xref: /linux-6.15/include/linux/binfmts.h (revision 779b96d2)
1 #ifndef _LINUX_BINFMTS_H
2 #define _LINUX_BINFMTS_H
3 
4 #include <linux/capability.h>
5 
6 struct pt_regs;
7 
8 /*
9  * These are the maximum length and maximum number of strings passed to the
10  * execve() system call.  MAX_ARG_STRLEN is essentially random but serves to
11  * prevent the kernel from being unduly impacted by misaddressed pointers.
12  * MAX_ARG_STRINGS is chosen to fit in a signed 32-bit integer.
13  */
14 #define MAX_ARG_STRLEN (PAGE_SIZE * 32)
15 #define MAX_ARG_STRINGS 0x7FFFFFFF
16 
17 /* sizeof(linux_binprm->buf) */
18 #define BINPRM_BUF_SIZE 128
19 
20 #ifdef __KERNEL__
21 #include <linux/list.h>
22 
23 #define CORENAME_MAX_SIZE 128
24 
25 /*
26  * This structure is used to hold the arguments that are used when loading binaries.
27  */
28 struct linux_binprm {
29 	char buf[BINPRM_BUF_SIZE];
30 #ifdef CONFIG_MMU
31 	struct vm_area_struct *vma;
32 	unsigned long vma_pages;
33 #else
34 # define MAX_ARG_PAGES	32
35 	struct page *page[MAX_ARG_PAGES];
36 #endif
37 	struct mm_struct *mm;
38 	unsigned long p; /* current top of mem */
39 	unsigned int
40 		cred_prepared:1,/* true if creds already prepared (multiple
41 				 * preps happen for interpreters) */
42 		cap_effective:1;/* true if has elevated effective capabilities,
43 				 * false if not; except for init which inherits
44 				 * its parent's caps anyway */
45 #ifdef __alpha__
46 	unsigned int taso:1;
47 #endif
48 	unsigned int recursion_depth;
49 	struct file * file;
50 	struct cred *cred;	/* new credentials */
51 	int unsafe;		/* how unsafe this exec is (mask of LSM_UNSAFE_*) */
52 	unsigned int per_clear;	/* bits to clear in current->personality */
53 	int argc, envc;
54 	const char * filename;	/* Name of binary as seen by procps */
55 	const char * interp;	/* Name of the binary really executed. Most
56 				   of the time same as filename, but could be
57 				   different for binfmt_{misc,script} */
58 	unsigned interp_flags;
59 	unsigned interp_data;
60 	unsigned long loader, exec;
61 };
62 
63 #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0
64 #define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT)
65 
66 /* fd of the binary should be passed to the interpreter */
67 #define BINPRM_FLAGS_EXECFD_BIT 1
68 #define BINPRM_FLAGS_EXECFD (1 << BINPRM_FLAGS_EXECFD_BIT)
69 
70 #define BINPRM_MAX_RECURSION 4
71 
72 /* Function parameter for binfmt->coredump */
73 struct coredump_params {
74 	long signr;
75 	struct pt_regs *regs;
76 	struct file *file;
77 	unsigned long limit;
78 	unsigned long mm_flags;
79 };
80 
81 /*
82  * This structure defines the functions that are used to load the binary formats that
83  * linux accepts.
84  */
85 struct linux_binfmt {
86 	struct list_head lh;
87 	struct module *module;
88 	int (*load_binary)(struct linux_binprm *, struct  pt_regs * regs);
89 	int (*load_shlib)(struct file *);
90 	int (*core_dump)(struct coredump_params *cprm);
91 	unsigned long min_coredump;	/* minimal dump size */
92 };
93 
94 extern int __register_binfmt(struct linux_binfmt *fmt, int insert);
95 
96 /* Registration of default binfmt handlers */
97 static inline int register_binfmt(struct linux_binfmt *fmt)
98 {
99 	return __register_binfmt(fmt, 0);
100 }
101 /* Same as above, but adds a new binfmt at the top of the list */
102 static inline int insert_binfmt(struct linux_binfmt *fmt)
103 {
104 	return __register_binfmt(fmt, 1);
105 }
106 
107 extern void unregister_binfmt(struct linux_binfmt *);
108 
109 extern int prepare_binprm(struct linux_binprm *);
110 extern int __must_check remove_arg_zero(struct linux_binprm *);
111 extern int search_binary_handler(struct linux_binprm *, struct pt_regs *);
112 extern int flush_old_exec(struct linux_binprm * bprm);
113 extern void setup_new_exec(struct linux_binprm * bprm);
114 extern void would_dump(struct linux_binprm *, struct file *);
115 
116 extern int suid_dumpable;
117 #define SUID_DUMP_DISABLE	0	/* No setuid dumping */
118 #define SUID_DUMP_USER		1	/* Dump as user of process */
119 #define SUID_DUMP_ROOT		2	/* Dump as root */
120 
121 /* Stack area protections */
122 #define EXSTACK_DEFAULT   0	/* Whatever the arch defaults to */
123 #define EXSTACK_DISABLE_X 1	/* Disable executable stacks */
124 #define EXSTACK_ENABLE_X  2	/* Enable executable stacks */
125 
126 extern int setup_arg_pages(struct linux_binprm * bprm,
127 			   unsigned long stack_top,
128 			   int executable_stack);
129 extern int bprm_mm_init(struct linux_binprm *bprm);
130 extern int copy_strings_kernel(int argc, const char *const *argv,
131 			       struct linux_binprm *bprm);
132 extern int prepare_bprm_creds(struct linux_binprm *bprm);
133 extern void install_exec_creds(struct linux_binprm *bprm);
134 extern void do_coredump(long signr, int exit_code, struct pt_regs *regs);
135 extern void set_binfmt(struct linux_binfmt *new);
136 extern void free_bprm(struct linux_binprm *);
137 
138 #endif /* __KERNEL__ */
139 #endif /* _LINUX_BINFMTS_H */
140