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| author | Al Viro <viro@zeniv.linux.org.uk> | 2020-05-08 06:16:31 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2020-06-03 22:59:45 +0200 |
| commit | b7e4b65f3fe92abbf4a1f57987a54c820969aebd (patch) | |
| tree | 9d107c7f803e1692da849422ff0afbaea060516d /kernel/bpf | |
| parent | x86: kvm_hv_set_msr(): use __put_user() instead of 32bit __clear_user() (diff) | |
| download | linux-b7e4b65f3fe92abbf4a1f57987a54c820969aebd.tar.xz linux-b7e4b65f3fe92abbf4a1f57987a54c820969aebd.zip | |
bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user()
... rather than open-coding it, and badly, at that.
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/syscall.c | 25 |
1 files changed, 6 insertions, 19 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 64783da34202..41ba746ecbc2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -67,32 +67,19 @@ 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; - unsigned char val; - int err; + unsigned char __user *addr = uaddr + expected_size; + int res; if (unlikely(actual_size > PAGE_SIZE)) /* silly large */ return -E2BIG; - if (unlikely(!access_ok(uaddr, actual_size))) - return -EFAULT; - if (actual_size <= expected_size) return 0; - addr = uaddr + expected_size; - end = uaddr + actual_size; - - for (; addr < end; addr++) { - err = get_user(val, addr); - if (err) - return err; - if (val) - return -E2BIG; - } - - return 0; + res = check_zeroed_user(addr, actual_size - expected_size); + if (res < 0) + return res; + return res ? 0 : -E2BIG; } const struct bpf_map_ops bpf_map_offload_ops = { |