add hook of ssl_ex version (#164)

Co-authored-by: Ivoripuion <Ivoropuion@github.com>

src/30-sslsniff/sslsniff.bpf.c

@@ -16,6 +16,13 @@ struct {
     __uint(value_size, sizeof(__u32));
 } perf_SSL_events SEC(".maps");
 
+struct {
+    __uint(type, BPF_MAP_TYPE_HASH);
+    __uint(max_entries, 10240);
+    __type(key, __u32);
+    __type(value, size_t*);
+} readbytes_ptrs SEC(".maps");
+
 #define BASE_EVENT_SIZE ((size_t)(&((struct probe_SSL_data_t *)0)->buf))
 #define EVENT_SIZE(X) (BASE_EVENT_SIZE + ((size_t)(X)))
 #define MAX_ENTRIES 10240
@@ -153,6 +160,142 @@ int BPF_URETPROBE(probe_SSL_write_exit) {
     return (SSL_exit(ctx, 1));
 }
 
+SEC("uprobe/SSL_write_ex")
+int BPF_UPROBE(probe_SSL_write_ex_enter, void *ssl, void *buf, size_t num, size_t *readbytes) {
+    u64 pid_tgid = bpf_get_current_pid_tgid();
+    u32 pid = pid_tgid >> 32;
+    u32 tid = (u32)pid_tgid;
+    u32 uid = bpf_get_current_uid_gid();
+    u64 ts = bpf_ktime_get_ns();
+
+    if (!trace_allowed(uid, pid)) {
+        return 0;
+    }
+
+    bpf_map_update_elem(&bufs, &tid, &buf, BPF_ANY);
+    bpf_map_update_elem(&start_ns, &tid, &ts, BPF_ANY); 
+    
+    bpf_map_update_elem(&readbytes_ptrs, &tid, &readbytes, BPF_ANY);
+
+    return 0;
+}
+
+SEC("uprobe/SSL_read_ex")
+int BPF_UPROBE(probe_SSL_read_ex_enter, void *ssl, void *buf, size_t num, size_t *readbytes) {
+    u64 pid_tgid = bpf_get_current_pid_tgid();
+    u32 pid = pid_tgid >> 32;
+    u32 tid = (u32)pid_tgid;
+    u32 uid = bpf_get_current_uid_gid();
+    u64 ts = bpf_ktime_get_ns();
+
+    if (!trace_allowed(uid, pid)) {
+        return 0;
+    }
+
+    bpf_map_update_elem(&bufs, &tid, &buf, BPF_ANY);
+    bpf_map_update_elem(&start_ns, &tid, &ts, BPF_ANY); 
+
+    bpf_map_update_elem(&readbytes_ptrs, &tid, &readbytes, BPF_ANY);
+
+    return 0;
+}
+
+static int ex_SSL_exit(struct pt_regs *ctx, int rw, int len) {
+    int ret = 0;
+    u32 zero = 0;
+    u64 pid_tgid = bpf_get_current_pid_tgid();
+    u32 pid = pid_tgid >> 32;
+    u32 tid = (u32)pid_tgid;
+    u32 uid = bpf_get_current_uid_gid();
+    u64 ts = bpf_ktime_get_ns();
+
+    if (!trace_allowed(uid, pid)) {
+        return 0;
+    }
+
+    /* store arg info for later lookup */
+    u64 *bufp = bpf_map_lookup_elem(&bufs, &tid);
+    if (bufp == 0)
+        return 0;
+
+    u64 *tsp = bpf_map_lookup_elem(&start_ns, &tid);
+    if (!tsp)
+        return 0;
+    u64 delta_ns = ts - *tsp;
+
+    if (len <= 0)  // no data
+        return 0;
+
+    struct probe_SSL_data_t *data = bpf_map_lookup_elem(&ssl_data, &zero);
+    if (!data)
+        return 0;
+
+    data->timestamp_ns = ts;
+    data->delta_ns = delta_ns;
+    data->pid = pid;
+    data->tid = tid;
+    data->uid = uid;
+    data->len = (u32)len;
+    data->buf_filled = 0;
+    data->rw = rw;
+    data->is_handshake = false;
+    u32 buf_copy_size = min((size_t)MAX_BUF_SIZE, (size_t)len);
+
+    bpf_get_current_comm(&data->comm, sizeof(data->comm));
+
+    if (bufp != 0)
+        ret = bpf_probe_read_user(&data->buf, buf_copy_size, (char *)*bufp);
+
+    bpf_map_delete_elem(&bufs, &tid);
+    bpf_map_delete_elem(&start_ns, &tid);
+
+    if (!ret)
+        data->buf_filled = 1;
+    else
+        buf_copy_size = 0;
+
+    bpf_perf_event_output(ctx, &perf_SSL_events, BPF_F_CURRENT_CPU, data,
+                            EVENT_SIZE(buf_copy_size));
+    
+    return 0;
+}
+
+SEC("uretprobe/SSL_write_ex")
+int BPF_URETPROBE(probe_SSL_write_ex_exit)
+{
+    u32 tid = (u32)bpf_get_current_pid_tgid();
+    size_t **readbytes_ptr = bpf_map_lookup_elem(&readbytes_ptrs, &tid);
+    if (!readbytes_ptr)
+        return 0;
+
+    size_t written = 0;
+    bpf_probe_read_user(&written, sizeof(written), *readbytes_ptr);
+    bpf_map_delete_elem(&readbytes_ptrs, &tid);
+
+    int ret = PT_REGS_RC(ctx);
+    int len = (ret == 1) ? written : 0;
+
+    return ex_SSL_exit(ctx, 1, len);
+}
+
+SEC("uretprobe/SSL_read_ex")
+int BPF_URETPROBE(probe_SSL_read_ex_exit)
+{
+    u32 tid = (u32)bpf_get_current_pid_tgid();
+    size_t **readbytes_ptr = bpf_map_lookup_elem(&readbytes_ptrs, &tid);
+    if (!readbytes_ptr)
+        return 0;
+
+    size_t written = 0;
+    bpf_probe_read_user(&written, sizeof(written), *readbytes_ptr);
+    bpf_map_delete_elem(&readbytes_ptrs, &tid);
+
+    int ret = PT_REGS_RC(ctx);
+    int len = (ret == 1) ? written : 0;
+
+    return ex_SSL_exit(ctx, 1, len);
+}
+
 SEC("uprobe/do_handshake")
 int BPF_UPROBE(probe_SSL_do_handshake_enter, void *ssl) {
     u64 pid_tgid = bpf_get_current_pid_tgid();
@@ -217,4 +360,4 @@ int BPF_URETPROBE(probe_SSL_do_handshake_exit) {
     return 0;
 }
 
