Adding the Swap feature #6

spalmer25 · 2023-09-13T11:25:11Z

This PR enables the Ledger swap function:

Add ENABLE_SWAP tag
Provide the 4 required functions:
- The swap_handle_check_address function which checks an address.
- The swap_handle_get_printable_amount function, which gives the print format for an amount.
- The swap_copy_transaction_parameters function, which backs up transaction parameters.
- The swap_finalize_exchange_sign_transaction function which finalizes the exchange.
During a swap, check that the transaction matches the backed-up parameters.

I made some choices in the implementation:

In check_address: the derivation_type is set to ED25519 (since no parameter defines it).
In check_address/copy_transaction_parameters: the extra_id must be non-null and empty.
In the get_printable_amount function: the ticker and the number of decimals given by the caller are those used for print. Should we instead force the display with tz and 6 decimals?
In copy_transaction_parameters/check_validity: the ticker and the number of decimals are not taken into account, the amount/fee values are just compared without decimals.

The feature tests are on an LedgerHQ/app-exchange fork: spalmer25/app-exchange#1

spalmer25 · 2023-09-14T12:35:43Z

Peer on GitLab:
https://gitlab.com/nomadic-labs/tezos-ledger-app-revamp/-/merge_requests/139

emturner

overall LGTM, will test manually against ledger live

app/src/handle_swap.c

emturner · 2023-09-18T08:52:44Z

app/src/parser/num_parser.c

+  return true;
+}
+
+bool tz_print_uint64(uint64_t value, char *out, int out_len, int nb_decimals) {


possibly something like tz_print_mutez instead?

I think that this is in lib_standard_app.

We should not use "print" in these function names, because they do not print.
tz_print_mutez() can be replaced by format_fpu64() from lib_standard_app in ledger-secure-sdk, I think.
If you are worried about building it outside for, say, tests, then use the approach in app/src/parser/compat.h and define:

bool tz_format_mutez(uint64_t value, char *out, size_t outlen) { #ifdef ACTUALLY_ON_LEDGER return format_fpu64(out, outlen, value, 6); #else size_t len = snprintf(out, outlen, "%u.%06u", value / 1000000, value % 1000000); return len < outlen; #endif }

I'm going to add the above comment to my review, if I can.

elric1 · 2023-09-22T10:16:08Z

app/src/keys.c

@@ -152,6 +152,30 @@ cx_err_t public_key_hash(uint8_t *hash_out, size_t hash_out_size,
    return error;
 }

+cx_err_t print_pkh(bip32_path_t bip32_path,


print_pkh() is a misleading name because it does not print anything. I think that derive_pkh() is more meaningful because it actually does derive the public key before it hashes and formats it.

elric1 · 2023-09-26T08:07:21Z

app/src/parser/num_parser.c

+  return true;
+}
+
+bool tz_print_uint64(uint64_t value, char *out, int out_len, int nb_decimals) {


I think that this is in lib_standard_app.

elric1 · 2023-09-26T19:40:25Z

app/src/keys.c

+    case DERIVATION_TYPE_SECP256R1: hash[0] = 2; break;
+    case DERIVATION_TYPE_ED25519:
+    case DERIVATION_TYPE_BIP32_ED25519: hash[0] = 0; break;
+    default: CX_CHECK(EXC_WRONG_PARAM); break;


CX_CHECK should be TZ_FAIL here.

elric1 · 2023-09-26T19:44:48Z

app/src/keys.h

@@ -67,3 +67,5 @@ check_derivation_type(derivation_type_t code)
 {
    return (code >= DERIVATION_TYPE_ED25519 && code < DERIVATION_TYPE_MAX);
 }
+
+void generate_pkh(derivation_type_t, const bip32_path_t *, char *, size_t);


It would look better to put this prototype with the other prototypes after generate_public_key().

elric1 · 2023-09-26T19:46:04Z

app/src/keys.c

@@ -134,6 +134,33 @@ public_key_hash(uint8_t *hash_out, size_t hash_out_size,
    TZ_POSTAMBLE;
 }

+void


The function above (public_key_hash()) should be static as we've removed its prototype and it therefore should not be accessible outside this C file.

elric1

I noticed another quick one. This should simplify things quite a lot.

