Add 2fa for authentification (#383)

Fix user tests

Add swagger docs

Fix lint

Add totp check when logging in

Make totp enrollment work

Add migration for totp table

go mod vendor

Add routes for totp routes

Add route handler for totp routes

Add basic implementation to enroll a user in totp

Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/api/pulls/383

vendor/github.com/boombuler/barcode/utils/gfpoly.go

@@ -0,0 +1,103 @@
+package utils
+
+type GFPoly struct {
+	gf           *GaloisField
+	Coefficients []int
+}
+
+func (gp *GFPoly) Degree() int {
+	return len(gp.Coefficients) - 1
+}
+
+func (gp *GFPoly) Zero() bool {
+	return gp.Coefficients[0] == 0
+}
+
+// GetCoefficient returns the coefficient of x ^ degree
+func (gp *GFPoly) GetCoefficient(degree int) int {
+	return gp.Coefficients[gp.Degree()-degree]
+}
+
+func (gp *GFPoly) AddOrSubstract(other *GFPoly) *GFPoly {
+	if gp.Zero() {
+		return other
+	} else if other.Zero() {
+		return gp
+	}
+	smallCoeff := gp.Coefficients
+	largeCoeff := other.Coefficients
+	if len(smallCoeff) > len(largeCoeff) {
+		largeCoeff, smallCoeff = smallCoeff, largeCoeff
+	}
+	sumDiff := make([]int, len(largeCoeff))
+	lenDiff := len(largeCoeff) - len(smallCoeff)
+	copy(sumDiff, largeCoeff[:lenDiff])
+	for i := lenDiff; i < len(largeCoeff); i++ {
+		sumDiff[i] = int(gp.gf.AddOrSub(int(smallCoeff[i-lenDiff]), int(largeCoeff[i])))
+	}
+	return NewGFPoly(gp.gf, sumDiff)
+}
+
+func (gp *GFPoly) MultByMonominal(degree int, coeff int) *GFPoly {
+	if coeff == 0 {
+		return gp.gf.Zero()
+	}
+	size := len(gp.Coefficients)
+	result := make([]int, size+degree)
+	for i := 0; i < size; i++ {
+		result[i] = int(gp.gf.Multiply(int(gp.Coefficients[i]), int(coeff)))
+	}
+	return NewGFPoly(gp.gf, result)
+}
+
+func (gp *GFPoly) Multiply(other *GFPoly) *GFPoly {
+	if gp.Zero() || other.Zero() {
+		return gp.gf.Zero()
+	}
+	aCoeff := gp.Coefficients
+	aLen := len(aCoeff)
+	bCoeff := other.Coefficients
+	bLen := len(bCoeff)
+	product := make([]int, aLen+bLen-1)
+	for i := 0; i < aLen; i++ {
+		ac := int(aCoeff[i])
+		for j := 0; j < bLen; j++ {
+			bc := int(bCoeff[j])
+			product[i+j] = int(gp.gf.AddOrSub(int(product[i+j]), gp.gf.Multiply(ac, bc)))
+		}
+	}
+	return NewGFPoly(gp.gf, product)
+}
+
+func (gp *GFPoly) Divide(other *GFPoly) (quotient *GFPoly, remainder *GFPoly) {
+	quotient = gp.gf.Zero()
+	remainder = gp
+	fld := gp.gf
+	denomLeadTerm := other.GetCoefficient(other.Degree())
+	inversDenomLeadTerm := fld.Invers(int(denomLeadTerm))
+	for remainder.Degree() >= other.Degree() && !remainder.Zero() {
+		degreeDiff := remainder.Degree() - other.Degree()
+		scale := int(fld.Multiply(int(remainder.GetCoefficient(remainder.Degree())), inversDenomLeadTerm))
+		term := other.MultByMonominal(degreeDiff, scale)
+		itQuot := NewMonominalPoly(fld, degreeDiff, scale)
+		quotient = quotient.AddOrSubstract(itQuot)
+		remainder = remainder.AddOrSubstract(term)
+	}
+	return
+}
+
+func NewMonominalPoly(field *GaloisField, degree int, coeff int) *GFPoly {
+	if coeff == 0 {
+		return field.Zero()
+	}
+	result := make([]int, degree+1)
+	result[0] = coeff
+	return NewGFPoly(field, result)
+}
+
+func NewGFPoly(field *GaloisField, coefficients []int) *GFPoly {
+	for len(coefficients) > 1 && coefficients[0] == 0 {
+		coefficients = coefficients[1:]
+	}
+	return &GFPoly{field, coefficients}
+}