source/include/safe_string.h

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Safe string handling routines.
   4    Copyright (C) Andrew Tridgell 1994-1998
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2003
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #ifndef _SAFE_STRING_H
  23 #define _SAFE_STRING_H
  24
  25 #ifndef _SPLINT_ /* http://www.splint.org */
  26
  27 /* Some macros to ensure people don't use buffer overflow vulnerable string
  28    functions. */
  29
  30 #ifdef bcopy
  31 #undef bcopy
  32 #endif /* bcopy */
  33 #define bcopy(src,dest,size) __ERROR__XX__NEVER_USE_BCOPY___;
  34
  35 #ifdef strcpy
  36 #undef strcpy
  37 #endif /* strcpy */
  38 #define strcpy(dest,src) __ERROR__XX__NEVER_USE_STRCPY___;
  39
  40 #ifdef strcat
  41 #undef strcat
  42 #endif /* strcat */
  43 #define strcat(dest,src) __ERROR__XX__NEVER_USE_STRCAT___;
  44
  45 #ifdef sprintf
  46 #undef sprintf
  47 #endif /* sprintf */
  48 #define sprintf __ERROR__XX__NEVER_USE_SPRINTF__;
  49
  50 #endif /* !_SPLINT_ */
  51
  52 #ifdef DEVELOPER
  53 #define SAFE_STRING_FUNCTION_NAME FUNCTION_MACRO
  54 #define SAFE_STRING_LINE __LINE__
  55 #else
  56 #define SAFE_STRING_FUNCTION_NAME ("")
  57 #define SAFE_STRING_LINE (0)
  58 #endif
  59
  60 /* We need a number of different prototypes for our
  61    non-existant fuctions */
  62 char * __unsafe_string_function_usage_here__(void);
  63
  64 size_t __unsafe_string_function_usage_here_size_t__(void);
  65
  66 size_t __unsafe_string_function_usage_here_char__(void);
  67
  68 #ifdef HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS
  69
  70 /* if the compiler will optimize out function calls, then use this to tell if we are
  71    have the correct types (this works only where sizeof() returns the size of the buffer, not
  72    the size of the pointer). */
  73
  74 #define CHECK_STRING_SIZE(d, len) (sizeof(d) != (len) && sizeof(d) != sizeof(char *))
  75
  76 #define fstrterminate(d) (CHECK_STRING_SIZE(d, sizeof(fstring)) \
  77     ? __unsafe_string_function_usage_here_char__() \
  78     : (((d)[sizeof(fstring)-1]) = '\0'))
  79 #define pstrterminate(d) (CHECK_STRING_SIZE(d, sizeof(pstring)) \
  80     ? __unsafe_string_function_usage_here_char__() \
  81     : (((d)[sizeof(pstring)-1]) = '\0'))
  82
  83 #define wpstrcpy(d,s) ((sizeof(d) != sizeof(wpstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
  84     ? __unsafe_string_function_usage_here__() \
  85     : safe_strcpy_w((d),(s),sizeof(wpstring)))
  86 #define wpstrcat(d,s) ((sizeof(d) != sizeof(wpstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
  87     ? __unsafe_string_function_usage_here__() \
  88     : safe_strcat_w((d),(s),sizeof(wpstring)))
  89 #define wfstrcpy(d,s) ((sizeof(d) != sizeof(wfstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
  90     ? __unsafe_string_function_usage_here__() \
  91     : safe_strcpy_w((d),(s),sizeof(wfstring)))
  92 #define wfstrcat(d,s) ((sizeof(d) != sizeof(wfstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
  93     ? __unsafe_string_function_usage_here__() \
  94     : safe_strcat_w((d),(s),sizeof(wfstring)))
  95
  96 #define push_pstring_base(dest, src, pstring_base) \
  97     (CHECK_STRING_SIZE(pstring_base, sizeof(pstring)) \
  98     ? __unsafe_string_function_usage_here_size_t__() \
