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fix CCM, as discovered when porting TLS to string #242

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merged 1 commit into from
Aug 20, 2024
Merged

fix CCM, as discovered when porting TLS to string #242

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16 changes: 8 additions & 8 deletions src/ccm.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -79,11 +79,11 @@ let crypto_core_into ~cipher ~mode ~key ~nonce ~adata src ~src_off dst ~dst_off

let small_q = 15 - String.length nonce in
let ctr_flag_val = flags 0 0 (small_q - 1) in
let ctrblock i block =
Bytes.set_uint8 block 0 ctr_flag_val;
Bytes.unsafe_blit_string nonce 0 block 1 (String.length nonce);
encode_len block ~off:(String.length nonce + 1) small_q i;
cipher ~key (Bytes.unsafe_to_string block) ~src_off:0 block ~dst_off:0
let ctrblock i block dst_off =
Bytes.set_uint8 block dst_off ctr_flag_val;
Bytes.unsafe_blit_string nonce 0 block (dst_off + 1) (String.length nonce);
encode_len block ~off:(dst_off + String.length nonce + 1) small_q i;
cipher ~key (Bytes.unsafe_to_string block) ~src_off:dst_off block ~dst_off
in

let cbc iv src_off block dst_off =
Expand Down Expand Up @@ -113,14 +113,14 @@ let crypto_core_into ~cipher ~mode ~key ~nonce ~adata src ~src_off dst ~dst_off
else if len < block_size then begin
let buf = Bytes.make block_size '\x00' in
Bytes.unsafe_blit dst dst_off buf 0 len ;
ctrblock ctr buf ;
ctrblock ctr buf 0 ;
Bytes.unsafe_blit buf 0 dst dst_off len ;
unsafe_xor_into src ~src_off dst ~dst_off len ;
Bytes.unsafe_blit_string cbcblock cbc_off buf 0 len ;
Bytes.unsafe_fill buf len (block_size - len) '\x00';
cbc (Bytes.unsafe_to_string buf) cbc_off iv 0
cbc (Bytes.unsafe_to_string buf) 0 iv 0
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Hmm is it safe to switch cbc_off with 0?

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Ah, it is. buf is the counter stuff and unrelated to src/dst.

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No, it's not the counter stuff, I am confusing myself. But this looks good.

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buf is the locally created 16 byte buffer that holds the last block (which is then partially blit into dst). the cbc is for the tag, and here the full buf is used -- where previously the cbcblock (depending on encrypt or decrypt, the src or dst) has been blit into, followed by clearing the remaining bytes with 0.

