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BUG#58246: INSTALL PLUGIN not secure & crashable

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When installing plugins, there is a missing check
for slash (/) in the path on Windows. Note that on
Windows, both / and \ can be used to separate
directories.

This patch fixes the issue by:
- Adding a FN_DIRSEP symbol for all platforms
  consisting of a string of legal directory
  separators.
- Adding a charset-aware version of strcspn().
- Adding a check_valid_path() function that uses
  my_strcspn() to check if any FN_DIRSEP character
  is in the supplied string.
- Using the check_valid_path() function in
  sql_plugin.cc and sql_udf.cc (which means
  replacing the existing test there).

include/config-netware.h:
  Adding FN_DIRSEP
  ******
  Adding FN_DIRSEP
include/config-win.h:
  Adding FN_DIRSEP
  ******
  Adding FN_DIRSEP
include/m_ctype.h:
  Adding my_strspn() and my_strcspn().
  
  ******
  Adding my_strspn() and my_strcspn().
include/my_global.h:
  Adding FN_DIRSEP
  ******
  Adding FN_DIRSEP
mysql-test/t/plugin_not_embedded.test:
  Adding test that file names containing / is
  disallowed on *all* platforms.
  ******
  Adding test that file names containing / is
  disallowed on *all* platforms.
sql/sql_plugin.cc:
  Introducing check_if_path() function for
  checking if filename is a path to include
  / on Windows.
  ******
  Introducing check_if_path() function for
  checking if filename is a path to include
  / on Windows.
sql/sql_udf.cc:
  Switching to use check_if_path() function.
  ******
  Switching to use check_if_path() function.
strings/my_strchr.c:
  Adding my_strspn() and my_strcspn().
  ******
  Adding my_strspn() and my_strcspn().
This commit is contained in:
Mats Kindahl 2010-12-01 13:54:50 +01:00
parent cd1c6e220d
commit fc9f3efaec
10 changed files with 105 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
include/config-netware.h
View File

@ -122,6 +122,7 @@ extern "C" {
#define CANT_DELETE_OPEN_FILES 1
#define FN_LIBCHAR '\\'
#define FN_DIRSEP "/\\" /* Valid directory separators */
#define FN_ROOTDIR "\\"
#define FN_DEVCHAR ':'

1
include/config-win.h
View File

@ -332,6 +332,7 @@ inline ulonglong double2ulonglong(double d)
/* File name handling */
#define FN_LIBCHAR '\\'
#define FN_DIRSEP "/\\" /* Valid directory separators */
#define FN_ROOTDIR "\\"
#define FN_DEVCHAR ':'
#define FN_NETWORK_DRIVES /* Uses \\ to indicate network drives */

2
include/m_ctype.h
View File

@ -464,6 +464,8 @@ extern my_bool my_parse_charset_xml(const char *bug, size_t len,
int (*add)(CHARSET_INFO *cs));
extern char *my_strchr(CHARSET_INFO *cs, const char *str, const char *end,
pchar c);
extern size_t my_strcspn(CHARSET_INFO *cs, const char *str, const char *end,
const char *accept);
my_bool my_propagate_simple(CHARSET_INFO *cs, const uchar *str, size_t len);
my_bool my_propagate_complex(CHARSET_INFO *cs, const uchar *str, size_t len);

1
include/my_global.h
View File

@ -758,6 +758,7 @@ typedef SOCKET_SIZE_TYPE size_socket;
#ifndef FN_LIBCHAR
#define FN_LIBCHAR '/'
#define FN_DIRSEP "/" /* Valid directory separators */
#define FN_ROOTDIR "/"
#endif
#define MY_NFILE 64 /* This is only used to save filenames */

2
mysql-test/r/plugin_not_embedded.result
View File

@ -8,3 +8,5 @@ ERROR 42000: DELETE command denied to user 'bug51770'@'localhost' for table 'plu
GRANT DELETE ON mysql.plugin TO bug51770@localhost;
UNINSTALL PLUGIN example;
DROP USER bug51770@localhost;
INSTALL PLUGIN example SONAME '../ha_example.so';
ERROR HY000: No paths allowed for shared library

11
mysql-test/t/plugin_not_embedded.test
View File

@ -18,3 +18,14 @@ UNINSTALL PLUGIN example;
disconnect con1;
connection default;
DROP USER bug51770@localhost;
#
# BUG#58246: INSTALL PLUGIN not secure & crashable
#
# The bug consisted of not recognizing / on Windows, so checking / on
# all platforms should cover this case.
let $path = `select CONCAT_WS('/', '..', $HA_EXAMPLE_SO)`;
--error ER_UDF_NO_PATHS
eval INSTALL PLUGIN example SONAME '$path';

