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kern: capture https plaintext failed with boringssl TLS 1.3 on android #271 #279

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merged 13 commits into from
Dec 10, 2022
Merged

kern: capture https plaintext failed with boringssl TLS 1.3 on android #271 #279

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59a76e0
fixes bug.
cfc4n Dec 1, 2022
4c83624
update boringssl offset calculate code.
cfc4n Dec 2, 2022
5a89d85
add tls log lable.
cfc4n Dec 3, 2022
ccfd467
add boringssl tls event struct.
cfc4n Dec 3, 2022
f203681
add new masterSecretEvent struct for BoringSSL
cfc4n Dec 5, 2022
8160351
kern : update boringssl offset calculation
cfc4n Dec 6, 2022
6696db3
update git repo exist check condition.
cfc4n Dec 8, 2022
fb85106
update boringssl offset for android boringssl, different from https:/…
cfc4n Dec 8, 2022
bf139ee
make format
cfc4n Dec 9, 2022
1252dff
remove libPthread shared-object lib.
cfc4n Dec 10, 2022
f59bdb0
sort include files.
cfc4n Dec 10, 2022
5946126
add deps directory.
cfc4n Dec 10, 2022
5a2ad8b
support boringssl event on TC model.
cfc4n Dec 10, 2022
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kern : update boringssl offset calculation 
add boringssl offset gen script.

Signed-off-by: CFC4N <cfc4n.cs@gmail.com>
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@cfc4n
cfc4n committed Dec 6, 2022
commit 81603519023152e0ca22d1cc4e6ef326f538744a
45 changes: 1 addition & 44 deletions kern/boringssl_1_1_1_kern.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,6 @@
/* OPENSSL_VERSION_TEXT: OpenSSL 1.1.1 (compatible; BoringSSL), OPENSSL_VERSION_NUMBER:0x1010107f */

//------------------------------------------
// android boringssl 版本
// ssl->version 在 ssl_st 结构体中的偏移量
#define SSL_ST_VERSION 0x10

Expand Down Expand Up @@ -44,50 +43,8 @@
// bssl::SSL_HANDSHAKE->max_version
#define BSSL__SSL_HANDSHAKE_MAX_VERSION 0x1e

// s3->established_session 在 SSL_HANDSHAKE 中的偏移量
#define SSL_ESTABLISHED_SESSION_OFFSET 456

// hs->new_session 在 SSL_HANDSHAKE 中的偏移量
#define SSL_HS_NEW_SESSION_OFFSET 656

// hs->early_session 在 SSL_HANDSHAKE 中的偏移量
#define SSL_HS_EARLY_SESSION_OFFSET 664

// s3->client_random 在 ssl3_state_st 中的偏移量
#define SSL_S3_CLIENT_RANDOM_OFFSET 48



/////////////////////////////////////////// DON'T REMOVE THIS CODE BLOCK. //////////////////////////////////////////

// SSL_MAX_MD_SIZE is size of the largest hash function used in TLS, SHA-384.
#define SSL_MAX_MD_SIZE 48

// memory layout, see README.md for more detail.
// ssl_st->s3->hs
// bssl::SSL_HANDSHAKE->secret_
#define SSL_HANDSHAKE_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*0

// bssl::SSL_HANDSHAKE->early_traffic_secret_
#define SSL_HANDSHAKE_EARLY_TRAFFIC_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*1

// bssl::SSL_HANDSHAKE->client_handshake_secret_
#define SSL_HANDSHAKE_CLIENT_HANDSHAKE_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*2

// bssl::SSL_HANDSHAKE->server_handshake_secret_
#define SSL_HANDSHAKE_SERVER_HANDSHAKE_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*3

// bssl::SSL_HANDSHAKE->client_traffic_secret_0_
#define SSL_HANDSHAKE_CLIENT_TRAFFIC_SECRET_0_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*4

// bssl::SSL_HANDSHAKE->server_traffic_secret_0_
#define SSL_HANDSHAKE_SERVER_TRAFFIC_SECRET_0_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*5

// bssl::SSL_HANDSHAKE->expected_client_finished_
#define SSL_HANDSHAKE_EXPECTED_CLIENT_FINISHED_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*6
/////////////////////////// END ///////////////////////////

#endif

#include "boringssl_const.h"
#include "openssl.h"
#include "boringssl_masterkey.h"
36 changes: 36 additions & 0 deletions kern/boringssl_const.h
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@@ -0,0 +1,36 @@
#ifndef ECAPTURE_BORINGSSL_CONST_H
#define ECAPTURE_BORINGSSL_CONST_H

/////////////////////////////////////////// DON'T REMOVE THIS CODE BLOCK. //////////////////////////////////////////

// memory layout from boringssl repo ssl/internal.h line 1720
// struct of struct SSL_HANDSHAKE

