diff options
Diffstat (limited to 'collectors/cgroups.plugin/cgroup-network.c')
| -rw-r--r-- | collectors/cgroups.plugin/cgroup-network.c | 682 |
1 files changed, 682 insertions, 0 deletions
diff --git a/collectors/cgroups.plugin/cgroup-network.c b/collectors/cgroups.plugin/cgroup-network.c new file mode 100644 index 000000000..0cf2a2633 --- /dev/null +++ b/collectors/cgroups.plugin/cgroup-network.c @@ -0,0 +1,682 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "libnetdata/libnetdata.h" + +#ifdef HAVE_SETNS +#ifndef _GNU_SOURCE +#define _GNU_SOURCE /* See feature_test_macros(7) */ +#endif +#include <sched.h> +#endif + +char environment_variable2[FILENAME_MAX + 50] = ""; +char *environment[] = { + "PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin", + environment_variable2, + NULL +}; + + +// ---------------------------------------------------------------------------- + +// callback required by fatal() +void netdata_cleanup_and_exit(int ret) { + exit(ret); +} + +// callbacks required by popen() +void signals_block(void) {}; +void signals_unblock(void) {}; +void signals_reset(void) {}; + +// callback required by eval() +int health_variable_lookup(const char *variable, uint32_t hash, struct rrdcalc *rc, calculated_number *result) { + (void)variable; + (void)hash; + (void)rc; + (void)result; + return 0; +}; + +// required by get_system_cpus() +char *netdata_configured_host_prefix = ""; + +// ---------------------------------------------------------------------------- + +struct iface { + const char *device; + uint32_t hash; + + unsigned int ifindex; + unsigned int iflink; + + struct iface *next; +}; + +unsigned int read_iface_iflink(const char *prefix, const char *iface) { + if(!prefix) prefix = ""; + + char filename[FILENAME_MAX + 1]; + snprintfz(filename, FILENAME_MAX, "%s/sys/class/net/%s/iflink", prefix, iface); + + unsigned long long iflink = 0; + int ret = read_single_number_file(filename, &iflink); + if(ret) error("Cannot read '%s'.", filename); + + return (unsigned int)iflink; +} + +unsigned int read_iface_ifindex(const char *prefix, const char *iface) { + if(!prefix) prefix = ""; + + char filename[FILENAME_MAX + 1]; + snprintfz(filename, FILENAME_MAX, "%s/sys/class/net/%s/ifindex", prefix, iface); + + unsigned long long ifindex = 0; + int ret = read_single_number_file(filename, &ifindex); + if(ret) error("Cannot read '%s'.", filename); + + return (unsigned int)ifindex; +} + +struct iface *read_proc_net_dev(const char *prefix) { + if(!prefix) prefix = ""; + + procfile *ff = NULL; + char filename[FILENAME_MAX + 1]; + + snprintfz(filename, FILENAME_MAX, "%s%s", prefix, (*prefix)?"/proc/1/net/dev":"/proc/net/dev"); + ff = procfile_open(filename, " \t,:|", PROCFILE_FLAG_DEFAULT); + if(unlikely(!ff)) { + error("Cannot open file '%s'", filename); + return NULL; + } + + ff = procfile_readall(ff); + if(unlikely(!ff)) { + error("Cannot read file '%s'", filename); + return NULL; + } + + size_t lines = procfile_lines(ff), l; + struct iface *root = NULL; + for(l = 2; l < lines ;l++) { + if (unlikely(procfile_linewords(ff, l) < 1)) continue; + + struct iface *t = callocz(1, sizeof(struct iface)); + t->device = strdupz(procfile_lineword(ff, l, 0)); + t->hash = simple_hash(t->device); + t->ifindex = read_iface_ifindex(prefix, t->device); + t->iflink = read_iface_iflink(prefix, t->device); + t->next = root; + root = t; + } + + procfile_close(ff); + + return