Skip to content

Global HTTP headers' masquerading: Add "curl"; Improve version generators #5916

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
RPRX merged 5 commits into from
Apr 11, 2026
+82 −20
Merged

Global HTTP headers' masquerading: Add "curl"; Improve version generators #5916

Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
fc4f40d
Version generators for cURL, Firefox & Safari.
PoneyClairDeLune Apr 11, 2026
d3a5fff
Scaled Chrome versions with curve.
PoneyClairDeLune Apr 11, 2026
c78de87
30 days to 31.15 (32) days for Chrome releases.
PoneyClairDeLune Apr 11, 2026
5e81569
35 for Chrome, 30 for Firefox.
PoneyClairDeLune Apr 11, 2026
48ed96c
Fixed a calendar bug in the Safari generator.
PoneyClairDeLune Apr 11, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
102 changes: 82 additions & 20 deletions common/utils/browser.go
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
package utils

import (
"hash/fnv"
"math"
"math/rand"
"strconv"
"time"
Expand All @@ -10,20 +12,57 @@ import (
"github.com/klauspost/cpuid/v2"
)

func GetRandomizer() *rand.Rand {
// Seed the PRNG with the hash of CPU info, increasing the overall probable space.
fnvHash := fnv.New64()
fnvHash.Write([]byte(strconv.Itoa(cpuid.CPU.Family) + strconv.Itoa(cpuid.CPU.Model) + strconv.Itoa(cpuid.CPU.PhysicalCores) + strconv.Itoa(cpuid.CPU.LogicalCores) + strconv.Itoa(cpuid.CPU.CacheLine) + strconv.Itoa(cpuid.CPU.ThreadsPerCore)))
return rand.New(rand.NewSource(int64(fnvHash.Sum64())))
}
var globalRng *rand.Rand = GetRandomizer()

// The Chrome version generator will suffer from deviation of a normal distribution.
func ChromeVersion() int {
// Use only CPU info as seed for PRNG
seed := int64(cpuid.CPU.Family + cpuid.CPU.Model + cpuid.CPU.PhysicalCores + cpuid.CPU.LogicalCores + cpuid.CPU.CacheLine)
rng := rand.New(rand.NewSource(seed))
// Start from Chrome 144 released on 2026.1.13
releaseDate := time.Date(2026, 1, 13, 0, 0, 0, 0, time.UTC)
version := 144
now := time.Now()
// Each version has random 25-45 day interval
for releaseDate.Before(now) {
releaseDate = releaseDate.AddDate(0, 0, rng.Intn(21)+25)
version++
// Start from Chrome 144, released on 2026.1.13.
var startVersion int = 144
var timeStart int64 = time.Date(2026, 1, 13, 0, 0, 0, 0, time.UTC).Unix() / 86400
var timeCurrent int64 = time.Now().Unix() / 86400
var timeDiff int = int((timeCurrent - timeStart - 35)) - int(math.Floor(math.Pow(globalRng.Float64(), 2) * 105))
return startVersion + (timeDiff / 35) // It's 31.15 currently.
}

var safariMinorMap [25]int = [25]int{0, 0, 0, 1, 1,
1, 2, 2, 2, 2, 3, 3, 3, 4, 4,
4, 5, 5, 5, 5, 5, 6, 6, 6, 6}

// The following version generators use deterministic generators, but with the distribution scaled by a curve.
func CurlVersion() string {
// curl 8.0.0 was released on 20/03/2023.
var timeCurrent int64 = time.Now().Unix() / 86400
var timeStart int64 = time.Date(2023, 3, 20, 0, 0, 0, 0, time.UTC).Unix() / 86400
var timeDiff int = int((timeCurrent - timeStart - 60)) - int(math.Floor(math.Pow(globalRng.Float64(), 2) * 165))
var minorValue int = int(timeDiff / 57) // The release cadence is actually 56.67 days.
return "8." + strconv.Itoa(minorValue) + ".0"
}
func FirefoxVersion() int {
// Firefox 128 ESR was released on 09/07/2023.
var timeCurrent int64 = time.Now().Unix() / 86400
var timeStart int64 = time.Date(2024, 7, 29, 0, 0, 0, 0, time.UTC).Unix() / 86400
var timeDiff = timeCurrent - timeStart - 25 - int64(math.Floor(math.Pow(globalRng.Float64(), 2) * 50))
return int(timeDiff / 30) + 128
}
func SafariVersion() string {
var anchoredTime time.Time = time.Now()
var releaseYear int = anchoredTime.Year()
var splitPoint time.Time = time.Date(releaseYear, 9, 23, 0, 0, 0, 0, time.UTC)
var delayedDays = int(math.Floor(math.Pow(globalRng.Float64(), 3) * 75))
splitPoint = splitPoint.AddDate(0, 0, delayedDays)
if (anchoredTime.Compare(splitPoint) < 0) {
releaseYear --
splitPoint = time.Date(releaseYear, 9, 23, 0, 0, 0, 0, time.UTC)
splitPoint = splitPoint.AddDate(0, 0, delayedDays)
}
return version - 1
var minorVersion = safariMinorMap[(anchoredTime.Unix() - splitPoint.Unix()) / 1296000]
return strconv.Itoa(releaseYear - 1999) + "." + strconv.Itoa(minorVersion)
}