-char LICENSE[] SEC("license") = "GPL";
+char LICENSE[] SEC("license") = "GPL";

src/30-sslsniff/sslsniff.c

@@ -8,9 +8,7 @@
 #include <bpf/libbpf.h>
 #include <ctype.h>
 #include <errno.h>
-#include <linux/types.h>
 #include <signal.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <time.h>
@@ -92,8 +90,8 @@ struct env {
 	.uid = INVALID_UID,
 	.pid = INVALID_PID,
 	.openssl = true,
-	.gnutls = true,
-	.nss = true,
+	.gnutls = false,
+	.nss = false,
 	.comm = NULL,
 };
 
@@ -197,6 +195,11 @@ int attach_openssl(struct sslsniff_bpf *skel, const char *lib) {
 	ATTACH_UPROBE_CHECKED(skel, lib, SSL_read, probe_SSL_rw_enter);
 	ATTACH_URETPROBE_CHECKED(skel, lib, SSL_read, probe_SSL_read_exit);
 
+	ATTACH_UPROBE_CHECKED(skel, lib, SSL_write_ex, probe_SSL_write_ex_enter);
+	ATTACH_URETPROBE_CHECKED(skel, lib, SSL_write_ex, probe_SSL_write_ex_exit);
+	ATTACH_UPROBE_CHECKED(skel, lib, SSL_read_ex, probe_SSL_read_ex_enter);
+	ATTACH_URETPROBE_CHECKED(skel, lib, SSL_read_ex, probe_SSL_read_ex_exit);
+
 	if (env.latency && env.handshake) {
 		ATTACH_UPROBE_CHECKED(skel, lib, SSL_do_handshake,
 							probe_SSL_do_handshake_enter);