root; +} + +void free_iface(struct iface *iface) { + freez((void *)iface->device); + freez(iface); +} + +void free_host_ifaces(struct iface *iface) { + while(iface) { + struct iface *t = iface->next; + free_iface(iface); + iface = t; + } +} + +int iface_is_eligible(struct iface *iface) { + if(iface->iflink != iface->ifindex) + return 1; + + return 0; +} + +int eligible_ifaces(struct iface *root) { + int eligible = 0; + + struct iface *t; + for(t = root; t ; t = t->next) + if(iface_is_eligible(t)) + eligible++; + + return eligible; +} + +static void continue_as_child(void) { + pid_t child = fork(); + int status; + pid_t ret; + + if (child < 0) + error("fork() failed"); + + /* Only the child returns */ + if (child == 0) + return; + + for (;;) { + ret = waitpid(child, &status, WUNTRACED); + if ((ret == child) && (WIFSTOPPED(status))) { + /* The child suspended so suspend us as well */ + kill(getpid(), SIGSTOP); + kill(child, SIGCONT); + } else { + break; + } + } + + /* Return the child's exit code if possible */ + if (WIFEXITED(status)) { + exit(WEXITSTATUS(status)); + } else if (WIFSIGNALED(status)) { + kill(getpid(), WTERMSIG(status)); + } + + exit(EXIT_FAILURE); +} + +int proc_pid_fd(const char *prefix, const char *ns, pid_t pid) { + if(!prefix) prefix = ""; + + char filename[FILENAME_MAX + 1]; + snprintfz(filename, FILENAME_MAX, "%s/proc/%d/%s", prefix, (int)pid, ns); + int fd = open(filename, O_RDONLY); + + if(fd == -1) + error("Cannot open proc_pid_fd() file '%s'", filename); + + return fd; +} + +static struct ns { + int nstype; + int fd; + int status; + const char *name; + const char *path; +} all_ns[] = { + // { .nstype = CLONE_NEWUSER, .fd = -1, .status = -1, .name = "user", .path = "ns/user" }, + // { .nstype = CLONE_NEWCGROUP, .fd = -1, .status = -1, .name = "cgroup", .path = "ns/cgroup" }, + // { .nstype = CLONE_NEWIPC, .fd = -1, .status = -1, .name = "ipc", .path = "ns/ipc" }, + // { .nstype = CLONE_NEWUTS, .fd = -1, .status = -1, .name = "uts", .path = "ns/uts" }, + { .nstype = CLONE_NEWNET, .fd = -1, .status = -1, .name = "network", .path = "ns/net" }, + { .nstype = CLONE_NEWPID, .fd = -1, .status = -1, .name = "pid", .path = "ns/pid" }, + { .nstype = CLONE_NEWNS, .fd = -1, .status = -1, .name = "mount", .path = "ns/mnt" }, + + // terminator + { .nstype = 0, .fd = -1, .status = -1, .name = NULL, .path = NULL } +}; + +int switch_namespace(const char *prefix, pid_t pid) { + if(!prefix) prefix = ""; + +#ifdef HAVE_SETNS + + int i; + for(i = 0; all_ns[i].name ; i++) + all_ns[i].fd = proc_pid_fd(prefix, all_ns[i].path, pid); + + int root_fd = proc_pid_fd(prefix, "root", pid); + int cwd_fd = proc_pid_fd(prefix, "cwd", pid); + + setgroups(0, NULL); + + // 2 passes - found it at nsenter source code + // this is related CLONE_NEWUSER functionality + + // This code cannot switch user namespace (it can all the other namespaces) + // Fortunately, we don't need to switch user namespaces. + + int pass, errors = 0; + for(pass = 0; pass < 2 ;pass++) { + for(i = 0; all_ns[i].name ; i++) { + if (all_ns[i].fd != -1 && all_ns[i].status == -1) { + if(setns(all_ns[i].fd, all_ns[i].nstype) == -1) { + if(pass == 1) { + all_ns[i].status = 0; + error("Cannot switch to %s namespace of pid %d", all_ns[i].name, (int) pid); + errors++; + } + } + else + all_ns[i].status = 1; + } + } + } + + setgroups(0, NULL); + + if(root_fd != -1) { + if(fchdir(root_fd) < 0) + error("Cannot fchdir() to