80 lines
1.7 KiB
C
80 lines
1.7 KiB
C
/* This program requires CAP_SYS_ADMIN */
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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 *allowed_netns[] = {
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"nb-joinmarket"
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};
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int is_netns_allowed(char *netns) {
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int n_allowed_netns = sizeof(allowed_netns) / sizeof(allowed_netns[0]);
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for (int i = 0; i < n_allowed_netns; i++) {
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if (strcmp(allowed_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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char netns_path[256];
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if (argc < 3) {
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printf("usage: %s <netns> <command>\n", argv[0]);
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return 1;
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}
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if (!is_netns_allowed(argv[1])) {
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printf("%s is not an allowed 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("Path length exceeded for netns %s.\n", argv[1]);
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return 1;
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}
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int 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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