| Line |
Branch |
Exec |
Source |
| 1 |
|
|
/** |
| 2 |
|
|
* This file is part of the CernVM File System. |
| 3 |
|
|
* |
| 4 |
|
|
* Runs mount/umount commands and removes scratch space on behalf of a |
| 5 |
|
|
* repository owner. Server-only utility. |
| 6 |
|
|
* |
| 7 |
|
|
* This binary does not use the cvmfs infrastructure code to stay lean. |
| 8 |
|
|
*/ |
| 9 |
|
|
|
| 10 |
|
|
#include <sys/xattr.h> // NOLINT |
| 11 |
|
|
|
| 12 |
|
|
#include <dirent.h> |
| 13 |
|
|
#include <errno.h> |
| 14 |
|
|
#include <sys/stat.h> |
| 15 |
|
|
#include <sys/wait.h> |
| 16 |
|
|
#include <unistd.h> |
| 17 |
|
|
|
| 18 |
|
|
#include <cstdio> |
| 19 |
|
|
#include <cstdlib> |
| 20 |
|
|
#include <cstring> |
| 21 |
|
|
#include <string> |
| 22 |
|
|
|
| 23 |
|
|
#include "cvmfs_suid_util.h" |
| 24 |
|
|
#include "sanitizer.h" |
| 25 |
|
|
#include "util/platform.h" |
| 26 |
|
|
|
| 27 |
|
|
using namespace std; // NOLINT |
| 28 |
|
|
|
| 29 |
|
|
const char *kSpoolArea = "/var/spool/cvmfs"; |
| 30 |
|
|
|
| 31 |
|
|
enum RemountType { |
| 32 |
|
|
kRemountRdonly, |
| 33 |
|
|
kRemountRw |
| 34 |
|
|
}; |
| 35 |
|
|
|
| 36 |
|
✗ |
static void GetCredentials(uid_t *calling_uid, uid_t *effective_uid) { |
| 37 |
|
✗ |
*calling_uid = getuid(); |
| 38 |
|
✗ |
*effective_uid = geteuid(); |
| 39 |
|
|
} |
| 40 |
|
|
|
| 41 |
|
✗ |
static void ExecAsRoot(const char *binary, |
| 42 |
|
|
const char *arg1, const char *arg2, const char *arg3, |
| 43 |
|
|
const char *arg4) |
| 44 |
|
|
{ |
| 45 |
|
✗ |
char *argv[] = { strdup(binary), |
| 46 |
|
✗ |
arg1 ? strdup(arg1) : NULL, |
| 47 |
|
✗ |
arg2 ? strdup(arg2) : NULL, |
| 48 |
|
✗ |
arg3 ? strdup(arg3) : NULL, |
| 49 |
|
✗ |
arg4 ? strdup(arg4) : NULL, |
| 50 |
|
✗ |
NULL }; |
| 51 |
|
✗ |
char *environ[] = { NULL }; |
| 52 |
|
|
|
| 53 |
|
✗ |
int retval = setuid(0); |
| 54 |
|
✗ |
if (retval != 0) { |
| 55 |
|
✗ |
fprintf(stderr, "failed to gain root privileges (%d)\n", errno); |
| 56 |
|
✗ |
exit(1); |
| 57 |
|
|
} |
| 58 |
|
|
|
| 59 |
|
✗ |
execve(binary, argv, environ); |
| 60 |
|
✗ |
fprintf(stderr, "failed to run %s... (%d)\n", binary, errno); |
| 61 |
|
✗ |
exit(1); |
| 62 |
|
|
} |
| 63 |
|
|
|
| 64 |
|
✗ |
static void ForkAndExecAsRoot(const char *binary, const char *arg1, |
| 65 |
|
|
const char *arg2, const char *arg3, |
| 66 |
|
|
const char *arg4) |
| 67 |
|
|
{ |
| 68 |
|
✗ |
pid_t child = fork(); |
| 69 |
|
✗ |
if (child == -1) { |
| 70 |
|
✗ |
fprintf(stderr, "failed to fork %s... (%d)\n", binary, errno); |
| 71 |
|
✗ |
exit(1); |
| 72 |
|
✗ |
} else if (child == 0) { |
| 73 |
|
✗ |
ExecAsRoot(binary, arg1, arg2, arg3, arg4); |
| 74 |
|
|
} else { |
| 75 |
|
|
int wstatus; |
| 76 |
|
✗ |
waitpid(child, &wstatus, 0); |
| 77 |
|
✗ |
if (WIFSIGNALED(wstatus)) { |
| 78 |
|
✗ |
exit(128 + WTERMSIG(wstatus)); |
| 79 |
|
✗ |
