diff options
author | Pauli <paul.dale@oracle.com> | 2017-08-17 10:10:07 +1000 |
---|---|---|
committer | Pauli <paul.dale@oracle.com> | 2017-09-28 06:53:40 +1000 |
commit | 1b3e2bbf64b96f636277ca29b31ba152c1831e74 (patch) | |
tree | 10a9f89306c04e3133f5e9c231e6aa4aa2a8841a /crypto/stack/stack.c | |
parent | 9f9442918aeaed5dc2442d81ab8d29fe3e1fb906 (diff) |
Add a reserve call to the stack data structure.
This allows the caller to guarantee that there is sufficient space for a
number of insertions without reallocation.
The expansion ratio when reallocating the array is reduced to 1.5 rather than 2.
Change bounds testing to use a single size rather than both INT_MAX and
SIZE_MAX. This simplifies some of the tests.
Switch the stack pointers to data from char * to void *
Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4386)
Diffstat (limited to 'crypto/stack/stack.c')
-rw-r--r-- | crypto/stack/stack.c | 127 |
1 files changed, 94 insertions, 33 deletions
diff --git a/crypto/stack/stack.c b/crypto/stack/stack.c index 43ddf30ac1..e71da73fb5 100644 --- a/crypto/stack/stack.c +++ b/crypto/stack/stack.c @@ -1,5 +1,5 @@ /* - * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved. + * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved. * * Licensed under the OpenSSL license (the "License"). You may not use * this file except in compliance with the License. You can obtain a copy @@ -12,20 +12,25 @@ #include "internal/numbers.h" #include <openssl/stack.h> #include <openssl/objects.h> +#include <errno.h> +#include <openssl/e_os2.h> /* For ossl_inline */ + +/* + * The initial number of nodes in the array. + */ +static const int min_nodes = 4; +static const int max_nodes = SIZE_MAX / sizeof(void *) < INT_MAX + ? (int)(SIZE_MAX / sizeof(void *)) + : INT_MAX; struct stack_st { int num; - const char **data; + const void **data; int sorted; - size_t num_alloc; + int num_alloc; OPENSSL_sk_compfunc comp; }; -#undef MIN_NODES -#define MIN_NODES 4 - -#include <errno.h> - OPENSSL_sk_compfunc OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk, OPENSSL_sk_compfunc c) { OPENSSL_sk_compfunc old = sk->comp; @@ -52,7 +57,7 @@ OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk) if ((ret->data = OPENSSL_malloc(sizeof(*ret->data) * sk->num_alloc)) == NULL) goto err; - memcpy(ret->data, sk->data, sizeof(char *) * sk->num); + memcpy(ret->data, sk->data, sizeof(void *) * sk->num); return ret; err: OPENSSL_sk_free(ret); @@ -75,7 +80,7 @@ OPENSSL_STACK *OPENSSL_sk_deep_copy(const OPENSSL_STACK *sk, /* direct structure assignment */ *ret = *sk; - ret->num_alloc = sk->num > MIN_NODES ? (size_t)sk->num : MIN_NODES; + ret->num_alloc = sk->num > min_nodes ? sk->num : min_nodes; ret->data = OPENSSL_zalloc(sizeof(*ret->data) * ret->num_alloc); if (ret->data == NULL) { OPENSSL_free(ret); @@ -107,10 +112,10 @@ OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_compfunc c) if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) goto err; - if ((ret->data = OPENSSL_zalloc(sizeof(*ret->data) * MIN_NODES)) == NULL) + if ((ret->data = OPENSSL_zalloc(sizeof(*ret->data) * min_nodes)) == NULL) goto err; ret->comp = c; - ret->num_alloc = MIN_NODES; + ret->num_alloc = min_nodes; return (ret); err: @@ -118,32 +123,88 @@ OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_compfunc c) return (NULL); } -int OPENSSL_sk_insert(OPENSSL_STACK *st, const void *data, int loc) +/* + * Calculate the array growth based on the target size. + * + * The growth faction is a rational number and is defined