Credentials.cpp

#include <xrpld/app/tx/detail/Credentials.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/ledger/ApplyView.h>
#include <xrpl/ledger/CredentialHelpers.h>
#include <xrpl/ledger/View.h>
#include <xrpl/protocol/Feature.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/TxFlags.h>
 
#include <chrono>
 
namespace xrpl {
 
/*
    Credentials
    ======
 
   A verifiable credentials (VC
   https://en.wikipedia.org/wiki/Verifiable_credentials), as defined by the W3C
   specification (https://www.w3.org/TR/vc-data-model-2.0/), is a
   secure and tamper-evident way to represent information about a subject, such
   as an individual, organization, or even an IoT device. These credentials are
   issued by a trusted entity and can be verified by third parties without
   directly involving the issuer at all.
*/
 
using namespace credentials;
 
// ------- CREATE --------------------------
 
std::uint32_t
CredentialCreate::getFlagsMask(PreflightContext const& ctx)
{
    // 0 means "Allow any flags"
    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
}
 
NotTEC
CredentialCreate::preflight(PreflightContext const& ctx)
{
    auto const& tx = ctx.tx;
    auto& j = ctx.j;
 
    if (!tx[sfSubject])
    {
        JLOG(j.trace()) << "Malformed transaction: Invalid Subject";
        return temMALFORMED;
    }
 
    auto const uri = tx[~sfURI];
    if (uri && (uri->empty() || (uri->size() > maxCredentialURILength)))
    {
        JLOG(j.trace()) << "Malformed transaction: invalid size of URI.";
        return temMALFORMED;
    }
 
    auto const credType = tx[sfCredentialType];
    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
    {
        JLOG(j.trace()) << "Malformed transaction: invalid size of CredentialType.";
        return temMALFORMED;
    }
 
    return tesSUCCESS;
}
 
TER
CredentialCreate::preclaim(PreclaimContext const& ctx)
{
    auto const credType(ctx.tx[sfCredentialType]);
    auto const subject = ctx.tx[sfSubject];
 
    if (!ctx.view.exists(keylet::account(subject)))
    {
        JLOG(ctx.j.trace()) << "Subject doesn't exist.";
        return tecNO_TARGET;
    }
 
    if (ctx.view.exists(keylet::credential(subject, ctx.tx[sfAccount], credType)))
    {
        JLOG(ctx.j.trace()) << "Credential already exists.";
        return tecDUPLICATE;
    }
 
    return tesSUCCESS;
}
 
TER
CredentialCreate::doApply()
{
    auto const subject = ctx_.tx[sfSubject];
    auto const credType(ctx_.tx[sfCredentialType]);
    Keylet const credentialKey = keylet::credential(subject, account_, credType);
 
    auto const sleCred = std::make_shared<SLE>(credentialKey);
    if (!sleCred)
        return tefINTERNAL;  // LCOV_EXCL_LINE
 
    auto const optExp = ctx_.tx[~sfExpiration];
    if (optExp)
    {
        std::uint32_t const closeTime = ctx_.view().header().parentCloseTime.time_since_epoch().count();
 
        if (closeTime > *optExp)
        {
            JLOG(j_.trace()) << "Malformed transaction: "
                                "Expiration time is in the past.";
            return tecEXPIRED;
        }
 
        sleCred->setFieldU32(sfExpiration, ctx_.tx.getFieldU32(sfExpiration));
    }
 
    auto const sleIssuer = view().peek(keylet::account(account_));
    if (!sleIssuer)
        return tefINTERNAL;  // LCOV_EXCL_LINE
 
    {
        STAmount const reserve{view().fees().accountReserve(sleIssuer->getFieldU32(sfOwnerCount) + 1)};
        if (mPriorBalance < reserve)
            return tecINSUFFICIENT_RESERVE;
    }
 
    sleCred->setAccountID(sfSubject, subject);
    sleCred->setAccountID(sfIssuer, account_);
    sleCred->setFieldVL(sfCredentialType, credType);
 
    if (ctx_.tx.isFieldPresent(sfURI))
        sleCred->setFieldVL(sfURI, ctx_.tx.getFieldVL(sfURI));
 
    {
        auto const page = view().dirInsert(keylet::ownerDir(account_), credentialKey, describeOwnerDir(account_));
        JLOG(j_.trace()) << "Adding Credential to owner directory " << to_string(credentialKey.key) << ": "
                         << (page ? "success" : "failure");
        if (!page)
            return tecDIR_FULL;
        sleCred->setFieldU64(sfIssuerNode, *page);
 
        adjustOwnerCount(view(), sleIssuer, 1, j_);
    }
 
    if (subject == account_)
    {
        sleCred->setFieldU32(sfFlags, lsfAccepted);
    }
    else
    {
        auto const page = view().dirInsert(keylet::ownerDir(subject), credentialKey, describeOwnerDir(subject));
        JLOG(j_.trace()) << "Adding Credential to owner directory " << to_string(credentialKey.key) << ": "
                         << (page ? "success" : "failure");
        if (!page)
            return tecDIR_FULL;
        sleCred->setFieldU64(sfSubjectNode, *page);
        view().update(view().peek(keylet::account(subject)));
    }
 
    view().insert(sleCred);
 
    return tesSUCCESS;
}
 
// ------- DELETE --------------------------
 
std::uint32_t
CredentialDelete::getFlagsMask(PreflightContext const& ctx)
{
    // 0 means "Allow any flags"
    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
}
 
