forked from
gazagnaire.org/ocaml-crypto
upstream: https://github.com/mirage/mirage-crypto
Add untracked directories
+155
+15
fuzz/dune
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fuzz/dune
···
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; Crowbar fuzz testing for crypto
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;
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; To run: dune exec ocaml-crypto/fuzz/fuzz_crypto.exe
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; With AFL: afl-fuzz -i fuzz/corpus -o fuzz/findings -- ./_build/default/ocaml-crypto/fuzz/fuzz_crypto.exe @@
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(executable
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(name fuzz_crypto)
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(modules fuzz_crypto)
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(libraries crypto crowbar))
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(rule
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(alias fuzz)
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(deps fuzz_crypto.exe)
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(action
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(run %{exe:fuzz_crypto.exe})))
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fuzz/fuzz_crypto.ml
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fuzz/fuzz_crypto.ml
···
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(*---------------------------------------------------------------------------
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Copyright (c) 2025 Thomas Gazagnaire. All rights reserved.
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SPDX-License-Identifier: MIT
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---------------------------------------------------------------------------*)
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(* Crowbar-based fuzz testing for cryptographic primitives *)
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open Crowbar
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(* AES key sizes: 16, 24, or 32 bytes *)
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let valid_aes_key_sizes = [ 16; 24; 32 ]
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(* AES block size: 16 bytes *)
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let aes_block_size = 16
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(* Generate a padded key of valid size *)
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let make_key size input =
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if String.length input >= size then String.sub input 0 size
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else input ^ String.make (size - String.length input) '\x00'
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(* Test AES ECB roundtrip for valid key sizes *)
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let test_aes_ecb_roundtrip key_input plaintext =
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List.iter
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(fun key_size ->
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let key_str = make_key key_size key_input in
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let key = Crypto.AES.ECB.of_secret key_str in
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(* Pad plaintext to block size *)
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let pt_len = String.length plaintext in
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let padded_len =
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if pt_len = 0 then aes_block_size
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else ((pt_len + aes_block_size - 1) / aes_block_size) * aes_block_size
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in
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let padded_pt =
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if pt_len >= padded_len then String.sub plaintext 0 padded_len
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else plaintext ^ String.make (padded_len - pt_len) '\x00'
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in
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let ciphertext = Crypto.AES.ECB.encrypt ~key padded_pt in
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let decrypted = Crypto.AES.ECB.decrypt ~key ciphertext in
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check_eq ~pp:Format.pp_print_string padded_pt decrypted)
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valid_aes_key_sizes
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(* Test AES CBC roundtrip *)
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let test_aes_cbc_roundtrip key_input iv_input plaintext =
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List.iter
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(fun key_size ->
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let key_str = make_key key_size key_input in
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let key = Crypto.AES.CBC.of_secret key_str in
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let iv = make_key aes_block_size iv_input in
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(* Pad plaintext to block size *)
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let pt_len = String.length plaintext in
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let padded_len =
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if pt_len = 0 then aes_block_size
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else ((pt_len + aes_block_size - 1) / aes_block_size) * aes_block_size
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in
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let padded_pt =
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if pt_len >= padded_len then String.sub plaintext 0 padded_len
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else plaintext ^ String.make (padded_len - pt_len) '\x00'
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in
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let ciphertext = Crypto.AES.CBC.encrypt ~key ~iv padded_pt in
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let decrypted = Crypto.AES.CBC.decrypt ~key ~iv ciphertext in
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check_eq ~pp:Format.pp_print_string padded_pt decrypted)
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valid_aes_key_sizes
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(* Test AES CTR roundtrip *)
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let test_aes_ctr_roundtrip key_input ctr_input plaintext =
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if String.length plaintext = 0 then ()
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else
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List.iter
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(fun key_size ->
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let key_str = make_key key_size key_input in
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let key = Crypto.AES.CTR.of_secret key_str in
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let ctr_str = make_key aes_block_size ctr_input in
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let ctr = Crypto.AES.CTR.ctr_of_octets ctr_str in
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let ciphertext = Crypto.AES.CTR.encrypt ~key ~ctr plaintext in
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let decrypted = Crypto.AES.CTR.decrypt ~key ~ctr ciphertext in
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check_eq ~pp:Format.pp_print_string plaintext decrypted)
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valid_aes_key_sizes
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(* Test AES GCM roundtrip *)
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let test_aes_gcm_roundtrip key_input nonce_input plaintext =
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List.iter
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(fun key_size ->
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let key_str = make_key key_size key_input in
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let key = Crypto.AES.GCM.of_secret key_str in
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(* GCM nonce should be 12 bytes for optimal performance *)
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let nonce = make_key 12 nonce_input in
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let adata = "" in
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let result = Crypto.AES.GCM.authenticate_encrypt ~key ~nonce ~adata plaintext in
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match Crypto.AES.GCM.authenticate_decrypt ~key ~nonce ~adata result with
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| Some decrypted -> check_eq ~pp:Format.pp_print_string plaintext decrypted
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| None -> fail "GCM decryption failed")
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valid_aes_key_sizes
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(* Test AES CCM roundtrip *)
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let test_aes_ccm_roundtrip key_input nonce_input plaintext =
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if String.length plaintext = 0 then ()
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else
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List.iter
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(fun key_size ->
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let key_str = make_key key_size key_input in
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let key = Crypto.AES.CCM16.of_secret key_str in
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(* CCM nonce should be 7-13 bytes; use 12 *)
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let nonce = make_key 12 nonce_input in
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let adata = "" in
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let result =
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Crypto.AES.CCM16.authenticate_encrypt ~key ~nonce ~adata plaintext
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in
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match Crypto.AES.CCM16.authenticate_decrypt ~key ~nonce ~adata result with
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| Some decrypted ->
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check_eq ~pp:Format.pp_print_string plaintext decrypted
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| None -> fail "CCM decryption failed")
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valid_aes_key_sizes
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(* Test ChaCha20-Poly1305 roundtrip *)
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let test_chacha20_poly1305_roundtrip key_input nonce_input plaintext =
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(* ChaCha20 key is 32 bytes, nonce is 12 bytes *)
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let key_str = make_key 32 key_input in
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let key = Crypto.Chacha20.of_secret key_str in
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let nonce = make_key 12 nonce_input in
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let adata = "" in
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let result =
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Crypto.Chacha20.authenticate_encrypt ~key ~nonce ~adata plaintext
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in
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match Crypto.Chacha20.authenticate_decrypt ~key ~nonce ~adata result with
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| Some decrypted -> check_eq ~pp:Format.pp_print_string plaintext decrypted
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| None -> fail "ChaCha20-Poly1305 decryption failed"
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let () =
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add_test ~name:"crypto: aes ecb roundtrip" [ bytes; bytes ]
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test_aes_ecb_roundtrip;
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add_test ~name:"crypto: aes cbc roundtrip" [ bytes; bytes; bytes ]
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test_aes_cbc_roundtrip;
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add_test ~name:"crypto: aes ctr roundtrip" [ bytes; bytes; bytes ]
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test_aes_ctr_roundtrip;
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add_test ~name:"crypto: aes gcm roundtrip" [ bytes; bytes; bytes ]
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test_aes_gcm_roundtrip;
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add_test ~name:"crypto: aes ccm roundtrip" [ bytes; bytes; bytes ]
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test_aes_ccm_roundtrip;
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add_test ~name:"crypto: chacha20-poly1305 roundtrip" [ bytes; bytes; bytes ]
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test_chacha20_poly1305_roundtrip