diff options
Diffstat (limited to 'src/firejail/no_sandbox.c')
-rw-r--r-- | src/firejail/no_sandbox.c | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/firejail/no_sandbox.c b/src/firejail/no_sandbox.c new file mode 100644 index 000000000..9dc01435f --- /dev/null +++ b/src/firejail/no_sandbox.c | |||
@@ -0,0 +1,119 @@ | |||
1 | #include "firejail.h" | ||
2 | #include <sys/types.h> | ||
3 | #include <sys/stat.h> | ||
4 | #include <unistd.h> | ||
5 | |||
6 | // check process space for kernel processes | ||
7 | // return 1 if found, 0 if not found | ||
8 | int check_kernel_procs(void) { | ||
9 | char *kern_proc[] = { | ||
10 | "kthreadd", | ||
11 | "ksoftirqd", | ||
12 | "kworker", | ||
13 | "rcu_sched", | ||
14 | "rcu_bh", | ||
15 | NULL // NULL terminated list | ||
16 | }; | ||
17 | int i; | ||
18 | |||
19 | // look at the first 10 processes | ||
20 | // if a kernel process is found, return 1 | ||
21 | for (i = 1; i <= 10; i++) { | ||
22 | struct stat s; | ||
23 | char *fname; | ||
24 | if (asprintf(&fname, "/proc/%d/comm", i) == -1) | ||
25 | errExit("asprintf"); | ||
26 | if (stat(fname, &s) == -1) { | ||
27 | free(fname); | ||
28 | continue; | ||
29 | } | ||
30 | |||
31 | // open file | ||
32 | FILE *fp = fopen(fname, "r"); | ||
33 | if (!fp) { | ||
34 | fprintf(stderr, "Warning: cannot open %s\n", fname); | ||
35 | free(fname); | ||
36 | continue; | ||
37 | } | ||
38 | |||
39 | // read file | ||
40 | char buf[100]; | ||
41 | if (fgets(buf, 10, fp) == NULL) { | ||
42 | fprintf(stderr, "Warning: cannot read %s\n", fname); | ||
43 | fclose(fp); | ||
44 | free(fname); | ||
45 | continue; | ||
46 | } | ||
47 | // clean /n | ||
48 | char *ptr; | ||
49 | if ((ptr = strchr(buf, '\n')) != NULL) | ||
50 | *ptr = '\0'; | ||
51 | |||
52 | // check process name against the kernel list | ||
53 | int j = 0; | ||
54 | while (kern_proc[j] != NULL) { | ||
55 | if (strncmp(buf, kern_proc[j], strlen(kern_proc[j])) == 0) { | ||
56 | fclose(fp); | ||
57 | free(fname); | ||
58 | return 1; | ||
59 | } | ||
60 | j++; | ||
61 | } | ||
62 | |||
63 | fclose(fp); | ||
64 | free(fname); | ||
65 | } | ||
66 | |||
67 | return 0; | ||
68 | } | ||
69 | |||
70 | void run_no_sandbox(int argc, char **argv) { | ||
71 | // drop privileges | ||
72 | int rv = setgroups(0, NULL); // this could fail | ||
73 | (void) rv; | ||
74 | if (setgid(getgid()) < 0) | ||
75 | errExit("setgid/getgid"); | ||
76 | if (setuid(getuid()) < 0) | ||
77 | errExit("setuid/getuid"); | ||
78 | |||
79 | |||
80 | // build command | ||
81 | char *command = NULL; | ||
82 | int allocated = 0; | ||
83 | if (argc == 1) | ||
84 | command = "/bin/bash"; | ||
85 | else { | ||
86 | // calculate length | ||
87 | int len = 0; | ||
88 | int i; | ||
89 | for (i = 1; i < argc; i++) { | ||
90 | if (*argv[i] == '-') | ||
91 | continue; | ||
92 | break; | ||
93 | } | ||
94 | int start_index = i; | ||
95 | for (i = start_index; i < argc; i++) | ||
96 | len += strlen(argv[i]) + 1; | ||
97 | |||
98 | // allocate | ||
99 | command = malloc(len + 1); | ||
100 | if (!command) | ||
101 | errExit("malloc"); | ||
102 | memset(command, 0, len + 1); | ||
103 | allocated = 1; | ||
104 | |||
105 | // copy | ||
106 | for (i = start_index; i < argc; i++) { | ||
107 | strcat(command, argv[i]); | ||
108 | strcat(command, " "); | ||
109 | } | ||
110 | } | ||
111 | |||
112 | // start the program in /bin/sh | ||
113 | fprintf(stderr, "Warning: an existing sandbox was detected. " | ||
114 | "%s will run without any additional sandboxing features in a /bin/sh shell\n", command); | ||
115 | system(command); | ||
116 | if (allocated) | ||
117 | free(command); | ||
118 | exit(1); | ||
119 | } | ||