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-rw-r--r--cipher-chachapoly.c25
1 files changed, 14 insertions, 11 deletions
diff --git a/cipher-chachapoly.c b/cipher-chachapoly.c
index 251b94ec8..0caccd297 100644
--- a/cipher-chachapoly.c
+++ b/cipher-chachapoly.c
@@ -14,7 +14,7 @@
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */ 15 */
16 16
17/* $OpenBSD: cipher-chachapoly.c,v 1.4 2014/01/31 16:39:19 tedu Exp $ */ 17/* $OpenBSD: cipher-chachapoly.c,v 1.5 2014/06/24 01:13:21 djm Exp $ */
18 18
19#include "includes.h" 19#include "includes.h"
20 20
@@ -24,16 +24,18 @@
24#include <stdio.h> /* needed for misc.h */ 24#include <stdio.h> /* needed for misc.h */
25 25
26#include "log.h" 26#include "log.h"
27#include "misc.h" 27#include "sshbuf.h"
28#include "ssherr.h"
28#include "cipher-chachapoly.h" 29#include "cipher-chachapoly.h"
29 30
30void chachapoly_init(struct chachapoly_ctx *ctx, 31int chachapoly_init(struct chachapoly_ctx *ctx,
31 const u_char *key, u_int keylen) 32 const u_char *key, u_int keylen)
32{ 33{
33 if (keylen != (32 + 32)) /* 2 x 256 bit keys */ 34 if (keylen != (32 + 32)) /* 2 x 256 bit keys */
34 fatal("%s: invalid keylen %u", __func__, keylen); 35 return SSH_ERR_INVALID_ARGUMENT;
35 chacha_keysetup(&ctx->main_ctx, key, 256); 36 chacha_keysetup(&ctx->main_ctx, key, 256);
36 chacha_keysetup(&ctx->header_ctx, key + 32, 256); 37 chacha_keysetup(&ctx->header_ctx, key + 32, 256);
38 return 0;
37} 39}
38 40
39/* 41/*
@@ -52,14 +54,14 @@ chachapoly_crypt(struct chachapoly_ctx *ctx, u_int seqnr, u_char *dest,
52 u_char seqbuf[8]; 54 u_char seqbuf[8];
53 const u_char one[8] = { 1, 0, 0, 0, 0, 0, 0, 0 }; /* NB little-endian */ 55 const u_char one[8] = { 1, 0, 0, 0, 0, 0, 0, 0 }; /* NB little-endian */
54 u_char expected_tag[POLY1305_TAGLEN], poly_key[POLY1305_KEYLEN]; 56 u_char expected_tag[POLY1305_TAGLEN], poly_key[POLY1305_KEYLEN];
55 int r = -1; 57 int r = SSH_ERR_INTERNAL_ERROR;
56 58
57 /* 59 /*
58 * Run ChaCha20 once to generate the Poly1305 key. The IV is the 60 * Run ChaCha20 once to generate the Poly1305 key. The IV is the
59 * packet sequence number. 61 * packet sequence number.
60 */ 62 */
61 memset(poly_key, 0, sizeof(poly_key)); 63 memset(poly_key, 0, sizeof(poly_key));
62 put_u64(seqbuf, seqnr); 64 POKE_U64(seqbuf, seqnr);
63 chacha_ivsetup(&ctx->main_ctx, seqbuf, NULL); 65 chacha_ivsetup(&ctx->main_ctx, seqbuf, NULL);
64 chacha_encrypt_bytes(&ctx->main_ctx, 66 chacha_encrypt_bytes(&ctx->main_ctx,
65 poly_key, poly_key, sizeof(poly_key)); 67 poly_key, poly_key, sizeof(poly_key));
@@ -71,8 +73,10 @@ chachapoly_crypt(struct chachapoly_ctx *ctx, u_int seqnr, u_char *dest,
71 const u_char *tag = src + aadlen + len; 73 const u_char *tag = src + aadlen + len;
72 74
73 poly1305_auth(expected_tag, src, aadlen + len, poly_key); 75 poly1305_auth(expected_tag, src, aadlen + len, poly_key);
74 if (timingsafe_bcmp(expected_tag, tag, POLY1305_TAGLEN) != 0) 76 if (timingsafe_bcmp(expected_tag, tag, POLY1305_TAGLEN) != 0) {
77 r = SSH_ERR_MAC_INVALID;
75 goto out; 78 goto out;
79 }
76 } 80 }
77 /* Crypt additional data */ 81 /* Crypt additional data */
78 if (aadlen) { 82 if (aadlen) {
@@ -88,7 +92,6 @@ chachapoly_crypt(struct chachapoly_ctx *ctx, u_int seqnr, u_char *dest,
88 poly_key); 92 poly_key);
89 } 93 }
90 r = 0; 94 r = 0;
91
92 out: 95 out:
93 explicit_bzero(expected_tag, sizeof(expected_tag)); 96 explicit_bzero(expected_tag, sizeof(expected_tag));
94 explicit_bzero(seqbuf, sizeof(seqbuf)); 97 explicit_bzero(seqbuf, sizeof(seqbuf));
@@ -104,11 +107,11 @@ chachapoly_get_length(struct chachapoly_ctx *ctx,
104 u_char buf[4], seqbuf[8]; 107 u_char buf[4], seqbuf[8];
105 108
106 if (len < 4) 109 if (len < 4)
107 return -1; /* Insufficient length */ 110 return SSH_ERR_MESSAGE_INCOMPLETE;
108 put_u64(seqbuf, seqnr); 111 POKE_U64(seqbuf, seqnr);
109 chacha_ivsetup(&ctx->header_ctx, seqbuf, NULL); 112 chacha_ivsetup(&ctx->header_ctx, seqbuf, NULL);
110 chacha_encrypt_bytes(&ctx->header_ctx, cp, buf, 4); 113 chacha_encrypt_bytes(&ctx->header_ctx, cp, buf, 4);
111 *plenp = get_u32(buf); 114 *plenp = PEEK_U32(buf);
112 return 0; 115 return 0;
113} 116}
114 117