} else if (WIFEXITED(wstatus) && WEXITSTATUS(wstatus)) { |
| 80 |
|
✗ |
exit(WEXITSTATUS(wstatus)); |
| 81 |
|
|
} |
| 82 |
|
|
} |
| 83 |
|
|
} |
| 84 |
|
|
|
| 85 |
|
✗ |
static void Remount(const string &path, const RemountType how) { |
| 86 |
|
✗ |
string remount_option = "remount,"; |
| 87 |
|
✗ |
switch (how) { |
| 88 |
|
✗ |
case kRemountRw: |
| 89 |
|
✗ |
remount_option += "rw"; |
| 90 |
|
✗ |
break; |
| 91 |
|
✗ |
case kRemountRdonly: |
| 92 |
|
✗ |
remount_option += "ro"; |
| 93 |
|
✗ |
break; |
| 94 |
|
✗ |
default: |
| 95 |
|
✗ |
fprintf(stderr, "internal error\n"); |
| 96 |
|
✗ |
exit(1); |
| 97 |
|
|
} |
| 98 |
|
|
|
| 99 |
|
|
// Note: the device name "dev" doesn't matter. It won't change from the |
| 100 |
|
|
// "overlayfs_<fqrn>" name used when originally mounting the path. It is |
| 101 |
|
|
// a dummy argument to appease the mount command. |
| 102 |
|
✗ |
ExecAsRoot("/bin/mount", "-o", remount_option.c_str(), "dev", path.c_str()); |
| 103 |
|
|
} |
| 104 |
|
|
|
| 105 |
|
✗ |
static void Mount(const string &path) { |
| 106 |
|
|
platform_stat64 info; |
| 107 |
|
✗ |
int retval = platform_stat("/bin/systemctl", &info); |
| 108 |
|
✗ |
if (retval == 0) { |
| 109 |
|
✗ |
string systemd_unit = cvmfs_suid::EscapeSystemdUnit(path); |
| 110 |
|
|
// On newer versions of systemd, the mount unit is based on the fully |
| 111 |
|
|
// resolved path (discovered on Ubuntu 18.04, test 539) |
| 112 |
|
✗ |
if (!cvmfs_suid::PathExists( |
| 113 |
|
✗ |
string("/run/systemd/generator/") + systemd_unit)) |
| 114 |
|
|
{ |
| 115 |
|
✗ |
string resolved_path = cvmfs_suid::ResolvePath(path); |
| 116 |
|
✗ |
if (resolved_path.empty()) { |
| 117 |
|
✗ |
fprintf(stderr, "cannot resolve %s\n", path.c_str()); |
| 118 |
|
✗ |
exit(1); |
| 119 |
|
|
} |
| 120 |
|
✗ |
systemd_unit = cvmfs_suid::EscapeSystemdUnit(resolved_path); |
| 121 |
|
|
} |
| 122 |
|
✗ |
ForkAndExecAsRoot("/bin/systemctl", "restart", systemd_unit.c_str(), |
| 123 |
|
|
NULL, NULL); |
| 124 |
|
✗ |
ExecAsRoot("/bin/systemctl", "reset-failed", systemd_unit.c_str(), |
| 125 |
|
|
NULL, NULL); |
| 126 |
|
✗ |
} else { |
| 127 |
|
✗ |
ExecAsRoot("/bin/mount", path.c_str(), NULL, NULL, NULL); |
| 128 |
|
|
} |
| 129 |
|
|
} |
| 130 |
|
|
|
| 131 |
|
✗ |
static void Umount(const string &path) { |
| 132 |
|
✗ |
ExecAsRoot("/bin/umount", path.c_str(), NULL, NULL, NULL); |
| 133 |
|
|
} |
| 134 |
|
|
|
| 135 |
|
✗ |
static void LazyUmount(const string &path) { |
| 136 |
|
✗ |
ExecAsRoot("/bin/umount", "-l", path.c_str(), NULL, NULL); |
| 137 |
|
|
} |
| 138 |
|
|
|
| 139 |
|
✗ |
static void KillCvmfs(const string &fqrn) { |
| 140 |
|
|
// prevent exploitation like: |
| 141 |
|
|
// fqrn = ../../../../usr/home/file_with_xattr_user.pid |
| 142 |
|
✗ |
if (fqrn.find("/") != string::npos || fqrn.find("\\") != string::npos) { |
| 143 |
|
✗ |
exit(1); |
| 144 |
|
