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kern : get correct master secrets while used TLS 1.3 in android borin…
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…gssl . fixes (#283)

Signed-off-by: CFC4N <cfc4n.cs@gmail.com>
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@cfc4n
cfc4n committed Jan 5, 2023
1 parent cbc300c commit 80f0dbc
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Showing 3 changed files with 54 additions and 42 deletions.
6 changes: 3 additions & 3 deletions kern/boringssl_1_1_1_kern.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,12 +13,12 @@
// ssl_st->s3
#define SSL_ST_S3 0x30

// ssl_session_st->secret
#define SSL_SESSION_ST_SECRET 0x10

// ssl_session_st->secret_length
#define SSL_SESSION_ST_SECRET_LENGTH 0xc

// ssl_session_st->secret
#define SSL_SESSION_ST_SECRET 0x10

// ssl_session_st->cipher
#define SSL_SESSION_ST_CIPHER 0xd0

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20 changes: 12 additions & 8 deletions kern/boringssl_masterkey.h
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Original file line number Diff line number Diff line change
Expand Up @@ -111,10 +111,9 @@ static __always_inline struct mastersecret_bssl_t *make_event() {
return bpf_map_lookup_elem(&bpf_context, &id);
}

// in boringssl, the master secret is stored in src/ssl/ssl_session.cc
// SSL_SESSION *SSL_get_session(const SSL *ssl)
// ssl_handshake_session
static __always_inline u64 get_session_addr(void *ssl_st_ptr, u64 s3_address, u64 *ssl_hs_st_ptr) {
// in boringssl, the master secret is stored in src/ssl/handshake.cc 581
// const SSL_SESSION *ssl_handshake_session(const SSL_HANDSHAKE *hs) {
static __always_inline u64 get_session_addr(void *ssl_st_ptr, u64 s3_address, u64 ssl_hs_st_ptr) {
u64 tmp_address;
int ret;

Expand Down Expand Up @@ -283,17 +282,22 @@ int probe_ssl_master_key(struct pt_regs *ctx) {
ret, ssl_hs_st_addr);
return 0;
}
debug_bpf_printk("SSL_HANDSHAKE_ALLBOOL:%d, ssl_hs_st_ptr:%lx\n", all_bool,
debug_bpf_printk("SSL_HANDSHAKE_ALLBOOL:%d, ssl_hs_st_addr:%lx\n", all_bool,
ssl_hs_st_addr);
// 是否为 state_done

///////////////////////// get TLS 1.2 master secret ////////////////////
if (mastersecret->version != TLS1_3_VERSION) {
// state12_finish_server_handshake
// state12_done
if (ssl3_hs_state.state < 20) {
// not finished yet.
return 0;
}
// Get ssl_session_st pointer
u64 ssl_session_st_addr;
ssl_session_st_addr = get_session_addr(ssl_st_ptr, s3_address, ssl_hs_st_ptr);
ssl_session_st_addr = get_session_addr(ssl_st_ptr, s3_address, ssl_hs_st_addr);
if (ssl_session_st_addr == 0) {
debug_bpf_printk("ssl_session_st_addr is null\n");
// debug_bpf_printk("ssl_session_st_addr is null\n");
return 0;
}
debug_bpf_printk("s3_address:%llx, ssl_session_st_addr addr :%llx\n",
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70 changes: 39 additions & 31 deletions user/module/probe_openssl.go
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Original file line number Diff line number Diff line change
Expand Up @@ -613,29 +613,31 @@ func (this *MOpenSSLProbe) saveMasterSecretBSSL(secretEvent *event.MasterSecretB
var b *bytes.Buffer
switch secretEvent.Version {
case event.TLS1_2_VERSION:
b = bytes.NewBufferString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelTLS12, secretEvent.ClientRandom, secretEvent.Secret))
if this.bSSLEvent12NullSecrets(secretEvent) {
return
}
var length = int(secretEvent.HashLen)
b = bytes.NewBufferString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelTLS12, secretEvent.ClientRandom, secretEvent.Secret[:length]))
this.masterKeys[k] = true
case event.TLS1_3_VERSION:
fallthrough
default:
var length int
length = int(secretEvent.HashLen)
// 判断 密钥是否为空
if this.verifyBSSLEvent(secretEvent) == false {
//this.logger.Printf("secretEvent is null.")
if this.bSSLEvent13NullSecrets(secretEvent) {
return
}
this.masterKeys[k] = true
this.logger.Printf("secretEvent.HashLen:%d, CipherId:%d", secretEvent.HashLen, secretEvent.HashLen)
//this.logger.Printf("secretEvent.HashLen:%d, CipherId:%d", secretEvent.HashLen, secretEvent.HashLen)
b = bytes.NewBufferString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelClientHandshake, secretEvent.ClientRandom, secretEvent.ClientHandshakeSecret[:length]))
b.WriteString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelClientEarlyTafficSecret, secretEvent.ClientRandom, secretEvent.EarlyTrafficSecret[:length]))
//b.WriteString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelClientEarlyTafficSecret, secretEvent.ClientRandom, secretEvent.EarlyTrafficSecret[:length]))
b.WriteString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelClientTraffic, secretEvent.ClientRandom, secretEvent.ClientTrafficSecret0[:length]))
b.WriteString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelServerHandshake, secretEvent.ClientRandom, secretEvent.ServerHandshakeSecret[:length]))
b.WriteString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelServerTraffic, secretEvent.ClientRandom, secretEvent.ServerTrafficSecret0[:length]))
b.WriteString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelExporterSecret, secretEvent.ClientRandom, secretEvent.ExporterSecret[:length]))