end else begin
ctrblock ctr dst ;
ctrblock ctr dst dst_off ;
unsafe_xor_into src ~src_off dst ~dst_off block_size ;
cbc cbcblock cbc_off iv 0 ;
(loop [@tailcall]) (succ ctr) src (src_off + block_size) dst (dst_off + block_size) (len - block_size)
Expand Down
154 changes: 153 additions & 1 deletion tests/test_cipher.ml
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Expand Up @@ -470,6 +470,158 @@ let ccm_regressions =
let cipher = authenticate_encrypt ~adata ~key ~nonce plaintext in
assert_oct_equal ~msg:"CCM encrypt of >=65280 adata" expected cipher
in
let regr_tls =
let key = of_secret (vx "063a 96fd 15f9 82d5 5aad 5bf9 d098 7546") in
(* discovered while moving ocaml-tls to string *)
let nonce = vx "81cd 4758 1880 9de0 c655 7c31"
and adata = vx "1703 0300 17"
and data = vx "0800 0002 0000 16"
and expected = vx "94ca 065a c948 c5d6 92fd 5fab c850 0611 a07c 4f6e 0710 90"
in
let a _ =
let cipher = authenticate_encrypt ~adata ~key ~nonce data in
assert_oct_equal ~msg:"TLS regression 0" expected cipher
and b _ =
match authenticate_decrypt ~key ~nonce ~adata expected with
| None -> assert_failure "TLS regression 0, decrypt broken"
| Some x -> assert_oct_equal ~msg:"TLS regression 0 decrypt" x data
in
let nonce = vx "81cd 4758 1880 9de0 c655 7c30"
and adata = vx "1703 0302 85"
and data = vx {|
0b00 0270 0000 026c 0002 6730 8202 6330
8201 cc02 0900 cb6c 4e84 4b58 a1d4 300d
|}
and expected = vx {|
1e59 904e e6d5 c2ac e538 78d7 e24f 6e46
6169 f8e2 d3dd 8b5d 788c 78ff ea9f e1d0
9885 ac1a c6d9 fb88 b66a 3a11 5ba5 6e7c
|}
in
let c _ =
let cipher = authenticate_encrypt ~adata ~key ~nonce data in
assert_oct_equal ~msg:"TLS regression 1" expected cipher
and d _ =
match authenticate_decrypt ~key ~nonce ~adata expected with
| None -> assert_failure "TLS regression 1, decrypt broken"
| Some x -> assert_oct_equal ~msg:"TLS regression 1 decrypt" x data
in
let data = vx {|
0b00 0270 0000 026c 0002 6730 8202 6330
8201 cc02 0900 cb6c 4e84 4b58 a1d4 300d
8201 cc02 0900
|}
and expected = vx {|
1e59 904e e6d5 c2ac e538 78d7 e24f 6e46
6169 f8e2 d3dd 8b5d 788c 78ff ea9f e1d0
7c8d 9993 6bfd cf76 9799 473b 58f4 ed69
d7a4 df7a 2d6b
|}
in
let e _ =
let cipher = authenticate_encrypt ~adata ~key ~nonce data in
assert_oct_equal ~msg:"TLS regression 2" expected cipher
and f _ =
match authenticate_decrypt ~key ~nonce ~adata expected with
| None -> assert_failure "TLS regression 2, decrypt broken"
| Some x -> assert_oct_equal ~msg:"TLS regression 2 decrypt" x data
in
let data = vx {|
0b00 0270 0000 026c 0002 6730 8202 6330
8201 cc02 0900 cb6c 4e84 4b58 a1d4 300d
0609 2a86 4886 f70d 0101 0505 0030 7631
0b30 0906 0355 0406 1302 4155 3113 3011
0603 5504 080c 0a53 6f6d 652d 5374 6174
6531 2130 1f06 0355 040a 0c18 496e 7465
726e 6574 2057 6964 6769 7473 2050 7479
204c 7464 3115 3013 0603 5504 030c 0c59
4f55 5220 4e41 4d45 2121 2131 1830 1606
092a 8648 86f7 0d01 0901 1609 6d65 4062
6172 2e64 6530 1e17 0d31 3430 3231 3732
3230 3834 355a 170d 3135 3032 3137 3232
3038 3435 5a30 7631 0b30 0906 0355 0406
1302 4155 3113 3011 0603 5504 080c 0a53
6f6d 652d 5374 6174 6531 2130 1f06 0355
040a 0c18 496e 7465 726e 6574 2057 6964
6769 7473 2050 7479 204c 7464 3115 3013
0603 5504 030c 0c59 4f55 5220 4e41 4d45
