binfmts.h

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#ifndef _LINUX_BINFMTS_H
#define _LINUX_BINFMTS_H

#include <linux/sched.h>
#include <linux/unistd.h>
#include <asm/exec.h>
#include <uapi/linux/binfmts.h>

#define CORENAME_MAX_SIZE 128

/*
 * This structure is used to hold the arguments that are used when loading binaries.
 */
struct linux_binprm {
    char buf[BINPRM_BUF_SIZE];
#ifdef CONFIG_MMU
    struct vm_area_struct *vma;
    unsigned long vma_pages;
#else
# define MAX_ARG_PAGES  32
    struct page *page[MAX_ARG_PAGES];
#endif
    struct mm_struct *mm;
    unsigned long p; /* current top of mem */
    unsigned int
        cred_prepared:1,/* true if creds already prepared (multiple
                 * preps happen for interpreters) */
        cap_effective:1;/* true if has elevated effective capabilities,
                 * false if not; except for init which inherits
                 * its parent's caps anyway */
#ifdef __alpha__
    unsigned int taso:1;
#endif
    unsigned int recursion_depth;
    struct file * file;
    struct cred *cred;  /* new credentials */
    int unsafe;     /* how unsafe this exec is (mask of LSM_UNSAFE_*) */
    unsigned int per_clear; /* bits to clear in current->personality */
    int argc, envc;
    const char * filename;  /* Name of binary as seen by procps */
    const char * interp;    /* Name of the binary really executed. Most
                   of the time same as filename, but could be
                   different for binfmt_{misc,script} */
    unsigned interp_flags;
    unsigned interp_data;
    unsigned long loader, exec;
    char tcomm[TASK_COMM_LEN];
};

#define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0
#define BINPRM_FLAGS_ENFORCE_NONDUMP (1 << BINPRM_FLAGS_ENFORCE_NONDUMP_BIT)

/* fd of the binary should be passed to the interpreter */
#define BINPRM_FLAGS_EXECFD_BIT 1
#define BINPRM_FLAGS_EXECFD (1 << BINPRM_FLAGS_EXECFD_BIT)

#define BINPRM_MAX_RECURSION 4

/* Function parameter for binfmt->coredump */
struct coredump_params {
    siginfo_t *siginfo;
    struct pt_regs *regs;
    struct file *file;
    unsigned long limit;
    unsigned long mm_flags;
};

/*
 * This structure defines the functions that are used to load the binary formats that
 * linux accepts.
 */
struct linux_binfmt {
    struct list_head lh;
    struct module *module;
    int (*load_binary)(struct linux_binprm *, struct  pt_regs * regs);
    int (*load_shlib)(struct file *);
    int (*core_dump)(struct coredump_params *cprm);
    unsigned long min_coredump; /* minimal dump size */
};

extern void __register_binfmt(struct linux_binfmt *fmt, int insert);

/* Registration of default binfmt handlers */
static inline void register_binfmt(struct linux_binfmt *fmt)
{
    __register_binfmt(fmt, 0);
}
/* Same as above, but adds a new binfmt at the top of the list */
static inline void insert_binfmt(struct linux_binfmt *fmt)
{
    __register_binfmt(fmt, 1);
}

extern void unregister_binfmt(struct linux_binfmt *);

extern int prepare_binprm(struct linux_binprm *);
extern int __must_check remove_arg_zero(struct linux_binprm *);
extern int search_binary_handler(struct linux_binprm *, struct pt_regs *);
extern int flush_old_exec(struct linux_binprm * bprm);
extern void setup_new_exec(struct linux_binprm * bprm);
extern void would_dump(struct linux_binprm *, struct file *);

extern int suid_dumpable;
#define SUID_DUMP_DISABLE   0   /* No setuid dumping */
#define SUID_DUMP_USER      1   /* Dump as user of process */
#define SUID_DUMP_ROOT      2   /* Dump as root */

/* Stack area protections */
#define EXSTACK_DEFAULT   0 /* Whatever the arch defaults to */
#define EXSTACK_DISABLE_X 1 /* Disable executable stacks */
#define EXSTACK_ENABLE_X  2 /* Enable executable stacks */

extern int setup_arg_pages(struct linux_binprm * bprm,
               unsigned long stack_top,
               int executable_stack);
extern int bprm_mm_init(struct linux_binprm *bprm);
extern int copy_strings_kernel(int argc, const char *const *argv,
                   struct linux_binprm *bprm);
extern int prepare_bprm_creds(struct linux_binprm *bprm);
extern void install_exec_creds(struct linux_binprm *bprm);
extern void set_binfmt(struct linux_binfmt *new);
extern void free_bprm(struct linux_binprm *);

#ifdef __ARCH_WANT_KERNEL_EXECVE
extern void ret_from_kernel_execve(struct pt_regs *normal) __noreturn;
#endif

#endif /* _LINUX_BINFMTS_H */