[lxc-devel] [lxc/master] attach: fix return value & cleanups
2xsec on Github
lxc-bot at linuxcontainers.org
Sat Jul 21 07:07:11 UTC 2018
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-------------- next part --------------
From ea918412a796ba346c34c091030b6ce0c8221e2b Mon Sep 17 00:00:00 2001
From: 2xsec <dh48.jeong at samsung.com>
Date: Sat, 21 Jul 2018 16:04:01 +0900
Subject: [PATCH] attach: fix return value & cleanups
Signed-off-by: 2xsec <dh48.jeong at samsung.com>
---
src/lxc/attach.c | 127 ++++++++++++++++++++++++++++++++++++++-----------------
src/lxc/start.c | 4 ++
src/lxc/utils.c | 7 +--
3 files changed, 97 insertions(+), 41 deletions(-)
diff --git a/src/lxc/attach.c b/src/lxc/attach.c
index 9bc3e23d1..993341961 100644
--- a/src/lxc/attach.c
+++ b/src/lxc/attach.c
@@ -108,18 +108,19 @@ static struct lxc_proc_context_info *lxc_proc_get_context_info(pid_t pid)
proc_file = fopen(proc_fn, "r");
if (!proc_file) {
- SYSERROR("Could not open %s.", proc_fn);
+ SYSERROR("Could not open %s", proc_fn);
goto on_error;
}
info = calloc(1, sizeof(*info));
if (!info) {
- SYSERROR("Could not allocate memory.");
+ SYSERROR("Could not allocate memory");
fclose(proc_file);
return NULL;
}
found = false;
+
while (getline(&line, &line_bufsz, proc_file) != -1) {
ret = sscanf(line, "CapBnd: %llx", &info->capability_mask);
if (ret != EOF && ret == 1) {
@@ -132,9 +133,8 @@ static struct lxc_proc_context_info *lxc_proc_get_context_info(pid_t pid)
fclose(proc_file);
if (!found) {
- SYSERROR("Could not read capability bounding set from %s.",
- proc_fn);
- errno = ENOENT;
+ ERROR("Could not read capability bounding set from %s",
+ proc_fn);
goto on_error;
}
@@ -156,6 +156,7 @@ static inline void lxc_proc_close_ns_fd(struct lxc_proc_context_info *ctx)
for (i = 0; i < LXC_NS_MAX; i++) {
if (ctx->ns_fd[i] < 0)
continue;
+
close(ctx->ns_fd[i]);
ctx->ns_fd[i] = -EBADF;
}
@@ -189,6 +190,7 @@ static void lxc_proc_put_context_info(struct lxc_proc_context_info *ctx)
static int in_same_namespace(pid_t pid1, pid_t pid2, const char *ns)
{
int ns_fd1 = -1, ns_fd2 = -1, ret = -1;
+ int saved_errno = errno;
struct stat ns_st1, ns_st2;
ns_fd1 = lxc_preserve_ns(pid1, ns);
@@ -199,52 +201,60 @@ static int in_same_namespace(pid_t pid1, pid_t pid2, const char *ns)
if (errno == ENOENT)
return -EINVAL;
+ saved_errno = errno;
goto out;
}
ns_fd2 = lxc_preserve_ns(pid2, ns);
- if (ns_fd2 < 0)
+ if (ns_fd2 < 0) {
+ saved_errno = errno;
goto out;
+ }
ret = fstat(ns_fd1, &ns_st1);
- if (ret < 0)
+ if (ret < 0) {
+ saved_errno = errno;
goto out;
+ }
ret = fstat(ns_fd2, &ns_st2);
- if (ret < 0)
+ if (ret < 0) {
+ saved_errno = errno;
goto out;
+ }
/* processes are in the same namespace */
- ret = -EINVAL;
- if ((ns_st1.st_dev == ns_st2.st_dev ) && (ns_st1.st_ino == ns_st2.st_ino))
+ if ((ns_st1.st_dev == ns_st2.st_dev ) && (ns_st1.st_ino == ns_st2.st_ino)) {
+ ret = -EINVAL;
goto out;
+ }
/* processes are in different namespaces */
ret = ns_fd2;
ns_fd2 = -1;
out:
-
if (ns_fd1 >= 0)
close(ns_fd1);
+
if (ns_fd2 >= 0)
close(ns_fd2);
