summaryrefslogtreecommitdiff
path: root/kernel/umh.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/umh.c')
-rw-r--r--kernel/umh.c125
1 files changed, 122 insertions, 3 deletions
diff --git a/kernel/umh.c b/kernel/umh.c
index f76b3ff876cf..30db93fd7e39 100644
--- a/kernel/umh.c
+++ b/kernel/umh.c
@@ -25,6 +25,8 @@
#include <linux/ptrace.h>
#include <linux/async.h>
#include <linux/uaccess.h>
+#include <linux/shmem_fs.h>
+#include <linux/pipe_fs_i.h>
#include <trace/events/module.h>
@@ -97,9 +99,13 @@ static int call_usermodehelper_exec_async(void *data)
commit_creds(new);
- retval = do_execve(getname_kernel(sub_info->path),
- (const char __user *const __user *)sub_info->argv,
- (const char __user *const __user *)sub_info->envp);
+ if (sub_info->file)
+ retval = do_execve_file(sub_info->file,
+ sub_info->argv, sub_info->envp);
+ else
+ retval = do_execve(getname_kernel(sub_info->path),
+ (const char __user *const __user *)sub_info->argv,
+ (const char __user *const __user *)sub_info->envp);
out:
sub_info->retval = retval;
/*
@@ -185,6 +191,8 @@ static void call_usermodehelper_exec_work(struct work_struct *work)
if (pid < 0) {
sub_info->retval = pid;
umh_complete(sub_info);
+ } else {
+ sub_info->pid = pid;
}
}
}
@@ -393,6 +401,117 @@ struct subprocess_info *call_usermodehelper_setup(const char *path, char **argv,
}
EXPORT_SYMBOL(call_usermodehelper_setup);
+struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
+ int (*init)(struct subprocess_info *info, struct cred *new),
+ void (*cleanup)(struct subprocess_info *info), void *data)
+{
+ struct subprocess_info *sub_info;
+
+ sub_info = kzalloc(sizeof(struct subprocess_info), GFP_KERNEL);
+ if (!sub_info)
+ return NULL;
+
+ INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
+ sub_info->path = "none";
+ sub_info->file = file;
+ sub_info->init = init;
+ sub_info->cleanup = cleanup;
+ sub_info->data = data;
+ return sub_info;
+}
+
+static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
+{
+ struct umh_info *umh_info = info->data;
+ struct file *from_umh[2];
+ struct file *to_umh[2];
+ int err;
+
+ /* create pipe to send data to umh */
+ err = create_pipe_files(to_umh, 0);
+ if (err)
+ return err;
+ err = replace_fd(0, to_umh[0], 0);
+ fput(to_umh[0]);
+ if (err < 0) {
+ fput(to_umh[1]);
+ return err;
+ }
+
+ /* create pipe to receive data from umh */
+ err = create_pipe_files(from_umh, 0);
+ if (err) {
+ fput(to_umh[1]);
+ replace_fd(0, NULL, 0);
+ return err;
+ }
+ err = replace_fd(1, from_umh[1], 0);
+ fput(from_umh[1]);
+ if (err < 0) {
+ fput(to_umh[1]);
+ replace_fd(0, NULL, 0);
+ fput(from_umh[0]);
+ return err;
+ }
+
+ umh_info->pipe_to_umh = to_umh[1];
+ umh_info->pipe_from_umh = from_umh[0];
+ return 0;
+}
+
+static void umh_save_pid(struct subprocess_info *info)
+{
+ struct umh_info *umh_info = info->data;
+
+ umh_info->pid = info->pid;
+}
+
+/**
+ * fork_usermode_blob - fork a blob of bytes as a usermode process
+ * @data: a blob of bytes that can be do_execv-ed as a file
+ * @len: length of the blob
+ * @info: information about usermode process (shouldn't be NULL)
+ *
+ * Returns either negative error or zero which indicates success
+ * in executing a blob of bytes as a usermode process. In such
+ * case 'struct umh_info *info' is populated with two pipes
+ * and a pid of the process. The caller is responsible for health
+ * check of the user process, killing it via pid, and closing the
+ * pipes when user process is no longer needed.
+ */
+int fork_usermode_blob(void *data, size_t len, struct umh_info *info)
+{
+ struct subprocess_info *sub_info;
+ struct file *file;
+ ssize_t written;
+ loff_t pos = 0;
+ int err;
+
+ file = shmem_kernel_file_setup("", len, 0);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ written = kernel_write(file, data, len, &pos);
+ if (written != len) {
+ err = written;
+ if (err >= 0)
+ err = -ENOMEM;
+ goto out;
+ }
+
+ err = -ENOMEM;
+ sub_info = call_usermodehelper_setup_file(file, umh_pipe_setup,
+ umh_save_pid, info);
+ if (!sub_info)
+ goto out;
+
+ err = call_usermodehelper_exec(sub_info, UMH_WAIT_EXEC);
+out:
+ fput(file);
+ return err;
+}
+EXPORT_SYMBOL_GPL(fork_usermode_blob);
+
/**
* call_usermodehelper_exec - start a usermode application
* @sub_info: information about the subprocessa