mariadb/mysql-test/t/repair_symlink-5543.test
Sergei Golubchik b27fd90ad3 MDEV-11902 mi_open race condition
TOCTOU bug. The path is checked to be valid, symlinks are resolved.
Then the resolved path is opened. Between the check and the open,
there's a window when one can replace some path component with a
symlink, bypassing validity checks.

Fix: after we resolved all symlinks in the path, don't allow open()
to resolve symlinks, there should be none.

Compared to the old MyISAM/Aria code:
* fastpath. Opening of not-symlinked files is just one open(),
  no fn_format() and lstat() anymore.
* opening of symlinked tables doesn't do fn_format() and lstat() either.
  it also doesn't to realpath() (which was lstat-ing every path
  component), instead if opens every path component with O_PATH.
* share->data_file_name stores realpath(path) not readlink(path). So,
  SHOW CREATE TABLE needs to do lstat/readlink() now (see ::info()),
  and certain error messages (cannot open file "XXX") show the real
  file path with all symlinks resolved.
2017-02-27 12:35:10 +01:00

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#
# MDEV-5543 MyISAM repair unsafe usage of TMD files
#
--source include/have_symlink.inc
--source include/not_windows.inc
--source include/have_maria.inc
--replace_result $MYSQL_TMP_DIR MYSQL_TMP_DIR
eval create table t1 (a int) engine=myisam data directory='$MYSQL_TMP_DIR';
insert t1 values (1);
--system ln -s $MYSQL_TMP_DIR/foobar5543 $MYSQL_TMP_DIR/t1.TMD
--replace_regex / '.*\/t1/ 'MYSQL_TMP_DIR\/t1/
repair table t1;
drop table t1;
--replace_result $MYSQL_TMP_DIR MYSQL_TMP_DIR
eval create table t2 (a int) engine=aria data directory='$MYSQL_TMP_DIR';
insert t2 values (1);
--system ln -s $MYSQL_TMP_DIR/foobar5543 $MYSQL_TMP_DIR/t2.TMD
--replace_regex / '.*\/t2/ 'MYSQL_TMP_DIR\/t2/
repair table t2;
drop table t2;
--list_files $MYSQL_TMP_DIR foobar5543
--system rm $MYSQL_TMP_DIR/t1.TMD $MYSQL_TMP_DIR/t2.TMD