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Handle base64 decoding correctly to avoid panic (#26483)

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Fix the panic if the "base64 secret" is too long.
This commit is contained in:
wxiaoguang 2023-08-14 18:30:16 +08:00 • committed by GitHub
parent cafce3b4b5
commit ed1be4ca68
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GPG key ID: 4AEE18F83AFDEB23
8 changed files with 43 additions and 30 deletions
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4
cmd/generate.go
View file

@ -70,12 +70,12 @@ func runGenerateInternalToken(c *cli.Context) error {
}
func runGenerateLfsJwtSecret(c *cli.Context) error {
JWTSecretBase64, err := generate.NewJwtSecretBase64()
_, jwtSecretBase64, err := generate.NewJwtSecretBase64()
if err != nil {
return err
}
fmt.Printf("%s", JWTSecretBase64)
fmt.Printf("%s", jwtSecretBase64)
if isatty.IsTerminal(os.Stdout.Fd()) {
fmt.Printf("\n")

6
modules/generate/generate.go
View file

@ -49,12 +49,12 @@ func NewJwtSecret() ([]byte, error) {
}
// NewJwtSecretBase64 generates a new base64 encoded value intended to be used for JWT secrets.
func NewJwtSecretBase64() (string, error) {
func NewJwtSecretBase64() ([]byte, string, error) {
bytes, err := NewJwtSecret()
if err != nil {
return "", err
return nil, "", err
}
return base64.RawURLEncoding.EncodeToString(bytes), nil
return bytes, base64.RawURLEncoding.EncodeToString(bytes), nil
}
// NewSecretKey generate a new value intended to be used by SECRET_KEY.

12
modules/setting/lfs.go
View file

@ -9,6 +9,7 @@ import (
"time"
"code.gitea.io/gitea/modules/generate"
"code.gitea.io/gitea/modules/util"
)
// LFS represents the configuration for Git LFS
@ -56,17 +57,14 @@ func loadLFSFrom(rootCfg ConfigProvider) error {
LFS.HTTPAuthExpiry = sec.Key("LFS_HTTP_AUTH_EXPIRY").MustDuration(24 * time.Hour)
if !LFS.StartServer {
if !LFS.StartServer || !InstallLock {
return nil
}
LFS.JWTSecretBase64 = loadSecret(rootCfg.Section("server"), "LFS_JWT_SECRET_URI", "LFS_JWT_SECRET")
LFS.JWTSecretBytes = make([]byte, 32)
n, err := base64.RawURLEncoding.Decode(LFS.JWTSecretBytes, []byte(LFS.JWTSecretBase64))
if (err != nil || n != 32) && InstallLock {
LFS.JWTSecretBase64, err = generate.NewJwtSecretBase64()
LFS.JWTSecretBytes, err = util.Base64FixedDecode(base64.RawURLEncoding, []byte(LFS.JWTSecretBase64), 32)
if err != nil {
LFS.JWTSecretBytes, LFS.JWTSecretBase64, err = generate.NewJwtSecretBase64()
if err != nil {
return fmt.Errorf("error generating JWT Secret for custom config: %v", err)
}

13
modules/setting/oauth2.go
View file

@ -10,6 +10,7 @@ import (
"code.gitea.io/gitea/modules/generate"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/util"
)
// OAuth2UsernameType is enum describing the way gitea 'name' should be generated from oauth2 data
@ -129,21 +130,19 @@ func loadOAuth2From(rootCfg ConfigProvider) {
}
if InstallLock {
key := make([]byte, 32)
n, err := base64.RawURLEncoding.Decode(key, []byte(OAuth2.JWTSecretBase64))
if err != nil || n != 32 {
key, err = generate.NewJwtSecret()
if _, err := util.Base64FixedDecode(base64.RawURLEncoding, []byte(OAuth2.JWTSecretBase64), 32); err != nil {
key, err := generate.NewJwtSecret()
if err != nil {
log.Fatal("error generating JWT secret: %v", err)
}
secretBase64 := base64.RawURLEncoding.EncodeToString(key)
OAuth2.JWTSecretBase64 = base64.RawURLEncoding.EncodeToString(key)
saveCfg, err := rootCfg.PrepareSaving()
if err != nil {
log.Fatal("save oauth2.JWT_SECRET failed: %v", err)
}
rootCfg.Section("oauth2").Key("JWT_SECRET").SetValue(secretBase64)
saveCfg.Section("oauth2").Key("JWT_SECRET").SetValue(secretBase64)
rootCfg.Section("oauth2").Key("JWT_SECRET").SetValue(OAuth2.JWTSecretBase64)
saveCfg.Section("oauth2").Key("JWT_SECRET").SetValue(OAuth2.JWTSecretBase64)
if err := saveCfg.Save(); err != nil {
log.Fatal("save oauth2.JWT_SECRET failed: %v", err)
}