by a numerator + * and a denominator. According to Andrew Koenig in his paper "Why Are + * Vectors Efficient?" from JOOP 11(5) 1998, this factor should be less + * than the golden ratio (1.618...). + * + * We use 3/2 = 1.5 for simplicty of calculation and overflow checking. + * Another option 8/5 = 1.6 allows for slightly faster growth, although safe + * computation is more difficult. + * + * The limit to avoid overflow is spot on. The modulo three correction term + * ensures that the limit is the largest number than can be expanded by the + * growth factor without exceeding the hard limit. + */ +static ossl_inline int compute_growth(int target, int current) { - if (st == NULL || st->num < 0 || st->num == INT_MAX) { - return 0; + const int limit = (max_nodes / 3) * 2 + (max_nodes % 3 ? 1 : 0); + + while (current < target) { + /* Check to see if we're at the hard limit */ + if (current >= max_nodes) + return 0; + + /* Expand the size by a factor of 3/2 if it is within range */ + current = current < limit ? current + current / 2 : max_nodes; } + return current; +} - if (st->num_alloc <= (size_t)(st->num + 1)) { - size_t doub_num_alloc = st->num_alloc * 2; - const char **tmpdata; +static int sk_reserve(OPENSSL_STACK *st, int n, int exact) +{ + const void **tmpdata; + int num_alloc; - /* Overflow checks */ - if (doub_num_alloc < st->num_alloc) - return 0; + /* Check to see the reservation isn't exceeding the hard limit */ + if (n > max_nodes - st->num) + return 0; - /* Avoid overflow due to multiplication by sizeof(char *) */ - if (doub_num_alloc > SIZE_MAX / sizeof(char *)) - return 0; + /* Figure out the new size */ + num_alloc = st->num + n; + if (num_alloc < min_nodes) + num_alloc = min_nodes; - tmpdata = OPENSSL_realloc((char *)st->data, - sizeof(char *) * doub_num_alloc); - if (tmpdata == NULL) + if (!exact) { + if (num_alloc <= st->num_alloc) + return 1; + num_alloc = compute_growth(num_alloc, st->num_alloc); + if (num_alloc == 0) return 0; - - st->data = tmpdata; - st->num_alloc = doub_num_alloc; + } else if (num_alloc == st->num_alloc) { + return 1; } + + tmpdata = OPENSSL_realloc((void *)st->data, sizeof(void *) * num_alloc); + if (tmpdata == NULL) + return 0; + + st->data = tmpdata; + st->num_alloc = num_alloc; + return 1; +} + +int OPENSSL_sk_reserve(OPENSSL_STACK *st, int n) +{ + if (st == NULL || st->num < 0) + return 0; + + if (n < 0) + return 1; + return sk_reserve(st, n, 1); +} + +int OPENSSL_sk_insert(OPENSSL_STACK *st, const void *data, int loc) +{ + if (st == NULL || st->num < 0 || st->num == max_nodes) + return 0; + + if (!sk_reserve(st, 1, 0)) + return 0; + if ((loc >= st->num) || (loc < 0)) { st->data[st->num] = data; } else { @@ -168,7 +229,7 @@ void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *st, const void *p) void *OPENSSL_sk_delete(OPENSSL_STACK *st, int loc) { - const char *ret; + const void *ret; if (st == NULL || loc < 0 || loc >= st->num) return NULL; @@ -203,7 +264,7 @@ static int internal_find(OPENSSL_STACK *st, const void *data, ret_val_options); if (r == NULL) return (-1); - return (int)((const char **)r - st->data); + return (int)((const void **)r - st->data); } int OPENSSL_sk_find(OPENSSL_STACK *st, const void *data) @@ -299,7 +360,7 @@ void *OPENSSL_sk_set(OPENSSL_STACK *st, int i, const void *data) void OPENSSL_sk_sort(OPENSSL_STACK *st) { if (st && !st->sorted && st->comp != NULL) { - qsort(st->data, st->num, sizeof(char *), st->comp); + qsort(st->data, st->num, sizeof(void *), st->comp); st->sorted = 1; } } |