{"record":{"id":"066acfa9a2ddc074","repo":"router-for-me/CLIProxyAPI","slug":"failed-to-generate-random-bytes-w","errorCode":null,"errorMessage":"failed to generate random bytes: %w","messagePattern":"failed to generate random bytes: %w","errorType":"console","errorClass":null,"httpStatus":null,"severity":"critical","filePath":"internal/auth/claude/pkce.go","lineNumber":44,"sourceCode":"\t}\n\n\t// Generate code challenge using S256 method\n\tcodeChallenge := generateCodeChallenge(codeVerifier)\n\n\treturn &PKCECodes{\n\t\tCodeVerifier:  codeVerifier,\n\t\tCodeChallenge: codeChallenge,\n\t}, nil\n}\n\n// generateCodeVerifier creates a cryptographically random string\n// of 128 characters using URL-safe base64 encoding\nfunc generateCodeVerifier() (string, error) {\n\t// Generate 96 random bytes (will result in 128 base64 characters)\n\tbytes := make([]byte, 96)\n\t_, err := rand.Read(bytes)\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"failed to generate random bytes: %w\", err)\n\t}\n\n\t// Encode to URL-safe base64 without padding\n\treturn base64.URLEncoding.WithPadding(base64.NoPadding).EncodeToString(bytes), nil\n}\n\n// generateCodeChallenge creates a SHA256 hash of the code verifier\n// and encodes it using URL-safe base64 encoding without padding\nfunc generateCodeChallenge(codeVerifier string) string {\n\thash := sha256.Sum256([]byte(codeVerifier))\n\treturn base64.URLEncoding.WithPadding(base64.NoPadding).EncodeToString(hash[:])\n}\n","sourceCodeStart":26,"sourceCodeEnd":57,"githubUrl":"https://github.com/router-for-me/CLIProxyAPI/blob/78f0c4079e3e6273d65d03b5549cffc898703264/internal/auth/claude/pkce.go#L26-L57","documentation":"The root cause behind error 188: crypto/rand.Read failed while generating the 96-byte PKCE verifier. Go's crypto/rand only errors when the OS entropy source is genuinely unavailable; on healthy Linux/macOS/Windows systems this effectively never happens. Treat it as an environment problem, not a code problem.","triggerScenarios":"rand.Read(bytes) returning an error inside generateCodeVerifier during any Claude OAuth login attempt; observed on early-boot systems where getrandom(2) blocks, or in sandboxed runtimes that do not implement the entropy syscalls.","commonSituations":"Containers started within seconds of host boot; embedded/minimal VMs; CI runners on exotic hypervisors with poor entropy passthrough; never on typical dev machines.","solutions":["Confirm host entropy is available: `cat /proc/sys/kernel/random/entropy_avail` and retry after boot settles.","Move the workload to a standard kernel/runtime with working getrandom(2).","If a startup script triggers login immediately at boot, delay it until the system is seeded."],"exampleFix":null,"handlingStrategy":"retry","validationCode":"b := make([]byte, 16)\nif _, err := rand.Read(b); err != nil {\n    return errors.New(\"entropy source unavailable; boot the host fully before OAuth flows\")\n}","typeGuard":null,"tryCatchPattern":"if _, err := rand.Read(buf); err != nil {\n    time.Sleep(2 * time.Second) // early-boot CRNG can block briefly\n    if _, err = rand.Read(buf); err != nil {\n        return fmt.Errorf(\"CSPRGM unavailable: %w\", err)\n    }\n}","preventionTips":["On fresh VMs/containers, wait for /proc/sys/kernel/random/entropy_avail to report seeded state before automating login.","Keep PKCE generation on crypto/rand only; do not swap in math/rand."],"tags":["claude","pkce","crypto","environment","entropy"],"backgroundTag":null,"analyzedSha":"78f0c4079e3e6273d65d03b5549cffc898703264","analyzedAt":"2026-08-15T12:26:37.444Z","schemaVersion":2},"datasetVersion":"2026-08-15T17:31:12.345Z"}