libsecurityd/lib/sec_xdr.c

   1 /*
   2  * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <string.h>
  25 #include <stdlib.h>
  26 #include <assert.h>
  27
  28 #include "sec_xdr.h"
  29
  30 #define ALIGNMENT sizeof(void*)
  31 #define ALIGNUP(LEN) (((LEN - 1) & ~(ALIGNMENT - 1)) + ALIGNMENT)
  32
  33 /*
  34  * XDR counted bytes
  35  * *cpp is a pointer to the bytes, *sizep is the count.
  36  * If *cpp is NULL maxsize bytes are allocated
  37  */
  38 bool_t sec_xdr_bytes(XDR *xdrs, uint8_t **cpp, u_int *sizep, u_int maxsize)
  39 {
  40     uint8_t *sp = cpp ? *cpp : NULL;  /* sp is the actual string pointer */
  41     u_int nodesize = sizep ? *sizep : 0;
  42
  43     /*
  44      * first deal with the length since xdr bytes are counted
  45      */
  46     if (! xdr_u_int(xdrs, &nodesize))
  47         return (FALSE);
  48
  49     if ((nodesize > maxsize) && (xdrs->x_op != XDR_FREE))
  50         return (FALSE);
  51
  52     if (sizep && (xdrs->x_op == XDR_DECODE))
  53         *sizep = nodesize;
  54
  55     bool_t sizeof_alloc = sec_xdr_arena_size_allocator(xdrs);
  56
  57     /*
  58      * now deal with the actual bytes
  59      */
  60     switch (xdrs->x_op) {
  61     case XDR_DECODE:
  62         if (nodesize == 0)
  63             return (TRUE);
  64         if (!sp) {
  65             if (!sec_mem_alloc(xdrs, nodesize, &sp))
  66                 return (FALSE);
  67             if (!sizeof_alloc)
  68                 *cpp = sp; /* sp can be NULL when counting required space */
  69         }
  70         /* FALLTHROUGH */
  71     case XDR_ENCODE:
  72         return (xdr_opaque(xdrs, (char *)sp, nodesize));
  73
  74     case XDR_FREE:
  75         if (sp != NULL) {
  76             sec_mem_free(xdrs, sp, nodesize);
  77             *cpp = NULL;
  78         }
  79         return (TRUE);
  80     }
  81     /* NOTREACHED */
  82     return (FALSE);
  83 }
  84
  85 bool_t sec_xdr_charp(XDR *xdrs, char **cpp, u_int maxsize)
  86 {
  87     char *sp = cpp ? *cpp : NULL;  /* sp is the actual string pointer */
  88     u_int size = 0;
  89
  90     switch (xdrs->x_op) {
  91     case XDR_FREE:
  92         if (sp == NULL) return(TRUE);   /* already free */
  93         sec_mem_free(xdrs, sp, size);
  94         *cpp = NULL;
  95         return (TRUE);
  96     case XDR_ENCODE:
  97         if (sp) size = (u_int)(strlen(sp) + 1);
  98         /* FALLTHROUGH */
  99     case XDR_DECODE:
 100         return sec_xdr_bytes(xdrs, (uint8_t**)cpp, &size, maxsize);
 101     }
 102     /* NOTREACHED */
 103     return (FALSE);
 104 }
 105
 106 bool_t sec_mem_alloc(XDR *xdr, u_int bsize, uint8_t **data)
 107 {
 108     if (!xdr || !data)
 109         return (FALSE);
 110
 111     assert(xdr->x_op == XDR_DECODE);
 112
 113     sec_xdr_arena_allocator_t *allocator = sec_xdr_arena_allocator(xdr);
 114     if (allocator) {
 115         if (*data != NULL)
 116             return (TRUE); // no allocation needed
 117         size_t bytes_left;
 118         switch(allocator->magic) {
 119         case xdr_arena_magic:
 120             bytes_left = allocator->end - allocator->offset;
 121             if (bsize > bytes_left)
 122                 return (FALSE);
 123             else {
 124                 uint8_t *temp = allocator->offset;
 125                 allocator->offset += bsize;
 126                 *data = temp;
 127                 return (TRUE);
 128             }
 129         case xdr_size_magic:
 130             allocator->offset = (uint8_t*)((size_t)allocator->offset + bsize);
 131             return (TRUE);
 132         }
 133     }
 134
 135     void *alloc = calloc(1, bsize);
 136     if (!alloc)
 137         return (FALSE);
 138
 139     *data = alloc;
 140     return (TRUE);
 141 }
 142
 143 void sec_mem_free(XDR *xdr, void *ptr, u_int bsize)
 144 {
 145     if (sec_xdr_arena_allocator(xdr))
 146         return;
 147
 148     return free(ptr);
 149 }
 150
 151 static const sec_xdr_arena_allocator_t size_alloc = { xdr_size_magic, 0, 0, 0 };
 152 void sec_xdr_arena_init_size_alloc(sec_xdr_arena_allocator_t *arena, XDR *xdr)
 153 {
 154     memcpy(arena, &size_alloc, sizeof(size_alloc));
 155     xdr->x_public = (char *)arena;
 156 }
 157
 158 bool_t sec_xdr_arena_init(sec_xdr_arena_allocator_t *arena, XDR *xdr,
 159         size_t in_length, uint8_t *in_data)