+ errno = saved_errno;
return ret;
}
static int lxc_attach_to_ns(pid_t pid, struct lxc_proc_context_info *ctx)
{
- int i, ret;
+ int i;
for (i = 0; i < LXC_NS_MAX; i++) {
if (ctx->ns_fd[i] < 0)
continue;
- ret = setns(ctx->ns_fd[i], ns_info[i].clone_flag);
- if (ret < 0) {
+ if (setns(ctx->ns_fd[i], ns_info[i].clone_flag) < 0) {
SYSERROR("Failed to attach to %s namespace of %d",
- ns_info[i].proc_name, pid);
+ ns_info[i].proc_name, pid);
return -1;
}
@@ -260,13 +270,13 @@ static int lxc_attach_remount_sys_proc(void)
ret = unshare(CLONE_NEWNS);
if (ret < 0) {
- SYSERROR("Failed to unshare mount namespace.");
+ SYSERROR("Failed to unshare mount namespace");
return -1;
}
if (detect_shared_rootfs()) {
if (mount(NULL, "/", NULL, MS_SLAVE | MS_REC, NULL)) {
- SYSERROR("Failed to make / rslave.");
+ SYSERROR("Failed to make / rslave");
ERROR("Continuing...");
}
}
@@ -274,13 +284,13 @@ static int lxc_attach_remount_sys_proc(void)
/* Assume /proc is always mounted, so remount it. */
ret = umount2("/proc", MNT_DETACH);
if (ret < 0) {
- SYSERROR("Failed to unmount /proc.");
+ SYSERROR("Failed to unmount /proc");
return -1;
}
ret = mount("none", "/proc", "proc", 0, NULL);
if (ret < 0) {
- SYSERROR("Failed to remount /proc.");
+ SYSERROR("Failed to remount /proc");
return -1;
}
@@ -289,13 +299,13 @@ static int lxc_attach_remount_sys_proc(void)
*/
ret = umount2("/sys", MNT_DETACH);
if (ret < 0 && errno != EINVAL) {
- SYSERROR("Failed to unmount /sys.");
+ SYSERROR("Failed to unmount /sys");
return -1;
} else if (ret == 0) {
/* Remount it. */
ret = mount("none", "/sys", "sysfs", 0, NULL);
if (ret < 0) {
- SYSERROR("Failed to remount /sys.");
+ SYSERROR("Failed to remount /sys");
return -1;
}
}
@@ -316,6 +326,7 @@ static int lxc_attach_drop_privs(struct lxc_proc_context_info *ctx)
SYSERROR("Failed to drop capability %d", cap);
return -1;
}
+
TRACE("Dropped capability %d", cap);
}
@@ -350,6 +361,7 @@ static int lxc_attach_set_environment(struct lxc_proc_context_info *init_ctx,
if (!extra_keep_store[i]) {
while (i > 0)
free(extra_keep_store[--i]);
+
free(extra_keep_store);
return -1;
}
@@ -370,7 +382,7 @@ static int lxc_attach_set_environment(struct lxc_proc_context_info *init_ctx,
free(extra_keep_store);
}
- SYSERROR("Failed to clear environment");
+ ERROR("Failed to clear environment");
return -1;
}
@@ -383,8 +395,10 @@ static int lxc_attach_set_environment(struct lxc_proc_context_info *init_ctx,
if (ret < 0)
SYSWARN("Failed to set environment variable");
}
+
free(extra_keep_store[i]);
}
+
free(extra_keep_store);
}
@@ -427,6 +441,7 @@ static int lxc_attach_set_environment(struct lxc_proc_context_info *init_ctx,
if (extra_env) {
for (; *extra_env; extra_env++) {
char *p;
+
/* We just assume the user knows what they are doing, so
* we don't do any checks.
*/
@@ -482,7 +497,7 @@ static char *lxc_attach_getpwshell(uid_t uid)
ret = dup2(pipes[1], STDOUT_FILENO);
close(pipes[1]);
if (ret < 0)
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
/* Get rid of stdin/stderr, so we try to associate it with
* /dev/null.
