source3/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 /*
  51  * strcasecmp/strncasecmp aren't an error, but it means you're not thinking about
  52  * multibyte. Don't use them. JRA.
  53  */
  54 #ifdef strcasecmp
  55 #undef strcasecmp
  56 #endif
  57 #define strcasecmp __ERROR__XX__NEVER_USE_STRCASECMP__;
  58
  59 #ifdef strncasecmp
  60 #undef strncasecmp
  61 #endif
  62 #define strncasecmp __ERROR__XX__NEVER_USE_STRCASECMP__;
  63
  64 #endif /* !_SPLINT_ */
  65
  66 #ifdef DEVELOPER
  67 #define SAFE_STRING_FUNCTION_NAME FUNCTION_MACRO
  68 #define SAFE_STRING_LINE __LINE__
  69 #else
  70 #define SAFE_STRING_FUNCTION_NAME ("")
  71 #define SAFE_STRING_LINE (0)
  72 #endif
  73
  74 /* We need a number of different prototypes for our
  75    non-existant fuctions */
  76 char * __unsafe_string_function_usage_here__(void);
  77
  78 size_t __unsafe_string_function_usage_here_size_t__(void);
  79
  80 size_t __unsafe_string_function_usage_here_char__(void);
  81
  82 #ifdef HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS
  83
  84 /* if the compiler will optimize out function calls, then use this to tell if we are
  85    have the correct types (this works only where sizeof() returns the size of the buffer, not
  86    the size of the pointer). */
  87
  88 #define CHECK_STRING_SIZE(d, len) (sizeof(d) != (len) && sizeof(d) != sizeof(char *))
  89
  90 #define fstrterminate(d) (CHECK_STRING_SIZE(d, sizeof(fstring)) \
  91     ? __unsafe_string_function_usage_here_char__() \
  92     : (((d)[sizeof(fstring)-1]) = '\0'))
  93 #define pstrterminate(d) (CHECK_STRING_SIZE(d, sizeof(pstring)) \
  94     ? __unsafe_string_function_usage_here_char__() \
  95     : (((d)[sizeof(pstring)-1]) = '\0'))
  96
  97 #define wpstrcpy(d,s) ((sizeof(d) != sizeof(wpstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
  98     ? __unsafe_string_function_usage_here__() \
  99     : safe_strcpy_w((d),(s),sizeof(wpstring)))
 100 #define wpstrcat(d,s) ((sizeof(d) != sizeof(wpstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
 101     ? __unsafe_string_function_usage_here__() \
 102     : safe_strcat_w((d),(s),sizeof(wpstring)))
 103 #define wfstrcpy(d,s) ((sizeof(d) != sizeof(wfstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
 104     ? __unsafe_string_function_usage_here__() \
 105     : safe_strcpy_w((d),(s),sizeof(wfstring)))
 106 #define wfstrcat(d,s) ((sizeof(d) != sizeof(wfstring) && sizeof(d) != sizeof(smb_ucs2_t *)) \
 107     ? __unsafe_string_function_usage_here__() \
 108     : safe_strcat_w((d),(s),sizeof(wfstring)))
 109
 110 #define push_pstring_base(dest, src, pstring_base) \
 111     (CHECK_STRING_SIZE(pstring_base, sizeof(pstring)) \
 112     ? __unsafe_string_function_usage_here_size_t__() \
 113     : push_ascii(dest, src, sizeof(pstring)-PTR_DIFF(dest,pstring_base)-1, STR_TERMINATE))
 114
 115 #else /* HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS */
 116
 117 #define fstrterminate(d) (((d)[sizeof(fstring)-1]) = '\0')
 118 #define pstrterminate(d) (((d)[sizeof(pstring)-1]) = '\0')
 119
 120 #define wpstrcpy(d,s) safe_strcpy_w((d),(s),sizeof(wpstring))
 121 #define wpstrcat(d,s) safe_strcat_w((d),(s),sizeof(wpstring))
 122 #define wfstrcpy(d,s) safe_strcpy_w((d),(s),sizeof(wfstring))
 123 #define wfstrcat(d,s) safe_strcat_w((d),(s),sizeof(wfstring))
 124
 125 #define push_pstring_base(dest, src, pstring_base) \
 126     push_ascii(dest, src, sizeof(pstring)-PTR_DIFF(dest,pstring_base)-1, STR_TERMINATE)
 127
 128 #endif /* HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS */
 129
 130 #define safe_strcpy_base(dest, src, base, size) \
 131     safe_strcpy(dest, src, size-PTR_DIFF(dest,base)-1)
 132
 133 /* String copy functions - macro hell below adds 'type checking' (limited,
 134    but the best we can do in C) and may tag with function name/number to
 135    record the last 'clobber region' on that string */
 136
 137 #define pstrcpy(d,s) safe_strcpy((d), (s),sizeof(pstring)-1)
 138 #define pstrcat(d,s) safe_strcat((d), (s),sizeof(pstring)-1)
 139 #define fstrcpy(d,s) safe_strcpy((d),(s),sizeof(fstring)-1)
 140 #define fstrcat(d,s) safe_strcat((d),(s),sizeof(fstring)-1)
 141 #define nstrcpy(d,s) safe_strcpy((d), (s),sizeof(nstring)-1)
 142
 143 /* the addition of the DEVELOPER checks in safe_strcpy means we must
