bpf.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH 9/9] bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user()
       [not found] <20200528234025.GT23230@ZenIV.linux.org.uk>
@ 2020-05-29 23:28 ` Al Viro
  2020-05-31 16:35   ` Alexei Starovoitov
  0 siblings, 1 reply; 2+ messages in thread
From: Al Viro @ 2020-05-29 23:28 UTC (permalink / raw)
  To: Linus Torvalds; +Cc: linux-kernel, linux-fsdevel, Alexei Starovoitov, bpf

From: Al Viro <viro@zeniv.linux.org.uk>

... rather than open-coding it, and badly, at that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 kernel/bpf/syscall.c | 25 ++++++-------------------
 1 file 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 = {
-- 
2.11.0


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH 9/9] bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user()
  2020-05-29 23:28 ` [PATCH 9/9] bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() Al Viro
@ 2020-05-31 16:35   ` Alexei Starovoitov
  0 siblings, 0 replies; 2+ messages in thread
From: Alexei Starovoitov @ 2020-05-31 16:35 UTC (permalink / raw)
  To: Al Viro
  Cc: Linus Torvalds, linux-kernel, linux-fsdevel, Alexei Starovoitov, bpf

On Sat, May 30, 2020 at 12:28:14AM +0100, Al Viro wrote:
> From: Al Viro <viro@zeniv.linux.org.uk>
> 
> ... rather than open-coding it, and badly, at that.
> 
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
>  kernel/bpf/syscall.c | 25 ++++++-------------------
>  1 file changed, 6 insertions(+), 19 deletions(-)

lgtm
Acked-by: Alexei Starovoitov <ast@kernel.org>

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2020-05-31 16:35 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
     [not found] <20200528234025.GT23230@ZenIV.linux.org.uk>
2020-05-29 23:28 ` [PATCH 9/9] bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() Al Viro
2020-05-31 16:35   ` Alexei Starovoitov

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).