X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fkmod.c;h=25b1031903642654eb43043ee016d78eebbb26dd;hb=dd8dbf2e6880e30c00b18600c962d0cb5a03c555;hp=d2dce71115d8cddf28dbe089b2b7bb29b59034c1;hpb=0ab4dc92278a0f3816e486d6350c6652a72e06c8;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/kmod.c b/kernel/kmod.c index d2dce71..25b1031 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -24,22 +24,26 @@ #include #include #include -#include #include #include +#include #include #include #include #include #include #include +#include +#include #include +#include + extern int max_threads; static struct workqueue_struct *khelper_wq; -#ifdef CONFIG_KMOD +#ifdef CONFIG_MODULES /* modprobe_path is set via /proc/sys. @@ -47,9 +51,10 @@ static struct workqueue_struct *khelper_wq; char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; /** - * request_module - try to load a kernel module - * @fmt: printf style format string for the name of the module - * @varargs: arguements as specified in the format string + * __request_module - try to load a kernel module + * @wait: wait (or not) for the operation to complete + * @fmt: printf style format string for the name of the module + * @...: arguments as specified in the format string * * Load a module using the user mode module loader. The function returns * zero on success or a negative errno code on failure. Note that a @@ -60,7 +65,7 @@ char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; * If module auto-loading support is disabled then this function * becomes a no-operation. */ -int request_module(const char *fmt, ...) +int __request_module(bool wait, const char *fmt, ...) { va_list args; char module_name[MODULE_NAME_LEN]; @@ -81,6 +86,10 @@ int request_module(const char *fmt, ...) if (ret >= MODULE_NAME_LEN) return -ENAMETOOLONG; + ret = security_kernel_module_request(module_name); + if (ret) + return ret; + /* If modprobe needs a service that is in a module, we get a recursive * loop. Limit the number of running kmod threads to max_threads/2 or * MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method @@ -105,21 +114,24 @@ int request_module(const char *fmt, ...) return -ENOMEM; } - ret = call_usermodehelper(modprobe_path, argv, envp, 1); + trace_module_request(module_name, wait, _RET_IP_); + + ret = call_usermodehelper(modprobe_path, argv, envp, + wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC); atomic_dec(&kmod_concurrent); return ret; } -EXPORT_SYMBOL(request_module); -#endif /* CONFIG_KMOD */ +EXPORT_SYMBOL(__request_module); +#endif /* CONFIG_MODULES */ struct subprocess_info { struct work_struct work; struct completion *complete; + struct cred *cred; char *path; char **argv; char **envp; - struct key *ring; - int wait; + enum umh_wait wait; int retval; struct file *stdin; void (*cleanup)(char **argv, char **envp); @@ -131,19 +143,20 @@ struct subprocess_info { static int ____call_usermodehelper(void *data) { struct subprocess_info *sub_info = data; - struct key *new_session, *old_session; int retval; - /* Unblock all signals and set the session keyring. */ - new_session = key_get(sub_info->ring); + BUG_ON(atomic_read(&sub_info->cred->usage) != 1); + + /* Unblock all signals */ spin_lock_irq(¤t->sighand->siglock); - old_session = __install_session_keyring(current, new_session); flush_signal_handlers(current, 1); sigemptyset(¤t->blocked); recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - key_put(old_session); + /* Install the credentials */ + commit_creds(sub_info->cred); + sub_info->cred = NULL; /* Install input pipe when needed */ if (sub_info->stdin) { @@ -163,7 +176,7 @@ static int ____call_usermodehelper(void *data) } /* We can run anywhere, unlike our parent keventd(). */ - set_cpus_allowed(current, CPU_MASK_ALL); + set_cpus_allowed_ptr(current, cpu_all_mask); /* * Our parent is keventd, which runs with elevated scheduling priority. @@ -171,10 +184,7 @@ static int ____call_usermodehelper(void *data) */ set_user_nice(current, 0); - retval = -EPERM; - if (current->fs->root) - retval = kernel_execve(sub_info->path, - sub_info->argv, sub_info->envp); + retval = kernel_execve(sub_info->path, sub_info->argv, sub_info->envp); /* Exec failed? */ sub_info->retval = retval; @@ -185,6 +195,8 @@ void call_usermodehelper_freeinfo(struct subprocess_info *info) { if (info->cleanup) (*info->cleanup)(info->argv, info->envp); + if (info->cred) + put_cred(info->cred); kfree(info); } EXPORT_SYMBOL(call_usermodehelper_freeinfo); @@ -225,7 +237,7 @@ static int wait_for_helper(void *data) sub_info->retval = ret; } - if (sub_info->wait < 0) + if (sub_info->wait == UMH_NO_WAIT) call_usermodehelper_freeinfo(sub_info); else complete(sub_info->complete); @@ -238,43 +250,125 @@ static void __call_usermodehelper(struct work_struct *work) struct subprocess_info *sub_info = container_of(work, struct subprocess_info, work); pid_t pid; - int wait = sub_info->wait; + enum umh_wait wait = sub_info->wait; + + BUG_ON(atomic_read(&sub_info->cred->usage) != 1); /* CLONE_VFORK: wait until the usermode helper has execve'd * successfully We need the data structures to stay around * until that is done. */ - if (wait) + if (wait == UMH_WAIT_PROC || wait == UMH_NO_WAIT) pid = kernel_thread(wait_for_helper, sub_info, CLONE_FS | CLONE_FILES | SIGCHLD); else pid = kernel_thread(____call_usermodehelper, sub_info, CLONE_VFORK | SIGCHLD); - if (wait < 0) - return; + switch (wait) { + case UMH_NO_WAIT: + break; - if (pid < 0) { + case UMH_WAIT_PROC: + if (pid > 0) + break; sub_info->retval = pid; + /* FALLTHROUGH */ + + case UMH_WAIT_EXEC: complete(sub_info->complete); - } else if (!wait) - complete(sub_info->complete); + } +} + +#ifdef CONFIG_PM_SLEEP +/* + * If set, call_usermodehelper_exec() will exit immediately returning -EBUSY + * (used for preventing user land processes from being created after the user + * land has been frozen during a system-wide hibernation or suspend operation). + */ +static int usermodehelper_disabled; + +/* Number of helpers running */ +static atomic_t running_helpers = ATOMIC_INIT(0); + +/* + * Wait queue head used by usermodehelper_pm_callback() to wait for all running + * helpers to finish. + */ +static DECLARE_WAIT_QUEUE_HEAD(running_helpers_waitq); + +/* + * Time to wait for running_helpers to become zero before the setting of + * usermodehelper_disabled in usermodehelper_pm_callback() fails + */ +#define RUNNING_HELPERS_TIMEOUT (5 * HZ) + +/** + * usermodehelper_disable - prevent new helpers from being started + */ +int usermodehelper_disable(void) +{ + long retval; + + usermodehelper_disabled = 1; + smp_mb(); + /* + * From now on call_usermodehelper_exec() won't start any new + * helpers, so it is sufficient if running_helpers turns out to + * be zero at one point (it may be increased later, but that + * doesn't matter). + */ + retval = wait_event_timeout(running_helpers_waitq, + atomic_read(&running_helpers) == 0, + RUNNING_HELPERS_TIMEOUT); + if (retval) + return 0; + + usermodehelper_disabled = 0; + return -EAGAIN; } /** + * usermodehelper_enable - allow new helpers to be started again + */ +void usermodehelper_enable(void) +{ + usermodehelper_disabled = 0; +} + +static void helper_lock(void) +{ + atomic_inc(&running_helpers); + smp_mb__after_atomic_inc(); +} + +static void helper_unlock(void) +{ + if (atomic_dec_and_test(&running_helpers)) + wake_up(&running_helpers_waitq); +} +#else /* CONFIG_PM_SLEEP */ +#define usermodehelper_disabled 