Commit cdf7fb0a authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Daniel Borkmann
Browse files

bpf: Introduce bpfptr_t user/kernel pointer. 



Similar to sockptr_t introduce bpfptr_t with few additions:
make_bpfptr() creates new user/kernel pointer in the same address space as
existing user/kernel pointer.
bpfptr_add() advances the user/kernel pointer.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210514003623.28033-3-alexei.starovoitov@gmail.com
parent 79a7f8bd

include/linux/bpfptr.h

0 → 100644
+75 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/* A pointer that can point to either kernel or userspace memory. */

#ifndef _LINUX_BPFPTR_H

#define _LINUX_BPFPTR_H



#include <linux/sockptr.h>



typedef sockptr_t bpfptr_t;



static inline bool bpfptr_is_kernel(bpfptr_t bpfptr)

{

	return bpfptr.is_kernel;

}



static inline bpfptr_t KERNEL_BPFPTR(void *p)

{

	return (bpfptr_t) { .kernel = p, .is_kernel = true };

}



static inline bpfptr_t USER_BPFPTR(void __user *p)

{

	return (bpfptr_t) { .user = p };

}



static inline bpfptr_t make_bpfptr(u64 addr, bool is_kernel)

{

	if (is_kernel)

		return KERNEL_BPFPTR((void*) (uintptr_t) addr);

	else

		return USER_BPFPTR(u64_to_user_ptr(addr));

}



static inline bool bpfptr_is_null(bpfptr_t bpfptr)

{

	if (bpfptr_is_kernel(bpfptr))

		return !bpfptr.kernel;

	return !bpfptr.user;

}



static inline void bpfptr_add(bpfptr_t *bpfptr, size_t val)

{

	if (bpfptr_is_kernel(*bpfptr))

		bpfptr->kernel += val;

	else

		bpfptr->user += val;

}



static inline int copy_from_bpfptr_offset(void *dst, bpfptr_t src,

					  size_t offset, size_t size)

{

	return copy_from_sockptr_offset(dst, (sockptr_t) src, offset, size);

}



static inline int copy_from_bpfptr(void *dst, bpfptr_t src, size_t size)

{

	return copy_from_bpfptr_offset(dst, src, 0, size);

}



static inline int copy_to_bpfptr_offset(bpfptr_t dst, size_t offset,

					const void *src, size_t size)

{

	return copy_to_sockptr_offset((sockptr_t) dst, offset, src, size);

}



static inline void *memdup_bpfptr(bpfptr_t src, size_t len)

{

	return memdup_sockptr((sockptr_t) src, len);

}



static inline long strncpy_from_bpfptr(char *dst, bpfptr_t src, size_t count)

{

	return strncpy_from_sockptr(dst, (sockptr_t) src, count);

}



#endif /* _LINUX_BPFPTR_H */