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openssl/crypto/ct/ct_oct.c
Richard Levitte d85d3c993e Fix faulty free 
On error, i2o_SCT_signature() and i2o_SCT() free a pointer that may
have wandered off from the start of the allocated block (not currently
true for i2o_SCT_signature(), but has that potential as the code may
change.  To avoid this, save away the start of the allocated block and
free that instead.

Thanks to Guido Vranken for reporting this issue.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2323)
2017-01-29 15:31:01 +01:00

407 lines
9.5 KiB
C
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/*
* Copyright 2016 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
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifdef OPENSSL_NO_CT
# error "CT is disabled"
#endif
#include <limits.h>
#include <string.h>
#include <openssl/asn1.h>
#include <openssl/buffer.h>
#include <openssl/ct.h>
#include <openssl/err.h>
#include "ct_locl.h"
int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len)
{
size_t siglen;
size_t len_remaining = len;
const unsigned char *p;
if (sct->version != SCT_VERSION_V1) {
CTerr(CT_F_O2I_SCT_SIGNATURE, CT_R_UNSUPPORTED_VERSION);
return -1;
}
/*
* digitally-signed struct header: (1 byte) Hash algorithm (1 byte)
* Signature algorithm (2 bytes + ?) Signature
*
* This explicitly rejects empty signatures: they're invalid for
* all supported algorithms.
*/
if (len <= 4) {
CTerr(CT_F_O2I_SCT_SIGNATURE, CT_R_SCT_INVALID_SIGNATURE);
return -1;
}
p = *in;
/* Get hash and signature algorithm */
sct->hash_alg = *p++;
sct->sig_alg = *p++;
if (SCT_get_signature_nid(sct) == NID_undef) {
CTerr(CT_F_O2I_SCT_SIGNATURE, CT_R_SCT_INVALID_SIGNATURE);
return -1;
}
/* Retrieve signature and check it is consistent with the buffer length */
n2s(p, siglen);
len_remaining -= (p - *in);
if (siglen > len_remaining) {
CTerr(CT_F_O2I_SCT_SIGNATURE, CT_R_SCT_INVALID_SIGNATURE);
return -1;
}
if (SCT_set1_signature(sct, p, siglen) != 1)
return -1;
len_remaining -= siglen;
*in = p + siglen;
return len - len_remaining;
}
SCT *o2i_SCT(SCT **psct, const unsigned char **in, size_t len)
{
SCT *sct = NULL;
const unsigned char *p;
if (len == 0 || len > MAX_SCT_SIZE) {
CTerr(CT_F_O2I_SCT, CT_R_SCT_INVALID);
goto err;
}
if ((sct = SCT_new()) == NULL)
goto err;
p = *in;
sct->version = *p;
if (sct->version == SCT_VERSION_V1) {
int sig_len;
size_t len2;
/*-
* Fixed-length header:
* struct {
* Version sct_version; (1 byte)
* log_id id; (32 bytes)
* uint64 timestamp; (8 bytes)
* CtExtensions extensions; (2 bytes + ?)
* }
*/
if (len < 43) {
CTerr(CT_F_O2I_SCT, CT_R_SCT_INVALID);
goto err;
}
len -= 43;
p++;
sct->log_id = BUF_memdup(p, CT_V1_HASHLEN);
if (sct->log_id == NULL)
goto err;
sct->log_id_len = CT_V1_HASHLEN;
p += CT_V1_HASHLEN;
n2l8(p, sct->timestamp);
n2s(p, len2);
if (len < len2) {
CTerr(CT_F_O2I_SCT, CT_R_SCT_INVALID);
goto err;
}
if (len2 > 0) {
sct->ext = BUF_memdup(p, len2);
if (sct->ext == NULL)
goto err;
}
sct->ext_len = len2;
p += len2;
len -= len2;
sig_len = o2i_SCT_signature(sct, &p, len);
if (sig_len <= 0) {
CTerr(CT_F_O2I_SCT, CT_R_SCT_INVALID);
goto err;
}
len -= sig_len;
*in = p + len;
} else {
/* If not V1 just cache encoding */
sct->sct = BUF_memdup(p, len);
if (sct->sct == NULL)
goto err;
sct->sct_len = len;
*in = p + len;
}
if (psct != NULL) {
SCT_free(*psct);
*psct = sct;
}
return sct;
err:
SCT_free(sct);
return NULL;
}
int i2o_SCT_signature(const SCT *sct, unsigned char **out)
{
size_t len;
unsigned char *p = NULL, *pstart = NULL;
if (!SCT_signature_is_complete(sct)) {
CTerr(CT_F_I2O_SCT_SIGNATURE, CT_R_SCT_INVALID_SIGNATURE);
goto err;
}
if (sct->version != SCT_VERSION_V1) {
CTerr(CT_F_I2O_SCT_SIGNATURE, CT_R_UNSUPPORTED_VERSION);
goto err;
}
/*
* (1 byte) Hash algorithm
* (1 byte) Signature algorithm
* (2 bytes + ?) Signature
*/
len = 4 + sct->sig_len;
if (out != NULL) {
if (*out != NULL) {
p = *out;
*out += len;
} else {
pstart = p = OPENSSL_malloc(len);
if (p == NULL) {
