X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fkmod.c;h=a27a5f64443dc5c9a27d04679171cf15dfc1eabf;hb=58763a297405024d23d8f1d0bba3e6603660c4b6;hp=4d32eb077179a2babd3f49b9f31631d4c6e27bb7;hpb=90cce03d9bfcb28600a56efef6b0a5a4fbf6c2b1;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/kmod.c b/kernel/kmod.c index 4d32eb0..a27a5f6 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -27,19 +27,22 @@ #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. @@ -48,8 +51,8 @@ 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 + * @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 @@ -110,18 +113,19 @@ int request_module(const char *fmt, ...) return ret; } EXPORT_SYMBOL(request_module); -#endif /* CONFIG_KMOD */ +#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); }; /* @@ -130,19 +134,20 @@ 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) { @@ -162,7 +167,7 @@ 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_MASK_ALL_PTR); /* * Our parent is keventd, which runs with elevated scheduling priority. @@ -170,16 +175,23 @@ 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; do_exit(0); } +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); + /* Keventd can't block, but this (a child) can. */ static int wait_for_helper(void *data) { @@ -216,8 +228,8 @@ static int wait_for_helper(void *data) sub_info->retval = ret; } - if (sub_info->wait < 0) - kfree(sub_info); + if (sub_info->wait == UMH_NO_WAIT) + call_usermodehelper_freeinfo(sub_info); else complete(sub_info->complete); return 0; @@ -229,34 +241,208 @@ 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; } /** - * call_usermodehelper_keys - start a usermode application - * @path: pathname for the application - * @argv: null-terminated argument list - * @envp: null-terminated environment list - * @session_keyring: session keyring for process (NULL for an empty keyring) + * 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 + * @gfp_mask: gfp mask for memory allocation + * + * 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, gfp_t gfp_mask) +{ + struct subprocess_info *sub_info; + sub_info = kzalloc(sizeof(struct subprocess_info), gfp_mask); + if (!sub_info) + goto out; + + INIT_WORK(&sub_info->work, __call_usermodehelper); + sub_info->path = path; + sub_info->argv = argv; + sub_info->envp = envp; + sub_info->cred = prepare_usermodehelper_creds(); + if (!sub_info->cred) + return NULL; + + out: + return sub_info; +} +EXPORT_SYMBOL(call_usermodehelper_setup); + +/** + * call_usermodehelper_setkeys - set the session keys for usermode helper + * @info: a subprocess_info returned by call_usermodehelper_setup + * @session_keyring: the session keyring for the process + */ +void call_usermodehelper_setkeys(struct subprocess_info *info, + struct key *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); + +/** + * call_usermodehelper_setcleanup - set a cleanup function + * @info: a subprocess_info returned by call_usermodehelper_setup + * @cleanup: a cleanup function + * + * The cleanup function is just befor ethe subprocess_info is about to + * be freed. This can be used for freeing the argv and envp. The + * Function must be runnable in either a process context or the + * context in which call_usermodehelper_exec is called. + */ +void call_usermodehelper_setcleanup(struct subprocess_info *info, + void (*cleanup)(char **argv, char **envp)) +{ + info->cleanup = cleanup; +} +EXPORT_SYMBOL(call_usermodehelper_setcleanup); + +/** + * call_usermodehelper_stdinpipe - set up a pipe to be used for stdin + * @sub_info: a subprocess_info returned by call_usermodehelper_setup + * @filp: set to the write-end of a pipe + * + * This constructs a pipe, and sets the read end to be the stdin of the + * subprocess, and returns the write-end in *@filp. + */ +int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info, + struct file **filp) +{ + struct file *f; + + f = create_write_pipe(0); + if (IS_ERR(f)) + return PTR_ERR(f); + *filp = f; + + f = create_read_pipe(f, 0); + if (IS_ERR(f)) { + free_write_pipe(*filp); + return PTR_ERR(f); + } + sub_info->stdin = f; + + return 0; +} +EXPORT_SYMBOL(call_usermodehelper_stdinpipe); + +/** + * call_usermodehelper_exec - start a usermode application + * @sub_info: information about the subprocessa * @wait: wait for the application to finish and return status. * when -1 don't wait at all, but you get no useful error back when * the program couldn't be exec'ed. This makes it safe to call @@ -265,81 +451,71 @@ static void __call_usermodehelper(struct work_struct *work) * Runs a user-space application. The application is started * asynchronously if wait is not set, and runs as a child of keventd. * (ie. it runs with full root capabilities). - * - * Must be called from process context. Returns a negative error code - * if program was not execed successfully, or 0. */ -int call_usermodehelper_keys(char *path, char **argv, char **envp, - struct key *session_keyring, int wait) +int call_usermodehelper_exec(struct subprocess_info *sub_info, + enum umh_wait wait) { DECLARE_COMPLETION_ONSTACK(done); - struct subprocess_info *sub_info; - int retval; + int retval = 0; - if (!khelper_wq) - return -EBUSY; + BUG_ON(atomic_read(&sub_info->cred->usage) != 1); - if (path[0] == '\0') - return 0; + helper_lock(); + if (sub_info->path[0] == '\0') + goto out; - sub_info = kzalloc(sizeof(struct subprocess_info), GFP_ATOMIC); - if (!sub_info) - return -ENOMEM; + if (!khelper_wq || usermodehelper_disabled) { + retval = -EBUSY; + goto out; + } - INIT_WORK(&sub_info->work, __call_usermodehelper); sub_info->complete = &done; - sub_info->path = path; - sub_info->argv = argv; - sub_info->envp = envp; - sub_info->ring = session_keyring; 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; - kfree(sub_info); + +out: + call_usermodehelper_freeinfo(sub_info); +unlock: + helper_unlock(); return retval; } -EXPORT_SYMBOL(call_usermodehelper_keys); +EXPORT_SYMBOL(call_usermodehelper_exec); +/** + * call_usermodehelper_pipe - call a usermode helper process with a pipe stdin + * @path: path to usermode executable + * @argv: arg vector for process + * @envp: environment for process + * @filp: set to the write-end of a pipe + * + * This is a simple wrapper which executes a usermode-helper function + * with a pipe as stdin. It is implemented entirely in terms of + * lower-level call_usermodehelper_* functions. + */ int call_usermodehelper_pipe(char *path, char **argv, char **envp, struct file **filp) { - DECLARE_COMPLETION(done); - struct subprocess_info sub_info = { - .work = __WORK_INITIALIZER(sub_info.work, - __call_usermodehelper), - .complete = &done, - .path = path, - .argv = argv, - .envp = envp, - .retval = 0, - }; - struct file *f; - - if (!khelper_wq) - return -EBUSY; + struct subprocess_info *sub_info; + int ret; - if (path[0] == '\0') - return 0; + sub_info = call_usermodehelper_setup(path, argv, envp, GFP_KERNEL); + if (sub_info == NULL) + return -ENOMEM; - f = create_write_pipe(); - if (IS_ERR(f)) - return PTR_ERR(f); - *filp = f; + ret = call_usermodehelper_stdinpipe(sub_info, filp); + if (ret < 0) + goto out; - f = create_read_pipe(f); - if (IS_ERR(f)) { - free_write_pipe(*filp); - return PTR_ERR(f); - } - sub_info.stdin = f; + return call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC); - queue_work(khelper_wq, &sub_info.work); - wait_for_completion(&done); - return sub_info.retval; + out: + call_usermodehelper_freeinfo(sub_info); + return ret; } EXPORT_SYMBOL(call_usermodehelper_pipe);