include/linux/binfmts.h

   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 */
 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 */
 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 */