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David Benjamin 6be491b7bb Work around more C language bugs with empty spans.
C's specification text around pointer arithmetic is buggy and fails to
account for empty spans. Empty spans are typically represented as
ptr=NULL and len=0, so (T*)NULL + 0 must be defined for ptr + len to
reliably work. C++ does not have this bug and specifies this correctly.
See https://crbug.com/1019588.

This language bug has made its way over to newer versions of UBSan,
which enforce this. In the short term, add bogus length checks as a
workaround. However, unlike the memcpy language bug, we cannot address
this systematically. In the long term, we need to switch libcrypto to
building as C++ for a real fix.

To test this, update our clang revision to that in
https://chromium-review.googlesource.com/c/chromium/src/+/1879890. Note
that clang revision was later reverted in Chromium for seemingly
unrelated reasons.

This newer UBSan also catches a memcpy/OPENSSL_memcpy issue in
siphash.c, from the earlier C NULL bug we'd been working around.

Bug: chromium:1019588, chromium:1019644
Change-Id: I460e547c8cd740db68da8cc2a3a970276ec92e90
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/38584
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>
2019-10-30 17:02:32 +00:00

173 lines
5.4 KiB
C

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/buf.h>
#include <string.h>
#include <openssl/mem.h>
#include <openssl/err.h>
#include "../internal.h"
BUF_MEM *BUF_MEM_new(void) {
BUF_MEM *ret;
ret = OPENSSL_malloc(sizeof(BUF_MEM));
if (ret == NULL) {
OPENSSL_PUT_ERROR(BUF, ERR_R_MALLOC_FAILURE);
return NULL;
}
OPENSSL_memset(ret, 0, sizeof(BUF_MEM));
return ret;
}
void BUF_MEM_free(BUF_MEM *buf) {
if (buf == NULL) {
return;
}
OPENSSL_free(buf->data);
OPENSSL_free(buf);
}
int BUF_MEM_reserve(BUF_MEM *buf, size_t cap) {
if (buf->max >= cap) {
return 1;
}
size_t n = cap + 3;
if (n < cap) {
// overflow
OPENSSL_PUT_ERROR(BUF, ERR_R_MALLOC_FAILURE);
return 0;
}
n = n / 3;
size_t alloc_size = n * 4;
if (alloc_size / 4 != n) {
// overflow
OPENSSL_PUT_ERROR(BUF, ERR_R_MALLOC_FAILURE);
return 0;
}
char *new_buf = OPENSSL_realloc(buf->data, alloc_size);
if (new_buf == NULL) {
OPENSSL_PUT_ERROR(BUF, ERR_R_MALLOC_FAILURE);
return 0;
}
buf->data = new_buf;
buf->max = alloc_size;
return 1;
}
size_t BUF_MEM_grow(BUF_MEM *buf, size_t len) {
if (!BUF_MEM_reserve(buf, len)) {
return 0;
}
if (buf->length < len) {
OPENSSL_memset(&buf->data[buf->length], 0, len - buf->length);
}
buf->length = len;
return len;
}
size_t BUF_MEM_grow_clean(BUF_MEM *buf, size_t len) {
return BUF_MEM_grow(buf, len);
}
int BUF_MEM_append(BUF_MEM *buf, const void *in, size_t len) {
// Work around a C language bug. See https://crbug.com/1019588.
if (len == 0) {
return 1;
}
size_t new_len = buf->length + len;
if (new_len < len) {
OPENSSL_PUT_ERROR(BUF, ERR_R_OVERFLOW);
return 0;
}
if (!BUF_MEM_reserve(buf, new_len)) {
return 0;
}
OPENSSL_memcpy(buf->data + buf->length, in, len);
buf->length = new_len;
return 1;
}
char *BUF_strdup(const char *str) { return OPENSSL_strdup(str); }
size_t BUF_strnlen(const char *str, size_t max_len) {
return OPENSSL_strnlen(str, max_len);
}
char *BUF_strndup(const char *str, size_t size) {
return OPENSSL_strndup(str, size);
}
size_t BUF_strlcpy(char *dst, const char *src, size_t dst_size) {
return OPENSSL_strlcpy(dst, src, dst_size);
}
size_t BUF_strlcat(char *dst, const char *src, size_t dst_size) {
return OPENSSL_strlcat(dst, src, dst_size);
}
void *BUF_memdup(const void *data, size_t size) {
return OPENSSL_memdup(data, size);
}