0 + +static inline void helper_lock(void) {} +static inline void helper_unlock(void) {} +#endif /* CONFIG_PM_SLEEP */ + +/** * call_usermodehelper_setup - prepare to call a usermode helper - * @path - path to usermode executable - * @argv - arg vector for process - * @envp - environment for process + * @path: path to usermode executable + * @argv: arg vector for process + * @envp: environment for process + * @gfp_mask: gfp mask for memory allocation * - * Returns either NULL on allocation failure, or a subprocess_info + * Returns either %NULL on allocation failure, or a subprocess_info * structure. This should be passed to call_usermodehelper_exec to * exec the process and free the structure. */ -struct subprocess_info *call_usermodehelper_setup(char *path, - char **argv, char **envp) +struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, + char **envp, gfp_t gfp_mask) { struct subprocess_info *sub_info; - sub_info = kzalloc(sizeof(struct subprocess_info), GFP_ATOMIC); + sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); if (!sub_info) goto out; @@ -282,6 +376,11 @@ struct subprocess_info *call_usermodehelper_setup(char *path, sub_info->path = path; sub_info->argv = argv; sub_info->envp = envp; + sub_info->cred = prepare_usermodehelper_creds(); + if (!sub_info->cred) { + kfree(sub_info); + return NULL; + } out: return sub_info; @@ -296,7 +395,13 @@ EXPORT_SYMBOL(call_usermodehelper_setup); void call_usermodehelper_setkeys(struct subprocess_info *info, struct key *session_keyring) { - info->ring = session_keyring; +#ifdef CONFIG_KEYS + struct thread_group_cred *tgcred = info->cred->tgcred; + key_put(tgcred->session_keyring); + tgcred->session_keyring = key_get(session_keyring); +#else + BUG(); +#endif } EXPORT_SYMBOL(call_usermodehelper_setkeys); @@ -330,12 +435,12 @@ int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info, { struct file *f; - f = create_write_pipe(); + f = create_write_pipe(0); if (IS_ERR(f)) return PTR_ERR(f); *filp = f; - f = create_read_pipe(f); + f = create_read_pipe(f, 0); if (IS_ERR(f)) { free_write_pipe(*filp); return PTR_ERR(f); @@ -359,17 +464,19 @@ EXPORT_SYMBOL(call_usermodehelper_stdinpipe); * (ie. it runs with full root capabilities). */ int call_usermodehelper_exec(struct subprocess_info *sub_info, - int wait) + enum umh_wait wait) { DECLARE_COMPLETION_ONSTACK(done); - int retval; + int retval = 0; + + BUG_ON(atomic_read(&sub_info->cred->usage) != 1); + validate_creds(sub_info->cred); - if (sub_info->path[0] == '\0') { - retval = 0; + helper_lock(); + if (sub_info->path[0] == '\0') goto out; - } - if (!khelper_wq) { + if (!khelper_wq || usermodehelper_disabled) { retval = -EBUSY; goto out; } @@ -378,13 +485,15 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, sub_info->wait = wait; queue_work(khelper_wq, &sub_info->work); - if (wait < 0) /* task has freed sub_info */ - return 0; + if (wait == UMH_NO_WAIT) /* task has freed sub_info */ + goto unlock; wait_for_completion(&done); retval = sub_info->retval; - out: +out: call_usermodehelper_freeinfo(sub_info); +unlock: + helper_unlock(); return retval; } EXPORT_SYMBOL(call_usermodehelper_exec); @@ -406,7 +515,7 @@ int call_usermodehelper_pipe(char *path, char **argv, char **envp, struct subprocess_info *sub_info; int ret; - sub_info = call_usermodehelper_setup(path, argv, envp); + sub_info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL); if (sub_info == NULL) return -ENOMEM; @@ -414,7 +523,7 @@ int call_usermodehelper_pipe(char *path, char **argv, char **envp, if (ret < 0) goto out; - return call_usermodehelper_exec(sub_info, 1); + return call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC); out: call_usermodehelper_freeinfo(sub_info);