elric1 · 2023-09-26T20:29:28Z

app/src/parser/num_parser.c

+bool
+tz_print_mutez(uint64_t value, char *out, int out_len, int nb_decimals)
+{
+    char     buff[TZ_NUM_BUFFER_SIZE] = {0};
+    uint64_t power                    = 10;
+    int      offset                   = 0;
+
+    while (power <= value)
+        power *= 10;
+
+    while (power != 1) {
+        power /= 10;
+        buff[offset++] = value / power + '0';
+        value %= power;
+    }
+
+    buff[offset] = '\0';
+
+    return tz_adjust_decimal(buff, offset, out, out_len, nb_decimals);
+}


This duplicates functionality that is already defined in ledger-secure-sdk/lib_standard_app/format.c. This function should be able to be rewritten something like this:

bool tz_print_mutez2(uint64_t value, char *out, int out_len, int nb_decimals) { #if ACTUALLY_ON_LEDGER format_fpu64(out, out_len, value, nb_decimals); #else size_t divisor = 1; size_t i; size_t ret; for (i=0; i < nb_decimals; i++) divisor *= 10; ret = snprintf(out, out_len, "%u.%0*u", value / divisor, nb_decimals, value % divisor); return ret < out_len; #endif }

ACTUALLY_ON_LEDGER can be found in app/src/parser/compat.h which is how you decide if you are inside the unit tests.
My function assumes that if you are not on a ledger, then you are on an LP64 box with a functioning snprintf(3) in libc.

This function is only useful in swap, so it would be better not to have this function in parser at all and to use the functions from ledger-secure-sdk/lib_standard_app/format.c directly.

Align master with P1

spalmer25 force-pushed the palmer/functori/swap-feature branch 6 times, most recently from 9c53f1e to 701485e Compare September 14, 2023 12:31

spalmer25 marked this pull request as ready for review September 14, 2023 12:36

spalmer25 requested review from elric1 and emturner September 14, 2023 12:36

spalmer25 assigned emturner and elric1 Sep 14, 2023

spalmer25 force-pushed the palmer/functori/swap-feature branch 2 times, most recently from 7dcbd21 to 701485e Compare September 15, 2023 14:07

emturner reviewed Sep 18, 2023

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spalmer25 force-pushed the palmer/functori/swap-feature branch 3 times, most recently from c87447c to c8a268e Compare September 25, 2023 14:06

spalmer25 mentioned this pull request Sep 26, 2023

Add new tezos app swap tests spalmer25/app-exchange#1

Merged

spalmer25 force-pushed the palmer/functori/swap-feature branch 2 times, most recently from 300ecde to 1031475 Compare September 26, 2023 09:38

elric1 suggested changes Sep 26, 2023

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spalmer25 force-pushed the palmer/functori/swap-feature branch from 1031475 to 57de80a Compare September 27, 2023 08:12

spalmer25 requested a review from elric1 September 27, 2023 08:15

spalmer25 force-pushed the palmer/functori/swap-feature branch from 57de80a to 0df2f64 Compare September 27, 2023 08:48

elric1 approved these changes Sep 27, 2023

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spalmer25 added 3 commits September 27, 2023 10:53

Move format_pkh in keys.h

f01edc0

Swap: handle check_address

0b23861

Swap: handle get_printable_amount

4fc0a33

spalmer25 added 7 commits September 27, 2023 10:53

Swap: copy transaction parameters and finalize sign transaction

b252ce6

Enabling swap feature

4e3f54e

Allows to extract uint64 from string

606db2c

Operation parser: differentiate the AMOUNT field from the FEE field

826d32a

Operation parser: remind data in order to check swap transaction

7f6ed32

Swap: check swap transaction validity

a2fd76a

Run the CI app-exchange tests

4496155

spalmer25 force-pushed the palmer/functori/swap-feature branch from 0df2f64 to 4496155 Compare September 27, 2023 08:53

elric1 merged commit 3783dd0 into main Sep 27, 2023
87 checks passed

elric1 deleted the palmer/functori/swap-feature branch September 27, 2023 09:28

ajinkyaraj-23 pushed a commit that referenced this pull request Jul 29, 2024

Merge pull request #6 from LedgerHQ/develop

40e76d4

Align master with P1

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Adding the Swap feature #6

Adding the Swap feature #6

spalmer25 commented Sep 13, 2023 •

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Adding the Swap feature #6

Adding the Swap feature #6

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spalmer25 commented Sep 13, 2023 • edited Loading

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spalmer25 commented Sep 13, 2023 •

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