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[v13] Fix backwards compatibility of GenerateUserSingleUseCerts #25485

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Merged
rosstimothy merged 1 commit into from
May 2, 2023
Merged

[v13] Fix backwards compatibility of GenerateUserSingleUseCerts #25485

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6 changes: 5 additions & 1 deletion lib/auth/grpcserver.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2565,6 +2565,10 @@ func isDBLocalProxyTunnelCertReq(req *proto.UserCertsRequest) bool {
req.RequesterName == proto.UserCertsRequest_TSH_DB_LOCAL_PROXY_TUNNEL
}

// ErrNoMFADevices is returned when an MFA ceremony is performed without possible devices to
// complete the challenge with.
var ErrNoMFADevices = trace.AccessDenied("MFA is required to access this resource but user has no MFA devices; use 'tsh mfa add' to register MFA devices")

func userSingleUseCertsAuthChallenge(gctx *grpcContext, stream proto.AuthService_GenerateUserSingleUseCertsServer, mfaRequired proto.MFARequired) (*types.MFADevice, error) {
ctx := stream.Context()
auth := gctx.authServer
Expand All @@ -2576,7 +2580,7 @@ func userSingleUseCertsAuthChallenge(gctx *grpcContext, stream proto.AuthService
return nil, trace.Wrap(err)
}
if challenge.TOTP == nil && challenge.WebauthnChallenge == nil {
return nil, trace.AccessDenied("MFA is required to access this resource but user has no MFA devices; use 'tsh mfa add' to register MFA devices")
return nil, ErrNoMFADevices
}

challenge.MFARequired = mfaRequired
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12 changes: 12 additions & 0 deletions lib/client/client.go
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@ import (
"context"
"crypto/tls"
"encoding/json"
"errors"
"fmt"
"io"
"net"
Expand All @@ -30,6 +31,7 @@ import (
"time"

"github.com/gravitational/trace"
"github.com/gravitational/trace/trail"
"github.com/moby/term"
"go.opentelemetry.io/otel/attribute"
"go.opentelemetry.io/otel/propagation"
Expand Down Expand Up @@ -570,6 +572,16 @@ func (proxy *ProxyClient) IssueUserCertsWithMFA(ctx context.Context, params Reis

resp, err := stream.Recv()
if err != nil {
// Older versions will NOT reply with a MFARequired response in the
// challenge and will terminate the stream with an auth.ErrNoMFADevices error.
// In this case for all protocols other than SSH fall back to reissuing
// certs without MFA.
if errors.Is(trail.FromGRPC(err), auth.ErrNoMFADevices) {
if params.usage() != proto.UserCertsRequest_SSH {
return proxy.reissueUserCerts(ctx, CertCacheKeep, params)
}
}

return nil, trace.Wrap(err)
}
mfaChal := resp.GetMFAChallenge()
Expand Down