Re: [ptxdist] [PATCH] bash: shellshock part 2 fix

[Michael Olbrich <m.olbrich@pengutronix.de>]

On Mon, Sep 29, 2014 at 11:45:10AM +0200, Bruno Thomsen wrote:
> Fix CVE-2014-7169.
> Applied patches 53 and 54 from version 3.2.
> 
> Signed-off-by: Bruno Thomsen <bth@kamstrup.dk>

Thanks. I've applied both patches.

Michael

> ---
>  patches/bash-3.2.48/0005-bash-3.2-patch53.patch |  51 +++++++
>  patches/bash-3.2.48/0006-bash-3.2-patch54.patch | 185 ++++++++++++++++++++++++
>  patches/bash-3.2.48/series                      |   2 +
>  3 files changed, 238 insertions(+)
>  create mode 100644 patches/bash-3.2.48/0005-bash-3.2-patch53.patch
>  create mode 100644 patches/bash-3.2.48/0006-bash-3.2-patch54.patch
> 
> diff --git a/patches/bash-3.2.48/0005-bash-3.2-patch53.patch b/patches/bash-3.2.48/0005-bash-3.2-patch53.patch
> new file mode 100644
> index 0000000..cad5435
> --- /dev/null
> +++ b/patches/bash-3.2.48/0005-bash-3.2-patch53.patch
> @@ -0,0 +1,51 @@
> +From bb47ebbc22117d0dfcff43734b5eeb293b4249e7 Mon Sep 17 00:00:00 2001
> +From: Bruno Thomsen <bth@kamstrup.dk>
> +Date: Mon, 29 Sep 2014 10:18:41 +0200
> +Subject: [PATCH] bash-3.2: patch 53
> +
> +Bash-Release: 3.2
> +Patch-ID: bash32-053
> +
> +Bug-Reported-by:	Tavis Ormandy <taviso@cmpxchg8b.com>
> +Bug-Reference-ID:
> +Bug-Reference-URL:	http://twitter.com/taviso/statuses/514887394294652929
> +
> +Bug-Description:
> +
> +Under certain circumstances, bash can incorrectly save a lookahead character and
> +return it on a subsequent call, even when reading a new line.
> +
> +Signed-off-by: Bruno Thomsen <bth@kamstrup.dk>
> +---
> + parse.y      | 2 ++
> + patchlevel.h | 2 +-
> + 2 files changed, 3 insertions(+), 1 deletion(-)
> +
> +diff --git a/parse.y b/parse.y
> +index 8a2b081..6cb2bce 100644
> +--- a/parse.y
> ++++ b/parse.y
> +@@ -2503,6 +2503,8 @@ reset_parser ()
> +   FREE (word_desc_to_read);
> +   word_desc_to_read = (WORD_DESC *)NULL;
> + 
> ++  eol_ungetc_lookahead = 0;
> ++
> +   last_read_token = '\n';
> +   token_to_read = '\n';
> + }
> +diff --git a/patchlevel.h b/patchlevel.h
> +index a2d65b2..e5d74f3 100644
> +--- a/patchlevel.h
> ++++ b/patchlevel.h
> +@@ -25,6 +25,6 @@
> +    regexp `^#define[ 	]*PATCHLEVEL', since that's what support/mkversion.sh
> +    looks for to find the patch level (for the sccs version string). */
> + 
> +-#define PATCHLEVEL 52
> ++#define PATCHLEVEL 53
> + 
> + #endif /* _PATCHLEVEL_H_ */
> +-- 
> +1.9.1
> +
> diff --git a/patches/bash-3.2.48/0006-bash-3.2-patch54.patch b/patches/bash-3.2.48/0006-bash-3.2-patch54.patch
> new file mode 100644
> index 0000000..0b7e14d
> --- /dev/null
> +++ b/patches/bash-3.2.48/0006-bash-3.2-patch54.patch
> @@ -0,0 +1,185 @@
> +From 3daa4e268f15c66675cccc4e17c901194ca19199 Mon Sep 17 00:00:00 2001
> +From: Bruno Thomsen <bth@kamstrup.dk>
> +Date: Mon, 29 Sep 2014 10:36:58 +0200
> +Subject: [PATCH] bash-3.2: patch 54
> +
> +Bash-Release: 3.2
> +Patch-ID: bash32-054
> +
> +Bug-Reported-by:	Florian Weimer <fweimer@redhat.com>
> +Bug-Reference-ID:
> +Bug-Reference-URL:
> +
> +Bug-Description:
> +
> +This patch changes the encoding bash uses for exported functions to avoid
> +clashes with shell variables and to avoid depending only on an environment
> +variable's contents to determine whether or not to interpret it as a shell
> +function.
> +
> +Signed-off-by: Bruno Thomsen <bth@kamstrup.dk>
> +---
> + patchlevel.h |  2 +-
> + variables.c  | 80 +++++++++++++++++++++++++++++++++++++++++++++---------------
> + 2 files changed, 61 insertions(+), 21 deletions(-)
> +
> +diff --git a/patchlevel.h b/patchlevel.h
> +index e5d74f3..d449c7c 100644
> +--- a/patchlevel.h
> ++++ b/patchlevel.h
> +@@ -25,6 +25,6 @@
> +    regexp `^#define[ 	]*PATCHLEVEL', since that's what support/mkversion.sh
> +    looks for to find the patch level (for the sccs version string). */
> + 
> +-#define PATCHLEVEL 53
> ++#define PATCHLEVEL 54
> + 
> + #endif /* _PATCHLEVEL_H_ */
> +diff --git a/variables.c b/variables.c
> +index eb80326..76501cf 100644
> +--- a/variables.c
> ++++ b/variables.c
> +@@ -74,6 +74,11 @@
> + 
