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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_BINFMT_MISC_H
#define _LINUX_BINFMT_MISC_H
#include <linux/types.h>
struct bpf_prog;
struct file;
struct linux_binprm;
struct ucounts;
struct user_namespace;
#define BINFMT_MISC_OPS_NAME_MAX 16
/* Longest name a 'B' entry can bind an interpreter under. */
#define BINFMT_MISC_INTERP_NAME_MAX 32
/* Most interpreters one entry can bind. */
#define BINFMT_MISC_INTERP_MAX 100
/**
* struct binfmt_misc_interp - an interpreter an entry was registered with
* @list: link in the entry's list, in registration order
* @file: the file, opened at registration and never resolved again
* @ucounts: the UCOUNT_BINFMT_MISC_INTERPRETERS charge the binding took
* @path: the path it was registered under, used as the name the interpreter
* runs under; stored after @name in the same allocation
* @name: the name the load program selects it by; empty for the fixed
* interpreter of a static 'F' entry
*
* Owned by the entry and living exactly as long as it does. The list head
* is handed to the handler's load program for the duration of one exec,
* which picks one with bpf_binprm_select_interp().
*/
struct binfmt_misc_interp {
struct list_head list;
struct file *file;
struct ucounts *ucounts;
const char *path;
char name[];
};
const struct binfmt_misc_interp *
binfmt_misc_find_interp(const struct list_head *interps, const char *name);
/**
* enum bpf_binprm_flags - per-exec invocation flags a load program can request
* @BPF_BINPRM_PRESERVE_ARGV0: keep the caller's argv[0] (like the 'P' flag)
* @BPF_BINPRM_CREDENTIALS: compute credentials from the binary; implies execfd
* (like the 'C' flag)
* @BPF_BINPRM_EXECFD: pass the binary via AT_EXECFD (like the 'O' flag)
* @BPF_BINPRM_TRANSPARENT: leave argv untouched, the interpreter takes the
* binary from AT_EXECFD (like the 'T' flag); implies
* execfd, excludes preserve-argv0
* @BPF_BINPRM_LOADER: substitute the interpreter for the binary's PT_INTERP
* and run the binary as a native exec (like the 'L'
* flag); excludes every other flag
*
* Set from a load program with bpf_binprm_set_flags(). Unlike a static entry,
* a bpf handler chooses these per exec rather than once at registration.
*/
enum bpf_binprm_flags {
BPF_BINPRM_PRESERVE_ARGV0 = (1ULL << 0),
BPF_BINPRM_CREDENTIALS = (1ULL << 1),
BPF_BINPRM_EXECFD = (1ULL << 2),
BPF_BINPRM_TRANSPARENT = (1ULL << 3),
BPF_BINPRM_LOADER = (1ULL << 4),
};
/**
* struct binfmt_misc_ops - bpf-backed binary type handler
* @match: decide whether the handler applies to @bprm; consulted from the
* entry lookup walk like static magic and extension matching, in
* registration order with first-match-wins semantics; sleepable,
* so it can read the binary to decide, but the verifier rejects
* the interpreter selection kfuncs in it
* @load: select an interpreter for the matched @bprm via
* bpf_binprm_set_interp(), or one the entry bound via
* bpf_binprm_select_interp(), and return zero; a match is
* committed, so a failure fails the exec instead of falling
* through to later entries; -ENOEXEC does not fail the exec but
* moves on to the remaining binary formats
* @name: name that 'B' entries reference the handler by
*/
struct binfmt_misc_ops {
bool (*match)(struct linux_binprm *bprm);
int (*load)(struct linux_binprm *bprm);
char name[BINFMT_MISC_OPS_NAME_MAX];
};
#ifdef CONFIG_BINFMT_MISC_BPF
const struct binfmt_misc_ops *binfmt_misc_get_ops(struct user_namespace *user_ns,
const char *name);
void binfmt_misc_put_ops(const struct binfmt_misc_ops *ops);
bool bpf_prog_is_binfmt_misc_ops(const struct bpf_prog *prog);
#else
static inline const struct binfmt_misc_ops *
binfmt_misc_get_ops(struct user_namespace *user_ns, const char *name)
{
return NULL;
}
static inline void binfmt_misc_put_ops(const struct binfmt_misc_ops *ops)
{
}
static inline bool bpf_prog_is_binfmt_misc_ops(const struct bpf_prog *prog)
{
return false;
}
#endif /* CONFIG_BINFMT_MISC_BPF */
#endif /* _LINUX_BINFMT_MISC_H */
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