pid %d root directory", (int)pid); + + if(chroot(".") < 0) + error("Cannot chroot() to pid %d root directory", (int)pid); + + close(root_fd); + } + + if(cwd_fd != -1) { + if(fchdir(cwd_fd) < 0) + error("Cannot fchdir() to pid %d current working directory", (int)pid); + + close(cwd_fd); + } + + int do_fork = 0; + for(i = 0; all_ns[i].name ; i++) + if(all_ns[i].fd != -1) { + + // CLONE_NEWPID requires a fork() to become effective + if(all_ns[i].nstype == CLONE_NEWPID && all_ns[i].status) + do_fork = 1; + + close(all_ns[i].fd); + } + + if(do_fork) + continue_as_child(); + + return 0; + +#else + + errno = ENOSYS; + error("setns() is missing on this system."); + return 1; + +#endif +} + +pid_t read_pid_from_cgroup_file(const char *filename) { + int fd = open(filename, procfile_open_flags); + if(fd == -1) { + error("Cannot open pid_from_cgroup() file '%s'.", filename); + return 0; + } + + FILE *fp = fdopen(fd, "r"); + if(!fp) { + error("Cannot upgrade fd to fp for file '%s'.", filename); + return 0; + } + + char buffer[100 + 1]; + pid_t pid = 0; + char *s; + while((s = fgets(buffer, 100, fp))) { + buffer[100] = '\0'; + pid = atoi(s); + if(pid > 0) break; + } + + fclose(fp); + return pid; +} + +pid_t read_pid_from_cgroup_files(const char *path) { + char filename[FILENAME_MAX + 1]; + + snprintfz(filename, FILENAME_MAX, "%s/cgroup.procs", path); + pid_t pid = read_pid_from_cgroup_file(filename); + if(pid > 0) return pid; + + snprintfz(filename, FILENAME_MAX, "%s/tasks", path); + return read_pid_from_cgroup_file(filename); +} + +pid_t read_pid_from_cgroup(const char *path) { + pid_t pid = read_pid_from_cgroup_files(path); + if (pid > 0) return pid; + + DIR *dir = opendir(path); + if (!dir) { + error("cannot read directory '%s'", path); + return 0; + } + + struct dirent *de = NULL; + while ((de = readdir(dir))) { + if (de->d_type == DT_DIR + && ( + (de->d_name[0] == '.' && de->d_name[1] == '\0') + || (de->d_name[0] == '.' && de->d_name[1] == '.' && de->d_name[2] == '\0') + )) + continue; + + if (de->d_type == DT_DIR) { + char filename[FILENAME_MAX + 1]; + snprintfz(filename, FILENAME_MAX, "%s/%s", path, de->d_name); + pid = read_pid_from_cgroup(filename); + if(pid > 0) break; + } + } + closedir(dir); + return pid; +} + +// ---------------------------------------------------------------------------- +// send the result to netdata + +struct found_device { + const char *host_device; + const char *guest_device; + + uint32_t host_device_hash; + + struct found_device *next; +} *detected_devices = NULL; + +void add_device(const char *host, const char *guest) { + uint32_t hash = simple_hash(host); + + if(guest && (!*guest || strcmp(host, guest) == 0)) + guest = NULL; + + struct found_device *f; + for(f = detected_devices; f ; f = f->next) { + if(f->host_device_hash == hash && strcmp(host, f->host_device) == 0) { + + if(guest && !f->guest_device) + f->guest_device = strdupz(guest); + + return; + } + } + + f = mallocz(sizeof(struct found_device)); + f->host_device = strdupz(host); + f->host_device_hash = hash; + f->guest_device = (guest)?strdupz(guest):NULL; + f->next = detected_devices; + detected_devices = f; +} + +int send_devices(void) { + int found = 0; + + struct found_device *f; + for(f = detected_devices; f ; f = f->next) { + found++; + printf("%s %s\n", f->host_device, (f->guest_device)?f->guest_device:f->host_device); + } + + return