|
} |
| 145 |
|
✗ |
string pid; |
| 146 |
|
✗ |
const string mountpoint = string(kSpoolArea) + "/" + fqrn + "/rdonly"; |
| 147 |
|
✗ |
const bool retval = platform_getxattr(mountpoint.c_str(), "user.pid", &pid); |
| 148 |
|
✗ |
if (!retval || pid.empty()) |
| 149 |
|
✗ |
exit(1); |
| 150 |
|
✗ |
sanitizer::PositiveIntegerSanitizer pid_sanitizer; |
| 151 |
|
✗ |
if (!pid_sanitizer.IsValid(pid)) |
| 152 |
|
✗ |
exit(1); |
| 153 |
|
✗ |
ExecAsRoot("/bin/kill", "-9", pid.c_str(), NULL, NULL); |
| 154 |
|
|
} |
| 155 |
|
|
|
| 156 |
|
|
class ScopedWorkingDirectory { |
| 157 |
|
|
public: |
| 158 |
|
✗ |
explicit ScopedWorkingDirectory(const string &path) |
| 159 |
|
✗ |
: previous_path_(GetCurrentWorkingDirectory()) |
| 160 |
|
✗ |
, directory_handle_(NULL) |
| 161 |
|
|
{ |
| 162 |
|
✗ |
ChangeDirectory(path); |
| 163 |
|
✗ |
directory_handle_ = opendir("."); |
| 164 |
|
|
} |
| 165 |
|
|
|
| 166 |
|
✗ |
~ScopedWorkingDirectory() { |
| 167 |
|
✗ |
if (directory_handle_ != NULL) { |
| 168 |
|
✗ |
closedir(directory_handle_); |
| 169 |
|
|
} |
| 170 |
|
✗ |
ChangeDirectory(previous_path_); |
| 171 |
|
|
} |
| 172 |
|
|
|
| 173 |
|
✗ |
operator bool() const { return directory_handle_ != NULL; } |
| 174 |
|
|
|
| 175 |
|
|
struct DirectoryEntry { |
| 176 |
|
|
bool is_directory; |
| 177 |
|
|
string name; |
| 178 |
|
|
}; |
| 179 |
|
|
|
| 180 |
|
✗ |
bool NextDirectoryEntry(DirectoryEntry *entry) { |
| 181 |
|
|
platform_dirent64 *dirent; |
| 182 |
|
✗ |
while ((dirent = platform_readdir(directory_handle_)) != NULL && |
| 183 |
|
✗ |
IsDotEntry(dirent)) {} |
| 184 |
|
✗ |
if (dirent == NULL) { |
| 185 |
|
✗ |
return false; |
| 186 |
|
|
} |
| 187 |
|
|
|
| 188 |
|
|
platform_stat64 info; |
| 189 |
|
✗ |
if (platform_lstat(dirent->d_name, &info) != 0) { |
| 190 |
|
✗ |
return false; |
| 191 |
|
|
} |
| 192 |
|
|
|
| 193 |
|
✗ |
entry->is_directory = S_ISDIR(info.st_mode); |
| 194 |
|
✗ |
entry->name = dirent->d_name; |
| 195 |
|
✗ |
return true; |
| 196 |
|
|
} |
| 197 |
|
|
|
| 198 |
|
|
protected: |
| 199 |
|
✗ |
string GetCurrentWorkingDirectory() { |
| 200 |
|
|
char path[PATH_MAX]; |
| 201 |
|
✗ |
const char* cwd = getcwd(path, PATH_MAX); |
| 202 |
|
✗ |
assert(cwd == path); |
| 203 |
|
✗ |
return string(cwd); |
| 204 |
|
|
} |
| 205 |
|
|
|
| 206 |
|
✗ |
void ChangeDirectory(const string &path) { |
| 207 |
|
✗ |
const int retval = chdir(path.c_str()); |
| 208 |
|
✗ |
assert(retval == 0); |
| 209 |
|
|
} |
| 210 |
|
|
|
| 211 |
|
✗ |
bool IsDotEntry(const platform_dirent64 *dirent) { |
| 212 |
|
✗ |
return (strcmp(dirent->d_name, ".") == 0) || |
| 213 |
|
✗ |
(strcmp(dirent->d_name, "..") == 0); |
| 214 |
|
|
} |
| 215 |
|
|
|
| 216 |
|
|
private: |
| 217 |
|
|
const string previous_path_; |
| 218 |
|
|
DIR *directory_handle_; |
| 219 |
|
|
}; |
| 220 |
|
|
|
| 221 |
|
✗ |