23
sql/sql_plugin.cc
View File

@ -231,6 +231,26 @@ extern bool check_if_table_exists(THD *thd, TABLE_LIST *table, bool *exists);
#endif /* EMBEDDED_LIBRARY */
/**
Check if the provided path is valid in the sense that it does cause
a relative reference outside the directory.
@note Currently, this function only check if there are any
characters in FN_DIRSEP in the string, but it might change in the
future.
@code
check_valid_path("../foo.so") -> true
check_valid_path("foo.so") -> false
@endcode
*/
bool check_valid_path(const char *path, size_t len)
{
size_t prefix= my_strcspn(files_charset_info, path, path + len, FN_DIRSEP);
return prefix < len;
}
/****************************************************************************
Value type thunks, allows the C world to play in the C++ world
****************************************************************************/
@ -354,13 +374,14 @@ static st_plugin_dl *plugin_dl_add(const LEX_STRING *dl, int report)
struct st_plugin_dl *tmp, plugin_dl;
void *sym;
DBUG_ENTER("plugin_dl_add");
DBUG_PRINT("enter", ("dl->str: '%s', dl->length: %d", dl->str, dl->length));
plugin_dir_len= strlen(opt_plugin_dir);
/*
Ensure that the dll doesn't have a path.
This is done to ensure that only approved libraries from the
plugin directory are used (to make this even remotely secure).
*/
if (my_strchr(files_charset_info, dl->str, dl->str + dl->length, FN_LIBCHAR) ||
if (check_valid_path(dl->str, dl->length) ||
check_string_char_length((LEX_STRING *) dl, "", NAME_CHAR_LEN,
system_charset_info, 1) ||
plugin_dir_len + dl->length + 1 >= FN_REFLEN)

1
sql/sql_plugin.h
View File

@ -131,6 +131,7 @@ extern bool mysql_uninstall_plugin(THD *thd, const LEX_STRING *name);
extern bool plugin_register_builtin(struct st_mysql_plugin *plugin);
extern void plugin_thdvar_init(THD *thd);
extern void plugin_thdvar_cleanup(THD *thd);
extern bool check_valid_path(const char *path, size_t length);
typedef my_bool (plugin_foreach_func)(THD *thd,
plugin_ref plugin,

12
sql/sql_udf.cc
View File

@ -173,10 +173,7 @@ void udf_init()
On windows we must check both FN_LIBCHAR and '/'.
*/
if (my_strchr(files_charset_info, dl_name,
dl_name + strlen(dl_name), FN_LIBCHAR) ||
IF_WIN(my_strchr(files_charset_info, dl_name,
dl_name + strlen(dl_name), '/'), 0) ||
if (check_valid_path(dl_name, strlen(dl_name)) ||
check_string_char_length(&name, "", NAME_CHAR_LEN,
system_charset_info, 1))
{
@ -416,13 +413,8 @@ int mysql_create_function(THD *thd,udf_func *udf)
Ensure that the .dll doesn't have a path
This is done to ensure that only approved dll from the system
directories are used (to make this even remotely secure).
On windows we must check both FN_LIBCHAR and '/'.
*/
if (my_strchr(files_charset_info, udf->dl,
udf->dl + strlen(udf->dl), FN_LIBCHAR) ||
IF_WIN(my_strchr(files_charset_info, udf->dl,
udf->dl + strlen(udf->dl), '/'), 0))
if (check_valid_path(udf->dl, strlen(udf->dl)))
{
my_message(ER_UDF_NO_PATHS, ER(ER_UDF_NO_PATHS), MYF(0));
DBUG_RETURN(1);

67
strings/my_strchr.c
View File

@ -13,6 +13,45 @@
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#include <my_global.h>
#include "m_string.h"
#include "m_ctype.h"
#define NEQ(A, B) ((A) != (B))
#define EQU(A, B) ((A) == (B))
/**
Macro for the body of the string scanning.
@param CS The character set of the string
@param STR Pointer to beginning of string
@param END Pointer to one-after-end of string
@param ACC Pointer to beginning of accept (or reject) string
@param LEN Length of accept (or reject) string
@param CMP is a function-like for doing the comparison of two characters.
*/
#define SCAN_STRING(CS, STR, END, ACC, LEN, CMP) \
do { \
uint mbl; \
const char *ptr_str, *ptr_acc; \
const char *acc_end= (ACC) + (LEN); \
for (ptr_str= (STR) ; ptr_str < (END) ; ptr_str+= mbl) \
{ \
mbl= my_mbcharlen((CS), *(uchar*)ptr_str); \
if (mbl < 2) \
{ \
DBUG_ASSERT(mbl == 1); \
for (ptr_acc= (ACC) ; ptr_acc < acc_end ; ++ptr_acc) \
if (CMP(*ptr_acc, *ptr_str)) \
goto end; \
} \
} \
end: \
return (size_t) (ptr_str - (STR)); \
} while (0)
/*
my_strchr(cs, str, end, c) returns a pointer to the first place in
str where c (1-byte character) occurs, or NULL if c does not occur
@ -21,11 +60,6 @@
frequently.
*/
#include <my_global.h>
#include "m_string.h"
#include "m_ctype.h"
char *my_strchr(CHARSET_INFO *cs, const char *str, const char *end,
pchar c)
{
@ -45,3 +79,26 @@ char *my_strchr(CHARSET_INFO *cs, const char *str, const char *end,
return(0);
}
/**
Calculate the length of the initial segment of 'str' which consists
entirely of characters not in 'reject'.
@note The reject string points to single-byte characters so it is
only possible to find the first occurrence of a single-byte
character. Multi-byte characters in 'str' are treated as not
matching any character in the reject string.
@todo should be moved to CHARSET_INFO if it's going to be called
frequently.
@internal The implementation builds on the assumption that 'str' is long,
while 'reject' is short. So it compares each character in string
with the characters in 'reject' in a tight loop over the characters
in 'reject'.
*/
size_t my_strcspn(CHARSET_INFO *cs, const char *str, const char *str_end,
const char *reject)
{
SCAN_STRING(cs, str, str_end, reject, strlen(reject), EQU);
}