876dcf2f3a
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: 449325b52b ("umh: introduce fork_usermode_blob() helper")
Signed-off-by: Olivier Brunel <jjk@jjacky.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
83 lines
2.2 KiB
C
83 lines
2.2 KiB
C
#ifndef __LINUX_UMH_H__
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#define __LINUX_UMH_H__
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#include <linux/gfp.h>
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#include <linux/stddef.h>
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#include <linux/errno.h>
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#include <linux/compiler.h>
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#include <linux/workqueue.h>
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#include <linux/sysctl.h>
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struct cred;
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struct file;
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#define UMH_NO_WAIT 0 /* don't wait at all */
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#define UMH_WAIT_EXEC 1 /* wait for the exec, but not the process */
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#define UMH_WAIT_PROC 2 /* wait for the process to complete */
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#define UMH_KILLABLE 4 /* wait for EXEC/PROC killable */
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struct subprocess_info {
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struct work_struct work;
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struct completion *complete;
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const char *path;
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char **argv;
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char **envp;
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struct file *file;
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int wait;
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int retval;
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pid_t pid;
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int (*init)(struct subprocess_info *info, struct cred *new);
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void (*cleanup)(struct subprocess_info *info);
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void *data;
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} __randomize_layout;
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extern int
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call_usermodehelper(const char *path, char **argv, char **envp, int wait);
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extern struct subprocess_info *
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call_usermodehelper_setup(const char *path, char **argv, char **envp,
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gfp_t gfp_mask,
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int (*init)(struct subprocess_info *info, struct cred *new),
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void (*cleanup)(struct subprocess_info *), void *data);
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struct subprocess_info *call_usermodehelper_setup_file(struct file *file,
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int (*init)(struct subprocess_info *info, struct cred *new),
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void (*cleanup)(struct subprocess_info *), void *data);
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struct umh_info {
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const char *cmdline;
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struct file *pipe_to_umh;
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struct file *pipe_from_umh;
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pid_t pid;
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};
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int fork_usermode_blob(void *data, size_t len, struct umh_info *info);
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extern int
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call_usermodehelper_exec(struct subprocess_info *info, int wait);
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extern struct ctl_table usermodehelper_table[];
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enum umh_disable_depth {
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UMH_ENABLED = 0,
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UMH_FREEZING,
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UMH_DISABLED,
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};
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extern int __usermodehelper_disable(enum umh_disable_depth depth);
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extern void __usermodehelper_set_disable_depth(enum umh_disable_depth depth);
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static inline int usermodehelper_disable(void)
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{
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return __usermodehelper_disable(UMH_DISABLED);
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}
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static inline void usermodehelper_enable(void)
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{
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__usermodehelper_set_disable_depth(UMH_ENABLED);
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}
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extern int usermodehelper_read_trylock(void);
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extern long usermodehelper_read_lock_wait(long timeout);
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extern void usermodehelper_read_unlock(void);
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#endif /* __LINUX_UMH_H__ */
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