11
modules/util/util.go
View file

@ -6,6 +6,7 @@ package util
import (
"bytes"
"crypto/rand"
"encoding/base64"
"fmt"
"math/big"
"strconv"
@ -261,3 +262,13 @@ func ToFloat64(number any) (float64, error) {
func ToPointer[T any](val T) *T {
return &val
}
func Base64FixedDecode(encoding *base64.Encoding, src []byte, length int) ([]byte, error) {
decoded := make([]byte, encoding.DecodedLen(len(src))+3)
if n, err := encoding.Decode(decoded, src); err != nil {
return nil, err
} else if n != length {
return nil, fmt.Errorf("invalid base64 decoded length: %d, expects: %d", n, length)
}
return decoded[:length], nil
}

14
modules/util/util_test.go
View file

@ -4,6 +4,7 @@
package util
import (
"encoding/base64"
"regexp"
"strings"
"testing"
@ -233,3 +234,16 @@ func TestToPointer(t *testing.T) {
val123 := 123
assert.False(t, &val123 == ToPointer(val123))
}
func TestBase64FixedDecode(t *testing.T) {
_, err := Base64FixedDecode(base64.RawURLEncoding, []byte("abcd"), 32)
assert.ErrorContains(t, err, "invalid base64 decoded length")
_, err = Base64FixedDecode(base64.RawURLEncoding, []byte(strings.Repeat("a", 64)), 32)
assert.ErrorContains(t, err, "invalid base64 decoded length")
str32 := strings.Repeat("x", 32)
encoded32 := base64.RawURLEncoding.EncodeToString([]byte(str32))
decoded32, err := Base64FixedDecode(base64.RawURLEncoding, []byte(encoded32), 32)
assert.NoError(t, err)
assert.Equal(t, str32, string(decoded32))
}

2
routers/install/install.go
View file

@ -415,7 +415,7 @@ func SubmitInstall(ctx *context.Context) {
cfg.Section("server").Key("LFS_START_SERVER").SetValue("true")
cfg.Section("lfs").Key("PATH").SetValue(form.LFSRootPath)
var lfsJwtSecret string
if lfsJwtSecret, err = generate.NewJwtSecretBase64(); err != nil {
if _, lfsJwtSecret, err = generate.NewJwtSecretBase64(); err != nil {
ctx.RenderWithErr(ctx.Tr("install.lfs_jwt_secret_failed", err), tplInstall, &form)
return
}

11
services/auth/source/oauth2/jwtsigningkey.go
View file

@ -336,16 +336,7 @@ func InitSigningKey() error {
// loadSymmetricKey checks if the configured secret is valid.
// If it is not valid, it will return an error.
func loadSymmetricKey() (any, error) {
key := make([]byte, 32)
n, err := base64.RawURLEncoding.Decode(key, []byte(setting.OAuth2.JWTSecretBase64))
if err != nil {
return nil, err
}
if n != 32 {
return nil, fmt.Errorf("JWT secret must be 32 bytes long")
}
return key, nil
return util.Base64FixedDecode(base64.RawURLEncoding, []byte(setting.OAuth2.JWTSecretBase64), 32)
}
// loadOrCreateAsymmetricKey checks if the configured private key exists.