// SSL_MAX_MD_SIZE is size of the largest hash function used in TLS, SHA-384.
#define SSL_MAX_MD_SIZE 48

// ssl_st->s3->hs
// bssl::SSL_HANDSHAKE->secret_
#define SSL_HANDSHAKE_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*0

// bssl::SSL_HANDSHAKE->early_traffic_secret_
#define SSL_HANDSHAKE_EARLY_TRAFFIC_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*1

// bssl::SSL_HANDSHAKE->client_handshake_secret_
#define SSL_HANDSHAKE_CLIENT_HANDSHAKE_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*2

// bssl::SSL_HANDSHAKE->server_handshake_secret_
#define SSL_HANDSHAKE_SERVER_HANDSHAKE_SECRET_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*3

// bssl::SSL_HANDSHAKE->client_traffic_secret_0_
#define SSL_HANDSHAKE_CLIENT_TRAFFIC_SECRET_0_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*4

// bssl::SSL_HANDSHAKE->server_traffic_secret_0_
#define SSL_HANDSHAKE_SERVER_TRAFFIC_SECRET_0_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*5

// bssl::SSL_HANDSHAKE->expected_client_finished_
#define SSL_HANDSHAKE_EXPECTED_CLIENT_FINISHED_ BSSL__SSL_HANDSHAKE_MAX_VERSION+8+SSL_MAX_MD_SIZE*6

/////////////////////////// END ///////////////////////////

#endif
160 changes: 48 additions & 112 deletions kern/boringssl_masterkey.h
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Original file line number Diff line number Diff line change
Expand Up @@ -15,14 +15,14 @@
#include "ecapture.h"

// https://wiki.openssl.org/index.php/TLS1.3
// 仅openssl 1.1.1 后才支持 TLS 1.3 协议
// 仅openssl/boringssl 1.1.1 后才支持 TLS 1.3 协议

// openssl 1.1.1.X 版本相关的常量
// boringssl 1.1.1 版本相关的常量
#define SSL3_RANDOM_SIZE 32
#define MASTER_SECRET_MAX_LEN 48
#define EVP_MAX_MD_SIZE 64

struct mastersecret_t {
struct mastersecret_bssl_t {
// TLS 1.2 or older
s32 version;
u8 client_random[SSL3_RANDOM_SIZE];
Expand Down Expand Up @@ -67,22 +67,22 @@ struct {
struct {
__uint(type, BPF_MAP_TYPE_LRU_HASH);
__type(key, u64);
__type(value, struct mastersecret_t);
__type(value, struct mastersecret_bssl_t);
__uint(max_entries, 2048);
} bpf_context SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, struct mastersecret_t);
__type(value, struct mastersecret_bssl_t);
__uint(max_entries, 1);
} bpf_context_gen SEC(".maps");

/////////////////////////COMMON FUNCTIONS ////////////////////////////////
//这个函数用来规避512字节栈空间限制，通过在堆上创建内存的方式，避开限制
static __always_inline struct mastersecret_t *make_event() {
static __always_inline struct mastersecret_bssl_t *make_event() {
u32 key_gen = 0;
struct mastersecret_t *bpf_ctx =
struct mastersecret_bssl_t *bpf_ctx =
bpf_map_lookup_elem(&bpf_context_gen, &key_gen);
if (!bpf_ctx) return 0;
u64 id = bpf_get_current_pid_tgid();
Expand All @@ -94,15 +94,7 @@ static __always_inline struct mastersecret_t *make_event() {
// SSL_SESSION *SSL_get_session(const SSL *ssl)
static __always_inline u64 get_session_addr(void *ssl_st_ptr, u64 s3_address) {
u64 tmp_address;
// zero: 优先获取 s3->established_session
u64 *ssl_established_session_ptr =
(u64 *)(s3_address + SSL_ESTABLISHED_SESSION_OFFSET);
int ret = bpf_probe_read_user(&tmp_address, sizeof(tmp_address),
ssl_established_session_ptr);
if (ret == 0 && tmp_address != 0) {
return tmp_address;
}

int ret;
// get hs pointer
u64 *ssl_hs_st_ptr = (u64 *)(s3_address + BSSL__SSL3_STATE_HS);
ret = bpf_probe_read_user(&tmp_address, sizeof(tmp_address), ssl_hs_st_ptr);
Expand All @@ -112,28 +104,16 @@ static __always_inline u64 get_session_addr(void *ssl_st_ptr, u64 s3_address) {
}
debug_bpf_printk("ssl_hs_st_ptr :%llx\n", ssl_hs_st_ptr);

