=false, skip_flush=false) at /test/10.5_dbg/sql/protocol.cc:282
 
#12 0x000055cf97c1b5b0 in Protocol::send_ok (this=0x7ff8e1815650, server_status=16386, statement_warn_count=0, affected_rows=0, last_insert_id=0, message=0x7ff8e181aba3 "", skip_flush=false) at /test/10.5_dbg/sql/protocol.cc:643
 
#13 0x000055cf97c1bf3b in Protocol::end_statement (this=0x7ff8e1815650) at /test/10.5_dbg/sql/protocol.cc:606
 
#14 0x000055cf97d0908c in dispatch_command (command=command@entry=COM_QUERY, thd=thd@entry=0x7ff8e1815088, packet=<optimized out>, packet@entry=0x7ff8e1867089 "set @a='MULTIPOLYGON(((0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0"..., packet_length=<optimized out>, packet_length@entry=526, is_com_multi=is_com_multi@entry=false, is_next_command=is_next_command@entry=false) at /test/10.5_dbg/sql/sql_parse.cc:2430
 
#15 0x000055cf97d0549b in do_command (thd=0x7ff8e1815088) at /test/10.5_dbg/sql/sql_parse.cc:1358
 
#16 0x000055cf97e60415 in do_handle_one_connection (connect=<optimized out>, connect@entry=0x7ff8ed3c53a8, put_in_cache=put_in_cache@entry=true) at /test/10.5_dbg/sql/sql_connect.cc:1422
 
#17 0x000055cf97e60744 in handle_one_connection (arg=arg@entry=0x7ff8ed3c53a8) at /test/10.5_dbg/sql/sql_connect.cc:1319
 
#18 0x000055cf982c0fb0 in pfs_spawn_thread (arg=0x7ff90cc45b08) at /test/10.5_dbg/storage/perfschema/pfs.cc:2201
 
#19 0x00007ff90e62d6db in start_thread (arg=0x7ff90f206700) at pthread_create.c:463
 
#20 0x00007ff90da2b88f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Bug confirmed present in:
MariaDB: 10.5.2 (dbg), 10.5.2 (opt), 10.5.3 (dbg), 10.5.3 (opt)

Bug confirmed not present in:
MariaDB: 10.1.45 (dbg), 10.1.45 (opt), 10.2.32 (dbg), 10.2.32 (opt), 10.3.23 (dbg), 10.3.23 (opt), 10.4.13 (dbg), 10.4.13 (opt)
MySQL: 5.5.62 (dbg), 5.5.62 (opt), 5.6.47 (dbg), 5.6.47 (opt), 5.7.29 (dbg), 5.7.29 (opt), 8.0.19 (dbg), 8.0.19 (opt)

MariaDB 10.4.3 (opt) output:

10.4.13>SET @@session.session_track_user_variables=1;
 
ERROR 1193 (HY000): Unknown system variable 'session_track_user_variables'
 
10.4.13>set @a='MULTIPOLYGON(((0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)))';
 
Query OK, 0 rows affected (0.000 sec)



 Comments   
Comment by Roel Van de Paar [ 2020-04-22 ]
  • It is not a real "regression" other than the fact that a previously working query now fails.
  • I suspect there are other cases that this Alloced_length length check may apply to.
Comment by Alexey Botchkov [ 2020-04-22 ]

Proposed fix.
https://github.com/MariaDB/server/commit/1b11f3a54c498b8676e091e7aecf5a6b7b9f0dd5

Comment by Oleksandr Byelkin [ 2020-04-28 ]

OK to push! Thanks!

Comment by Oleksandr Byelkin [ 2020-04-28 ]

I think at least second part of the patch shoud be moved to 10.2

Comment by Roel Van de Paar [ 2020-05-04 ]

Saw a testcase in an previous run today which causes stack smashing (before the fix was introduced, works fine now). Adding it for completeness.

SET @@session.session_track_user_variables=1;
 
SET @b='?k;E1S={]8u?yV_ta=Gg"0N:pU,ENpD"/Gg.7N?A4Z0n=AF"$Yxw=y@-ESk$H0g390[]Fm]1JyD&X=_MlwGd"Mrh,VB[)S:mY].G/0OPo&kkAbuhI-_Opg&N:om$=~yTcR%E^ld{:PJcDx{cT,W1_w=[})u-"kY:bE9:NZO8zhb=J"OOZp?+@=l{0D$dL"2"R)TnwW+J-3b1}%gh$rQ4-WU=%r,SI-INq[+%b(^7ON5=[fDoy9uDD;xSV%@%qGh.YRwb]Ef=wNrg]wMn8FeSY;VIsnhh=FszZMQTFwhBXWv/HZE{4_gps_L~TndPl_B8^8[SDQ:?$:/91vn6WGd=bTO#=s=~ylr:){9%BuL,Hg=n&D?sCKXBF+iy_7;N(W#=9QtQKIYapEY@.mro)vu=rQVV6/Q/$ji7R0K{dy~*@~kD:&#%#&[G,LS^6=ZeJD5Wd9^x^#o+qP^x6+~U*(?PguiAeE1AM=tQE.Qzq~X{"~%WKC}[9p=wfTx6=dg#=q%k3p=Ym=24=6f@2(G$*zf1_fCYV[muJo3EhM=;CE&M,89-fQp/=pVYCWzd"YF]7=KjbV=ECSx4s#[i10~Ar:,PFL=7JnN_4gM1B^vA@(1s;*fn#5R-8VHtM&&QBCWf?tEg19S5mO)k.w+gR0UT-e6t}7.OfSck8#u~wN_PehioD;rKpn=pr[gex/=vad~"Lz=7TtB^[DoAL5F{+BNJ%LC3d(EX"92DlVtaj={CPDpKQ=CnE@xw5eX:f}gu5DRYy4Prv[Z=YXKi]Je0fifDMWjB0nb,QKPEf,f}e=tWpoE/v^i?KHI4Qv&;-:I';


Version: '10.5.3-MariaDB'  socket: '/test/MD300420-mariadb-10.5.3-linux-x86_64-opt/socket.sock'  port: 10419  MariaDB Server
 
*** stack smashing detected ***: <unknown> terminated
 
200504  4:02:15 [ERROR] mysqld got signal 6 ;

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