static bool ClearDirectory(const string &path) { |
| 222 |
|
✗ |
ScopedWorkingDirectory swd(path); |
| 223 |
|
✗ |
if (!swd) { |
| 224 |
|
✗ |
return false; |
| 225 |
|
|
} |
| 226 |
|
|
|
| 227 |
|
✗ |
bool success = true; |
| 228 |
|
✗ |
ScopedWorkingDirectory::DirectoryEntry dirent; |
| 229 |
|
✗ |
while (success && swd.NextDirectoryEntry(&dirent)) { |
| 230 |
|
✗ |
success = (dirent.is_directory) |
| 231 |
|
✗ |
? ClearDirectory(dirent.name) && (rmdir(dirent.name.c_str()) == 0) |
| 232 |
|
✗ |
: (unlink(dirent.name.c_str()) == 0); |
| 233 |
|
|
} |
| 234 |
|
|
|
| 235 |
|
✗ |
return success; |
| 236 |
|
|
} |
| 237 |
|
|
|
| 238 |
|
✗ |
static int CleanupDirectory(const string &path) { |
| 239 |
|
✗ |
if (!ClearDirectory(path)) { |
| 240 |
|
✗ |
fprintf(stderr, "failed to clear %s\n", path.c_str()); |
| 241 |
|
✗ |
return 1; |
| 242 |
|
|
} |
| 243 |
|
✗ |
return 0; |
| 244 |
|
|
} |
| 245 |
|
|
|
| 246 |
|
✗ |
static int DoSynchronousScratchCleanup(const string &fqrn) { |
| 247 |
|
✗ |
const string scratch = string(kSpoolArea) + "/" + fqrn + "/scratch/current"; |
| 248 |
|
✗ |
return CleanupDirectory(scratch); |
| 249 |
|
|
} |
| 250 |
|
|
|
| 251 |
|
✗ |
static int DoAsynchronousScratchCleanup(const string &fqrn) { |
| 252 |
|
✗ |
const string wastebin = string(kSpoolArea) + "/" + fqrn + "/scratch/wastebin"; |
| 253 |
|
|
|
| 254 |
|
|
// double-fork to daemonize the process and redirect I/O to /dev/null |
| 255 |
|
|
pid_t pid; |
| 256 |
|
|
int statloc; |
| 257 |
|
✗ |
if ((pid = fork()) == 0) { |
| 258 |
|
✗ |
int retval = setsid(); |
| 259 |
|
✗ |
assert(retval != -1); |
| 260 |
|
✗ |
if ((pid = fork()) == 0) { |
| 261 |
|
✗ |
int null_read = open("/dev/null", O_RDONLY); |
| 262 |
|
✗ |
int null_write = open("/dev/null", O_WRONLY); |
| 263 |
|
✗ |
assert((null_read >= 0) && (null_write >= 0)); |
| 264 |
|
✗ |
retval = dup2(null_read, 0); |
| 265 |
|
✗ |
assert(retval == 0); |
| 266 |
|
✗ |
retval = dup2(null_write, 1); |
| 267 |
|
✗ |
assert(retval == 1); |
| 268 |
|
✗ |
retval = dup2(null_write, 2); |
| 269 |
|
✗ |
assert(retval == 2); |
| 270 |
|
✗ |
close(null_read); |
| 271 |
|
✗ |
close(null_write); |
| 272 |
|
|
} else { |
| 273 |
|
✗ |
assert(pid > 0); |
| 274 |
|
✗ |
_exit(0); |
| 275 |
|
|
} |
| 276 |
|
|
} else { |
| 277 |
|
✗ |
assert(pid > 0); |
| 278 |
|
✗ |
waitpid(pid, &statloc, 0); |
| 279 |
|
✗ |
_exit(0); |
| 280 |
|
|
} |
| 281 |
|
|
|
| 282 |
|
✗ |
return CleanupDirectory(wastebin); |
| 283 |
|
|
} |
| 284 |
|
|
|
| 285 |
|
✗ |
static void Usage(const string &exe, FILE *output) { |
| 286 |
|
✗ |
fprintf(output, |
| 287 |
|
|
"Usage: %s lock|open|rw_mount|rw_umount|rdonly_mount|rdonly_umount|" |
| 288 |
|
|
"clear_scratch|clear_scratch_async|kill_cvmfs <fqrn>\n" |
| 289 |
|
|
"Example: %s rw_umount atlas.cern.ch\n" |
| 290 |
|
|
"This binary is typically called by cvmfs_server.\n", |