// first: ssl_st->s3->hs->early_session
u64 *ssl_early_session_st_ptr =
(u64 *)(ssl_hs_st_ptr + SSL_HS_EARLY_SESSION_OFFSET);
ret = bpf_probe_read_user(&tmp_address, sizeof(tmp_address),
ssl_early_session_st_ptr);
if (ret == 0 && tmp_address != 0) {
debug_bpf_printk(
"ssl_st->s3->hs->early_session is not null, address :%llx",
tmp_address);
return tmp_address;
}

// second: ssl_st->s3->hs->new_session
u64 *ssl_new_session_st_ptr =
(u64 *)(ssl_hs_st_ptr + SSL_HS_NEW_SESSION_OFFSET);
(u64 *)(ssl_hs_st_ptr + BSSL__SSL_HANDSHAKE_NEW_SESSION);
ret = bpf_probe_read_user(&tmp_address, sizeof(tmp_address),
ssl_new_session_st_ptr);
// if ret !=0 or tmp_address == 0 then we try to get the session from
// ssl_st
if (ret == 0 && tmp_address != 0) {
debug_bpf_printk(
"ssl_st->s3->hs->new_session is not null, address :%llx",
"ssl_st->s3->hs->new_session is not null, address :%llx\n",
tmp_address);
return tmp_address;
}
Expand All @@ -149,7 +129,7 @@ static __always_inline u64 get_session_addr(void *ssl_st_ptr, u64 s3_address) {
ssl_st_ptr, ssl_new_session_st_ptr, ret);
return 0;
}
debug_bpf_printk("ssl_st:%llx, ssl_st->session is not null, address :%llx",
debug_bpf_printk("ssl_st:%llx, ssl_st->session is not null, address :%llx\n",
ssl_st_ptr, tmp_address);
return tmp_address;
}
Expand All @@ -173,8 +153,8 @@ int probe_ssl_master_key(struct pt_regs *ctx) {
#endif
debug_bpf_printk("openssl uprobe/SSL_write masterKey PID :%d\n", pid);

// mastersecret_t sent to userspace
struct mastersecret_t *mastersecret = make_event();
// mastersecret_bssl_t sent to userspace
struct mastersecret_bssl_t *mastersecret = make_event();
// Get a ssl_st pointer
void *ssl_st_ptr = (void *)PT_REGS_PARM1(ctx);
if (!mastersecret) {
Expand Down Expand Up @@ -206,6 +186,8 @@ int probe_ssl_master_key(struct pt_regs *ctx) {
return 0;
}
s3_address = address;
debug_bpf_printk("s3_address :%llx\n",s3_address);

struct ssl3_state_st ssl3_stat;
ret = bpf_probe_read_user(&ssl3_stat, sizeof(ssl3_stat), (void *)address);
if (ret) {
Expand All @@ -225,89 +207,24 @@ int probe_ssl_master_key(struct pt_regs *ctx) {
return 0;
}

// Get ssl_session_st pointer
u64 *ssl_session_st_ptr;
u64 ssl_session_st_addr;
ssl_session_st_addr = get_session_addr(ssl_st_ptr, s3_address);
if (ssl_session_st_addr == 0) {
debug_bpf_printk("ssl_session_st_addr is null\n");
return 0;
}
debug_bpf_printk("ssl_session_st_addr addr :%d",ssl_session_st_addr);
// get s3->hs address first
u64 ssl_hs_st_addr;
u64 *ssl_hs_st_ptr = (u64 *)(s3_address + BSSL__SSL3_STATE_HS);
ret = bpf_probe_read_user(&ssl_hs_st_addr, sizeof(ssl_hs_st_addr), ssl_hs_st_ptr);
if (ret) {
debug_bpf_printk("bpf_probe_read ssl_hs_st_ptr failed, ret :%d\n", ret);
return 0;
}

// TODO
debug_bpf_printk("s3_address:%d, ssl_hs_st_ptr :%llx, ssl_hs_st_addr:%llx\n", s3_address, ssl_hs_st_ptr, ssl_hs_st_addr);

void *hs_ptr_tls13 = (void *)(ssl_hs_st_addr + SSL_HANDSHAKE_CLIENT_HANDSHAKE_SECRET_);
ret = bpf_probe_read_user(&mastersecret->client_handshake_secret_,
sizeof(mastersecret->client_handshake_secret_),
(void *)hs_ptr_tls13);
if (ret) {
debug_bpf_printk(
"bpf_probe_read SSL_HANDSHAKE_CLIENT_HANDSHAKE_SECRET_ failed, ret :%d\n", ret);
return 0;
}

///////////////////////// get TLS cipher info ////////////////////
// Get SSL_SESSION->cipher pointer
u64 *ssl_cipher_st_ptr =
(u64 *)(ssl_session_st_addr + SSL_SESSION_ST_CIPHER);

