1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <limits.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/sendfile.h>
#include <sys/capability.h>
static int get_self_filepath(char *buffer, size_t size) {
ssize_t bytes_written = readlink("/proc/self/exe", buffer, size - 1);
if(bytes_written == -1)
return 0;
buffer[bytes_written] = '\0';
return 1;
}
static int file_has_sys_admin_capability(const char *filepath) {
cap_t cap = cap_get_file(filepath);
if(!cap)
return 0;
cap_flag_value_t res = CAP_CLEAR;
cap_get_flag(cap, CAP_SYS_ADMIN, CAP_PERMITTED, &res);
int cap_set = res == CAP_SET;
cap_free(cap);
return cap_set;
}
static int file_set_sys_admin_capability(const char *filepath, int setfcap) {
cap_t cap = cap_get_file(filepath);
if(!cap && errno != ENODATA)
return 0;
if(!cap) {
cap = cap_init();
if(!cap)
return 0;
}
const cap_value_t cap_to_set[] = { CAP_SYS_ADMIN, CAP_SETFCAP };
int num_caps = 1;
if(setfcap)
num_caps = 2;
int res = 0;
res |= cap_set_flag(cap, CAP_EFFECTIVE, num_caps, cap_to_set, CAP_SET);
res |= cap_set_flag(cap, CAP_PERMITTED, num_caps, cap_to_set, CAP_SET);
/*cap_set_flag(cap, CAP_INHERITABLE, num_caps, cap_to_set, CAP_SET);*/
res |= cap_set_file(filepath, cap);
cap_free(cap);
return res == 0;
}
static int create_local_kms_server_proxy_directory(const char *home) {
char path[PATH_MAX];
int err;
const char *paths[] = { ".local", ".local/share", ".local/share/gpu-screen-recorder", NULL };
for(size_t i = 0; paths[i]; ++i) {
const char *path_part = paths[i];
snprintf(path, sizeof(path), "%s/%s", home, path_part);
err = mkdir(path, S_IRWXU);
if(err == -1 && errno != EEXIST)
return 0;
}
return 1;
}
static int create_local_kms_server_proxy_file(const char *source_path, const char *dest_path) {
int in_fd = -1;
int out_fd = -1;
int res = 0;
in_fd = open(source_path, O_RDONLY);
if(in_fd == -1)
goto done;
struct stat st;
if(fstat(in_fd, &st) == -1)
goto done;
out_fd = open(dest_path, O_RDWR | O_CREAT | O_TRUNC, 0755);
if(out_fd == -1)
goto done;
if(sendfile(out_fd, in_fd, NULL, st.st_size) != st.st_size)
goto done;
res = 1;
done:
if(in_fd)
close(in_fd);
if(out_fd)
close(out_fd);
if(res)
res = file_set_sys_admin_capability(dest_path, 1);
return res;
}
int main(int argc, char **argv) {
if(argc != 4)
return 1;
const char *gsr_kms_server_filepath = "/var/lib/flatpak/app/com.dec05eba.gpu_screen_recorder/current/active/files/bin/gsr-kms-server";
const char *initial_socket_path = argv[1];
const char *card_path = argv[2];
const char *user_homepath = argv[3];
char self_path[PATH_MAX];
if(!get_self_filepath(self_path, sizeof(self_path)))
return 1;
char kms_server_proxy_local_filepath[PATH_MAX];
snprintf(kms_server_proxy_local_filepath, sizeof(kms_server_proxy_local_filepath), "%s/.local/share/gpu-screen-recorder/kms-server-proxy", user_homepath);
if(file_has_sys_admin_capability(gsr_kms_server_filepath)) {
const char *args[] = { gsr_kms_server_filepath, initial_socket_path, card_path, NULL };
return execv(args[0], (char *const*)args);
} else if(file_has_sys_admin_capability(kms_server_proxy_local_filepath)) {
if(strcmp(self_path, kms_server_proxy_local_filepath) != 0) {
const char *args[] = { kms_server_proxy_local_filepath, initial_socket_path, card_path, user_homepath, NULL };
return execv(args[0], (char *const*)args);
}
/* TODO: Remove the need for this. Instead inherit capabilities */
if(file_set_sys_admin_capability(gsr_kms_server_filepath, 0)) {
const char *args[] = { gsr_kms_server_filepath, initial_socket_path, card_path, NULL };
return execv(args[0], (char *const*)args);
}
const char *args[] = { "pkexec", gsr_kms_server_filepath, initial_socket_path, card_path, NULL };
return execvp(args[0], (char *const*)args);
} else if(geteuid() == 0) { /* is current user root */
file_set_sys_admin_capability(gsr_kms_server_filepath, 0);
create_local_kms_server_proxy_file(self_path, kms_server_proxy_local_filepath);
const char *args[] = { gsr_kms_server_filepath, initial_socket_path, card_path, NULL };
return execv(args[0], (char *const*)args);
} else {
create_local_kms_server_proxy_directory(user_homepath);
const char *args[] = { "pkexec", self_path, initial_socket_path, card_path, user_homepath, NULL };
return execvp(args[0], (char *const*)args);
}
}
|
