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Date: Thu, 25 Sep 2014 23:19:24 +0530
From: Huzaifa Sidhpurwala <huzaifas@...hat.com>
To: oss-security@...ts.openwall.com
Subject: Fwd: Non-upstream patches for bash
Hi All,
Based on the current situation and the fact that there is confusion
about what patch to use for the bash issue. I wanted to post this here.
We have found a few more issues (OOB memory access). Also I am posting
Florain's patch here which should fix the issue in a more deeper way
rather than just apply duct-tape.
Any feed back etc is welcome!
-------- Forwarded Message --------
Subject: Non-upstream patches for bash
Date: Thu, 25 Sep 2014 19:37:36 +0200
From: Florian Weimer <fweimer@...hat.com>
To: Huzaifa Sidhpurwala <huzaifas@...hat.com>, Joshua Bressers
<bressers@...hat.com>
Note that if you ship 4.3, you might want to reevaluate a decision to
enable array variable import from the environment.
Internal analysis revealed two out-of-bounds array accesses in the bash
parser. This was also independently and privately reported by Todd
Sabin <tsabin@...online.net>.
The redir_stack issue is this:
$ bash -c 'true <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF <<EOF
<<EOF <<EOF <<EOF <<EOF <<EOF'
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: warning: here-document at line 2 delimited by end-of-file
(wanted `EOF')
bash: line 2: make_here_document: bad instruction type 33
Segmentation fault (core dumped)
The word_lineno issue is this (only visible with address sanitizer, but
it's probably to come up with something better):
$ (for x in {1..200} ; do echo "for x$x in ; do :"; done; for x in
{1..200} ; do echo done ; done) > test-script.sh $ bash test-script.sh
Both issues are fixed by the parser-oob patches.
I'm also including the function definition affix patch which has already
been posted to oss-security. (variables-affix-3.0.patch has only seen
very light review and testing yet, but it's a fairly straightforward
backport.)
You'll also want Chet's one-liner patch posted to oss-security.
--
Florian Weimer / Red Hat Product Security
--- ../bash-4.2-orig/parse.y 2014-09-25 13:07:59.218209276 +0200
+++ parse.y 2014-09-25 15:26:52.813159810 +0200
@@ -264,9 +264,21 @@
/* Variables to manage the task of reading here documents, because we need to
defer the reading until after a complete command has been collected. */
-static REDIRECT *redir_stack[10];
+static REDIRECT **redir_stack;
int need_here_doc;
+/* Pushes REDIR onto redir_stack, resizing it as needed. */
+static void
+push_redir_stack (REDIRECT *redir)
+{
+ /* Guard against oveflow. */
+ if (need_here_doc + 1 > INT_MAX / sizeof (*redir_stack))
+ abort ();
+ redir_stack = xrealloc (redir_stack,
+ (need_here_doc + 1) * sizeof (*redir_stack));
+ redir_stack[need_here_doc++] = redir;
+}
+
/* Where shell input comes from. History expansion is performed on each
line when the shell is interactive. */
static char *shell_input_line = (char *)NULL;
@@ -519,42 +531,42 @@
source.dest = 0;
redir.filename = $2;
$$ = make_redirection (source, r_reading_until, redir, 0);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| NUMBER LESS_LESS WORD
{
source.dest = $1;
redir.filename = $3;
$$ = make_redirection (source, r_reading_until, redir, 0);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| REDIR_WORD LESS_LESS WORD
{
source.filename = $1;
redir.filename = $3;
$$ = make_redirection (source, r_reading_until, redir, REDIR_VARASSIGN);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| LESS_LESS_MINUS WORD
{
source.dest = 0;
redir.filename = $2;
$$ = make_redirection (source, r_deblank_reading_until, redir, 0);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| NUMBER LESS_LESS_MINUS WORD
{
source.dest = $1;
redir.filename = $3;
$$ = make_redirection (source, r_deblank_reading_until, redir, 0);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| REDIR_WORD LESS_LESS_MINUS WORD
{
source.filename = $1;
redir.filename = $3;
$$ = make_redirection (source, r_deblank_reading_until, redir, REDIR_VARASSIGN);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| LESS_LESS_LESS WORD
{
@@ -4757,7 +4769,7 @@
case CASE:
case SELECT:
case FOR:
- if (word_top < MAX_CASE_NEST)
+ if (word_top + 1 < MAX_CASE_NEST)
word_top++;
word_lineno[word_top] = line_number;
break;
--- bash-3.0-orig/variables.c 2014-09-25 18:50:08.987614049 +0200
+++ bash-3.0/variables.c 2014-09-25 18:50:45.588769468 +0200
@@ -227,7 +227,7 @@
static void propagate_temp_var __P((PTR_T));
static void dispose_temporary_env __P((sh_free_func_t *));
-static inline char *mk_env_string __P((const char *, const char *));
+static inline char *mk_env_string __P((const char *, const char *, int));
static char **make_env_array_from_var_list __P((SHELL_VAR **));
static char **make_var_export_array __P((VAR_CONTEXT *));
static char **make_func_export_array __P((void));
@@ -240,6 +240,13 @@
static void push_exported_var __P((PTR_T));
static inline int find_special_var __P((const char *));
+
+/* Prefix and suffix for environment variable names which contain
+ shell functions. */
+#define FUNCDEF_PREFIX "BASH_FUNC_"
+#define FUNCDEF_PREFIX_LEN (strlen (FUNCDEF_PREFIX))
+#define FUNCDEF_SUFFIX "()"
+#define FUNCDEF_SUFFIX_LEN (strlen (FUNCDEF_SUFFIX))
/* Initialize the shell variables from the current environment.