| 291 |
|
|
exe.c_str(), exe.c_str()); |
| 292 |
|
|
} |
| 293 |
|
|
|
| 294 |
|
|
|
| 295 |
|
✗ |
int main(int argc, char *argv[]) { |
| 296 |
|
✗ |
umask(077); |
| 297 |
|
|
int retval; |
| 298 |
|
|
|
| 299 |
|
|
// Figure out real and effective uid |
| 300 |
|
|
uid_t calling_uid, effective_uid, repository_uid; |
| 301 |
|
✗ |
GetCredentials(&calling_uid, &effective_uid); |
| 302 |
|
✗ |
if (effective_uid != 0) { |
| 303 |
|
✗ |
fprintf(stderr, "Needs to run as root\n"); |
| 304 |
|
✗ |
return 1; |
| 305 |
|
|
} |
| 306 |
|
|
|
| 307 |
|
|
// Arguments |
| 308 |
|
✗ |
if (argc != 3) { |
| 309 |
|
✗ |
Usage(argv[0], stderr); |
| 310 |
|
✗ |
return 1; |
| 311 |
|
|
} |
| 312 |
|
✗ |
const string command = argv[1]; |
| 313 |
|
✗ |
const string fqrn = argv[2]; |
| 314 |
|
|
|
| 315 |
|
|
// Verify if repository exists |
| 316 |
|
|
platform_stat64 info; |
| 317 |
|
✗ |
retval = platform_lstat((string(kSpoolArea) + "/" + fqrn).c_str(), &info); |
| 318 |
|
✗ |
if (retval != 0) { |
| 319 |
|
✗ |
fprintf(stderr, "unknown repository: %s\n", fqrn.c_str()); |
| 320 |
|
✗ |
return 1; |
| 321 |
|
|
} |
| 322 |
|
✗ |
repository_uid = info.st_uid; |
| 323 |
|
|
|
| 324 |
|
|
// Verify if caller uid matches |
| 325 |
|
✗ |
if ((calling_uid != 0) && (calling_uid != repository_uid)) { |
| 326 |
|
✗ |
fprintf(stderr, "called as %d, repository owned by %d\n", |
| 327 |
|
|
calling_uid, repository_uid); |
| 328 |
|
✗ |
return 1; |
| 329 |
|
|
} |
| 330 |
|
|
|
| 331 |
|
✗ |
if (command == "lock") { |
| 332 |
|
✗ |
Remount("/cvmfs/" + fqrn, kRemountRdonly); |
| 333 |
|
✗ |
} else if (command == "open") { |
| 334 |
|
✗ |
Remount("/cvmfs/" + fqrn, kRemountRw); |
| 335 |
|
✗ |
} else if (command == "kill_cvmfs") { |
| 336 |
|
✗ |
KillCvmfs(fqrn); |
| 337 |
|
✗ |
} else if (command == "rw_mount") { |
| 338 |
|
✗ |
Mount("/cvmfs/" + fqrn); |
| 339 |
|
✗ |
} else if (command == "rw_umount") { |
| 340 |
|
✗ |
Umount("/cvmfs/" + fqrn); |
| 341 |
|
✗ |
} else if (command == "rw_lazy_umount") { |
| 342 |
|
✗ |
LazyUmount("/cvmfs/" + fqrn); |
| 343 |
|
✗ |
} else if (command == "rdonly_mount") { |
| 344 |
|
✗ |
Mount(string(kSpoolArea) + "/" + fqrn + "/rdonly"); |
| 345 |
|
✗ |
} else if (command == "rdonly_umount") { |
| 346 |
|
✗ |
Umount(string(kSpoolArea) + "/" + fqrn + "/rdonly"); |
| 347 |
|
✗ |
} else if (command == "rdonly_lazy_umount") { |
| 348 |
|
✗ |
LazyUmount(string(kSpoolArea) + "/" + fqrn + "/rdonly"); |
| 349 |
|
✗ |
} else if (command == "clear_scratch") { |
| 350 |
|
✗ |
return DoSynchronousScratchCleanup(fqrn); |
| 351 |
|
✗ |
} else if (command == "clear_scratch_async") { |
| 352 |
|
✗ |
return DoAsynchronousScratchCleanup(fqrn); |
| 353 |
|
|
} else { |
| 354 |
|
✗ |
Usage(argv[0], stderr); |
| 355 |
|
✗ |
return 1; |
| 356 |
|
|
} |
| 357 |
|
|
|
| 358 |
|
✗ |
return 0; |
| 359 |
|
|
} |
| 360 |
|
|
|