BASH PATCH REPORT
=
Bash-Release: 4.3
Patch-ID: bash43-047
Bug-Reported-by:Bernd Dietzel
Bug-Reference-ID:
Bug-Reference-URL:
https://bugs.launchpad.net/ubuntu/+source/bash/+bug/1507025
Bug-Description:
Bash performs word expansions on the prompt strings after the special
escape sequences are expanded. If a malicious user can modify the system
hostname or change the name of the bash executable and coerce a user into
executing it, and the new name contains word expansions (including
command substitution), bash will expand them in prompt strings containing
the \h or \H and \s escape sequences, respectively.
Patch (apply with `patch -p0'):
*** ../bash-4.3-patched/parse.y 2015-08-13 15:11:54.0 -0400
--- parse.y 2016-03-07 15:44:14.0 -0500
***
*** 5259,5263
int result_size, result_index;
int c, n, i;
! char *temp, octal_string[4];
struct tm *tm;
time_t the_time;
--- 5259,5263
int result_size, result_index;
int c, n, i;
! char *temp, *t_host, octal_string[4];
struct tm *tm;
time_t the_time;
***
*** 5407,5411
case 's':
temp = base_pathname (shell_name);
! temp = savestring (temp);
goto add_string;
--- 5407,5415
case 's':
temp = base_pathname (shell_name);
! /* Try to quote anything the user can set in the file system */
! if (promptvars || posixly_correct)
! temp = sh_backslash_quote_for_double_quotes (temp);
! else
! temp = savestring (temp);
goto add_string;
***
*** 5497,5503
case 'h':
case 'H':
! temp = savestring (current_host_name);
! if (c == 'h' && (t = (char *)strchr (temp, '.')))
*t = '\0';
goto add_string;
--- 5501,5515
case 'h':
case 'H':
! t_host = savestring (current_host_name);
! if (c == 'h' && (t = (char *)strchr (t_host, '.')))
*t = '\0';
+ if (promptvars || posixly_correct)
+ /* Make sure that expand_prompt_string is called with a
+ second argument of Q_DOUBLE_QUOTES if we use this
+ function here. */
+ temp = sh_backslash_quote_for_double_quotes (t_host);
+ else
+ temp = savestring (t_host);
+ free (t_host);
goto add_string;
*** ../bash-4.3-patched/y.tab.c 2015-08-13 15:11:54.0 -0400
--- y.tab.c 2016-03-07 15:44:14.0 -0500
***
*** 7571,7575
int result_size, result_index;
int c, n, i;
! char *temp, octal_string[4];
struct tm *tm;
time_t the_time;
--- 7571,7575
int result_size, result_index;
int c, n, i;
! char *temp, *t_host, octal_string[4];
struct tm *tm;
time_t the_time;
***
*** 7719,7723
case 's':
temp = base_pathname (shell_name);
! temp = savestring (temp);
goto add_string;
--- 7719,7727
case 's':
temp = base_pathname (shell_name);
! /* Try to quote anything the user can set in the file system */
! if (promptvars || posixly_correct)
! temp = sh_backslash_quote_for_double_quotes (temp);
! else
! temp = savestring (temp);
goto add_string;
***
*** 7809,7815
case 'h':
case 'H':
! temp = savestring (current_host_name);
! if (c == 'h' && (t = (char *)strchr (temp, '.')))
*t = '\0';
goto add_string;
--- 7813,7827
case 'h':
case 'H':
! t_host = savestring (current_host_name);
! if (c == 'h' && (t = (char *)strchr (t_host, '.')))
*t = '\0';
+ if (promptvars || posixly_correct)
+ /* Make sure that expand_prompt_string is called with a
+ second argument of Q_DOUBLE_QUOTES if we use this
+ function here. */
+ temp = sh_backslash_quote_for_double_quotes (t_host);
+ else
+ temp = savestring (t_host);
+ free (t_host);
goto add_string;
*** ../bash-4.3/patchlevel.h2012-12-29 10:47:57.0 -0500
--- patchlevel.h2014-03-20 20:01:28.0 -0400
***
*** 26,30
looks for to find the patch level (for the sccs version string). */
! #define PATCHLEVEL 46
#endif /* _PATCHLEVEL_H_ */
--- 26,30
looks for to find the patch level (for the sccs version string). */
! #define PATCHLEVEL 47
#endif /* _PATCHLEVEL_H_ */
--
``The lyf so short, the craft