//b = bytes.NewBufferString(fmt.Sprintf("%s %02x %02x\n", hkdf.KeyLogLabelTLS12, secretEvent.ClientRandom, secretEvent.Secret))
}

v := event.TlsVersion{Version: secretEvent.Version}
l, e := this.keylogger.WriteString(b.String())
if e != nil {
Expand All @@ -656,47 +658,53 @@ func (this *MOpenSSLProbe) saveMasterSecretBSSL(secretEvent *event.MasterSecretB
this.logger.Printf("%s: save CLIENT_RANDOM %02x to file success, %d bytes", v.String(), secretEvent.ClientRandom, l)
}
}
func (this *MOpenSSLProbe) verifyBSSLEvent(e *event.MasterSecretBSSLEvent) bool {
var isNUllCount = 0

func (this *MOpenSSLProbe) bSSLEvent12NullSecrets(e *event.MasterSecretBSSLEvent) bool {
var isNull = true
var hashLen = int(e.HashLen)
for i := 0; i < hashLen; i++ {
if e.ClientHandshakeSecret[i] != 0 {
isNUllCount += 1
if e.Secret[i] != 0 {
isNull = false
break
}
}
return isNull
}

func (this *MOpenSSLProbe) bSSLEvent13NullSecrets(e *event.MasterSecretBSSLEvent) bool {
var isNUllCount = 5

var hashLen = int(e.HashLen)
var chsChecked, ctsChecked, shsChecked, stsChecked, esChecked bool
for i := 0; i < hashLen; i++ {
if e.ClientTrafficSecret0[i] != 0 {
isNUllCount += 1
break
if !chsChecked && e.ClientHandshakeSecret[i] != 0 {
isNUllCount -= 1
chsChecked = true
}
}

for i := 0; i < hashLen; i++ {
if e.ServerHandshakeSecret[i] != 0 {
isNUllCount += 1
break
if !ctsChecked && e.ClientTrafficSecret0[i] != 0 {
isNUllCount -= 1
ctsChecked = true
}
}

for i := 0; i < hashLen; i++ {
if e.ServerTrafficSecret0[i] != 0 {
isNUllCount += 1
break
if !shsChecked && e.ServerHandshakeSecret[i] != 0 {
isNUllCount -= 1
shsChecked = true
}
}

for i := 0; i < hashLen; i++ {
if e.ExporterSecret[i] != 0 {
isNUllCount += 1
break
if !stsChecked && e.ServerTrafficSecret0[i] != 0 {
isNUllCount -= 1
stsChecked = true
}
}

return isNUllCount == 5
if !esChecked && e.ExporterSecret[i] != 0 {
isNUllCount -= 1
esChecked = true
}
}
return isNUllCount != 0
}

func (this *MOpenSSLProbe) Dispatcher(eventStruct event.IEventStruct) {
// detect eventStruct type
switch eventStruct.(type) {
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