CTerr(CT_F_I2O_SCT_SIGNATURE, ERR_R_MALLOC_FAILURE);
goto err;
}
*out = p;
}
*p++ = sct->hash_alg;
*p++ = sct->sig_alg;
s2n(sct->sig_len, p);
memcpy(p, sct->sig, sct->sig_len);
}
return len;
err:
OPENSSL_free(pstart);
return -1;
}
int i2o_SCT(const SCT *sct, unsigned char **out)
{
size_t len;
unsigned char *p = NULL, *pstart = NULL;
if (!SCT_is_complete(sct)) {
CTerr(CT_F_I2O_SCT, CT_R_SCT_NOT_SET);
goto err;
}
/*
* Fixed-length header: struct { (1 byte) Version sct_version; (32 bytes)
* log_id id; (8 bytes) uint64 timestamp; (2 bytes + ?) CtExtensions
* extensions; (1 byte) Hash algorithm (1 byte) Signature algorithm (2
* bytes + ?) Signature
*/
if (sct->version == SCT_VERSION_V1)
len = 43 + sct->ext_len + 4 + sct->sig_len;
else
len = sct->sct_len;
if (out == NULL)
return len;
if (*out != NULL) {
p = *out;
*out += len;
} else {
pstart = p = OPENSSL_malloc(len);
if (p == NULL) {
CTerr(CT_F_I2O_SCT, ERR_R_MALLOC_FAILURE);
goto err;
}
*out = p;
}
if (sct->version == SCT_VERSION_V1) {
*p++ = sct->version;
memcpy(p, sct->log_id, CT_V1_HASHLEN);
p += CT_V1_HASHLEN;
l2n8(sct->timestamp, p);
s2n(sct->ext_len, p);
if (sct->ext_len > 0) {
memcpy(p, sct->ext, sct->ext_len);
p += sct->ext_len;
}
if (i2o_SCT_signature(sct, &p) <= 0)
goto err;
} else {
memcpy(p, sct->sct, len);
}
return len;
err:
OPENSSL_free(pstart);
return -1;
}
STACK_OF(SCT) *o2i_SCT_LIST(STACK_OF(SCT) **a, const unsigned char **pp,
size_t len)
{
STACK_OF(SCT) *sk = NULL;
size_t list_len, sct_len;
if (len < 2 || len > MAX_SCT_LIST_SIZE) {
CTerr(CT_F_O2I_SCT_LIST, CT_R_SCT_LIST_INVALID);
return NULL;
}
n2s(*pp, list_len);
if (list_len != len - 2) {
CTerr(CT_F_O2I_SCT_LIST, CT_R_SCT_LIST_INVALID);
return NULL;
}
if (a == NULL || *a == NULL) {
sk = sk_SCT_new_null();
if (sk == NULL)
return NULL;
} else {
SCT *sct;
/* Use the given stack, but empty it first. */
sk = *a;
while ((sct = sk_SCT_pop(sk)) != NULL)
SCT_free(sct);
}
while (list_len > 0) {
SCT *sct;
if (list_len < 2) {
CTerr(CT_F_O2I_SCT_LIST, CT_R_SCT_LIST_INVALID);
goto err;
}
n2s(*pp, sct_len);
list_len -= 2;
if (sct_len == 0 || sct_len > list_len) {
CTerr(CT_F_O2I_SCT_LIST, CT_R_SCT_LIST_INVALID);
goto err;
}
list_len -= sct_len;
if ((sct = o2i_SCT(NULL, pp, sct_len)) == NULL)
goto err;
if (!sk_SCT_push(sk, sct)) {
SCT_free(sct);
goto err;
}
}
if (a != NULL && *a == NULL)
*a = sk;
return sk;
err:
if (a == NULL || *a == NULL)
SCT_LIST_free(sk);
return NULL;
}
int i2o_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **pp)
{
int len, sct_len, i, is_pp_new = 0;
size_t len2;
unsigned char *p = NULL, *p2;
if (pp != NULL) {
if (*pp == NULL) {
if ((len = i2o_SCT_LIST(a, NULL)) == -1) {
CTerr(CT_F_I2O_SCT_LIST, CT_R_SCT_LIST_INVALID);
return -1;
}
if ((*pp = OPENSSL_malloc(len)) == NULL) {
CTerr(CT_F_I2O_SCT_LIST, ERR_R_MALLOC_FAILURE);
return -1;
}
is_pp_new = 1;
}
p = *pp + 2;
}
len2 = 2;
for (i = 0; i < sk_SCT_num(a); i++) {
if (pp != NULL) {
p2 = p;
p += 2;
if ((sct_len = i2o_SCT(sk_SCT_value(a, i), &p)) == -1)
goto err;
s2n(sct_len, p2);
} else {
if ((sct_len = i2o_SCT(sk_SCT_value(a, i), NULL)) == -1)
goto err;
}
len2 += 2 + sct_len;
}
if (len2 > MAX_SCT_LIST_SIZE)
goto err;
if (pp != NULL) {
p = *pp;
s2n(len2 - 2, p);
if (!is_pp_new)
*pp += len2;
}
return len2;
err:
if (is_pp_new) {
OPENSSL_free(*pp);
*pp = NULL;
}
return -1;
}
STACK_OF(SCT) *d2i_SCT_LIST(STACK_OF(SCT) **a, const unsigned char **pp,
long len)
{
ASN1_OCTET_STRING *oct = NULL;
STACK_OF(SCT) *sk = NULL;
const unsigned char *p;
p = *pp;
if (d2i_ASN1_OCTET_STRING(&oct, &p, len) == NULL)
return NULL;
p = oct->data;
if ((sk = o2i_SCT_LIST(a, &p, oct->length)) != NULL)
*pp += len;
ASN1_OCTET_STRING_free(oct);
return sk;
}
int i2d_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **out)
{
ASN1_OCTET_STRING oct;
int len;
oct.data = NULL;
if ((oct.length = i2o_SCT_LIST(a, &oct.data)) == -1)
return -1;
len = i2d_ASN1_OCTET_STRING(&oct, out);
OPENSSL_free(oct.data);
return len;
}
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