2121 2131 1830 1606 092a 8648 86f7 0d01
0901 1609 6d65 4062 6172 2e64 6530 819f
300d 0609 2a86 4886 f70d 0101 0105 0003
818d 0030 8189 0281 8100 b640 48de e6bc
2194 3da2 ab5e b6f8 d837 007f 417c 0fe3
3492 c3aa 2f55 3e4d 5e31 4346 89c2 6f2b
e68e 00d2 88b0 e3ab f6fe 1188 45d9 4989
8512 f192 cbe4 9fd5 b083 1f01 cb2d 274d
b3a6 38f5 befb 3ce8 1ab6 b559 3934 4404
4fed d6ca 154f 76bf bd52 5608 bb55 0a39
bbd2 ed12 e6d7 1f9f 84ba 21aa 5e21 8015
0267 1aab 049a f864 0da1 0203 0100 0130
0d06 092a 8648 86f7 0d01 0105 0500 0381
8100 8a38 669a 4896 9dc9 4729 6d44 2d7f
0320 82d2 db21 e537 4cdd 6ef6 e7cc 1da0
fde5 11ed 3c52 52f0 a673 dc68 9fdc 5fca
cc1b 85df e22b 7bef 2adb 56b5 3732 e981
1063 794d 6e23 9f8f a267 215b a7a4 d3dc
e505 e799 ec5c 38cd 1c16 ee75 e0d5 a46b
8f4c 8e82 6505 6153 9a84 305d f19a 5a24
1be5 55f8 7083 4e09 4d41 cf9f 74b3 342e
8345 0000 16
|}
and expected = vx {|
1e59 904e e6d5 c2ac e538 78d7 e24f 6e46
6169 f8e2 d3dd 8b5d 788c 78ff ea9f e1d0
f885 7f17 2a7b f163 d29e 0a8e 8636 418f
a9da 651b f2ba 36aa a1a4 14d0 6a9a f991
0836 eb93 80b9 bbe2 1f20 98d9 be0b c16f
d58c c98d 4082 dadd f575 57a4 43f7 af31
c1b7 1eeb 2590 a887 e31c 590a 7e56 798c
69aa 4576 fde6 63d2 1b62 d00d 98f6 4015
dae7 8454 b96a f7f9 774f f539 24bf efe6
4629 ee35 4c81 32d4 43df ffa9 17a2 6306
fd07 f9ab b462 2bcd bb0a 3750 af1a 3525
66ad 6c67 b647 2ca7 d6b5 b13e ea34 d90d
5731 a599 e608 d037 bc77 40aa b305 84ad
8d78 43fc 7f55 70a2 fbbb 1b30 a14a 2f5f
b3c3 2584 1f9e 7f3f 3dfa 19e2 9539 a1be
ead8 e051 d847 915b ed23 87ab 7082 7df4
71a0 e0a6 46db a780 1e7b fb98 dac4 0af1
c3eb 42d4 3a6c 3c71 f55a b377 e4de ff20
14d7 b47c 8743 f291 56f3 6d8c 45d1 7cb3
0321 e2cf 8ffd babf a129 ea0d cc1b 7a0d
b1ec 448d 0e3b 4386 9cc2 2b5a 5569 2930
ea33 080e 9168 3696 b224 6238 34fc 3e25
7895 6af3 cd60 f3c8 6643 3d6f 5736 4e78
6aca 8b2d 1575 2d34 4533 79bd e27e 9c46
f9f4 be4a 2fe3 f377 3acf 7b6e e4f0 3eb0
ec85 95a6 ed04 2316 fe4e 2a54 25aa c40a
c464 4128 0e35 1003 9f5d abfa e8e9 dc73
f709 f29b f930 0bdc d941 981b c5b3 8295
97a5 c7e9 481d ce99 c6b6 5dfb 672d 3fdb
38bb a6be d7f8 9863 345d c3a8 77f3 6b77
f309 5c3b b9df fa40 8d42 ff79 6724 23da
8f24 c9b0 e02d 4794 581f e185 32e6 94bb
5b6a 6d5c 3b80 4c83 a0d8 0b42 d575 4fc3
4353 a78d fdb5 003c 4f0b 437d 75fb 5886
a76a 35f5 892d a10b ce33 3ce6 ffd9 f09c
7264 5b09 c50a 7013 344c 11a1 ab92 5728
43e1 bc8c 8c1b 3fad 4a02 25a9 cb96 5fd2
1962 4b0c b46b 9f8f 1225 b18c 2572 6297
c890 238f 22d6 2bb0 7678 568a 3c9b 75e5
b8fc 10f3 13c7 aa16 8165 a29c 67f1 46f4
6e44 8e84 f5
|}
in
let g _ =
let cipher = authenticate_encrypt ~adata ~key ~nonce data in
assert_oct_equal ~msg:"TLS regression 3" expected cipher
and h _ =
match authenticate_decrypt ~key ~nonce ~adata expected with
| None -> assert_failure "TLS regression 3, decrypt broken"
| Some x -> assert_oct_equal ~msg:"TLS regression 3 decrypt" x data
in
[ a ; b ; c ; d ; e ; f ; g ; h ]
in
[
test_case no_vs_empty_ad ;
test_case short_nonce_enc ;
Expand All @@ -478,7 +630,7 @@ let ccm_regressions =
test_case long_nonce_enc ;
test_case enc_dec_empty_message ;
test_case long_adata ;
]
] @ List.map test_case regr_tls

let gcm_regressions =
let open AES.GCM in
Expand Down
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