AcoSail/kernel_optimize_test
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bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user()

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... 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>
This commit is contained in:
Al Viro 2020-05-08 00:16:31 -04:00
parent 9eb41c5214
commit b7e4b65f3f
1 changed files with 6 additions and 19 deletions
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25
kernel/bpf/syscall.c
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@ -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 = {