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412afb2aef
Fix ubsan warning null pointer passed as argument 2 when the source pointer is NULL. The calls to memcpy are now guarded by an if (len > 0) Signed-off-by: Gary Lockyer <gary@catalyst.net.nz> Reviewed-by: Andreas Schneider <asn@samba.org> Autobuild-User(master): Gary Lockyer <gary@samba.org> Autobuild-Date(master): Mon May 27 01:29:48 UTC 2019 on sn-devel-184
122 lines
3.0 KiB
C
122 lines
3.0 KiB
C
/*
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AES-CMAC-128 (rfc 4493)
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Copyright (C) Stefan Metzmacher 2012
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Copyright (C) Jeremy Allison 2012
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Copyright (C) Michael Adam 2012
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "replace.h"
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#include "lib/crypto/aes.h"
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#include "lib/crypto/aes_cmac_128.h"
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static const uint8_t const_Zero[] = {
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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static const uint8_t const_Rb[] = {
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x87
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};
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#define _MSB(x) (((x)[0] & 0x80)?1:0)
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void aes_cmac_128_init(struct aes_cmac_128_context *ctx,
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const uint8_t K[AES_BLOCK_SIZE])
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{
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ZERO_STRUCTP(ctx);
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AES_set_encrypt_key(K, 128, &ctx->aes_key);
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/* step 1 - generate subkeys k1 and k2 */
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AES_encrypt(const_Zero, ctx->L, &ctx->aes_key);
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if (_MSB(ctx->L) == 0) {
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aes_block_lshift(ctx->L, ctx->K1);
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} else {
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aes_block_lshift(ctx->L, ctx->tmp);
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aes_block_xor(ctx->tmp, const_Rb, ctx->K1);
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}
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if (_MSB(ctx->K1) == 0) {
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aes_block_lshift(ctx->K1, ctx->K2);
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} else {
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aes_block_lshift(ctx->K1, ctx->tmp);
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aes_block_xor(ctx->tmp, const_Rb, ctx->K2);
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}
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}
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void aes_cmac_128_update(struct aes_cmac_128_context *ctx,
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const uint8_t *msg, size_t msg_len)
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{
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/*
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* check if we expand the block
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*/
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if (ctx->last_len < AES_BLOCK_SIZE) {
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size_t len = MIN(AES_BLOCK_SIZE - ctx->last_len, msg_len);
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if (len > 0) {
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memcpy(&ctx->last[ctx->last_len], msg, len);
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msg += len;
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msg_len -= len;
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ctx->last_len += len;
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}
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}
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if (msg_len == 0) {
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/* if it is still the last block, we are done */
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return;
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}
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/*
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* now checksum everything but the last block
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*/
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aes_block_xor(ctx->X, ctx->last, ctx->Y);
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AES_encrypt(ctx->Y, ctx->X, &ctx->aes_key);
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while (msg_len > AES_BLOCK_SIZE) {
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aes_block_xor(ctx->X, msg, ctx->Y);
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AES_encrypt(ctx->Y, ctx->X, &ctx->aes_key);
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msg += AES_BLOCK_SIZE;
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msg_len -= AES_BLOCK_SIZE;
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}
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/*
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* copy the last block, it will be processed in
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* aes_cmac_128_final().
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*/
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ZERO_STRUCT(ctx->last);
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memcpy(ctx->last, msg, msg_len);
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ctx->last_len = msg_len;
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}
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void aes_cmac_128_final(struct aes_cmac_128_context *ctx,
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uint8_t T[AES_BLOCK_SIZE])
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{
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if (ctx->last_len < AES_BLOCK_SIZE) {
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ctx->last[ctx->last_len] = 0x80;
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aes_block_xor(ctx->last, ctx->K2, ctx->tmp);
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} else {
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aes_block_xor(ctx->last, ctx->K1, ctx->tmp);
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}
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aes_block_xor(ctx->tmp, ctx->X, ctx->Y);
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AES_encrypt(ctx->Y, T, &ctx->aes_key);
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ZERO_STRUCTP(ctx);
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}
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