 144  * update a lot of code. To make this a little easier here are some
 145  * functions that provide the lengths with less pain */
 146 #define pstrcpy_base(dest, src, pstring_base) \
 147     safe_strcpy(dest, src, sizeof(pstring)-PTR_DIFF(dest,pstring_base)-1)
 148
 149
 150 /* Inside the _fn variants of these is a call to clobber_region(), -
 151  * which might destroy the stack on a buggy function.  We help the
 152  * debugging process by putting the function and line who last caused
 153  * a clobbering into a static buffer.  If the program crashes at
 154  * address 0xf1f1f1f1 then this function is probably, but not
 155  * necessarily, to blame. */
 156
 157 /* overmalloc_safe_strcpy: DEPRECATED!  Used when you know the
 158  * destination buffer is longer than maxlength, but you don't know how
 159  * long.  This is not a good situation, because we can't do the normal
 160  * sanity checks. Don't use in new code! */
 161
 162 #define overmalloc_safe_strcpy(dest,src,maxlength)      safe_strcpy_fn(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE,dest,src,maxlength)
 163 #define safe_strcpy(dest,src,maxlength) safe_strcpy_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE,dest,src,maxlength)
 164 #define safe_strcat(dest,src,maxlength) safe_strcat_fn2(SAFE_STRING_FUNCTION_NAME, SAFE_STRING_LINE,dest,src,maxlength)
 165 #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)
 166 #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)
 167 #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)
 168 #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)
 169 #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)
 170
 171 #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)
 172 #define StrnCpy(dest,src,n)             StrnCpy_fn(SAFE_STRING_FUNCTION_NAME,SAFE_STRING_LINE,dest,src,n)
 173
 174 #ifdef HAVE_COMPILER_WILL_OPTIMIZE_OUT_FNS
 175
 176 /* if the compiler will optimize out function calls, then use this to tell if we are
 177    have the correct types (this works only where sizeof() returns the size of the buffer, not
 178    the size of the pointer). */
 179
 180 #define safe_strcpy_fn2(fn_name, fn_line, d, s, max_len) \
 181     (CHECK_STRING_SIZE(d, max_len+1) \
 182     ? __unsafe_string_function_usage_here__() \
 183     : safe_strcpy_fn(fn_name, fn_line, (d), (s), (max_len)))
 184
 185 #define safe_strcat_fn2(fn_name, fn_line, d, s, max_len) \
 186     (CHECK_STRING_SIZE(d, max_len+1) \
 187     ? __unsafe_string_function_usage_here__() \
 188     : safe_strcat_fn(fn_name, fn_line, (d), (s), (max_len)))
 189
 190 #define push_string_fn2(fn_name, fn_line, base_ptr, dest, src, dest_len, flags) \
 191     (CHECK_STRING_SIZE(dest, dest_len) \
 192     ? __unsafe_string_function_usage_here_size_t__() \
 193     : push_string_fn(fn_name, fn_line, base_ptr, dest, src, dest_len, flags))
 194
 195 #define pull_string_fn2(fn_name, fn_line, base_ptr, dest, src, dest_len, src_len, flags) \
 196     (CHECK_STRING_SIZE(dest, dest_len) \
 197     ? __unsafe_string_function_usage_here_size_t__() \
 198     : pull_string_fn(fn_name, fn_line, base_ptr, dest, src, dest_len, src_len, flags))
 199
 200 #define clistr_push_fn2(fn_name, fn_line, cli, dest, src, dest_len, flags) \
 201     (CHECK_STRING_SIZE(dest, dest_len) \
 202     ? __unsafe_string_function_usage_here_size_t__() \
 203     : clistr_push_fn(fn_name, fn_line, cli, dest, src, dest_len, flags))
 204
 205 #define clistr_pull_fn2(fn_name, fn_line, cli, dest, src, dest_len, srclen, flags) \
 206     (CHECK_STRING_SIZE(dest, dest_len) \
 207     ? __unsafe_string_function_usage_here_size_t__() \
 208     : clistr_pull_fn(fn_name, fn_line, cli, dest, src, dest_len, srclen, flags))
 209
 210 #define srvstr_push_fn2(fn_name, fn_line, base_ptr, dest, src, dest_len, flags) \
 211     (CHECK_STRING_SIZE(dest, dest_len) \
 212     ? __unsafe_string_function_usage_here_size_t__() \
 213     : srvstr_push_fn(fn_name, fn_line, base_ptr, dest, src, dest_len, flags))
 214
 215 #else
 216
 217 #define safe_strcpy_fn2 safe_strcpy_fn
 218 #define safe_strcat_fn2 safe_strcat_fn
 219 #define push_string_fn2 push_string_fn
 220 #define pull_string_fn2 pull_string_fn
 221 #define clistr_push_fn2 clistr_push_fn
 222 #define clistr_pull_fn2 clistr_pull_fn
 223 #define srvstr_push_fn2 srvstr_push_fn
 224
 225 #endif
 226
 227 #endif