found; +} + +// ---------------------------------------------------------------------------- +// this function should be called only **ONCE** +// also it has to be the **LAST** to be called +// since it switches namespaces, so after this call, everything is different! + +void detect_veth_interfaces(pid_t pid) { + struct iface *host = NULL, *cgroup = NULL, *h, *c; + + host = read_proc_net_dev(netdata_configured_host_prefix); + if(!host) { + errno = 0; + error("cannot read host interface list."); + goto cleanup; + } + + if(!eligible_ifaces(host)) { + errno = 0; + error("there are no double-linked host interfaces available."); + goto cleanup; + } + + if(switch_namespace(netdata_configured_host_prefix, pid)) { + errno = 0; + error("cannot switch to the namespace of pid %u", (unsigned int) pid); + goto cleanup; + } + + cgroup = read_proc_net_dev(NULL); + if(!cgroup) { + errno = 0; + error("cannot read cgroup interface list."); + goto cleanup; + } + + if(!eligible_ifaces(cgroup)) { + errno = 0; + error("there are not double-linked cgroup interfaces available."); + goto cleanup; + } + + for(h = host; h ; h = h->next) { + if(iface_is_eligible(h)) { + for (c = cgroup; c; c = c->next) { + if(iface_is_eligible(c) && h->ifindex == c->iflink && h->iflink == c->ifindex) { + add_device(h->device, c->device); + } + } + } + } + +cleanup: + free_host_ifaces(cgroup); + free_host_ifaces(host); +} + +// ---------------------------------------------------------------------------- +// call the external helper + +#define CGROUP_NETWORK_INTERFACE_MAX_LINE 2048 +void call_the_helper(pid_t pid, const char *cgroup) { + if(setresuid(0, 0, 0) == -1) + error("setresuid(0, 0, 0) failed."); + + char command[CGROUP_NETWORK_INTERFACE_MAX_LINE + 1]; + if(cgroup) + snprintfz(command, CGROUP_NETWORK_INTERFACE_MAX_LINE, "exec " PLUGINS_DIR "/cgroup-network-helper.sh --cgroup '%s'", cgroup); + else + snprintfz(command, CGROUP_NETWORK_INTERFACE_MAX_LINE, "exec " PLUGINS_DIR "/cgroup-network-helper.sh --pid %d", pid); + + info("running: %s", command); + + pid_t cgroup_pid; + FILE *fp = mypopene(command, &cgroup_pid, environment); + if(fp) { + char buffer[CGROUP_NETWORK_INTERFACE_MAX_LINE + 1]; + char *s; + while((s = fgets(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, fp))) { + trim(s); + + if(*s && *s != '\n') { + char *t = s; + while(*t && *t != ' ') t++; + if(*t == ' ') { + *t = '\0'; + t++; + } + + if(!*s || !*t) continue; + add_device(s, t); + } + } + + mypclose(fp, cgroup_pid); + } + else + error("cannot execute cgroup-network helper script: %s", command); +} + +int is_valid_path_symbol(char c) { + switch(c) { + case '/': // path separators + case '\\': // needed for virsh domains \x2d1\x2dname + case ' ': // space + case '-': // hyphen + case '_': // underscore + case '.': // dot + case ',': // comma + return 1; + + default: + return 0; + } +} + +// we will pass this path a shell script running as root +// so, we need to make sure the path will be valid +// and will not include anything that could allow +// the caller use shell expansion for gaining escalated +// privileges. +int verify_path(const char *path) { + struct stat sb; + + char c; + const char *s = path; + while((c = *s++)) { + if(!