87 lines
1.9 KiB
C
87 lines
1.9 KiB
C
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/* This program must be run with CAP_SYS_ADMIN. This can be achieved for example
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* with
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* # setcap CAP_SYS_ADMIN+ep ./main
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*/
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#define _GNU_SOURCE
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#include <sched.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/capability.h>
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static char *available_netns[] = {
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"nb-lnd",
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"nb-bitcoind",
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"nb-liquidd"
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};
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int check_netns(char *netns) {
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int i;
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int n_available_netns = sizeof(available_netns) / sizeof(available_netns[0]);
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for (i = 0; i < n_available_netns; i++) {
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if (strcmp(available_netns[i], netns) == 0) {
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return 1;
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}
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}
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return 0;
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}
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void print_capabilities() {
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cap_t caps = cap_get_proc();
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printf("Capabilities: %s\n", cap_to_text(caps, NULL));
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cap_free(caps);
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}
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void drop_capabilities() {
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cap_t caps = cap_get_proc();
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cap_clear(caps);
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cap_set_proc(caps);
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cap_free(caps);
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}
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int main(int argc, char **argv) {
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int fd;
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char netns_path[256];
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if (argc < 3) {
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printf("usage: %s <netns> <command to execute>\n", argv[0]);
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return 1;
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}
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if (!check_netns(argv[1])) {
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printf("Failed checking %s against available netns.\n", argv[1]);
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return 1;
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}
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if(snprintf(netns_path, sizeof(netns_path), "/var/run/netns/%s", argv[1]) < 0) {
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printf("Failed concatenating %s to the netns path.\n", argv[1]);
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return 1;
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}
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fd = open(netns_path, O_RDONLY);
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if (fd < 0) {
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printf("Failed opening netns %s: %d, %s \n", netns_path, errno, strerror(errno));
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return 1;
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}
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if (setns(fd, CLONE_NEWNET) < 0) {
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printf("Failed setns %d, %s \n", errno, strerror(errno));
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return 1;
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}
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/* Drop capabilities */
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#ifdef DEBUG
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print_capabilities();
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#endif
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drop_capabilities();
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#ifdef DEBUG
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print_capabilities();
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#endif
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execvp(argv[2], &argv[2]);
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return 0;
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}
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