@@ -500,11 +515,11 @@ static char *lxc_attach_getpwshell(uid_t uid)
/* Finish argument list. */
ret = snprintf(uid_buf, sizeof(uid_buf), "%ld", (long)uid);
if (ret <= 0 || ret >= sizeof(uid_buf))
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
/* Try to run getent program. */
(void)execvp("getent", arguments);
- exit(EXIT_FAILURE);
+ _exit(EXIT_FAILURE);
}
close(pipes[1]);
@@ -541,7 +556,7 @@ static char *lxc_attach_getpwshell(uid_t uid)
token = strtok_r(NULL, ":", &saveptr);
value = token ? strtol(token, &endptr, 10) : 0;
if (!token || !endptr || *endptr || value == LONG_MIN ||
- value == LONG_MAX)
+ value == LONG_MAX)
continue;
/* dummy sanity check: user id matches */
@@ -554,8 +569,10 @@ static char *lxc_attach_getpwshell(uid_t uid)
if (!token)
continue;
}
+
if (!token)
continue;
+
free(result);
result = strdup(token);
@@ -566,6 +583,7 @@ static char *lxc_attach_getpwshell(uid_t uid)
found = true;
}
+
free(line);
fclose(pipe_f);
@@ -614,6 +632,7 @@ static void lxc_attach_get_init_uidgid(uid_t *init_uid, gid_t *init_gid)
if (ret != EOF && ret == 1)
gid = (gid_t)value;
}
+
if (uid != (uid_t)-1 && gid != (gid_t)-1)
break;
}
@@ -624,6 +643,7 @@ static void lxc_attach_get_init_uidgid(uid_t *init_uid, gid_t *init_gid)
/* Only override arguments if we found something. */
if (uid != (uid_t)-1)
*init_uid = uid;
+
if (gid != (gid_t)-1)
*init_gid = gid;
@@ -658,14 +678,14 @@ static bool fetch_seccomp(struct lxc_container *c, lxc_attach_options_t *options
/* Remove current setting. */
if (!c->set_config_item(c, "lxc.seccomp.profile", "") &&
- !c->set_config_item(c, "lxc.seccomp", "")) {
+ !c->set_config_item(c, "lxc.seccomp", ""))
return false;
- }
/* Fetch the current profile path over the cmd interface. */
path = c->get_running_config_item(c, "lxc.seccomp.profile");
if (!path) {
INFO("Failed to retrieve lxc.seccomp.profile");
+
path = c->get_running_config_item(c, "lxc.seccomp");
if (!path) {
INFO("Failed to retrieve lxc.seccomp");
@@ -778,6 +798,7 @@ static int attach_child_main(struct attach_clone_payload *payload)
ret = lxc_attach_remount_sys_proc();
if (ret < 0)
goto on_error;
+
TRACE("Remounted \"/proc\" and \"/sys\"");
}
@@ -790,9 +811,11 @@ static int attach_child_main(struct attach_clone_payload *payload)
new_personality = init_ctx->personality;
else
new_personality = options->personality;
+
ret = personality(new_personality);
if (ret < 0)
goto on_error;
+
TRACE("Set new personality");
}
#endif
@@ -801,6 +824,7 @@ static int attach_child_main(struct attach_clone_payload *payload)
ret = lxc_attach_drop_privs(init_ctx);
if (ret < 0)
goto on_error;
+
TRACE("Dropped capabilities");
}
@@ -813,6 +837,7 @@ static int attach_child_main(struct attach_clone_payload *payload)
options->extra_keep_env);
if (ret < 0)
goto on_error;
+
TRACE("Set up environment");
/* This remark only affects fully unprivileged containers:
@@ -847,6 +872,7 @@ static int attach_child_main(struct attach_clone_payload *payload)
/* Set {u,g}id. */
new_uid = 0;
new_gid = 0;
+
/* Ignore errors, we will fall back to root in that case (/proc was not
* mounted etc.).
*/
@@ -855,6 +881,7 @@ static int attach_child_main(struct attach_clone_payload *payload)
if (options->uid != (uid_t)-1)
new_uid = options->uid;
+
if (options->gid != (gid_t)-1)
new_gid = options->gid;
@@ -875,6 +902,7 @@ static int attach_child_main(struct attach_clone_payload *payload)
ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);
if (ret < 0)
goto on_error;
+
TRACE("Set PR_SET_NO_NEW_PRIVS");
}
@@ -883,10 +911,12 @@ static int attach_child_main(struct attach_clone_payload *payload)
/* Change into our new LSM profile. */
on_exec = options->attach_flags & LXC_ATTACH_LSM_EXEC ? true : false;
+
ret = lsm_process_label_set_at(lsm_fd, init_ctx->lsm_label, on_exec);
close(lsm_fd);
if (ret < 0)
goto on_error;
+
