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 /* Set when "comm" must come from the dentry. */
47 comm_from_dentry:1,
48 /*
49 * Set by user space to check executability according to the
50 * caller's environment.
51 */
52 is_check:1;
53 struct file *executable; /* Executable to pass to the interpreter */
54 struct file *interpreter;
55 struct file *file;
56 struct cred *cred; /* new credentials */
57 int unsafe; /* how unsafe this exec is (mask of LSM_UNSAFE_*) */
58 unsigned int per_clear; /* bits to clear in current->personality */
59 int argc, envc;
60 const char *filename; /* Name of binary as seen by procps */
61 const char *interp; /* Name of the binary really executed. Most
62 of the time same as filename, but could be
63 different for binfmt_{misc,script} */
64 const char *fdpath; /* generated filename for execveat */
65 unsigned interp_flags;
66 int execfd; /* File descriptor of the executable */
67 unsigned long loader, exec;
68
69 struct rlimit rlim_stack; /* Saved RLIMIT_STACK used during exec. */
70
71 char buf[BINPRM_BUF_SIZE];
72 } __randomize_layout;
73
74 #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0
75 #define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT)
76
77 /* filename of the binary will be inaccessible after exec */
78 #define BINPRM_FLAGS_PATH_INACCESSIBLE_BIT 2
79 #define BINPRM_FLAGS_PATH_INACCESSIBLE (1 << BINPRM_FLAGS_PATH_INACCESSIBLE_BIT)
80
81 /* preserve argv0 for the interpreter */
82 #define BINPRM_FLAGS_PRESERVE_ARGV0_BIT 3
83 #define BINPRM_FLAGS_PRESERVE_ARGV0 (1 << BINPRM_FLAGS_PRESERVE_ARGV0_BIT)
84
85 /*
86 * This structure defines the functions that are used to load the binary formats that
87 * linux accepts.
88 */
89 struct linux_binfmt {
90 struct list_head lh;
91 struct module *module;
92 int (*load_binary)(struct linux_binprm *);
93 int (*load_shlib)(struct file *);
94 #ifdef CONFIG_COREDUMP
95 int (*core_dump)(struct coredump_params *cprm);
96 unsigned long min_coredump; /* minimal dump size */
97 #endif
98 } __randomize_layout;
99
100 #if IS_ENABLED(CONFIG_BINFMT_MISC)
101 struct binfmt_misc {
102 struct list_head entries;
103 rwlock_t entries_lock;
104 bool enabled;
105 } __randomize_layout;
106
107 extern struct binfmt_misc init_binfmt_misc;
108 #endif
109
110 extern void __register_binfmt(struct linux_binfmt *fmt, int insert);
111
112 /* Registration of default binfmt handlers */
register_binfmt(struct linux_binfmt * fmt)113 static inline void register_binfmt(struct linux_binfmt *fmt)
114 {
115 __register_binfmt(fmt, 0);
116 }
117 /* Same as above, but adds a new binfmt at the top of the list */
insert_binfmt(struct linux_binfmt * fmt)118 static inline void insert_binfmt(struct linux_binfmt *fmt)
119 {
120 __register_binfmt(fmt, 1);
121 }
122
123 extern void unregister_binfmt(struct linux_binfmt *);
124
125 extern int __must_check remove_arg_zero(struct linux_binprm *);
126 extern int begin_new_exec(struct linux_binprm * bprm);
127 extern void setup_new_exec(struct linux_binprm * bprm);
128 extern void finalize_exec(struct linux_binprm *bprm);
129 extern void would_dump(struct linux_binprm *, struct file *);
130
131 extern int suid_dumpable;
132
133 /* Stack area protections */
134 #define EXSTACK_DEFAULT 0 /* Whatever the arch defaults to */
135 #define EXSTACK_DISABLE_X 1 /* Disable executable stacks */
136 #define EXSTACK_ENABLE_X 2 /* Enable executable stacks */
137
138 extern int setup_arg_pages(struct linux_binprm * bprm,
139 unsigned long stack_top,
140 int executable_stack);
141 extern int transfer_args_to_stack(struct linux_binprm *bprm,
142 unsigned long *sp_location);
143 extern int bprm_change_interp(const char *interp, struct linux_binprm *bprm);
144 int copy_string_kernel(const char *arg, struct linux_binprm *bprm);
145 extern void set_binfmt(struct linux_binfmt *new);
146 extern ssize_t read_code(struct file *, unsigned long, loff_t, size_t);
147
148 int kernel_execve(const char *filename,
149 const char *const *argv, const char *const *envp);
150
151 #endif /* _LINUX_BINFMTS_H */
152