1/*
2 * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include "internal/cryptlib.h"
12#include "internal/numbers.h"
13#include <openssl/stack.h>
14#include <openssl/objects.h>
15#include <errno.h>
16#include <openssl/e_os2.h>      /* For ossl_inline */
17
18/*
19 * The initial number of nodes in the array.
20 */
21static const int min_nodes = 4;
22static const int max_nodes = SIZE_MAX / sizeof(void *) < INT_MAX
23                             ? (int)(SIZE_MAX / sizeof(void *))
24                             : INT_MAX;
25
26struct stack_st {
27    int num;
28    const void **data;
29    int sorted;
30    int num_alloc;
31    OPENSSL_sk_compfunc comp;
32};
33
34OPENSSL_sk_compfunc OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk, OPENSSL_sk_compfunc c)
35{
36    OPENSSL_sk_compfunc old = sk->comp;
37
38    if (sk->comp != c)
39        sk->sorted = 0;
40    sk->comp = c;
41
42    return old;
43}
44
45OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk)
46{
47    OPENSSL_STACK *ret;
48
49    if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
50        CRYPTOerr(CRYPTO_F_OPENSSL_SK_DUP, ERR_R_MALLOC_FAILURE);
51        return NULL;
52    }
53
54    /* direct structure assignment */
55    *ret = *sk;
56
57    if (sk->num == 0) {
58        /* postpone |ret->data| allocation */
59        ret->data = NULL;
60        ret->num_alloc = 0;
61        return ret;
62    }
63    /* duplicate |sk->data| content */
64    if ((ret->data = OPENSSL_malloc(sizeof(*ret->data) * sk->num_alloc)) == NULL)
65        goto err;
66    memcpy(ret->data, sk->data, sizeof(void *) * sk->num);
67    return ret;
68 err:
69    OPENSSL_sk_free(ret);
70    return NULL;
71}
72
73OPENSSL_STACK *OPENSSL_sk_deep_copy(const OPENSSL_STACK *sk,
74                             OPENSSL_sk_copyfunc copy_func,
75                             OPENSSL_sk_freefunc free_func)
76{
77    OPENSSL_STACK *ret;
78    int i;
79
80    if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
81        CRYPTOerr(CRYPTO_F_OPENSSL_SK_DEEP_COPY, ERR_R_MALLOC_FAILURE);
82        return NULL;
83    }
84
85    /* direct structure assignment */
86    *ret = *sk;
87
88    if (sk->num == 0) {
89        /* postpone |ret| data allocation */
90        ret->data = NULL;
91        ret->num_alloc = 0;
92        return ret;
93    }
94
95    ret->num_alloc = sk->num > min_nodes ? sk->num : min_nodes;
96    ret->data = OPENSSL_zalloc(sizeof(*ret->data) * ret->num_alloc);
97    if (ret->data == NULL) {
98        OPENSSL_free(ret);
99        return NULL;
100    }
101
102    for (i = 0; i < ret->num; ++i) {
103        if (sk->data[i] == NULL)
104            continue;
105        if ((ret->data[i] = copy_func(sk->data[i])) == NULL) {
106            while (--i >= 0)
107                if (ret->data[i] != NULL)
108                    free_func((void *)ret->data[i]);
109            OPENSSL_sk_free(ret);
110            return NULL;
111        }
112    }
113    return ret;
114}
115
116OPENSSL_STACK *OPENSSL_sk_new_null(void)
117{
118    return OPENSSL_sk_new_reserve(NULL, 0);
119}
120
121OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_compfunc c)
122{
123    return OPENSSL_sk_new_reserve(c, 0);
124}
125
126/*
127 * Calculate the array growth based on the target size.
128 *
129 * The growth fraction is a rational number and is defined by a numerator
130 * and a denominator.  According to Andrew Koenig in his paper "Why Are
131 * Vectors Efficient?" from JOOP 11(5) 1998, this factor should be less
132 * than the golden ratio (1.618...).
133 *
134 * We use 3/2 = 1.5 for simplicity of calculation and overflow checking.
135 * Another option 8/5 = 1.6 allows for slightly faster growth, although safe
136 * computation is more difficult.
137 *
138 * The limit to avoid overflow is spot on.  The modulo three correction term
139 * ensures that the limit is the largest number than can be expanded by the
140 * growth factor without exceeding the hard limit.
