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 #else
23 # define MAX_ARG_PAGES	32
24 	struct page *page[MAX_ARG_PAGES];
25 #endif
26 	struct mm_struct *mm;
27 	unsigned long p; /* current top of mem */
28 	unsigned long argmin; /* rlimit marker for copy_strings() */
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 extern void __register_binfmt(struct linux_binfmt *fmt, int insert);
94 
95 /* Registration of default binfmt handlers */
register_binfmt(struct linux_binfmt * fmt)96 static inline void register_binfmt(struct linux_binfmt *fmt)
97 {
98 	__register_binfmt(fmt, 0);
99 }
100 /* Same as above, but adds a new binfmt at the top of the list */
insert_binfmt(struct linux_binfmt * fmt)101 static inline void insert_binfmt(struct linux_binfmt *fmt)
102 {
103 	__register_binfmt(fmt, 1);
104 }
105 
106 extern void unregister_binfmt(struct linux_binfmt *);
107 
108 extern int __must_check remove_arg_zero(struct linux_binprm *);
109 extern int begin_new_exec(struct linux_binprm * bprm);
110 extern void setup_new_exec(struct linux_binprm * bprm);
111 extern void finalize_exec(struct linux_binprm *bprm);
112 extern void would_dump(struct linux_binprm *, struct file *);
113 
114 extern int suid_dumpable;
115 
116 /* Stack area protections */
117 #define EXSTACK_DEFAULT   0	/* Whatever the arch defaults to */
118 #define EXSTACK_DISABLE_X 1	/* Disable executable stacks */
119 #define EXSTACK_ENABLE_X  2	/* Enable executable stacks */
120 
121 extern int setup_arg_pages(struct linux_binprm * bprm,
122 			   unsigned long stack_top,
123 			   int executable_stack);
124 extern int transfer_args_to_stack(struct linux_binprm *bprm,
125 				  unsigned long *sp_location);
126 extern int bprm_change_interp(const char *interp, struct linux_binprm *bprm);
127 int copy_string_kernel(const char *arg, struct linux_binprm *bprm);
128 extern void set_binfmt(struct linux_binfmt *new);
129 extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);
130 
131 int kernel_execve(const char *filename,
132 		  const char *const *argv, const char *const *envp);
133 
134 #endif /* _LINUX_BINFMTS_H */
135