// The full Chromium brand GREASE implementation
Expand All @@ -49,7 +88,7 @@ func getGreasedChOrder(brandLength int, seed int) []int {
default:
return clientHintShuffle4[seed % len(clientHintShuffle4)][:]
}
return []int{}
//return []int{}
}
func getUngreasedChUa(majorVersion int, forkName string) []string {
// Set the capacity to 4, the maximum allowed brand size, so Go will never allocate memory twice
Expand All @@ -74,11 +113,12 @@ func getGreasedChUa(majorVersion int, forkName string) string {
return strings.Join(shuffledCh, ", ")
}

// It's better to pin on Firefox ESR releases, and there could be a Firefox ESR version generator later.
// However, if the Firefox fingerprint in uTLS doesn't have its update cadence match that of Firefox ESR, then it's better to update the Firefox version manually instead every time a new major ESR release is available.
var FirefoxUA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:140.0) Gecko/20100101 Firefox/140.0"

// The code below provides a coherent default browser user agent string based on a CPU-seeded PRNG.
var CurlUA = "curl/" + CurlVersion()
var AnchoredFirefoxVersion = strconv.Itoa(FirefoxVersion())
var FirefoxUA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:" + AnchoredFirefoxVersion + ".0) Gecko/20100101 Firefox/" + AnchoredFirefoxVersion + ".0"
var SafariUA = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/" + SafariVersion() + " Safari/605.1.15"
// Chromium browsers.
var AnchoredChromeVersion = ChromeVersion()
var ChromeUA = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/" + strconv.Itoa(AnchoredChromeVersion) + ".0.0.0 Safari/537.36"
var ChromeUACH = getGreasedChUa(AnchoredChromeVersion, "chrome")
Expand Down Expand Up @@ -106,10 +146,16 @@ func applyMasqueradedHeaders(header http.Header, browser string, variant string)
header.Set("User-Agent", FirefoxUA)
header["DNT"] = []string{"1"}
header.Set("Accept-Language", "en-US,en;q=0.5")
case "safari":
header.Set("User-Agent", SafariUA)
header.Set("Accept-Language", "en-US,en;q=0.9")
case "golang":
// Expose the default net/http header.
header.Del("User-Agent")
return
case "curl":
header.Set("User-Agent", CurlUA)
return
}
// Context-specific.
switch variant {
Expand All @@ -125,18 +171,28 @@ func applyMasqueradedHeaders(header http.Header, browser string, variant string)
switch browser {
case "chrome", "edge":
header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/jxl,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7")
case "firefox":
case "firefox", "safari":
header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8")
}
}
header.Set("Sec-Fetch-Site", "none")
header.Set("Sec-Fetch-Mode", "navigate")
header.Set("Sec-Fetch-User", "?1")
switch browser {
case "safari":
default:
header.Set("Sec-Fetch-User", "?1")
}
header.Set("Sec-Fetch-Dest", "document")
header.Set("Priority", "u=0, i")
case "ws":
header.Set("Sec-Fetch-Mode", "websocket")
header.Set("Sec-Fetch-Dest", "empty")
switch browser {
case "safari":
// Safari is NOT web-compliant here!
header.Set("Sec-Fetch-Dest", "websocket")
default:
header.Set("Sec-Fetch-Dest", "empty")
}
header.Set("Sec-Fetch-Site", "same-origin")
if header.Get("Cache-Control") == "" {
header.Set("Cache-Control", "no-cache")
Expand All @@ -157,6 +213,8 @@ func applyMasqueradedHeaders(header http.Header, browser string, variant string)
header.Set("Priority", "u=1, i")
case "firefox":
header.Set("Priority", "u=4")
case "safari":
header.Set("Priority", "u=3, i")
}
}
if header.Get("Cache-Control") == "" {
Expand All @@ -182,8 +240,12 @@ func TryDefaultHeadersWith(header http.Header, variant string) {
applyMasqueradedHeaders(header, "chrome", variant)
case "firefox":
applyMasqueradedHeaders(header, "firefox", variant)
case "safari":
applyMasqueradedHeaders(header, "safari", variant)
case "edge":
applyMasqueradedHeaders(header, "edge", variant)
case "curl":
applyMasqueradedHeaders(header, "curl", variant)
case "golang":
applyMasqueradedHeaders(header, "golang", variant)
}
Expand Down