From b7e4b65f3fe92abbf4a1f57987a54c820969aebd Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 8 May 2020 00:16:31 -0400 Subject: bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() ... rather than open-coding it, and badly, at that. Acked-by: Alexei Starovoitov Signed-off-by: Al Viro --- kernel/bpf/syscall.c | 25 ++++++------------------- 1 file changed, 6 insertions(+), 19 deletions(-) (limited to 'kernel/bpf/syscall.c') 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 = { -- cgit v1.2.3