Add "-Wnon-const-format" which checks for non-constant format strings for

auditing purposes.

Submitted by:	kris
Obtained from:	NetBSD

2 files changed, 176 insertions, 25 deletions

diff --git a/lang/egcs/files/patch-fa b/lang/egcs/files/patch-fa
index 7f5e0e6..b4cc8fd 100644
--- a/lang/egcs/files/patch-fa
+++ b/lang/egcs/files/patch-fa
@@ -1,15 +1,15 @@
---- gcc/c-common.c.orig	Mon Feb 15 16:40:05 1999
-+++ gcc/c-common.c	Tue Mar 30 03:35:22 1999
-@@ -61,7 +61,7 @@
+--- gcc/c-common.c.orig	Tue Sep  7 01:11:16 1999
++++ gcc/c-common.c	Sun Nov 26 15:35:38 2000
+@@ -64,7 +64,7 @@
  					       int, int, int));
  static void init_attributes		PROTO((void));
  static void record_function_format	PROTO((tree, tree, enum format_type,
 -					       int, int));
 +					       int, int, int));
  static void record_international_format	PROTO((tree, tree, int));
- 
- /* Keep a stack of if statements.  We record the number of compound
-@@ -669,6 +669,7 @@
+ static tree c_find_base_decl            PROTO((tree));
+ static int default_valid_lang_attribute PROTO ((tree, tree, tree, tree));
+@@ -715,6 +715,7 @@
  	      = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (args)));
  	    int format_num;
  	    int first_arg_num;
@@ -17,7 +17,7 @@
  	    enum format_type format_type;
  	    tree argument;
  	    int arg_num;
-@@ -682,7 +683,7 @@
+@@ -728,7 +729,7 @@
  	
  	    if (TREE_CODE (format_type_id) != IDENTIFIER_NODE)
  	      {
@@ -26,8 +26,8 @@
  		continue;
  	      }
  	    else
-@@ -690,12 +691,26 @@
- 		char *p = IDENTIFIER_POINTER (format_type_id);
+@@ -736,12 +737,26 @@
+ 		const char *p = IDENTIFIER_POINTER (format_type_id);
  		
  		if (!strcmp (p, "printf") || !strcmp (p, "__printf__"))
 +		  {
@@ -52,8 +52,8 @@
 +		  }
  		else
  		  {
- 		    error ("`%s' is an unrecognized format function type", p);
-@@ -766,7 +781,8 @@
+ 		    warning ("`%s' is an unrecognized format function type", p);
+@@ -812,7 +827,8 @@
  
  	    record_function_format (DECL_NAME (decl),
  				    DECL_ASSEMBLER_NAME (decl),
@@ -63,7 +63,7 @@
  	    break;
  	  }
  
-@@ -1010,6 +1026,11 @@
+@@ -1090,6 +1106,11 @@
  } format_char_info;
  
  static format_char_info print_char_table[] = {
@@ -75,7 +75,7 @@
    { "di",	0,	T_I,	T_I,	T_I,	T_L,	T_LL,	T_LL,	T_ST,	"-wp0 +"	},
    { "oxX",	0,	T_UI,	T_UI,	T_UI,	T_UL,	T_ULL,	T_ULL,	T_ST,	"-wp0#"		},
    { "u",	0,	T_UI,	T_UI,	T_UI,	T_UL,	T_ULL,	T_ULL,	T_ST,	"-wp0"		},
-@@ -1070,6 +1091,7 @@
+@@ -1150,6 +1171,7 @@
    tree name;			/* identifier such as "printf" */
    tree assembler_name;		/* optional mangled identifier (for C++) */
    enum format_type format_type;	/* type of format (printf, scanf, etc.) */
@@ -83,7 +83,7 @@
    int format_num;		/* number of format argument */
    int first_arg_num;		/* number of first arg (zero for varargs) */
  } function_format_info;
-@@ -1102,25 +1124,25 @@
+@@ -1182,25 +1204,25 @@
  init_function_format_info ()
  {
    record_function_format (get_identifier ("printf"), NULL_TREE,
@@ -119,7 +119,7 @@
  