( isalnum(c) || is_valid_path_symbol(c) )) { + error("invalid character in path '%s'", path); + return -1; + } + } + + if(strstr(path, "\\") && !strstr(path, "\\x")) { + error("invalid escape sequence in path '%s'", path); + return 1; + } + + if(strstr(path, "/../")) { + error("invalid parent path sequence detected in '%s'", path); + return 1; + } + + if(path[0] != '/') { + error("only absolute path names are supported - invalid path '%s'", path); + return -1; + } + + if (stat(path, &sb) == -1) { + error("cannot stat() path '%s'", path); + return -1; + } + + if((sb.st_mode & S_IFMT) != S_IFDIR) { + error("path '%s' is not a directory", path); + return -1; + } + + return 0; +} + +/* +char *fix_path_variable(void) { + const char *path = getenv("PATH"); + if(!path || !*path) return 0; + + char *p = strdupz(path); + char *safe_path = callocz(1, strlen(p) + strlen("PATH=") + 1); + strcpy(safe_path, "PATH="); + + int added = 0; + char *ptr = p; + while(ptr && *ptr) { + char *s = strsep(&ptr, ":"); + if(s && *s) { + if(verify_path(s) == -1) { + error("the PATH variable includes an invalid path '%s' - removed it.", s); + } + else { + info("the PATH variable includes a valid path '%s'.", s); + if(added) strcat(safe_path, ":"); + strcat(safe_path, s); + added++; + } + } + } + + info("unsafe PATH: '%s'.", path); + info(" safe PATH: '%s'.", safe_path); + + freez(p); + return safe_path; +} +*/ + +// ---------------------------------------------------------------------------- +// main + +void usage(void) { + fprintf(stderr, "%s [ -p PID | --pid PID | --cgroup /path/to/cgroup ]\n", program_name); + exit(1); +} + +int main(int argc, char **argv) { + pid_t pid = 0; + + program_name = argv[0]; + program_version = VERSION; + error_log_syslog = 0; + + // since cgroup-network runs as root, prevent it from opening symbolic links + procfile_open_flags = O_RDONLY|O_NOFOLLOW; + + // ------------------------------------------------------------------------ + // make sure NETDATA_HOST_PREFIX is safe + + netdata_configured_host_prefix = getenv("NETDATA_HOST_PREFIX"); + if(verify_netdata_host_prefix() == -1) exit(1); + + if(netdata_configured_host_prefix[0] != '\0' && verify_path(netdata_configured_host_prefix) == -1) + fatal("invalid NETDATA_HOST_PREFIX '%s'", netdata_configured_host_prefix); + + // ------------------------------------------------------------------------ + // build a safe environment for our script + + // the first environment variable is a fixed PATH= + snprintfz(environment_variable2, sizeof(environment_variable2) - 1, "NETDATA_HOST_PREFIX=%s", netdata_configured_host_prefix); + + // ------------------------------------------------------------------------ + + if(argc == 2 && (!strcmp(argv[1], "version") || !strcmp(argv[1], "-version") || !strcmp(argv[1], "--version") || !strcmp(argv[1], "-v") || !strcmp(argv[1], "-V"))) { + fprintf(stderr, "cgroup-network %s\n", VERSION); + exit(0); + } + + if(argc != 3) + usage(); + + if(!strcmp(argv[1], "-p") || !strcmp(argv[1], "--pid")) { + pid = atoi(argv[2]); + + if(pid <= 0) { + errno = 0; + error("Invalid pid %d given", (int) pid); + return 2; + } + + call_the_helper(pid, NULL); + } + else if(!strcmp(argv[1], "--cgroup")) { + char *cgroup = argv[2]; + if(verify_path(cgroup) == -1) + fatal("cgroup '%s' does not exist or is not valid.", cgroup); + + pid = read_pid_from_cgroup(cgroup); + call_the_helper(pid, cgroup); + + if(pid <= 0 && !detected_devices) { + errno = 0; + error("Cannot find a cgroup PID from cgroup '%s'", cgroup); + } + } + else + usage(); + + if(pid > 0) + detect_veth_interfaces(pid); + + int found = send_devices(); + if(found <= 0) return 1; + return 0; +} |