NotTEC
CredentialDelete::preflight(PreflightContext const& ctx)
{
    auto const subject = ctx.tx[~sfSubject];
    auto const issuer = ctx.tx[~sfIssuer];
 
    if (!subject && !issuer)
    {
        // Neither field is present, the transaction is malformed.
        JLOG(ctx.j.trace()) << "Malformed transaction: "
                               "No Subject or Issuer fields.";
        return temMALFORMED;
    }
 
    // Make sure that the passed account is valid.
    if ((subject && subject->isZero()) || (issuer && issuer->isZero()))
    {
        JLOG(ctx.j.trace()) << "Malformed transaction: Subject or Issuer "
                               "field zeroed.";
        return temINVALID_ACCOUNT_ID;
    }
 
    auto const credType = ctx.tx[sfCredentialType];
    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
    {
        JLOG(ctx.j.trace()) << "Malformed transaction: invalid size of CredentialType.";
        return temMALFORMED;
    }
 
    return tesSUCCESS;
}
 
TER
CredentialDelete::preclaim(PreclaimContext const& ctx)
{
    AccountID const account{ctx.tx[sfAccount]};
    auto const subject = ctx.tx[~sfSubject].value_or(account);
    auto const issuer = ctx.tx[~sfIssuer].value_or(account);
    auto const credType(ctx.tx[sfCredentialType]);
 
    if (!ctx.view.exists(keylet::credential(subject, issuer, credType)))
        return tecNO_ENTRY;
 
    return tesSUCCESS;
}
 
TER
CredentialDelete::doApply()
{
    auto const subject = ctx_.tx[~sfSubject].value_or(account_);
    auto const issuer = ctx_.tx[~sfIssuer].value_or(account_);
 
    auto const credType(ctx_.tx[sfCredentialType]);
    auto const sleCred = view().peek(keylet::credential(subject, issuer, credType));
    if (!sleCred)
        return tefINTERNAL;  // LCOV_EXCL_LINE
 
    if ((subject != account_) && (issuer != account_) && !checkExpired(sleCred, ctx_.view().header().parentCloseTime))
    {
        JLOG(j_.trace()) << "Can't delete non-expired credential.";
        return tecNO_PERMISSION;
    }
 
    return deleteSLE(view(), sleCred, j_);
}
 
// ------- APPLY --------------------------
 
std::uint32_t
CredentialAccept::getFlagsMask(PreflightContext const& ctx)
{
    // 0 means "Allow any flags"
    return ctx.rules.enabled(fixInvalidTxFlags) ? tfUniversalMask : 0;
}
 
NotTEC
CredentialAccept::preflight(PreflightContext const& ctx)
{
    if (!ctx.tx[sfIssuer])
    {
        JLOG(ctx.j.trace()) << "Malformed transaction: Issuer field zeroed.";
        return temINVALID_ACCOUNT_ID;
    }
 
    auto const credType = ctx.tx[sfCredentialType];
    if (credType.empty() || (credType.size() > maxCredentialTypeLength))
    {
        JLOG(ctx.j.trace()) << "Malformed transaction: invalid size of CredentialType.";
        return temMALFORMED;
    }
 
    return tesSUCCESS;
}
 
TER
CredentialAccept::preclaim(PreclaimContext const& ctx)
{
    AccountID const subject = ctx.tx[sfAccount];
    AccountID const issuer = ctx.tx[sfIssuer];
    auto const credType(ctx.tx[sfCredentialType]);
 
    if (!ctx.view.exists(keylet::account(issuer)))
    {
        JLOG(ctx.j.warn()) << "No issuer: " << to_string(issuer);
        return tecNO_ISSUER;
    }
 
    auto const sleCred = ctx.view.read(keylet::credential(subject, issuer, credType));
    if (!sleCred)
    {
        JLOG(ctx.j.warn()) << "No credential: " << to_string(subject) << ", " << to_string(issuer) << ", " << credType;
        return tecNO_ENTRY;
    }
 
    if (sleCred->getFieldU32(sfFlags) & lsfAccepted)
    {
        JLOG(ctx.j.warn()) << "Credential already accepted: " << to_string(subject) << ", " << to_string(issuer) << ", "
                           << credType;
        return tecDUPLICATE;
    }
 
    return tesSUCCESS;
}
 
TER
CredentialAccept::doApply()
{
    AccountID const issuer{ctx_.tx[sfIssuer]};
 
    // Both exist as credential object exist itself (checked in preclaim)
    auto const sleSubject = view().peek(keylet::account(account_));
    auto const sleIssuer = view().peek(keylet::account(issuer));
 
    if (!sleSubject || !sleIssuer)
        return tefINTERNAL;  // LCOV_EXCL_LINE
 
    {
        STAmount const reserve{view().fees().accountReserve(sleSubject->getFieldU32(sfOwnerCount) + 1)};
        if (mPriorBalance < reserve)
            return tecINSUFFICIENT_RESERVE;
    }
 
    auto const credType(ctx_.tx[sfCredentialType]);
    Keylet const credentialKey = keylet::credential(account_, issuer, credType);
    auto const sleCred = view().peek(credentialKey);  // Checked in preclaim()
 
    if (checkExpired(sleCred, view().header().parentCloseTime))
    {
        JLOG(j_.trace()) << "Credential is expired: " << sleCred->getText();
        // delete expired credentials even if the transaction failed
        auto const err = credentials::deleteSLE(view(), sleCred, j_);
        return isTesSuccess(err) ? tecEXPIRED : err;
    }
 
    sleCred->setFieldU32(sfFlags, lsfAccepted);
    view().update(sleCred);
 
    adjustOwnerCount(view(), sleIssuer, -1, j_);
    adjustOwnerCount(view(), sleSubject, 1, j_);
 
    return tesSUCCESS;
}
 
}  // namespace xrpl