If PRIVMODE is nonzero, don't import functions from ENV or
@@ -289,22 +296,31 @@
/* If exported function, define it now. Don't import functions from
the environment in privileged mode. */
- if (privmode == 0 && read_but_dont_execute == 0 && STREQN ("() {", string, 4))
- {
- string_length = strlen (string);
- temp_string = (char *)xmalloc (3 + string_length + char_index);
-
- strcpy (temp_string, name);
- temp_string[char_index] = ' ';
- strcpy (temp_string + char_index + 1, string);
+ if (privmode == 0 && read_but_dont_execute == 0
+ && STREQN (FUNCDEF_PREFIX, name, FUNCDEF_PREFIX_LEN)
+ && STREQ (name + char_index - FUNCDEF_SUFFIX_LEN, FUNCDEF_SUFFIX)
+ && STREQN ("() {", string, 4))
+ {
+ size_t name_length
+ = char_index - (FUNCDEF_PREFIX_LEN + FUNCDEF_SUFFIX_LEN);
+ char *temp_name = name + FUNCDEF_PREFIX_LEN;
+ /* Temporarily remove the suffix. */
+ temp_name[name_length] = '\0';
+
+ string_length = strlen (string);
+ temp_string = (char *)xmalloc (name_length + 1 + string_length + 1);
+ memcpy (temp_string, temp_name, name_length);
+ temp_string[name_length] = ' ';
+ memcpy (temp_string + name_length + 1, string, string_length + 1);
/* Don't import function names that are invalid identifiers from the
environment, though we still allow them to be defined as shell
variables. */
- if (legal_identifier (name))
- parse_and_execute (temp_string, name, SEVAL_NONINT|SEVAL_NOHIST|SEVAL_FUNCDEF|SEVAL_ONECMD);
+ if (legal_identifier (temp_name))
+ parse_and_execute (temp_string, temp_name,
+ SEVAL_NONINT|SEVAL_NOHIST|SEVAL_FUNCDEF|SEVAL_ONECMD);
- if (temp_var = find_function (name))
+ if (temp_var = find_function (temp_name))
{
VSETATTR (temp_var, (att_exported|att_imported));
array_needs_making = 1;
@@ -312,9 +328,8 @@
else
report_error (_("error importing function definition for `%s'"), name);
- /* ( */
- if (name[char_index - 1] == ')' && name[char_index - 2] == '\0')
- name[char_index - 2] = '('; /* ) */
+ /* Restore the original suffix. */
+ temp_name[name_length] = FUNCDEF_SUFFIX[0];
}
#if defined (ARRAY_VARS)
# if 0
@@ -2117,7 +2132,7 @@
var->context = variable_context; /* XXX */
INVALIDATE_EXPORTSTR (var);
- var->exportstr = mk_env_string (name, value);
+ var->exportstr = mk_env_string (name, value, 0);
array_needs_making = 1;
@@ -2899,22 +2914,43 @@
/* */
/* **************************************************************** */
+/* Returns the string NAME=VALUE if !FUNCTIONP or if VALUE == NULL (in
+ which case it is treated as empty). Otherwise, decorate NAME with
+ FUNCDEF_PREFIX and FUNCDEF_SUFFIX, and return a string of the form
+ FUNCDEF_PREFIX NAME FUNCDEF_SUFFIX = VALUE (without spaces). */
static inline char *
-mk_env_string (name, value)
+mk_env_string (name, value, functionp)
const char *name, *value;
+ int functionp;
{
- int name_len, value_len;
- char *p;
+ size_t name_len, value_len;
+ char *p, *q;
name_len = strlen (name);
value_len = STRLEN (value);
- p = (char *)xmalloc (2 + name_len + value_len);
- strcpy (p, name);
- p[name_len] = '=';
+ if (functionp && value != NULL)
+ {
+ p = (char *)xmalloc (FUNCDEF_PREFIX_LEN + name_len + FUNCDEF_SUFFIX_LEN
+ + 1 + value_len + 1);
+ q = p;
+ memcpy (q, FUNCDEF_PREFIX, FUNCDEF_PREFIX_LEN);
+ q += FUNCDEF_PREFIX_LEN;
+ memcpy (q, name, name_len);
+ q += name_len;
+ memcpy (q, FUNCDEF_SUFFIX, FUNCDEF_SUFFIX_LEN);
