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-rw-r--r--fs/exec.c63
-rw-r--r--include/linux/kmod.h7
-rw-r--r--kernel/kmod.c82
3 files changed, 56 insertions, 96 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 9badbc0bfb1..63f459cf20d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -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 f9edf63e90e..5c058778ad3 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 531ef62cf53..d1544547fea 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");