PR 60324 Unbounded stack allocations in libgfortran.

2014-11-13  Janne Blomqvist  <jb@gcc.gnu.org>

	PR libfortran/60324
	* configure: Regenerated.
	* configure.ac (AM_CFLAGS): Add Werror=vla.
	* libgfortran.h (gfc_alloca): Remove macro.
	(fc_strdup_notrim): New prototype.
	* intrinsics/access.c (access_func): Use fc_strdup rather than
	stack allocation.
	* intrinsics/chdir.c (chdir_i4_sub): Likewise.
	(chdir_i8_sub): Likewise.
	* intrinsics/chmod.c (chmod_internal): New function, move logic
	here.
	(chmod_func): Call chmod_internal.
	* intrinsics/env.c (getenv): Use fc_strdup rather than stack
	allocation.
	(get_environment_variable_i4): Likewise.
	* intrinsics/execute_command_line.c (execute_command_line):
	Likewise.
	* intrinsics/hostnm.c (hostnm_0): New function, use static buffer
	rather than VLA.
	(hostnm_i4_sub): Call hostnm_0.
	(hostnm_i8_sub): Likewise.
	(hostnm): Likewise.
	* intrinsics/link.c (link_internal): New function, use fc_strdup
	rather than stack allocation.
	(link_i4_sub): Call link_internal.
	(link_i8_sub): Likewise.
	(link_i4): Likewise.
	(link_i8): Likewise.
	* intrinsics/perror.c (perror_sub): Use fc_strdup rather than
	stack allocation.
	* intrinsics/random.c (random_seed_i4): Use static buffer rather
	than VLA, use _Static_assert to make sure it's big enough.
	* intrinsics/rename.c (rename_internal): New function, use
	fc_strdup rather than stack allocation.
	(rename_i4_sub): Call rename_internal.
	(rename_i8_sub): Likewise.
	(rename_i4): Likewise.
	(rename_i8): Likewise.
	* intrinsics/stat.c (stat_i4_sub_0): Use fc_strdup rather than
	stack allocation.
	(stat_i8_sub_0): Likewise.
	* intrinsics/symlink.c (symlnk_internal): New function, use
	fc_strdup rather than stack allocation.
	(symlnk_i4_sub): Call symlnk_internal.
	(symlnk_i8_sub): Likewise.
	(symlnk_i4): Likewise.
	(symlnk_i8): Likewise.
	* intrinsics/system.c (system_sub): Use fc_strdup rather than
	stack allocation.
	* intrinsics/unlink.c (unlink_i4_sub): Likewise.
	* io/file_pos.c (READ_CHUNK): Make it a macro rather than variable.
	* io/list_read.c (nml_get_obj_data): Use fixed stack buffer, fall
	back to xmalloc/free for large sizes.
	* io/read.c (read_f): Likewise.
	* io/transfer.c (MAX_READ): Make it a macro rather than variable.
	(WRITE_CHUNK): Likewise.
	* io/write_float.def (write_float): Use fixed stack buffer, fall
	back to xmalloc/free for large sizes.
	* runtime/string.c (fc_strdup_notrim): New function.

From-SVN: r217480

1 files changed, 9 insertions, 21 deletions

diff --git a/libgfortran/intrinsics/env.c b/libgfortran/intrinsics/env.c
index 9f45073..ffdc54a 100644
--- a/libgfortran/intrinsics/env.c
+++ b/libgfortran/intrinsics/env.c
@@ -52,27 +52,19 @@ PREFIX(getenv) (char * name, char * value, gfc_charlen_type name_len,
   else
     memset (value, ' ', value_len); /* Blank the string.  */
 
-  /* Trim trailing spaces from name.  */
-  while (name_len > 0 && name[name_len - 1] == ' ')
-    name_len--;
-
   /* Make a null terminated copy of the string.  */
-  name_nt = gfc_alloca (name_len + 1);
-  memcpy (name_nt, name, name_len);
-  name_nt[name_len] = '\0'; 
+  name_nt = fc_strdup (name, name_len);
 
   res = getenv(name_nt);
 
+  free (name_nt);
+
   /* If res is NULL, it means that the environment variable didn't 
      exist, so just return.  */
   if (res == NULL)
     return;
 
-  res_len = strlen(res);
-  if (value_len < res_len)
-    memcpy (value, res, value_len);
-  else
-    memcpy (value, res, res_len);
+  cf_strcpy (value, value_len, res);
 }
 
 
@@ -127,18 +119,14 @@ get_environment_variable_i4 (char *name, char *value, GFC_INTEGER_4 *length,
     }
 
   if ((!trim_name) || *trim_name)
-    {
-      /* Trim trailing spaces from name.  */
-      while (name_len > 0 && name[name_len - 1] == ' ')
-	name_len--;
-    }
-  /* Make a null terminated copy of the name.  */
-  name_nt = gfc_alloca (name_len + 1);
-  memcpy (name_nt, name, name_len);
-  name_nt[name_len] = '\0'; 
+    name_nt = fc_strdup (name, name_len);
+  else
+    name_nt = fc_strdup_notrim (name, name_len);
   
   res = getenv(name_nt);
 
+  free (name_nt);
+
   if (res == NULL)
     stat = GFC_NAME_DOES_NOT_EXIST;
   else