    record_international_format (get_identifier ("gettext"), NULL_TREE, 1);
    record_international_format (get_identifier ("dgettext"), NULL_TREE, 2);
-@@ -1137,11 +1159,12 @@
+@@ -1217,11 +1239,12 @@
     (e.g. for varargs such as vfprintf).  */
  
  static void
@@ -133,7 +133,7 @@
        int format_num;
        int first_arg_num;
  {
-@@ -1165,6 +1188,7 @@
+@@ -1245,6 +1268,7 @@
      }
  
    info->format_type = format_type;
@@ -141,17 +141,150 @@
    info->format_num = format_num;
    info->first_arg_num = first_arg_num;
  }
-@@ -1314,7 +1338,8 @@
+@@ -1292,6 +1316,21 @@
+   warning ("too few arguments for format");
+ }
+ 
++static function_format_info *
++find_function_format (name, assembler_name)
++     tree name;
++     tree assembler_name;
++{
++  function_format_info *info;
++
++  for (info = function_format_list; info; info = info->next)
++    if (info->assembler_name
++	? (info->assembler_name == assembler_name)
++	: (info->name == name))
++      return info;
++  return 0;
++}
++
+ /* Check the argument list of a call to printf, scanf, etc.
+    NAME is the function identifier.
+    ASSEMBLER_NAME is the function's assembler identifier.
+@@ -1307,17 +1346,10 @@
+   function_format_info *info;
+ 
+   /* See if this function is a format function.  */
+-  for (info = function_format_list; info; info = info->next)
+-    {
+-      if (info->assembler_name
+-	  ? (info->assembler_name == assembler_name)
+-	  : (info->name == name))
+-	{
+-	  /* Yup; check it.  */
+-	  check_format_info (info, params);
+-	  break;
+-	}
+-    }
++  info = find_function_format (name, assembler_name);
++
++  if (info)
++    check_format_info (info, params);
+ }
+ 
+ /* Check the argument list of a call to printf, scanf, etc.
+@@ -1361,6 +1393,7 @@
+     return;
  
+   /* We can only check the format if it's a string constant.  */
++ again:
+   while (TREE_CODE (format_tree) == NOP_EXPR)
+     format_tree = TREE_OPERAND (format_tree, 0); /* strip coercion */
+ 
+@@ -1396,16 +1429,73 @@
+ 	  }
+     }
+ 
++  if (TREE_CODE (format_tree) == COND_EXPR) 
++    {
++      format_tree = TREE_OPERAND(format_tree, 1);
++      goto again;
++    }
++
    if (integer_zerop (format_tree))
      {
 -      warning ("null format string");
 +      if (!info->null_format_ok)
 +	warning ("null format string");
++      return;
++    }
++  if (TREE_CODE (format_tree) != ADDR_EXPR) 
++    {
++      if ((info->first_arg_num == 0) &&
++	  (TREE_CODE(format_tree) == PARM_DECL)) 
++	{
++	  function_format_info *i2;
++	  tree p;
++	  int n;
++
++	  /* Now, we need to determine if the current function is printf-like,
++	     and, if so, if the parameter we have here is as a parameter of 
++	     the current function and is in the argument slot declared to 
++	     contain the format argument. */
++
++	  p = current_function_decl;
++
++	  i2 = find_function_format (p->decl.name, p->decl.assembler_name);
++
++	  if (i2 == NULL) 
++	    {
++	      if (warn_format > 1)
++		warning("non-constant format parameter");
++	    }
++	  else
++	    {
++	      for (n = 1, p = current_function_decl->decl.arguments;
++		   (n < i2->format_num) && (p != NULL); 
++		   n++, p = TREE_CHAIN(p)) 
++		;
++	      if ((p == NULL) || (n != i2->format_num)) 
++		warning("can't find format arg for current format function");
++	      else if (p != format_tree)
++		warning("format argument passed here is not declared as format argument");
++	    }
++	}
++      else if ((info->format_type != strftime_format_type) &&
++	       (warn_format > 1))
++	warning("non-constant format parameter");
        return;
      }
-   if (TREE_CODE (format_tree) != ADDR_EXPR)
-@@ -1485,12 +1510,13 @@
+-  if (TREE_CODE (format_tree) != ADDR_EXPR)
+-    return;
+   format_tree = TREE_OPERAND (format_tree, 0);
+-  if (TREE_CODE (format_tree) != STRING_CST)
+-    return;
++  if (warn_format > 1 &&
++      (TREE_CODE (format_tree) == VAR_DECL) &&
++      TREE_READONLY(format_tree) &&
++      (DECL_INITIAL(format_tree) != NULL) && 
++      TREE_CODE(DECL_INITIAL(format_tree)) == STRING_CST)
++    format_tree = DECL_INITIAL(format_tree);
++       
++  if (TREE_CODE (format_tree) != STRING_CST) 
++    {
++      if ((info->format_type != strftime_format_type) &&
++	  (warn_format > 1))
++	warning("non-constant format parameter");
++      return;
++    }
+   format_chars = TREE_STRING_POINTER (format_tree);
+   format_length = TREE_STRING_LENGTH (format_tree);
+   if (format_length <= 1)
+@@ -1433,7 +1523,10 @@
+ 	  if (format_chars - TREE_STRING_POINTER (format_tree) != format_length)
+ 	    warning ("embedded `\\0' in format");
+ 	  if (info->first_arg_num != 0 && params != 0 && ! has_operand_number)
+-	    warning ("too many arguments for format");
++	    {
++	      if (warn_format_extra_args)
++		warning ("too many arguments for format");
++	    }
+ 	  return;
+ 	}
+       if (*format_chars++ != '%')
+@@ -1569,12 +1662,13 @@
  		     It will work on most machines, because size_t and int
  		     have the same mode.  But might as well warn anyway,
  		     since it will fail on other machines.  */
@@ -166,7 +299,7 @@
  		}
  	    }
  	  else
-@@ -1535,6 +1561,53 @@
+@@ -1619,6 +1713,53 @@
  		}
  	    }
  	}
@@ -220,7 +353,7 @@
  