TRACE("Set %s LSM label to \"%s\"", lsm_name(), init_ctx->lsm_label);
}
@@ -895,8 +925,10 @@ static int attach_child_main(struct attach_clone_payload *payload)
ret = lxc_seccomp_load(init_ctx->container->lxc_conf);
if (ret < 0)
goto on_error;
+
TRACE("Loaded seccomp profile");
}
+
shutdown(payload->ipc_socket, SHUT_RDWR);
close(payload->ipc_socket);
payload->ipc_socket = -EBADF;
@@ -948,6 +980,7 @@ static int attach_child_main(struct attach_clone_payload *payload)
SYSERROR("Failed to prepare terminal file descriptor %d", payload->terminal_slave_fd);
goto on_error;
}
+
TRACE("Prepared terminal file descriptor %d", payload->terminal_slave_fd);
}
@@ -968,7 +1001,7 @@ static int lxc_attach_terminal(struct lxc_conf *conf,
ret = lxc_terminal_create(terminal);
if (ret < 0) {
- SYSERROR("Failed to create terminal");
+ ERROR("Failed to create terminal");
return -1;
}
@@ -1060,7 +1093,7 @@ int lxc_attach(const char *name, const char *lxcpath,
ret = access("/proc/self/ns", X_OK);
if (ret) {
- ERROR("Does this kernel version support namespaces?");
+ SYSERROR("Does this kernel version support namespaces?");
return -1;
}
@@ -1097,7 +1130,7 @@ int lxc_attach(const char *name, const char *lxcpath,
init_ctx->container->lxc_conf = lxc_conf_init();
if (!init_ctx->container->lxc_conf) {
lxc_proc_put_context_info(init_ctx);
- return -ENOMEM;
+ return -1;
}
}
conf = init_ctx->container->lxc_conf;
@@ -1138,8 +1171,9 @@ int lxc_attach(const char *name, const char *lxcpath,
}
pid = lxc_raw_getpid();
+
for (i = 0; i < LXC_NS_MAX; i++) {
- int j, saved_errno;
+ int j;
if (options->namespaces & ns_info[i].clone_flag)
init_ctx->ns_fd[i] = lxc_preserve_ns(init_pid, ns_info[i].proc_name);
@@ -1147,6 +1181,7 @@ int lxc_attach(const char *name, const char *lxcpath,
init_ctx->ns_fd[i] = in_same_namespace(pid, init_pid, ns_info[i].proc_name);
else
continue;
+
if (init_ctx->ns_fd[i] >= 0)
continue;
@@ -1158,16 +1193,15 @@ int lxc_attach(const char *name, const char *lxcpath,
}
/* We failed to preserve the namespace. */
- saved_errno = errno;
+ SYSERROR("Failed to attach to %s namespace of %d",
+ ns_info[i].proc_name, pid);
+
/* Close all already opened file descriptors before we return an
* error, so we don't leak them.
*/
for (j = 0; j < i; j++)
close(init_ctx->ns_fd[j]);
- errno = saved_errno;
- SYSERROR("Failed to attach to %s namespace of %d",
- ns_info[i].proc_name, pid);
free(cwd);
lxc_proc_put_context_info(init_ctx);
return -1;
@@ -1288,6 +1322,7 @@ int lxc_attach(const char *name, const char *lxcpath,
ret = lxc_attach_terminal_mainloop_init(&terminal, &descr);
if (ret < 0)
goto on_error;
+
TRACE("Initialized terminal mainloop");
}
@@ -1296,12 +1331,14 @@ int lxc_attach(const char *name, const char *lxcpath,
ret = lxc_write_nointr(ipc_sockets[0], &status, sizeof(status));
if (ret != sizeof(status))
goto close_mainloop;
+
TRACE("Told intermediate process to start initializing");
/* Get pid of attached process from intermediate process. */
ret = lxc_read_nointr(ipc_sockets[0], &attached_pid, sizeof(attached_pid));
if (ret != sizeof(attached_pid))
goto close_mainloop;
+
TRACE("Received pid %d of attached process in parent pid namespace", attached_pid);
/* Ignore SIGKILL (CTRL-C) and SIGQUIT (CTRL-\) - issue #313. */
@@ -1314,6 +1351,7 @@ int lxc_attach(const char *name, const char *lxcpath,
ret = wait_for_pid(pid);
if (ret < 0)
goto close_mainloop;
+
TRACE("Intermediate process %d exited", pid);
/* We will always have to reap the attached process now. */
@@ -1331,6 +1369,7 @@ int lxc_attach(const char *name, const char *lxcpath,
labelfd = lsm_process_label_fd_get(attached_pid, on_exec);
if (labelfd < 0)
goto close_mainloop;
+
TRACE("Opened LSM label file descriptor %d", labelfd);
/* Send child fd of the LSM security module to write to. */
@@ -1361,6 +1400,7 @@ int lxc_attach(const char *name, const char *lxcpath,
