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Basic example (to be run with debug server, as it uses a debug injection):
#include <stddef.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <mysql.h>
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int main(int argc, char **argv)
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{
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MYSQL *con = mysql_init(NULL);
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MYSQL *con2 = mysql_init(NULL);
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mysql_real_connect(con, "127.0.0.1", "root", "", NULL, 0, NULL, 0);
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mysql_query(con, "set global debug_dbug= '+d,vio_peer_addr_fake_ipv4,getnameinfo_error_again'");
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if (mysql_real_connect(con2, "127.0.0.1", "root", "",
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NULL, 0, NULL, 0) == NULL)
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fprintf(stderr, "%i: %s\n", mysql_errno(con2), mysql_error(con2));
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mysql_query(con, "set global debug_dbug= ''");
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mysql_close(con);
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mysql_close(con2);
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exit(0);
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}
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If it's linked with libmariadb, it gets and shows ER_HOST_NOT_PRIVILEGED, as expected:
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connects to 10.2 5ecaf52d
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$ ldd test-libmariadb | grep -E 'libmariadb|libmysql'
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libmariadb.so.3 => /lib/x86_64-linux-gnu/libmariadb.so.3 (0x00007fe29d3a5000)
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$ ./test-libmariadb
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1130: Host '192.0.2.4' is not allowed to connect to this MariaDB server
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But if it's linked with libmysqlclient (18, 20, 21), it shows the generic 2013 with slightly varying "system errors":
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connects to 10.2 5ecaf52d
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$ ldd test-libmysqlclient21 | grep -E 'libmariadb|libmysql'
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libmysqlclient.so.21 => /lib/x86_64-linux-gnu/libmysqlclient.so.21 (0x00007f46671af000)
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$ ./test-libmysqlclient21
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2013: Lost connection to MySQL server at 'reading initial communication packet', system error: 2
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connects to 10.2 5ecaf52d
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$ LD_LIBRARY_PATH=/data/bld/mysql-5.7/lib ldd ./test-libmysqlclient20 | grep -E 'libmariadb|libmysql'
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libmysqlclient.so.20 => /data/bld/mysql-5.7/lib/libmysqlclient.so.20 (0x00007f98d5036000)
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$ LD_LIBRARY_PATH=/data/bld/mysql-5.7/lib ./test-libmysqlclient20
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2013: Lost connection to MySQL server at 'reading initial communication packet', system error: 0
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connects to 10.2 5ecaf52d
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$ LD_LIBRARY_PATH=/data/bld/10.1/lib ldd ./test-libmysqlclient18 | grep -E 'libmariadb|libmysql'
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libmysqlclient.so.18 => /data/bld/10.1/lib/libmysqlclient.so.18 (0x00007fa35d039000)
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$ LD_LIBRARY_PATH=/data/bld/10.1/lib ./test-libmysqlclient18
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2013: Lost connection to MySQL server at 'reading initial communication packet', system error: 2 "No such file or directory"
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Reproducible with 10.2-10.6 servers.
While connecting to 10.1 server, all of them (either linked with libmysqlclient or libmariadb) return the expected error ER_HOST_NOT_PRIVILEGED.
As a practical example, libdbd-mysql-perl linked with libmysqlclient returns the wrong error. For example, Ubuntu 20.4 Focal (latest LTS) offers such libdbd-mysql-perl:
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Ubuntu Focal
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$ apt-cache depends libdbd-mysql-perl
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libdbd-mysql-perl
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Depends: perl
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Depends: <perl-dbdabi-94>
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libdbi-perl
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Depends: <perlapi-5.30.0>
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perl-base
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Depends: libc6
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Depends: libmysqlclient21
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Depends: libdbi-perl
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And that's how it works:
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MTR test using perl DBD
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call mtr.add_suppression("Temporary failure in name resolution");
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set global debug_dbug= "+d,vio_peer_addr_fake_ipv4,getnameinfo_error_again";
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--echo
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--echo # "Native" MTR connection:
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--echo
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--error ER_HOST_NOT_PRIVILEGED
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--connect (con1,127.0.0.1,root,,$MASTER_MYPORT)
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--echo
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--echo # Perl connection:
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--echo
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--perl
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use DBI;
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$dbh= DBI->connect("dbi:mysql:user=root:host=127.0.0.1:port=$ENV{MASTER_MYPORT}");
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if ($dbh) {
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print "Connected\n";
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$dbh->disconnect();
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} else {
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print DBI->err, ": ", DBI->errstr, "\n";
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}
|
EOF
|
--echo
|
|
set global debug_dbug= "";
|
|
10.2 5ecaf52d
|
# "Native" MTR connection:
|
|
connect(127.0.0.1,root,,16000,16000,/data/bld/10.2-debug/mysql-test/var/tmp/mysqld.1.sock);
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connect con1,127.0.0.1,root,,$MASTER_MYPORT;
|
ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
|
|
# Perl connection:
|
|
2013: Lost connection to MySQL server at 'reading initial communication packet', system error: 0
|
|
Debian Sid (unstable) offers libdbd-mysql-perl linked with libmariadb:
|
Debian Sid
|
$ apt-cache depends libdbd-mysql-perl
|
libdbd-mysql-perl
|
Depends: perl
|
Depends: <perl-dbdabi-94>
|
libdbi-perl
|
Depends: <perlapi-5.32.0>
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perl-base
|
Depends: libc6
|
Depends: libmariadb3
|
Depends: libdbi-perl
|
And there the error is correct (same MTR test on 10.2):
# "Native" MTR connection:
|
|
connect(127.0.0.1,root,,16000,16000,/home/buildbot/10.2/mysql-test/var/tmp/mysqld.1.sock);
|
connect con1,127.0.0.1,root,,$MASTER_MYPORT;
|
ERROR HY000: Host '192.0.2.4' is not allowed to connect to this MariaDB server
|
|
# Perl connection:
|
|
1130: Host '192.0.2.4' is not allowed to connect to this MariaDB server
|
|
|