1  /* SPDX-License-Identifier: GPL-2.0 */
2  #ifndef _LINUX_BINFMTS_H
3  #define _LINUX_BINFMTS_H
4  
5  #include <linux/sched.h>
6  #include <linux/unistd.h>
7  #include <asm/exec.h>
8  #include <uapi/linux/binfmts.h>
9  
10  struct filename;
11  struct coredump_params;
12  
13  #define CORENAME_MAX_SIZE 128
14  
15  /*
16   * This structure is used to hold the arguments that are used when loading binaries.
17   */
18  struct linux_binprm {
19  #ifdef CONFIG_MMU
20  	struct vm_area_struct *vma;
21  	unsigned long vma_pages;
22  	unsigned long argmin; /* rlimit marker for copy_strings() */
23  #else
24  # define MAX_ARG_PAGES	32
25  	struct page *page[MAX_ARG_PAGES];
26  #endif
27  	struct mm_struct *mm;
28  	unsigned long p; /* current top of mem */
29  	unsigned int
30  		/* Should an execfd be passed to userspace? */
31  		have_execfd:1,
32  
33  		/* Use the creds of a script (see binfmt_misc) */
34  		execfd_creds:1,
35  		/*
36  		 * Set by bprm_creds_for_exec hook to indicate a
37  		 * privilege-gaining exec has happened. Used to set
38  		 * AT_SECURE auxv for glibc.
39  		 */
40  		secureexec:1,
41  		/*
42  		 * Set when errors can no longer be returned to the
43  		 * original userspace.
44  		 */
45  		point_of_no_return:1;
46  	struct file *executable; /* Executable to pass to the interpreter */
47  	struct file *interpreter;
48  	struct file *file;
49  	struct cred *cred;	/* new credentials */
50  	int unsafe;		/* how unsafe this exec is (mask of LSM_UNSAFE_*) */
51  	unsigned int per_clear;	/* bits to clear in current->personality */
52  	int argc, envc;
53  	const char *filename;	/* Name of binary as seen by procps */
54  	const char *interp;	/* Name of the binary really executed. Most
55  				   of the time same as filename, but could be
56  				   different for binfmt_{misc,script} */
57  	const char *fdpath;	/* generated filename for execveat */
58  	unsigned interp_flags;
59  	int execfd;		/* File descriptor of the executable */
60  	unsigned long loader, exec;
61  
62  	struct rlimit rlim_stack; /* Saved RLIMIT_STACK used during exec. */
63  
64  	char buf[BINPRM_BUF_SIZE];
65  } __randomize_layout;
66  
67  #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0
68  #define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT)
69  
70  /* filename of the binary will be inaccessible after exec */
71  #define BINPRM_FLAGS_PATH_INACCESSIBLE_BIT 2
72  #define BINPRM_FLAGS_PATH_INACCESSIBLE (1 << BINPRM_FLAGS_PATH_INACCESSIBLE_BIT)
73  
74  /* preserve argv0 for the interpreter  */
75  #define BINPRM_FLAGS_PRESERVE_ARGV0_BIT 3
76  #define BINPRM_FLAGS_PRESERVE_ARGV0 (1 << BINPRM_FLAGS_PRESERVE_ARGV0_BIT)
77  
78  /*
79   * This structure defines the functions that are used to load the binary formats that
80   * linux accepts.
81   */
82  struct linux_binfmt {
83  	struct list_head lh;
84  	struct module *module;
85  	int (*load_binary)(struct linux_binprm *);
86  	int (*load_shlib)(struct file *);
87  #ifdef CONFIG_COREDUMP
88  	int (*core_dump)(struct coredump_params *cprm);
89  	unsigned long min_coredump;	/* minimal dump size */
90  #endif
91  } __randomize_layout;
92  
93  #if IS_ENABLED(CONFIG_BINFMT_MISC)
94  struct binfmt_misc {
95  	struct list_head entries;
96  	rwlock_t entries_lock;
97  	bool enabled;
98  } __randomize_layout;
99  
100  extern struct binfmt_misc init_binfmt_misc;
101  #endif
102  
103  extern void __register_binfmt(struct linux_binfmt *fmt, int insert);
104  
105  /* Registration of default binfmt handlers */
register_binfmt(struct linux_binfmt * fmt)106  static inline void register_binfmt(struct linux_binfmt *fmt)
107  {
108  	__register_binfmt(fmt, 0);
109  }
110  /* Same as above, but adds a new binfmt at the top of the list */
insert_binfmt(struct linux_binfmt * fmt)111  static inline void insert_binfmt(struct linux_binfmt *fmt)
112  {
113  	__register_binfmt(fmt, 1);
114  }
115  
116  extern void unregister_binfmt(struct linux_binfmt *);
117  
118  extern int __must_check remove_arg_zero(struct linux_binprm *);
119  extern int begin_new_exec(struct linux_binprm * bprm);
120  extern void setup_new_exec(struct linux_binprm * bprm);
121  extern void finalize_exec(struct linux_binprm *bprm);
122  extern void would_dump(struct linux_binprm *, struct file *);
123  
124  extern int suid_dumpable;
125  
126  /* Stack area protections */
127  #define EXSTACK_DEFAULT   0	/* Whatever the arch defaults to */
128  #define EXSTACK_DISABLE_X 1	/* Disable executable stacks */
129  #define EXSTACK_ENABLE_X  2	/* Enable executable stacks */
130  
131  extern int setup_arg_pages(struct linux_binprm * bprm,
132  			   unsigned long stack_top,
133  			   int executable_stack);
134  extern int transfer_args_to_stack(struct linux_binprm *bprm,
135  				  unsigned long *sp_location);
136  extern int bprm_change_interp(const char *interp, struct linux_binprm *bprm);
137  int copy_string_kernel(const char *arg, struct linux_binprm *bprm);
138  extern void set_binfmt(struct linux_binfmt *new);
139  extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);
140  
141  int kernel_execve(const char *filename,
142  		  const char *const *argv, const char *const *envp);
143  
144  #endif /* _LINUX_BINFMTS_H */
145