141 *
142 * Do not call it with |current| lower than 2, or it will infinitely loop.
143 */
144static ossl_inline int compute_growth(int target, int current)
145{
146    const int limit = (max_nodes / 3) * 2 + (max_nodes % 3 ? 1 : 0);
147
148    while (current < target) {
149        /* Check to see if we're at the hard limit */
150        if (current >= max_nodes)
151            return 0;
152
153        /* Expand the size by a factor of 3/2 if it is within range */
154        current = current < limit ? current + current / 2 : max_nodes;
155    }
156    return current;
157}
158
159/* internal STACK storage allocation */
160static int sk_reserve(OPENSSL_STACK *st, int n, int exact)
161{
162    const void **tmpdata;
163    int num_alloc;
164
165    /* Check to see the reservation isn't exceeding the hard limit */
166    if (n > max_nodes - st->num)
167        return 0;
168
169    /* Figure out the new size */
170    num_alloc = st->num + n;
171    if (num_alloc < min_nodes)
172        num_alloc = min_nodes;
173
174    /* If |st->data| allocation was postponed */
175    if (st->data == NULL) {
176        /*
177         * At this point, |st->num_alloc| and |st->num| are 0;
178         * so |num_alloc| value is |n| or |min_nodes| if greater than |n|.
179         */
180        if ((st->data = OPENSSL_zalloc(sizeof(void *) * num_alloc)) == NULL) {
181            CRYPTOerr(CRYPTO_F_SK_RESERVE, ERR_R_MALLOC_FAILURE);
182            return 0;
183        }
184        st->num_alloc = num_alloc;
185        return 1;
186    }
187
188    if (!exact) {
189        if (num_alloc <= st->num_alloc)
190            return 1;
191        num_alloc = compute_growth(num_alloc, st->num_alloc);
192        if (num_alloc == 0)
193            return 0;
194    } else if (num_alloc == st->num_alloc) {
195        return 1;
196    }
197
198    tmpdata = OPENSSL_realloc((void *)st->data, sizeof(void *) * num_alloc);
199    if (tmpdata == NULL)
200        return 0;
201
202    st->data = tmpdata;
203    st->num_alloc = num_alloc;
204    return 1;
205}
206
207OPENSSL_STACK *OPENSSL_sk_new_reserve(OPENSSL_sk_compfunc c, int n)
208{
209    OPENSSL_STACK *st = OPENSSL_zalloc(sizeof(OPENSSL_STACK));
210
211    if (st == NULL)
212        return NULL;
213
214    st->comp = c;
215
216    if (n <= 0)
217        return st;
218
219    if (!sk_reserve(st, n, 1)) {
220        OPENSSL_sk_free(st);
221        return NULL;
222    }
223
224    return st;
225}
226
227int OPENSSL_sk_reserve(OPENSSL_STACK *st, int n)
228{
229    if (st == NULL)
230        return 0;
231
232    if (n < 0)
233        return 1;
234    return sk_reserve(st, n, 1);
235}
236
237int OPENSSL_sk_insert(OPENSSL_STACK *st, const void *data, int loc)
238{
239    if (st == NULL || st->num == max_nodes)
240        return 0;
241
242    if (!sk_reserve(st, 1, 0))
243        return 0;
244
245    if ((loc >= st->num) || (loc < 0)) {
246        st->data[st->num] = data;
247    } else {
248        memmove(&st->data[loc + 1], &st->data[loc],
249                sizeof(st->data[0]) * (st->num - loc));
250        st->data[loc] = data;
251    }
252    st->num++;
253    st->sorted = 0;
254    return st->num;
255}
256
257static ossl_inline void *internal_delete(OPENSSL_STACK *st, int loc)
258{
259    const void *ret = st->data[loc];
260
261    if (loc != st->num - 1)
262         memmove(&st->data[loc], &st->data[loc + 1],
263                 sizeof(st->data[0]) * (st->num - loc - 1));
264    st->num--;
265
266    return (void *)ret;
267}
268
269void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *st, const void *p)
270{
271    int i;
272
273    for (i = 0; i < st->num; i++)
