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Merge pull request #492 from richardmaw-codethink/nspawn-automatic-uid-shift-fix-v2

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nspawn: Communicate determined UID shift to parent version 2
This commit is contained in:
Lennart Poettering
2015-07-06 20:53:56 +02:00
parent 5b7a135265 825d5287d7
commit eff8efe671
1 changed files with 39 additions and 1 deletions
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src/nspawn/nspawn.c
+39 -1
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@@ -341,6 +341,11 @@ static int custom_mounts_prepare(void) {
for (i = 0; i < arg_n_custom_mounts; i++) {
CustomMount *m = &arg_custom_mounts[i];
if (arg_userns && arg_uid_shift == UID_INVALID && path_equal(m->destination, "/")) {
log_error("--private-users with automatic UID shift may not be combined with custom root mounts.");
return -EINVAL;
}
if (m->type != CUSTOM_MOUNT_OVERLAY)
continue;
@@ -1028,6 +1033,7 @@ static int tmpfs_patch_options(const char *options, char **ret) {
char *buf = NULL;
if (arg_userns && arg_uid_shift != 0) {
assert(arg_uid_shift != UID_INVALID);
if (options)
(void) asprintf(&buf, "%s,uid=" UID_FMT ",gid=" UID_FMT, options, arg_uid_shift, arg_uid_shift);
@@ -4259,6 +4265,7 @@ static int outer_child(
int pid_socket,
int kmsg_socket,
int rtnl_socket,
int uid_shift_socket,
FDSet *fds,
int argc,
char *argv[]) {
@@ -4317,6 +4324,16 @@ static int outer_child(
if (r < 0)
return r;
if (arg_userns) {
l = send(uid_shift_socket, &arg_uid_shift, sizeof(arg_uid_shift), MSG_NOSIGNAL);
if (l < 0)
return log_error_errno(errno, "Failed to send UID shift: %m");
if (l != sizeof(arg_uid_shift)) {
log_error("Short write while sending UID shift.");
return -EIO;
}
}
/* Turn directory into bind mount */
if (mount(directory, directory, NULL, MS_BIND|MS_REC, NULL) < 0)
return log_error_errno(errno, "Failed to make bind mount: %m");
@@ -4397,6 +4414,7 @@ static int outer_child(
if (pid == 0) {
pid_socket = safe_close(pid_socket);
uid_shift_socket = safe_close(uid_shift_socket);
/* The inner child has all namespaces that are
* requested, so that we all are owned by the user if
@@ -4687,7 +4705,8 @@ int main(int argc, char *argv[]) {
}
for (;;) {
_cleanup_close_pair_ int kmsg_socket_pair[2] = { -1, -1 }, rtnl_socket_pair[2] = { -1, -1 }, pid_socket_pair[2] = { -1, -1 };
_cleanup_close_pair_ int kmsg_socket_pair[2] = { -1, -1 }, rtnl_socket_pair[2] = { -1, -1 }, pid_socket_pair[2] = { -1, -1 },
uid_shift_socket_pair[2] = { -1, -1 };
ContainerStatus container_status;
_cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL;
static const struct sigaction sa = {
@@ -4722,6 +4741,12 @@ int main(int argc, char *argv[]) {
goto finish;
}
if (arg_userns)
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, uid_shift_socket_pair) < 0) {
r = log_error_errno(errno, "Failed to create uid shift socket pair: %m");
goto finish;
}
/* Child can be killed before execv(), so handle SIGCHLD
* in order to interrupt parent's blocking calls and
* give it a chance to call wait() and terminate. */
@@ -4756,6 +4781,7 @@ int main(int argc, char *argv[]) {
kmsg_socket_pair[0] = safe_close(kmsg_socket_pair[0]);
rtnl_socket_pair[0] = safe_close(rtnl_socket_pair[0]);
pid_socket_pair[0] = safe_close(pid_socket_pair[0]);
uid_shift_socket_pair[0] = safe_close(uid_shift_socket_pair[0]);
(void) reset_all_signal_handlers();
(void) reset_signal_mask();
@@ -4771,6 +4797,7 @@ int main(int argc, char *argv[]) {
pid_socket_pair[1],
kmsg_socket_pair[1],
rtnl_socket_pair[1],
uid_shift_socket_pair[1],
fds,
argc, argv);
if (r < 0)
@@ -4819,6 +4846,17 @@ int main(int argc, char *argv[]) {
goto finish;
}
l = recv(uid_shift_socket_pair[0], &arg_uid_shift, sizeof(arg_uid_shift), 0);
if (l < 0) {
r = log_error_errno(errno, "Failed to read UID shift: %m");
goto finish;
}
if (l != sizeof(arg_uid_shift)) {
log_error("Short read while reading UID shift: %m");
r = EIO;
goto finish;
}
r = setup_uid_map(pid);
if (r < 0)
goto finish;