[PATCH bpf-next 1/7] bpf: Expose check_uarg_tail_zero()

[Martin KaFai Lau]

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: Martin KaFai Lau <ka...@fb.com>
---
 include/linux/bpf.h  |  2 ++
 kernel/bpf/syscall.c | 14 +++++++-------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index ed0122b45b63..f6fe3c719ca8 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -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.
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index bfcde949c7f8..2b29ef84ded3 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -65,9 +65,9 @@ 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,
-                               size_t expected_size,
-                               size_t actual_size)
+int bpf_check_uarg_tail_zero(void __user *uaddr,
+                            size_t expected_size,
+                            size_t actual_size)
 {
        unsigned char __user *addr;
        unsigned char __user *end;
@@ -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));
-- 
2.9.5