ret_parent = 0;
to_cleanup_pid = -1;
+
if (options->attach_flags & LXC_ATTACH_TERMINAL) {
ret = lxc_mainloop(&descr, -1);
if (ret < 0) {
@@ -1386,6 +1426,7 @@ int lxc_attach(const char *name, const char *lxcpath,
lxc_terminal_delete(&terminal);
lxc_terminal_conf_free(&terminal);
}
+
lxc_proc_put_context_info(init_ctx);
return ret_parent;
}
@@ -1393,6 +1434,7 @@ int lxc_attach(const char *name, const char *lxcpath,
/* close unneeded file descriptors */
close(ipc_sockets[0]);
ipc_sockets[0] = -EBADF;
+
if (options->attach_flags & LXC_ATTACH_TERMINAL) {
lxc_attach_terminal_close_master(&terminal);
lxc_attach_terminal_close_peer(&terminal);
@@ -1406,6 +1448,7 @@ int lxc_attach(const char *name, const char *lxcpath,
lxc_proc_put_context_info(init_ctx);
rexit(-1);
}
+
TRACE("Intermediate process starting to initialize");
/* Attach now, create another subprocess later, since pid namespaces
@@ -1418,6 +1461,7 @@ int lxc_attach(const char *name, const char *lxcpath,
lxc_proc_put_context_info(init_ctx);
rexit(-1);
}
+
/* close namespace file descriptors */
lxc_proc_close_ns_fd(init_ctx);
@@ -1453,8 +1497,10 @@ int lxc_attach(const char *name, const char *lxcpath,
ret = attach_child_main(&payload);
if (ret < 0)
ERROR("Failed to exec");
+
_exit(EXIT_FAILURE);
}
+
if (options->attach_flags & LXC_ATTACH_TERMINAL)
lxc_attach_terminal_close_slave(&terminal);
@@ -1471,6 +1517,7 @@ int lxc_attach(const char *name, const char *lxcpath,
lxc_proc_put_context_info(init_ctx);
rexit(-1);
}
+
TRACE("Sending pid %d of attached process", pid);
/* The rest is in the hands of the initial and the attached process. */
@@ -1483,7 +1530,8 @@ int lxc_attach_run_command(void* payload)
lxc_attach_command_t* cmd = (lxc_attach_command_t*)payload;
execvp(cmd->program, cmd->argv);
- SYSERROR("Failed to exec \"%s\".", cmd->program);
+
+ SYSERROR("Failed to exec \"%s\"", cmd->program);
return -1;
}
@@ -1511,7 +1559,7 @@ int lxc_attach_run_shell(void* payload)
ret = getpwuid_r(uid, &pwent, buf, bufsize, &pwentp);
if (!pwentp) {
if (ret == 0)
- WARN("Could not find matched password record.");
+ WARN("Could not find matched password record");
WARN("Failed to get password record - %u", uid);
}
@@ -1527,6 +1575,7 @@ int lxc_attach_run_shell(void* payload)
user_shell = lxc_attach_getpwshell(uid);
else
user_shell = pwent.pw_shell;
+
if (user_shell)
execlp(user_shell, user_shell, (char *)NULL);
@@ -1534,9 +1583,11 @@ int lxc_attach_run_shell(void* payload)
* on /bin/sh as a default shell.
*/
execlp("/bin/sh", "/bin/sh", (char *)NULL);
+
SYSERROR("Failed to execute shell");
if (!pwentp)
free(user_shell);
+
free(buf);
return -1;
}
diff --git a/src/lxc/start.c b/src/lxc/start.c
index a970d3c15..1d22a6a59 100644
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -868,12 +868,16 @@ int lxc_init(const char *name, struct lxc_handler *handler)
out_delete_terminal:
lxc_terminal_delete(&handler->conf->console);
+
out_restore_sigmask:
(void)pthread_sigmask(SIG_SETMASK, &handler->oldmask, NULL);
+
out_delete_tty:
lxc_delete_tty(&conf->ttys);
+
out_aborting:
(void)lxc_set_state(name, handler, ABORTING);
+
out_close_maincmd_fd:
lxc_abstract_unix_close(conf->maincmd_fd);
conf->maincmd_fd = -1;
diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 6bb05df00..dd6cdc91a 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -2038,9 +2038,10 @@ int lxc_preserve_ns(const int pid, const char *ns)
ret = snprintf(path, __NS_PATH_LEN, "/proc/%d/ns%s%s", pid,
!ns || strcmp(ns, "") == 0 ? "" : "/",
!ns || strcmp(ns, "") == 0 ? "" : ns);
- errno = EFBIG;
- if (ret < 0 || (size_t)ret >= __NS_PATH_LEN)
- return -EFBIG;
+ if (ret < 0 || (size_t)ret >= __NS_PATH_LEN) {
+ errno = EFBIG;
+ return -1;
+ }
return open(path, O_RDONLY | O_CLOEXEC);
}
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