// get cipher_suite_st pointer
debug_bpf_printk("cipher_suite_st pointer: %x\n", ssl_cipher_st_ptr);
ret = bpf_probe_read_user(&address, sizeof(address), ssl_cipher_st_ptr);
if (ret || address == 0) {
debug_bpf_printk(
"bpf_probe_read ssl_cipher_st_ptr failed, ret :%d, address:%x\n",
ret, address);
// return 0;
void *cipher_id_ptr =
(void *)(address + SSL_CIPHER_ST_ID);
ret =
bpf_probe_read_user(&mastersecret->cipher_id,
sizeof(mastersecret->cipher_id), cipher_id_ptr);
if (ret) {
debug_bpf_printk(
"bpf_probe_read SSL_CIPHER_ST_ID failed from "
"ssl_cipher_st->id, ret :%d\n",
ret);
return 0;
}
} else {
debug_bpf_printk("cipher_suite_st value: %x\n", address);
void *cipher_id_ptr = (void *)(address + SSL_CIPHER_ST_ID);
ret =
bpf_probe_read_user(&mastersecret->cipher_id,
sizeof(mastersecret->cipher_id), cipher_id_ptr);
if (ret) {
debug_bpf_printk(
"bpf_probe_read SSL_CIPHER_ST_ID failed from "
"ssl_cipher_st->id, ret :%d\n",
ret);
return 0;
}
}

debug_bpf_printk("cipher_id: %d\n", mastersecret->cipher_id);


///////////////////////// get TLS 1.2 master secret ////////////////////
if (mastersecret->version != TLS1_3_VERSION) {
void *ms_ptr =
(void *)(ssl_hs_st_addr + SSL_HANDSHAKE_SECRET_);
// Get ssl_session_st pointer
u64 *ssl_session_st_ptr;
u64 ssl_session_st_addr;
ssl_session_st_addr = get_session_addr(ssl_st_ptr, s3_address);
if (ssl_session_st_addr == 0) {
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", s3_address, ssl_session_st_addr);
u64 *ms_ptr =
(u64 *)(ssl_session_st_addr + SSL_SESSION_ST_SECRET);
ret = bpf_probe_read_user(&mastersecret->secret_,
sizeof(mastersecret->secret_), ms_ptr);
if (ret) {
debug_bpf_printk(
"bpf_probe_read MASTER_KEY_OFFSET failed, ms_ptr:%llx, ret "
"bpf_probe_read SSL_SESSION_ST_SECRET failed, ms_ptr:%llx, ret "
":%d\n",
ms_ptr, ret);
return 0;
Expand All @@ -318,11 +235,30 @@ int probe_ssl_master_key(struct pt_regs *ctx) {
mastersecret->secret_[2]);

bpf_perf_event_output(ctx, &mastersecret_events, BPF_F_CURRENT_CPU,
mastersecret, sizeof(struct mastersecret_t));
mastersecret, sizeof(struct mastersecret_bssl_t));
return 0;
}


// get s3->hs address first
u64 ssl_hs_st_addr;
u64 *ssl_hs_st_ptr = (u64 *)(s3_address + BSSL__SSL3_STATE_HS);
ret = bpf_probe_read_user(&ssl_hs_st_addr, sizeof(ssl_hs_st_addr), ssl_hs_st_ptr);
if (ret) {
debug_bpf_printk("bpf_probe_read ssl_hs_st_ptr failed, ret :%d\n", ret);
return 0;
}

void *hs_ptr_tls13 = (void *)(ssl_hs_st_addr + SSL_HANDSHAKE_CLIENT_HANDSHAKE_SECRET_);
ret = bpf_probe_read_user(&mastersecret->client_handshake_secret_,
sizeof(mastersecret->client_handshake_secret_),
(void *)hs_ptr_tls13);
if (ret) {
debug_bpf_printk(
"bpf_probe_read SSL_HANDSHAKE_CLIENT_HANDSHAKE_SECRET_ failed, ret :%d\n", ret);
return 0;
}

//////////////////// TLS 1.3 master secret ////////////////////////

void *hth_ptr_tls13 = (void *)(ssl_hs_st_addr + SSL_HANDSHAKE_SERVER_TRAFFIC_SECRET_0_);
Expand Down Expand Up @@ -372,6 +308,6 @@ int probe_ssl_master_key(struct pt_regs *ctx) {
"*****master_secret*****: %x %x %x\n", mastersecret->secret_[0],
mastersecret->secret_[1], mastersecret->secret_[2]);
bpf_perf_event_output(ctx, &mastersecret_events, BPF_F_CURRENT_CPU,
mastersecret, sizeof(struct mastersecret_t));
mastersecret, sizeof(struct mastersecret_bssl_t));
return 0;
}
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