274        if (st->data[i] == p)
275            return internal_delete(st, i);
276    return NULL;
277}
278
279void *OPENSSL_sk_delete(OPENSSL_STACK *st, int loc)
280{
281    if (st == NULL || loc < 0 || loc >= st->num)
282        return NULL;
283
284    return internal_delete(st, loc);
285}
286
287static int internal_find(OPENSSL_STACK *st, const void *data,
288                         int ret_val_options)
289{
290    const void *r;
291    int i;
292
293    if (st == NULL || st->num == 0)
294        return -1;
295
296    if (st->comp == NULL) {
297        for (i = 0; i < st->num; i++)
298            if (st->data[i] == data)
299                return i;
300        return -1;
301    }
302
303    if (!st->sorted) {
304        if (st->num > 1)
305            qsort(st->data, st->num, sizeof(void *), st->comp);
306        st->sorted = 1; /* empty or single-element stack is considered sorted */
307    }
308    if (data == NULL)
309        return -1;
310    r = OBJ_bsearch_ex_(&data, st->data, st->num, sizeof(void *), st->comp,
311                        ret_val_options);
312
313    return r == NULL ? -1 : (int)((const void **)r - st->data);
314}
315
316int OPENSSL_sk_find(OPENSSL_STACK *st, const void *data)
317{
318    return internal_find(st, data, OBJ_BSEARCH_FIRST_VALUE_ON_MATCH);
319}
320
321int OPENSSL_sk_find_ex(OPENSSL_STACK *st, const void *data)
322{
323    return internal_find(st, data, OBJ_BSEARCH_VALUE_ON_NOMATCH);
324}
325
326int OPENSSL_sk_push(OPENSSL_STACK *st, const void *data)
327{
328    if (st == NULL)
329        return -1;
330    return OPENSSL_sk_insert(st, data, st->num);
331}
332
333int OPENSSL_sk_unshift(OPENSSL_STACK *st, const void *data)
334{
335    return OPENSSL_sk_insert(st, data, 0);
336}
337
338void *OPENSSL_sk_shift(OPENSSL_STACK *st)
339{
340    if (st == NULL || st->num == 0)
341        return NULL;
342    return internal_delete(st, 0);
343}
344
345void *OPENSSL_sk_pop(OPENSSL_STACK *st)
346{
347    if (st == NULL || st->num == 0)
348        return NULL;
349    return internal_delete(st, st->num - 1);
350}
351
352void OPENSSL_sk_zero(OPENSSL_STACK *st)
353{
354    if (st == NULL || st->num == 0)
355        return;
356    memset(st->data, 0, sizeof(*st->data) * st->num);
357    st->num = 0;
358}
359
360void OPENSSL_sk_pop_free(OPENSSL_STACK *st, OPENSSL_sk_freefunc func)
361{
362    int i;
363
364    if (st == NULL)
365        return;
366    for (i = 0; i < st->num; i++)
367        if (st->data[i] != NULL)
368            func((char *)st->data[i]);
369    OPENSSL_sk_free(st);
370}
371
372void OPENSSL_sk_free(OPENSSL_STACK *st)
373{
374    if (st == NULL)
375        return;
376    OPENSSL_free(st->data);
377    OPENSSL_free(st);
378}
379
380int OPENSSL_sk_num(const OPENSSL_STACK *st)
381{
382    return st == NULL ? -1 : st->num;
383}
384
385void *OPENSSL_sk_value(const OPENSSL_STACK *st, int i)
386{
387    if (st == NULL || i < 0 || i >= st->num)
388        return NULL;
389    return (void *)st->data[i];
390}
391
392void *OPENSSL_sk_set(OPENSSL_STACK *st, int i, const void *data)
393{
394    if (st == NULL || i < 0 || i >= st->num)
395        return NULL;
396    st->data[i] = data;
397    st->sorted = 0;
398    return (void *)st->data[i];
399}
400
401void OPENSSL_sk_sort(OPENSSL_STACK *st)
402{
403    if (st != NULL && !st->sorted && st->comp != NULL) {
404        if (st->num > 1)
405            qsort(st->data, st->num, sizeof(void *), st->comp);
406        st->sorted = 1; /* empty or single-element stack is considered sorted */
407    }
408}
409
410int OPENSSL_sk_is_sorted(const OPENSSL_STACK *st)
411{
412    return st == NULL ? 1 : st->sorted;
413}
414