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Commit dcab51f1 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Daniel Borkmann
Browse files

bpf: Expose check_uarg_tail_zero() 



This patch exposes check_uarg_tail_zero() which will
be reused by a later BTF patch.  Its name is changed to
bpf_check_uarg_tail_zero().

Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 3fb48d88

include/linux/bpf.h

+2 −0
Original line number Diff line number Diff line
@@ -463,6 +463,8 @@ int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file, 
int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value);



int bpf_get_file_flag(int flags);

int bpf_check_uarg_tail_zero(void __user *uaddr, size_t expected_size,

			     size_t actual_size);



/* memcpy that is used with 8-byte aligned pointers, power-of-8 size and

 * forced to use 'long' read/writes to try to atomically copy long counters.

kernel/bpf/syscall.c

+7 −7
Original line number Diff line number Diff line
@@ -65,7 +65,7 @@ static const struct bpf_map_ops * const bpf_map_types[] = { 
 * copy_from_user() call. However, this is not a concern since this function is

 * meant to be a future-proofing of bits.

 */

static int check_uarg_tail_zero(void __user *uaddr,

int bpf_check_uarg_tail_zero(void __user *uaddr,

			     size_t expected_size,

			     size_t actual_size)

{
@@ -1899,7 +1899,7 @@ static int bpf_prog_get_info_by_fd(struct bpf_prog *prog, 
	u32 ulen;

	int err;



	err = check_uarg_tail_zero(uinfo, sizeof(info), info_len);

	err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);

	if (err)

		return err;

	info_len = min_t(u32, sizeof(info), info_len);
@@ -1998,7 +1998,7 @@ static int bpf_map_get_info_by_fd(struct bpf_map *map, 
	u32 info_len = attr->info.info_len;

	int err;



	err = check_uarg_tail_zero(uinfo, sizeof(info), info_len);

	err = bpf_check_uarg_tail_zero(uinfo, sizeof(info), info_len);

	if (err)

		return err;

	info_len = min_t(u32, sizeof(info), info_len);
@@ -2038,7 +2038,7 @@ static int bpf_btf_get_info_by_fd(struct btf *btf, 
	u32 info_len = attr->info.info_len;

	int err;



	err = check_uarg_tail_zero(uinfo, sizeof(*uinfo), info_len);

	err = bpf_check_uarg_tail_zero(uinfo, sizeof(*uinfo), info_len);

	if (err)

		return err;
@@ -2110,7 +2110,7 @@ SYSCALL_DEFINE3(bpf, int, cmd, union bpf_attr __user *, uattr, unsigned int, siz 
	if (sysctl_unprivileged_bpf_disabled && !capable(CAP_SYS_ADMIN))

		return -EPERM;



	err = check_uarg_tail_zero(uattr, sizeof(attr), size);

	err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);

	if (err)

		return err;

	size = min_t(u32, size, sizeof(attr));