diff options
| -rw-r--r-- | fs/exec.c | 63 | ||||
| -rw-r--r-- | include/linux/kmod.h | 7 | ||||
| -rw-r--r-- | kernel/kmod.c | 82 |
3 files changed, 56 insertions, 96 deletions
@@ -1787,6 +1787,50 @@ static void wait_for_dump_helpers(struct file *file) } +/* + * uhm_pipe_setup + * helper function to customize the process used + * to collect the core in userspace. Specifically + * it sets up a pipe and installs it as fd 0 (stdin) + * for the process. Returns 0 on success, or + * PTR_ERR on failure. + * Note that it also sets the core limit to 1. This + * is a special value that we use to trap recursive + * core dumps + */ +static int umh_pipe_setup(struct subprocess_info *info) +{ + struct file *rp, *wp; + struct fdtable *fdt; + struct coredump_params *cp = (struct coredump_params *)info->data; + struct files_struct *cf = current->files; + + wp = create_write_pipe(0); + if (IS_ERR(wp)) + return PTR_ERR(wp); + + rp = create_read_pipe(wp, 0); + if (IS_ERR(rp)) { + free_write_pipe(wp); + return PTR_ERR(rp); + } + + cp->file = wp; + + sys_close(0); + fd_install(0, rp); + spin_lock(&cf->file_lock); + fdt = files_fdtable(cf); + FD_SET(0, fdt->open_fds); + FD_CLR(0, fdt->close_on_exec); + spin_unlock(&cf->file_lock); + + /* and disallow core files too */ + current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; + + return 0; +} + void do_coredump(long signr, int exit_code, struct pt_regs *regs) { struct core_state core_state; @@ -1874,15 +1918,15 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) goto fail_unlock; if (ispipe) { - if (cprm.limit == 0) { + if (cprm.limit == 1) { /* * Normally core limits are irrelevant to pipes, since * we're not writing to the file system, but we use - * cprm.limit of 0 here as a speacial value. Any - * non-zero limit gets set to RLIM_INFINITY below, but + * cprm.limit of 1 here as a speacial value. Any + * non-1 limit gets set to RLIM_INFINITY below, but * a limit of 0 skips the dump. This is a consistent * way to catch recursive crashes. We can still crash - * if the core_pattern binary sets RLIM_CORE = !0 + * if the core_pattern binary sets RLIM_CORE = !1 * but it runs as root, and can do lots of stupid things * Note that we use task_tgid_vnr here to grab the pid * of the process group leader. That way we get the @@ -1890,7 +1934,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) * core_pattern process dies. */ printk(KERN_WARNING - "Process %d(%s) has RLIMIT_CORE set to 0\n", + "Process %d(%s) has RLIMIT_CORE set to 1\n", task_tgid_vnr(current), current->comm); printk(KERN_WARNING "Aborting core\n"); goto fail_unlock; @@ -1914,8 +1958,13 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) cprm.limit = RLIM_INFINITY; /* SIGPIPE can happen, but it's just never processed */ - if (call_usermodehelper_pipe(helper_argv[0], helper_argv, NULL, - &cprm.file)) { + cprm.file = NULL; + if (call_usermodehelper_fns(helper_argv[0], helper_argv, NULL, + UMH_WAIT_EXEC, umh_pipe_setup, + NULL, &cprm)) { + if (cprm.file) + filp_close(cprm.file, NULL); + printk(KERN_INFO "Core dump to %s pipe failed\n", corename); goto fail_dropcount; diff --git a/include/linux/kmod.h b/include/linux/kmod.h index f9edf63..5c05877 100644 --- a/include/linux/kmod.h +++ b/include/linux/kmod.h @@ -62,7 +62,6 @@ struct subprocess_info { char **envp; enum umh_wait wait; int retval; - struct file *stdin; int (*init)(struct subprocess_info *info); void (*cleanup)(struct subprocess_info *info); void *data; @@ -75,8 +74,6 @@ struct subprocess_info *call_usermodehelper_setup(char *path, char **argv, /* Set various pieces of state into the subprocess_info structure */ void call_usermodehelper_setkeys(struct subprocess_info *info, struct key *session_keyring); -int call_usermodehelper_stdinpipe(struct subprocess_info *sub_info, - struct file **filp); void call_usermodehelper_setfns(struct subprocess_info *info, int (*init)(struct subprocess_info *info), void (*cleanup)(struct subprocess_info *info), @@ -132,10 +129,6 @@ call_usermodehelper_keys(char *path, char **argv, char **envp, extern void usermodehelper_init(void); -struct file; -extern int call_usermodehelper_pipe(char *path, char *argv[], char *envp[], - struct file **filp); - extern int usermodehelper_disable(void); extern void usermodehelper_enable(void); diff --git a/kernel/kmod.c b/kernel/kmod.c index 531ef62..d154454 100644 --- a/kernel/kmod.c +++ b/kernel/kmod.c @@ -147,23 +147,6 @@ static int ____call_usermodehelper(void *data) commit_creds(sub_info->cred); sub_info->cred = NULL; - /* Install input pipe when needed */ - if (sub_info->stdin) { - struct files_struct *f = current->files; - struct fdtable *fdt; - /* no races because files should be private here */ - sys_close(0); - fd_install(0, sub_info->stdin); - spin_lock(&f->file_lock); - fdt = files_fdtable(f); - FD_SET(0, fdt->open_fds); - FD_CLR(0, fdt->close_on_exec); - spin_unlock(&f->file_lock); - - /* and disallow core files too */ - current->signal->rlim[RLIMIT_CORE] = (struct rlimit){0, 0}; - } - /* We can run anywhere, unlike our parent keventd(). */ set_cpus_allowed_ptr(current, cpu_all_mask); @@ -429,35 +412,6 @@ void call_usermodehelper_setfns(struct subprocess_info *info, EXPORT_SYMBOL(call_usermodehelper_setfns); /** - * 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. @@ -504,42 +458,6 @@ unlock: } 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) -{ - struct subprocess_info *sub_info; - int ret; - - sub_info = call_usermodehelper_setup(path, argv, envp, - GFP_KERNEL); - if (sub_info == NULL) - return -ENOMEM; - - ret = call_usermodehelper_stdinpipe(sub_info, filp); - if (ret < 0) { - call_usermodehelper_freeinfo(sub_info); - return ret; - } - - ret = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC); - if (ret < 0) /* Failed to execute helper, close pipe */ - filp_close(*filp, NULL); - - return ret; -} -EXPORT_SYMBOL(call_usermodehelper_pipe); - void __init usermodehelper_init(void) { khelper_wq = create_singlethread_workqueue("khelper"); |