 160 {
 161     if (!xdr)
 162         return FALSE;
 163     uint8_t *data = in_data ? in_data : calloc(1, ALIGNUP(in_length));
 164     if (!data)
 165         return FALSE;
 166     arena->magic = xdr_arena_magic;
 167     arena->offset = data;
 168     arena->data = data;
 169     arena->end = data + in_length;
 170     xdr->x_public = (void*)arena;
 171     return TRUE;
 172 }
 173
 174 void sec_xdr_arena_free(sec_xdr_arena_allocator_t *arena,
 175         void *ptr, size_t bsize)
 176 {
 177     assert(arena->magic == xdr_arena_magic);
 178     free(arena->data);
 179 }
 180
 181 void *sec_xdr_arena_data(sec_xdr_arena_allocator_t *arena)
 182 {
 183     if (arena)
 184         return arena->data;
 185
 186     return NULL;
 187 }
 188
 189 sec_xdr_arena_allocator_t *sec_xdr_arena_allocator(XDR *xdr)
 190 {
 191     sec_xdr_arena_allocator_t *allocator = xdr ? (sec_xdr_arena_allocator_t *)xdr->x_public : NULL;
 192
 193     if (allocator &&
 194             (allocator->magic == xdr_arena_magic ||
 195              allocator->magic == xdr_size_magic))
 196         return allocator;
 197
 198     return NULL;
 199 }
 200
 201 bool_t sec_xdr_arena_size_allocator(XDR *xdr)
 202 {
 203     sec_xdr_arena_allocator_t *allocator = xdr ? (sec_xdr_arena_allocator_t *)xdr->x_public : NULL;
 204     if (allocator && (allocator->magic == xdr_size_magic))
 205         return TRUE;
 206
 207     return FALSE;
 208 }
 209
 210
 211 bool_t copyin(void *data, xdrproc_t proc, void** copy, u_int *size)
 212 {
 213     if (!copy)
 214         return (FALSE);
 215
 216     // xdr_sizeof is illbehaved
 217     u_int length = sec_xdr_sizeof_in(proc, data);
 218     uint8_t *xdr_data = malloc(length);
 219     if (!xdr_data)
 220         return (FALSE);
 221
 222     XDR xdr;
 223     sec_xdrmem_create(&xdr, (char *)xdr_data, length, XDR_ENCODE);
 224
 225     // cast to void* - function can go both ways (xdr->x_op)
 226     if (proc(&xdr, data, 0)) {
 227         *copy = xdr_data;
 228         if (size) *size = length;
 229         return (TRUE);
 230     }
 231
 232     free(xdr_data);
 233     return (FALSE);
 234 }
 235
 236 // Unmarshall xdr data and return pointer to single allocation containing data
 237 // Generally use *_PTR for xdrproc_t taking an objp that matches data's type
 238 // ie. xdr_CSSM_POSSIBLY_KEY_IN_DATA_PTR(XDR *xdrs, CSSM_DATA_PTR *objp)
 239 // with data matching objp
 240 // If you pass in length pointing to a non-zero value, data will be assumed
 241 // to have pre-allocated space for use by copyout in that amount.
 242 // If *data is not NULL it will be assumed to be allocated already.
 243 bool_t copyout(const void *copy, u_int size, xdrproc_t proc, void **data, u_int *length)
 244 {
 245
 246     if (!data || (size > ~(u_int)0))
 247         return (FALSE);
 248
 249     XDR xdr;
 250     sec_xdrmem_create(&xdr, (void *)copy, size, XDR_DECODE);
 251
 252     u_int length_required = sec_xdr_sizeof_out(copy, size, proc, data);
 253     u_int length_out = length ? *length : 0;
 254
 255     if (length_out && (length_required > length_out))
 256         return (FALSE);
 257
 258     bool_t passed_in_data = (*data && length_out);
 259     sec_xdr_arena_allocator_t arena;
 260     // set up arena with memory passed in (length_out > 0) or ask to allocate
 261     if (!sec_xdr_arena_init(&arena, &xdr, length_out ? length_out : length_required, length_out ? *data : NULL))
 262         return (FALSE);
 263
 264     if (proc(&xdr, data, 0))
 265     {
 266         *length = length_required;
 267         return (TRUE);
 268     }
 269
 270     if (!passed_in_data)
 271         sec_xdr_arena_free(sec_xdr_arena_allocator(&xdr), NULL, 0);
 272     return (FALSE);
 273 }
 274
 275 // unmarshall xdr data and return pointer to individual allocations containing data
 276 // only use *_PTR for xdrproc_ts and pointers for data
 277 bool_t copyout_chunked(const void *copy, u_int size, xdrproc_t proc, void **data)
 278 {
 279     if (!data || (size > ~(u_int)0))
 280         return (FALSE);
 281
 282     XDR xdr;
 283     sec_xdrmem_create(&xdr, (void *)copy, size, XDR_DECODE);
 284
 285     void *data_out = NULL;
 286
 287     if (proc(&xdr, &data_out, 0))
 288     {
 289         *data = data_out;
 290         return (TRUE);
 291     }
 292     return (FALSE);
 293 }