+ q += FUNCDEF_SUFFIX_LEN;
+ }
+ else
+ {
+ p = (char *)xmalloc (name_len + 1 + value_len + 1);
+ memcpy (p, name, name_len);
+ q = p + name_len;
+ }
+ q[0] = '=';
if (value && *value)
- strcpy (p + name_len + 1, value);
+ memcpy (q + 1, value, value_len + 1);
else
- p[name_len + 1] = '\0';
+ q[1] = '\0';
return (p);
}
@@ -2989,7 +3025,7 @@
/* Gee, I'd like to get away with not using savestring() if we're
using the cached exportstr... */
list[list_index] = USE_EXPORTSTR ? savestring (value)
- : mk_env_string (var->name, value);
+ : mk_env_string (var->name, value, function_p (var));
if (USE_EXPORTSTR == 0)
SAVE_EXPORTSTR (var, list[list_index]);
--- bash-3.2-orig/parse.y 2014-09-25 18:00:08.742924560 +0200
+++ bash-3.2/parse.y 2014-09-25 17:59:33.488769406 +0200
@@ -253,9 +253,21 @@
/* Variables to manage the task of reading here documents, because we need to
defer the reading until after a complete command has been collected. */
-static REDIRECT *redir_stack[10];
+static REDIRECT **redir_stack;
int need_here_doc;
+/* Pushes REDIR onto redir_stack, resizing it as needed. */
+static void
+push_redir_stack (REDIRECT *redir)
+{
+ /* Guard against oveflow. */
+ if (need_here_doc + 1 > INT_MAX / sizeof (*redir_stack))
+ abort ();
+ redir_stack = xrealloc (redir_stack,
+ (need_here_doc + 1) * sizeof (*redir_stack));
+ redir_stack[need_here_doc++] = redir;
+}
+
/* Where shell input comes from. History expansion is performed on each
line when the shell is interactive. */
static char *shell_input_line = (char *)NULL;
@@ -424,13 +436,13 @@
{
redir.filename = $2;
$$ = make_redirection (0, r_reading_until, redir);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| NUMBER LESS_LESS WORD
{
redir.filename = $3;
$$ = make_redirection ($1, r_reading_until, redir);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| LESS_LESS_LESS WORD
{
@@ -487,14 +499,14 @@
redir.filename = $2;
$$ = make_redirection
(0, r_deblank_reading_until, redir);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| NUMBER LESS_LESS_MINUS WORD
{
redir.filename = $3;
$$ = make_redirection
($1, r_deblank_reading_until, redir);
- redir_stack[need_here_doc++] = $$;
+ push_redir_stack ($$);
}
| GREATER_AND '-'
{
@@ -3767,7 +3779,7 @@
case CASE:
case SELECT:
case FOR:
- if (word_top < MAX_CASE_NEST)
+ if (word_top + 1 < MAX_CASE_NEST)
word_top++;
word_lineno[word_top] = line_number;
break;
--- ../bash-4.2-orig/variables.c 2014-09-25 13:07:59.313209541 +0200
+++ variables.c 2014-09-25 13:15:29.869420719 +0200
@@ -268,7 +268,7 @@
static void propagate_temp_var __P((PTR_T));
static void dispose_temporary_env __P((sh_free_func_t *));
-static inline char *mk_env_string __P((const char *, const char *));
+static inline char *mk_env_string __P((const char *, const char *, int));
static char **make_env_array_from_var_list __P((SHELL_VAR **));
static char **make_var_export_array __P((VAR_CONTEXT *));
static char **make_func_export_array __P((void));
@@ -301,6 +301,14 @@
#endif
}
+/* Prefix and suffix for environment variable names which contain
+ shell functions. */
+#define FUNCDEF_PREFIX "BASH_FUNC_"
+#define FUNCDEF_PREFIX_LEN (strlen (FUNCDEF_PREFIX))
+#define FUNCDEF_SUFFIX "()"
+#define FUNCDEF_SUFFIX_LEN (strlen (FUNCDEF_SUFFIX))
+
+
/* Initialize the shell variables from the current environment.