> + #define ifsname(s)	((s)[0] == 'I' && (s)[1] == 'F' && (s)[2] == 'S' && (s)[3] == '\0')
> + 
> ++#define BASHFUNC_PREFIX		"BASH_FUNC_"
> ++#define BASHFUNC_PREFLEN	10	/* == strlen(BASHFUNC_PREFIX */
> ++#define BASHFUNC_SUFFIX		"%%"
> ++#define BASHFUNC_SUFFLEN	2	/* == strlen(BASHFUNC_SUFFIX) */
> ++
> + extern char **environ;
> + 
> + /* Variables used here and defined in other files. */
> +@@ -241,7 +246,7 @@ static void push_temp_var __P((PTR_T));
> + 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));
> +@@ -309,27 +314,41 @@ initialize_shell_variables (env, privmode)
> + 
> +       /* 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))
> ++      if (privmode == 0 && read_but_dont_execute == 0 &&
> ++	  STREQN (BASHFUNC_PREFIX, name, BASHFUNC_PREFLEN) &&
> ++	  STREQ (BASHFUNC_SUFFIX, name + char_index - BASHFUNC_SUFFLEN) &&
> ++	  STREQN ("() {", string, 4))
> + 	{
> ++	  size_t namelen;
> ++	  char *tname;		/* desired imported function name */
> ++
> ++	  namelen = char_index - BASHFUNC_PREFLEN - BASHFUNC_SUFFLEN;
> ++
> ++	  tname = name + BASHFUNC_PREFLEN;	/* start of func name */
> ++	  tname[namelen] = '\0';		/* now tname == func name */
> ++
> + 	  string_length = strlen (string);
> +-	  temp_string = (char *)xmalloc (3 + string_length + char_index);
> ++	  temp_string = (char *)xmalloc (namelen + string_length + 2);
> + 
> +-	  strcpy (temp_string, name);
> +-	  temp_string[char_index] = ' ';
> +-	  strcpy (temp_string + char_index + 1, string);
> ++	  memcpy (temp_string, tname, namelen);
> ++	  temp_string[namelen] = ' ';
> ++	  memcpy (temp_string + namelen + 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 (absolute_program (tname) == 0 && (posixly_correct == 0 || legal_identifier (tname)))
> ++	    parse_and_execute (temp_string, tname, SEVAL_NONINT|SEVAL_NOHIST|SEVAL_FUNCDEF|SEVAL_ONECMD);
> + 
> +-	  if (temp_var = find_function (name))
> ++	  if (temp_var = find_function (tname))
> + 	    {
> + 	      VSETATTR (temp_var, (att_exported|att_imported));
> + 	      array_needs_making = 1;
> + 	    }
> + 	  else
> +-	    report_error (_("error importing function definition for `%s'"), name);
> ++	    report_error (_("error importing function definition for `%s'"), tname);
> ++
> ++	  /* Restore original suffix */
> ++	  tname[namelen] = BASHFUNC_SUFFIX[0];
> + 	}
> + #if defined (ARRAY_VARS)
> + #  if 0
> +@@ -2207,7 +2226,7 @@ assign_in_env (word)
> +   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;
> + 
> +@@ -2998,21 +3017,42 @@ merge_temporary_env ()
> + /* **************************************************************** */
> + 
> + static inline char *
> +-mk_env_string (name, value)
> ++mk_env_string (name, value, isfunc)
> +      const char *name, *value;
> ++     int isfunc;
> + {
> +-  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 we are exporting a shell function, construct the encoded function
> ++     name. */
> ++  if (isfunc && value)
> ++    {
> ++      p = (char *)xmalloc (BASHFUNC_PREFLEN + name_len + BASHFUNC_SUFFLEN + value_len + 2);
> ++      q = p;
> ++      memcpy (q, BASHFUNC_PREFIX, BASHFUNC_PREFLEN);
> ++      q += BASHFUNC_PREFLEN;
> ++      memcpy (q, name, name_len);
> ++      q += name_len;
> ++      memcpy (q, BASHFUNC_SUFFIX, BASHFUNC_SUFFLEN);
> ++      q += BASHFUNC_SUFFLEN;
> ++    }
> ++  else
> ++    {
> ++      p = (char *)xmalloc (2 + name_len + value_len);
> ++      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);
> + }
> + 
> +@@ -3087,7 +3127,7 @@ make_env_array_from_var_list (vars)
> + 	  /* 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]);
> +-- 
> +1.9.1
> +
> diff --git a/patches/bash-3.2.48/series b/patches/bash-3.2.48/series
> index 0ede824..9ae2d65 100644
> --- a/patches/bash-3.2.48/series
> +++ b/patches/bash-3.2.48/series
> @@ -2,3 +2,5 @@
>  0002-bash-3.2-patch50.patch
>  0003-bash-3.2-patch51.patch
>  0004-bash-3.2-patch52.patch
> +0005-bash-3.2-patch53.patch
> +0006-bash-3.2-patch54.patch
> -- 
> 1.9.1
> 
> 
> -- 
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> ptxdist@pengutronix.de
> 

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