  99     : push_ascii(dest, src, sizeof(pstring)-PTR_DIFF(dest,pstring_base)-1, STR_TERMINATE))
 100
 101 #else /* HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS */
 102
 103 #define fstrterminate(d) (((d)[sizeof(fstring)-1]) = '\0')
 104 #define pstrterminate(d) (((d)[sizeof(pstring)-1]) = '\0')
 105
 106 #define wpstrcpy(d,s) safe_strcpy_w((d),(s),sizeof(wpstring))
 107 #define wpstrcat(d,s) safe_strcat_w((d),(s),sizeof(wpstring))
 108 #define wfstrcpy(d,s) safe_strcpy_w((d),(s),sizeof(wfstring))
 109 #define wfstrcat(d,s) safe_strcat_w((d),(s),sizeof(wfstring))
 110
 111 #define push_pstring_base(dest, src, pstring_base) \
 112     push_ascii(dest, src, sizeof(pstring)-PTR_DIFF(dest,pstring_base)-1, STR_TERMINATE)
 113
 114 #endif /* HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS */
 115
 116 #define safe_strcpy_base(dest, src, base, size) \
 117     safe_strcpy(dest, src, size-PTR_DIFF(dest,base)-1)
 118
 119 /* String copy functions - macro hell below adds 'type checking' (limited,
 120    but the best we can do in C) and may tag with function name/number to
 121    record the last 'clobber region' on that string */
 122
 123 #define pstrcpy(d,s) safe_strcpy((d), (s),sizeof(pstring)-1)
 124 #define pstrcat(d,s) safe_strcat((d), (s),sizeof(pstring)-1)
 125 #define fstrcpy(d,s) safe_strcpy((d),(s),sizeof(fstring)-1)
 126 #define fstrcat(d,s) safe_strcat((d),(s),sizeof(fstring)-1)
 127 #define nstrcpy(d,s) safe_strcpy((d), (s),sizeof(nstring)-1)
 128
 129 /* the addition of the DEVELOPER checks in safe_strcpy means we must
 130  * update a lot of code. To make this a little easier here are some
 131  * functions that provide the lengths with less pain */
 132 #define pstrcpy_base(dest, src, pstring_base) \
 133     safe_strcpy(dest, src, sizeof(pstring)-PTR_DIFF(dest,pstring_base)-1)
 134
 135
 136 /* Inside the _fn variants of these is a call to clobber_region(), -
 137  * which might destroy the stack on a buggy function.  We help the
 138  * debugging process by putting the function and line who last caused
 139  * a clobbering into a static buffer.  If the program crashes at
 140  * address 0xf1f1f1f1 then this function is probably, but not
 141  * necessarily, to blame. */
 142
 143 /* overmalloc_safe_strcpy: DEPRECATED!  Used when you know the
 144  * destination buffer is longer than maxlength, but you don't know how
 145  * long.  This is not a good situation, because we can't do the normal
 146  * sanity checks. Don't use in new code! */
 147
 148 #define overmalloc_safe_strcpy(dest,src,maxlength)      safe_strcpy_fn(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE,dest,src,maxlength)
 149 #define safe_strcpy(dest,src,maxlength) safe_strcpy_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE,dest,src,maxlength)
 150 #define safe_strcat(dest,src,maxlength) safe_strcat_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE,dest,src,maxlength)
 151 #define push_string(base_ptr, dest, src, dest_len, flags) push_string_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE, base_ptr, dest, src, dest_len, flags)
 152 #define pull_string(base_ptr, dest, src, dest_len, src_len, flags) pull_string_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE, base_ptr, dest, src, dest_len, src_len, flags)
