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https://www.chromium.org/updates/same-site/incompatible-clients SameSite=None validation written in golang
package main
import (
"regexp"
"strconv"
)
// Don’t send `SameSite=None` to known incompatible clients.
func shouldSendSameSiteNone(useragent string) (bool, error) {
sameSiteNoneIncompatible, err := isSameSiteNoneIncompatible(useragent)
if err != nil {
return false, nil
}
return !sameSiteNoneIncompatible, nil
}
// Classes of browsers known to be incompatible.
func isSameSiteNoneIncompatible(useragent string) (bool, error) {
sameSiteBug, err := hasWebKitSameSiteBug(useragent)
if err != nil {
return false, nil
}
cookies, err := dropsUnrecognizedSameSiteCookies(useragent)
if err != nil {
return false, nil
}
return sameSiteBug || cookies, nil
}
func hasWebKitSameSiteBug(useragent string) (bool, error) {
isIosBVersion, err := isIosVersion(12, useragent)
if err != nil {
return false, nil
}
isMacOsVersion, err := isMacosxVersion(10, 14, useragent)
if err != nil {
return false, nil
}
safari, err := isSafari(useragent)
macEmbeddedBrowser, err := isMacEmbeddedBrowser(useragent)
return isIosBVersion || (isMacOsVersion && (safari || macEmbeddedBrowser)), nil
}
func dropsUnrecognizedSameSiteCookies(useragent string) (bool, error) {
browser, err := isUcBrowser(useragent)
if err != nil {
return false, nil
}
if browser {
ucBrowserVersionAtLeast, err := isUcBrowserVersionAtLeast(12, 13, 2, useragent)
if err != nil {
return false, nil
}
return !ucBrowserVersionAtLeast, nil
}
chromiumBased, err := isChromiumBased(useragent)
if err != nil {
return false, nil
}
chromiumVersionAtLeast, err := isChromiumVersionAtLeast(51, useragent)
if err != nil {
return false, nil
}
versionAtLeast, err := isChromiumVersionAtLeast(67, useragent)
if err != nil {
return false, nil
}
return chromiumBased && chromiumVersionAtLeast && !versionAtLeast, nil
}
// Regex parsing of User-Agent string. (See note above!)
// Regex parsing of User-Agent string. (See note above!)
func isIosVersion(major int, useragent string) (bool, error) {
regex := "\\(iP.+; CPU .*OS (\\d+)[_\\d]*.*\\) AppleWebKit\\/"
r, err := regexp.Compile(regex)
if err != nil {
return false, nil
}
matches := r.FindAllStringSubmatch(useragent, -1)
if matches == nil {
return false, nil
}
majorVersion, err := strconv.Atoi(matches[0][1])
if err != nil {
return false, err
}
return majorVersion == major, nil
}
func isMacosxVersion(major int, minor int, useragent string) (bool, error) {
regex := "\\(Macintosh;.*Mac OS X (\\d+)_(\\d+)[_\\d]*.*\\) AppleWebKit\\/"
r, err := regexp.Compile(regex)
if err != nil {
return false, nil
}
// Extract digits from first and second capturing groups.
matches := r.FindAllStringSubmatch(useragent, -1)
if matches == nil {
return false, nil
}
majorVersion, err := strconv.Atoi(matches[0][1])
if err != nil {
return false, err
}
minorVersion, err := strconv.Atoi(matches[0][2])
if err != nil {
return false, err
}
return majorVersion == major && minorVersion == minor, nil
}
func isSafari(useragent string) (bool, error) {
regex := "Version\\/.* Safari\\/"
r, err := regexp.Compile(regex)
if err != nil {
return false, nil
}
isChromiumBased, err := isChromiumBased(useragent)
if err != nil {
return false, err
}
return r.MatchString(useragent) && !isChromiumBased, nil
}
func isMacEmbeddedBrowser(useragent string) (bool, error) {
regex := "^Mozilla\\/[\\.\\d]+ \\(Macintosh;.*Mac OS X [_\\d]+\\)" + "AppleWebKit\\/[\\.\\d]+ \\(KHTML, like Gecko\\)$"
r, err := regexp.Compile(regex)
if err != nil {
return false, err
}
return r.MatchString(useragent), nil
}
func isChromiumBased(useragent string) (bool, error) {
regex := "Chrom(e|ium)"
r, err := regexp.Compile(regex)
if err != nil {
return false, err
}
return r.MatchString(useragent), nil
}
func isChromiumVersionAtLeast(major int, useragent string) (bool, error) {
regex := "Chrom[^ \\/]+\\/(\\d+)[\\.\\d]* "
r, err := regexp.Compile(regex)
if err != nil {
return false, err
}
// Extract digits from first capturing group.
matches := r.FindAllStringSubmatch(useragent, -1)
if matches == nil {
return false, nil
}
majorVersion, err := strconv.Atoi(matches[0][1])
return majorVersion >= major, err
}
func isUcBrowser(useragent string) (bool, error) {
regex := "UCBrowser\\/"
r, err := regexp.Compile(regex)
if err != nil {
return false, err
}
return r.MatchString(useragent), nil
}
func isUcBrowserVersionAtLeast(major int, minor int, build int, useragent string) (bool, error) {
regex := "UCBrowser\\/(\\d+)\\.(\\d+)\\.(\\d+)[\\.\\d]* "
r, err := regexp.Compile(regex)
if err != nil {
return false, err
}
matches := r.FindAllStringSubmatch(useragent, -1)
if matches == nil {
return false, nil
}
majorVersion, err := strconv.Atoi(matches[0][1])
if err != nil {
return false, err
}
minorVersion, err := strconv.Atoi(matches[0][2])
if err != nil {
return false, err
}
buildVersion, err := strconv.Atoi(matches[0][3])
if err != nil {
return false, err
}
// Extract digits from three capturing groups.
if majorVersion != major {
return majorVersion > major, nil
}
if minorVersion != minor {
return minorVersion > minor, nil
}
return buildVersion >= build, nil
}
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