If PRIVMODE is nonzero, don't import functions from ENV or
parse $SHELLOPTS. */
@@ -338,27 +346,39 @@
/* If exported function, define it now. Don't import functions from
the environment in privileged mode. */
- if (privmode == 0 && read_but_dont_execute == 0 && STREQN ("() {", string, 4))
- {
- string_length = strlen (string);
- temp_string = (char *)xmalloc (3 + string_length + char_index);
+ if (privmode == 0 && read_but_dont_execute == 0
+ && STREQN (FUNCDEF_PREFIX, name, FUNCDEF_PREFIX_LEN)
+ && STREQ (name + char_index - FUNCDEF_SUFFIX_LEN, FUNCDEF_SUFFIX)
+ && STREQN ("() {", string, 4))
+ {
+ size_t name_length
+ = char_index - (FUNCDEF_PREFIX_LEN + FUNCDEF_SUFFIX_LEN);
+ char *temp_name = name + FUNCDEF_PREFIX_LEN;
+ /* Temporarily remove the suffix. */
+ temp_name[name_length] = '\0';
- strcpy (temp_string, name);
- temp_string[char_index] = ' ';
- strcpy (temp_string + char_index + 1, string);
+ string_length = strlen (string);
+ temp_string = (char *)xmalloc (name_length + 1 + string_length + 1);
+ memcpy (temp_string, temp_name, name_length);
+ temp_string[name_length] = ' ';
+ memcpy (temp_string + name_length + 1, string, string_length + 1);
/* Don't import function names that are invalid identifiers from the
environment. */
- if (legal_identifier (name))
- parse_and_execute (temp_string, name, SEVAL_NONINT|SEVAL_NOHIST|SEVAL_FUNCDEF|SEVAL_ONECMD);
+ if (legal_identifier (temp_name))
+ parse_and_execute (temp_string, temp_name,
+ SEVAL_NONINT|SEVAL_NOHIST|SEVAL_FUNCDEF|SEVAL_ONECMD);
- if (temp_var = find_function (name))
+ if (temp_var = find_function (temp_name))
{
VSETATTR (temp_var, (att_exported|att_imported));
array_needs_making = 1;
}
else
report_error (_("error importing function definition for `%s'"), name);
+
+ /* Restore the original suffix. */
+ temp_name[name_length] = FUNCDEF_SUFFIX[0];
}
#if defined (ARRAY_VARS)
# if 0
@@ -2537,7 +2557,7 @@
var->context = variable_context; /* XXX */
INVALIDATE_EXPORTSTR (var);
- var->exportstr = mk_env_string (name, value);
+ var->exportstr = mk_env_string (name, value, 0);
array_needs_making = 1;
@@ -3388,22 +3408,43 @@
/* */
/* **************************************************************** */
+/* Returns the string NAME=VALUE if !FUNCTIONP or if VALUE == NULL (in
+ which case it is treated as empty). Otherwise, decorate NAME with
+ FUNCDEF_PREFIX and FUNCDEF_SUFFIX, and return a string of the form
+ FUNCDEF_PREFIX NAME FUNCDEF_SUFFIX = VALUE (without spaces). */
static inline char *
-mk_env_string (name, value)
+mk_env_string (name, value, functionp)
const char *name, *value;
+ int functionp;
{
- int name_len, value_len;
- char *p;
+ size_t name_len, value_len;
+ char *p, *q;
name_len = strlen (name);
value_len = STRLEN (value);
- p = (char *)xmalloc (2 + name_len + value_len);
- strcpy (p, name);
- p[name_len] = '=';
+ if (functionp && value != NULL)
+ {
+ p = (char *)xmalloc (FUNCDEF_PREFIX_LEN + name_len + FUNCDEF_SUFFIX_LEN
+ + 1 + value_len + 1);
+ q = p;
+ memcpy (q, FUNCDEF_PREFIX, FUNCDEF_PREFIX_LEN);
+ q += FUNCDEF_PREFIX_LEN;
+ memcpy (q, name, name_len);
+ q += name_len;
+ memcpy (q, FUNCDEF_SUFFIX, FUNCDEF_SUFFIX_LEN);
+ q += FUNCDEF_SUFFIX_LEN;
+ }
+ else
+ {
+ p = (char *)xmalloc (name_len + 1 + value_len + 1);
+ memcpy (p, name, name_len);
+ q = p + name_len;
+ }
+ q[0] = '=';
if (value && *value)
- strcpy (p + name_len + 1, value);
+ memcpy (q + 1, value, value_len + 1);
else
- p[name_len + 1] = '\0';
+ q[1] = '\0';
return (p);
}
@@ -3489,7 +3530,7 @@
/* Gee, I'd like to get away with not using savestring() if we're
using the cached exportstr... */
list[list_index] = USE_EXPORTSTR ? savestring (value)
- : mk_env_string (var->name, value);
+ : mk_env_string (var->name, value, function_p (var));
if (USE_EXPORTSTR == 0)
SAVE_EXPORTSTR (var, list[list_index]);
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