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authorFederico Ceratto <federico.ceratto@gmail.com>2018-03-27 21:28:21 +0000
committerFederico Ceratto <federico.ceratto@gmail.com>2018-03-27 21:28:21 +0000
commitd4dd00f58a502c9ca4b63e36ce6bc7a9945dc63c (patch)
treefaac99f51f182bb8c0a03e95e393d421ac9ddf42 /src/cgroup-network.c
parentNew upstream version 1.9.0+dfsg (diff)
downloadnetdata-d4dd00f58a502c9ca4b63e36ce6bc7a9945dc63c.tar.xz
netdata-d4dd00f58a502c9ca4b63e36ce6bc7a9945dc63c.zip
New upstream version 1.10.0+dfsgupstream/1.10.0+dfsg
Diffstat (limited to 'src/cgroup-network.c')
-rw-r--r--src/cgroup-network.c273
1 files changed, 229 insertions, 44 deletions
diff --git a/src/cgroup-network.c b/src/cgroup-network.c
index 7b1a02342..0e2d5163a 100644
--- a/src/cgroup-network.c
+++ b/src/cgroup-network.c
@@ -8,17 +8,28 @@
#include <sched.h>
#endif
+char *host_prefix = "";
+
+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);
}
-
void health_reload(void) {};
void rrdhost_save_all(void) {};
+// ----------------------------------------------------------------------------
+
struct iface {
const char *device;
uint32_t hash;
@@ -87,6 +98,19 @@ struct iface *read_proc_net_dev(const char *prefix) {
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;
@@ -247,25 +271,18 @@ int switch_namespace(const char *prefix, pid_t pid) {
#endif
}
-pid_t read_pid_from_cgroup(const char *path) {
- char buffer[FILENAME_MAX + 1];
-
- snprintfz(buffer, FILENAME_MAX, "%s/cgroup.procs", path);
- FILE *fp = fopen(buffer, "r");
- if(!fp) {
- error("Cannot read file '%s'.", buffer);
- snprintfz(buffer, FILENAME_MAX, "%s/tasks", path);
- fp = fopen(buffer, "r");
- }
-
+pid_t read_pid_from_cgroup_file(const char *filename) {
+ FILE *fp = fopen(filename, "r");
if(!fp) {
- error("Cannot read file '%s'.", buffer);
+ error("Cannot read file '%s'.", filename);
return 0;
}
+ char buffer[100 + 1];
pid_t pid = 0;
char *s;
- while((s = fgets(buffer, FILENAME_MAX, fp))) {
+ while((s = fgets(buffer, 100, fp))) {
+ buffer[100] = '\0';
pid = atoi(s);
if(pid > 0) break;
}
@@ -274,6 +291,46 @@ pid_t read_pid_from_cgroup(const char *path) {
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
@@ -298,7 +355,7 @@ void add_device(const char *host, const char *guest) {
if(f->host_device_hash == hash && strcmp(host, f->host_device) == 0) {
if(guest && !f->guest_device)
- f->guest_device = strdup(guest);
+ f->guest_device = strdupz(guest);
return;
}
@@ -334,21 +391,36 @@ void detect_veth_interfaces(pid_t pid) {
const char *prefix = getenv("NETDATA_HOST_PREFIX");
host = read_proc_net_dev(prefix);
- if(!host)
- fatal("cannot read host interface list.");
+ if(!host) {
+ errno = 0;
+ error("cannot read host interface list.");
+ return;
+ }
- if(!eligible_ifaces(host))
- fatal("there are no double-linked host interfaces available.");
+ if(!eligible_ifaces(host)) {
+ errno = 0;
+ error("there are no double-linked host interfaces available.");
+ goto cleanup;
+ }
- if(switch_namespace(prefix, pid))
- fatal("cannot switch to the namespace of pid %u", (unsigned int)pid);
+ if(switch_namespace(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)
- fatal("cannot read cgroup interface list.");
+ if(!cgroup) {
+ errno = 0;
+ error("cannot read cgroup interface list.");
+ goto cleanup;
+ }
- if(!eligible_ifaces(cgroup))
- fatal("there are not double-linked cgroup interfaces available.");
+ 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)) {
@@ -359,34 +431,29 @@ void detect_veth_interfaces(pid_t pid) {
}
}
}
+
+cleanup:
+ free_host_ifaces(host);
}
// ----------------------------------------------------------------------------
// call the external helper
#define CGROUP_NETWORK_INTERFACE_MAX_LINE 2048
-void call_the_helper(const char *me, pid_t pid, const char *cgroup) {
- const char *pluginsdir = getenv("NETDATA_PLUGINS_DIR");
- char *m = NULL;
-
- if(!pluginsdir || !*pluginsdir) {
- m = strdupz(me);
- pluginsdir = dirname(m);
- }
-
+void call_the_helper(pid_t pid, const char *cgroup) {
if(setresuid(0, 0, 0) == -1)
error("setresuid(0, 0, 0) failed.");
char buffer[CGROUP_NETWORK_INTERFACE_MAX_LINE + 1];
if(cgroup)
- snprintfz(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, "exec %s/cgroup-network-helper.sh --cgroup '%s'", pluginsdir, cgroup);
+ snprintfz(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, "exec " PLUGINS_DIR "/cgroup-network-helper.sh --cgroup '%s'", cgroup);
else
- snprintfz(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, "exec %s/cgroup-network-helper.sh --pid %d", pluginsdir, pid);
+ snprintfz(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, "exec " PLUGINS_DIR "/cgroup-network-helper.sh --pid %d", pid);
info("running: %s", buffer);
pid_t cgroup_pid;
- FILE *fp = mypopen(buffer, &cgroup_pid);
+ FILE *fp = mypopene(buffer, &cgroup_pid, environment);
if(fp) {
char *s;
while((s = fgets(buffer, CGROUP_NETWORK_INTERFACE_MAX_LINE, fp))) {
@@ -409,10 +476,102 @@ void call_the_helper(const char *me, pid_t pid, const char *cgroup) {
}
else
error("cannot execute cgroup-network helper script: %s", buffer);
+}
+
+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;
+ }
- freez(m);
+ 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
@@ -429,6 +588,25 @@ int main(int argc, char **argv) {
program_version = VERSION;
error_log_syslog = 0;
+
+ // ------------------------------------------------------------------------
+ // make sure NETDATA_HOST_PREFIX is safe
+
+ host_prefix = getenv("NETDATA_HOST_PREFIX");
+ if(!host_prefix || !*host_prefix)
+ host_prefix = "";
+
+ if(host_prefix[0] != '\0' && verify_path(host_prefix) == -1)
+ fatal("invalid NETDATA_HOST_PREFIX '%s'", 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", 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);
@@ -442,18 +620,23 @@ int main(int argc, char **argv) {
if(pid <= 0) {
errno = 0;
- fatal("Invalid pid %d given", (int) pid);
+ error("Invalid pid %d given", (int) pid);
+ return 2;
}
- call_the_helper(argv[0], pid, NULL);
+ call_the_helper(pid, NULL);
}
else if(!strcmp(argv[1], "--cgroup")) {
- pid = read_pid_from_cgroup(argv[2]);
- call_the_helper(argv[0], pid, argv[2]);
+ 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;
- fatal("Invalid pid %d read from cgroup '%s'", (int) pid, argv[2]);
+ error("Cannot find a cgroup PID from cgroup '%s'", cgroup);
}
}
else
@@ -462,5 +645,7 @@ int main(int argc, char **argv) {
if(pid > 0)
detect_veth_interfaces(pid);
- return send_devices();
+ int found = send_devices();
+ if(found <= 0) return 1;
+ return 0;
}