Commit 876dcf2f authored by Olivier Brunel's avatar Olivier Brunel Committed by David S. Miller

umh: Add command line to user mode helpers

User mode helpers were spawned without a command line, and because
an empty command line is used by many tools to identify processes as
kernel threads, this could cause some issues.

Notably during killing spree on shutdown, since such helper would then
be skipped (i.e. not killed) which would result in the process remaining
alive, and thus preventing unmouting of the rootfs (as experienced with
the bpfilter umh).

Fixes: 449325b5 ("umh: introduce fork_usermode_blob() helper")
Signed-off-by: default avatarOlivier Brunel <jjk@jjacky.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c94f026f
...@@ -44,6 +44,7 @@ struct subprocess_info *call_usermodehelper_setup_file(struct file *file, ...@@ -44,6 +44,7 @@ struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
int (*init)(struct subprocess_info *info, struct cred *new), int (*init)(struct subprocess_info *info, struct cred *new),
void (*cleanup)(struct subprocess_info *), void *data); void (*cleanup)(struct subprocess_info *), void *data);
struct umh_info { struct umh_info {
const char *cmdline;
struct file *pipe_to_umh; struct file *pipe_to_umh;
struct file *pipe_from_umh; struct file *pipe_from_umh;
pid_t pid; pid_t pid;
......
...@@ -405,11 +405,19 @@ struct subprocess_info *call_usermodehelper_setup_file(struct file *file, ...@@ -405,11 +405,19 @@ struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
void (*cleanup)(struct subprocess_info *info), void *data) void (*cleanup)(struct subprocess_info *info), void *data)
{ {
struct subprocess_info *sub_info; struct subprocess_info *sub_info;
struct umh_info *info = data;
const char *cmdline = (info->cmdline) ? info->cmdline : "usermodehelper";
sub_info = kzalloc(sizeof(struct subprocess_info), GFP_KERNEL); sub_info = kzalloc(sizeof(struct subprocess_info), GFP_KERNEL);
if (!sub_info) if (!sub_info)
return NULL; return NULL;
sub_info->argv = argv_split(GFP_KERNEL, cmdline, NULL);
if (!sub_info->argv) {
kfree(sub_info);
return NULL;
}
INIT_WORK(&sub_info->work, call_usermodehelper_exec_work); INIT_WORK(&sub_info->work, call_usermodehelper_exec_work);
sub_info->path = "none"; sub_info->path = "none";
sub_info->file = file; sub_info->file = file;
...@@ -458,10 +466,11 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) ...@@ -458,10 +466,11 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
return 0; return 0;
} }
static void umh_save_pid(struct subprocess_info *info) static void umh_clean_and_save_pid(struct subprocess_info *info)
{ {
struct umh_info *umh_info = info->data; struct umh_info *umh_info = info->data;
argv_free(info->argv);
umh_info->pid = info->pid; umh_info->pid = info->pid;
} }
...@@ -471,6 +480,9 @@ static void umh_save_pid(struct subprocess_info *info) ...@@ -471,6 +480,9 @@ static void umh_save_pid(struct subprocess_info *info)
* @len: length of the blob * @len: length of the blob
* @info: information about usermode process (shouldn't be NULL) * @info: information about usermode process (shouldn't be NULL)
* *
* If info->cmdline is set it will be used as command line for the
* user process, else "usermodehelper" is used.
*
* Returns either negative error or zero which indicates success * Returns either negative error or zero which indicates success
* in executing a blob of bytes as a usermode process. In such * in executing a blob of bytes as a usermode process. In such
* case 'struct umh_info *info' is populated with two pipes * case 'struct umh_info *info' is populated with two pipes
...@@ -500,7 +512,7 @@ int fork_usermode_blob(void *data, size_t len, struct umh_info *info) ...@@ -500,7 +512,7 @@ int fork_usermode_blob(void *data, size_t len, struct umh_info *info)
err = -ENOMEM; err = -ENOMEM;
sub_info = call_usermodehelper_setup_file(file, umh_pipe_setup, sub_info = call_usermodehelper_setup_file(file, umh_pipe_setup,
umh_save_pid, info); umh_clean_and_save_pid, info);
if (!sub_info) if (!sub_info)
goto out; goto out;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment