boringssl/crypto/evp/evp_asn1.c
Adam Langley 62882187c9 Update comments to better document in-place semantics.
(Comment-only change; no functional difference.)

Some code was broken by the |d2i_ECDSA_SIG| change in 87897a8c. It was
passing in a pointer to an existing |ECDSA_SIG| as the first argument
and then simply assuming that the structure would be updated in place.
The comments on the function suggested that this was reasonable.

This change updates the comments that use similar wording to either note
that the function will never update in-place, or else to note that
depending on that is a bad idea for the future.

I've also audited all the uses of these functions that I can find and,
in addition to the one case with |d2i_ECDSA_SIG|, there are several
users of |d2i_PrivateKey| that could become a problem in the future.
I'll try to fix them before it does become an issue.

Change-Id: I769f7b2e0b5308d09ea07dd447e02fc161795071
Reviewed-on: https://boringssl-review.googlesource.com/6902
Reviewed-by: David Benjamin <davidben@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>
2016-01-19 17:01:37 +00:00

183 lines
6.2 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/evp.h>
#include <openssl/asn1.h>
#include <openssl/err.h>
#include <openssl/obj.h>
#include <openssl/x509.h>
#include "internal.h"
EVP_PKEY *d2i_PrivateKey(int type, EVP_PKEY **out, const uint8_t **inp,
long len) {
EVP_PKEY *ret;
if (out == NULL || *out == NULL) {
ret = EVP_PKEY_new();
if (ret == NULL) {
OPENSSL_PUT_ERROR(EVP, ERR_R_EVP_LIB);
return NULL;
}
} else {
ret = *out;
}
if (!EVP_PKEY_set_type(ret, type)) {
OPENSSL_PUT_ERROR(EVP, EVP_R_UNKNOWN_PUBLIC_KEY_TYPE);
goto err;
}
const uint8_t *in = *inp;
/* If trying to remove |old_priv_decode|, note that some code depends on this
* function writing into |*out| and the |priv_decode| path doesn't support
* that. */
if (!ret->ameth->old_priv_decode ||
!ret->ameth->old_priv_decode(ret, &in, len)) {
if (ret->ameth->priv_decode) {
/* Reset |in| in case |old_priv_decode| advanced it on error. */
in = *inp;
PKCS8_PRIV_KEY_INFO *p8 = d2i_PKCS8_PRIV_KEY_INFO(NULL, &in, len);
if (!p8) {
goto err;
}
EVP_PKEY_free(ret);
ret = EVP_PKCS82PKEY(p8);
PKCS8_PRIV_KEY_INFO_free(p8);
if (ret == NULL) {
goto err;
}
} else {
OPENSSL_PUT_ERROR(EVP, ERR_R_ASN1_LIB);
goto err;
}
}
if (out != NULL) {
*out = ret;
}
*inp = in;
return ret;
err:
if (out == NULL || *out != ret) {
EVP_PKEY_free(ret);
}
return NULL;
}
EVP_PKEY *d2i_AutoPrivateKey(EVP_PKEY **out, const uint8_t **inp, long len) {
STACK_OF(ASN1_TYPE) *inkey;
const uint8_t *p;
int keytype;
p = *inp;
/* Dirty trick: read in the ASN1 data into out STACK_OF(ASN1_TYPE):
* by analyzing it we can determine the passed structure: this
* assumes the input is surrounded by an ASN1 SEQUENCE. */
inkey = d2i_ASN1_SEQUENCE_ANY(NULL, &p, len);
/* Since we only need to discern "traditional format" RSA and DSA
* keys we can just count the elements. */
if (sk_ASN1_TYPE_num(inkey) == 6) {
keytype = EVP_PKEY_DSA;
} else if (sk_ASN1_TYPE_num(inkey) == 4) {
keytype = EVP_PKEY_EC;
} else if (sk_ASN1_TYPE_num(inkey) == 3) {
/* This seems to be PKCS8, not traditional format */
p = *inp;
PKCS8_PRIV_KEY_INFO *p8 = d2i_PKCS8_PRIV_KEY_INFO(NULL, &p, len);
EVP_PKEY *ret;
sk_ASN1_TYPE_pop_free(inkey, ASN1_TYPE_free);
if (!p8) {
OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_PUBLIC_KEY_TYPE);
return NULL;
}
ret = EVP_PKCS82PKEY(p8);
PKCS8_PRIV_KEY_INFO_free(p8);
if (ret == NULL) {
return NULL;
}
*inp = p;
if (out) {
*out = ret;
}
return ret;
} else {
keytype = EVP_PKEY_RSA;
}
sk_ASN1_TYPE_pop_free(inkey, ASN1_TYPE_free);
return d2i_PrivateKey(keytype, out, inp, len);
}
int i2d_PublicKey(EVP_PKEY *key, uint8_t **outp) {
switch (key->type) {
case EVP_PKEY_RSA:
return i2d_RSAPublicKey(key->pkey.rsa, outp);
case EVP_PKEY_DSA:
return i2d_DSAPublicKey(key->pkey.dsa, outp);
case EVP_PKEY_EC:
return i2o_ECPublicKey(key->pkey.ec, outp);
default:
OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_PUBLIC_KEY_TYPE);
return -1;
}
}