 153 #define clistr_push(cli, dest, src, dest_len, flags) clistr_push_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE, cli, dest, src, dest_len, flags)
 154 #define clistr_pull(cli, dest, src, dest_len, src_len, flags) clistr_pull_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE, cli, dest, src, dest_len, src_len, flags)
 155 #define srvstr_push(base_ptr, dest, src, dest_len, flags) srvstr_push_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE, base_ptr, dest, src, dest_len, flags)
 156
 157 #define alpha_strcpy(dest,src,other_safe_chars,maxlength) alpha_strcpy_fn(SAFE_STRING_FUNCTION_NAME,SAFE_STRING_LINE,dest,src,other_safe_chars,maxlength)
 158 #define StrnCpy(dest,src,n)             StrnCpy_fn(SAFE_STRING_FUNCTION_NAME,SAFE_STRING_LINE,dest,src,n)
 159
 160 #ifdef HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS
 161
 162 /* if the compiler will optimize out function calls, then use this to tell if we are
 163    have the correct types (this works only where sizeof() returns the size of the buffer, not
 164    the size of the pointer). */
 165
 166 #define safe_strcpy_fn2(fn_name, fn_line, d, s, max_len) \
 167     (CHECK_STRING_SIZE(d, max_len+1) \
 168     ? __unsafe_string_function_usage_here__() \
 169     : safe_strcpy_fn(fn_name, fn_line, (d), (s), (max_len)))
 170
 171 #define safe_strcat_fn2(fn_name, fn_line, d, s, max_len) \
 172     (CHECK_STRING_SIZE(d, max_len+1) \
 173     ? __unsafe_string_function_usage_here__() \
 174     : safe_strcat_fn(fn_name, fn_line, (d), (s), (max_len)))
 175
 176 #define push_string_fn2(fn_name, fn_line, base_ptr, dest, src, dest_len, flags) \
 177     (CHECK_STRING_SIZE(dest, dest_len) \
 178     ? __unsafe_string_function_usage_here_size_t__() \
 179     : push_string_fn(fn_name, fn_line, base_ptr, dest, src, dest_len, flags))
 180
 181 #define pull_string_fn2(fn_name, fn_line, base_ptr, dest, src, dest_len, src_len, flags) \
 182     (CHECK_STRING_SIZE(dest, dest_len) \
 183     ? __unsafe_string_function_usage_here_size_t__() \
 184     : pull_string_fn(fn_name, fn_line, base_ptr, dest, src, dest_len, src_len, flags))
 185
 186 #define clistr_push_fn2(fn_name, fn_line, cli, dest, src, dest_len, flags) \
 187     (CHECK_STRING_SIZE(dest, dest_len) \
 188     ? __unsafe_string_function_usage_here_size_t__() \
 189     : clistr_push_fn(fn_name, fn_line, cli, dest, src, dest_len, flags))
 190
 191 #define clistr_pull_fn2(fn_name, fn_line, cli, dest, src, dest_len, srclen, flags) \
 192     (CHECK_STRING_SIZE(dest, dest_len) \
 193     ? __unsafe_string_function_usage_here_size_t__() \
 194     : clistr_pull_fn(fn_name, fn_line, cli, dest, src, dest_len, srclen, flags))
 195
 196 #define srvstr_push_fn2(fn_name, fn_line, base_ptr, dest, src, dest_len, flags) \
 197     (CHECK_STRING_SIZE(dest, dest_len) \
 198     ? __unsafe_string_function_usage_here_size_t__() \
 199     : srvstr_push_fn(fn_name, fn_line, base_ptr, dest, src, dest_len, flags))
 200
 201 #else
 202
 203 #define safe_strcpy_fn2 safe_strcpy_fn
 204 #define safe_strcat_fn2 safe_strcat_fn
 205 #define push_string_fn2 push_string_fn
 206 #define pull_string_fn2 pull_string_fn
 207 #define clistr_push_fn2 clistr_push_fn
 208 #define clistr_pull_fn2 clistr_pull_fn
 209 #define srvstr_push_fn2 srvstr_push_fn
 210
 211 #endif
 212
 213 #endif