        aflag = 0;
  
-@@ -1604,7 +1677,8 @@
+@@ -1688,7 +1829,8 @@
        switch (info->format_type)
  	{
  	case printf_format_type:
@@ -230,3 +363,11 @@
  	  break;
  	case scanf_format_type:
  	  fci = scan_char_table;
+@@ -1787,7 +1929,6 @@
+ 	warning ("use of `%c' length character with `%c' type character",
+ 		 length_char, format_char);
+ 
+-      /* Finally. . .check type of argument against desired type!  */
+       if (info->first_arg_num == 0)
+ 	continue;
+       if (fci->pointer_count == 0 && wanted_type == void_type_node)
diff --git a/lang/egcs/files/patch-fc b/lang/egcs/files/patch-fc
index a3f44c5..081cdcb 100644
--- a/lang/egcs/files/patch-fc
+++ b/lang/egcs/files/patch-fc
@@ -1,6 +1,6 @@
---- gcc/toplev.c.orig	Mon Mar 22 15:23:26 1999
-+++ gcc/toplev.c	Tue Mar 30 13:13:44 1999
-@@ -754,6 +754,9 @@
+--- gcc/toplev.c.orig	Thu Oct 21 00:01:37 1999
++++ gcc/toplev.c	Sun Nov 26 15:25:45 2000
+@@ -771,6 +771,9 @@
  
  int flag_no_ident = 0;
  
@@ -10,7 +10,7 @@
  /* Table of supported debugging formats.  */
  static struct
  {
-@@ -954,6 +957,8 @@
+@@ -971,6 +974,8 @@
     "Generate code to check every memory access" },
    {"prefix-function-name", &flag_prefix_function_name, 1,
     "Add a prefix to all function names" },
@@ -19,3 +19,13 @@
    {"dump-unnumbered", &flag_dump_unnumbered, 1,
     "Suppress output of instruction numbers and line number notes in debugging dumps"},
    {"instrument-functions", &flag_instrument_function_entry_exit, 1,
+@@ -1051,7 +1056,9 @@
+   { "-Wconversion", "Warn about possibly confusing type conversions" },
+   { "-Wno-conversion", "" },
+   { "-Wformat", "Warn about printf format anomalies" },
++  { "-Wnon-const-format", "Warn about printf-like format strings" },
+   { "-Wno-format", "" },
++  { "-Wno-format-extra-args", "" },
+   { "-Wimplicit-function-declaration",
+     "Warn about implicit function declarations" },
+   { "-Wno-implicit-function-declaration", "" },