From: Christian Brauner <christian.brauner@ubuntu.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
bpf@vger.kernel.org
Cc: Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
Christian Brauner <christian.brauner@ubuntu.com>
Subject: [PATCH 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero()
Date: Wed, 9 Oct 2019 18:09:05 +0200 [thread overview]
Message-ID: <20191009160907.10981-2-christian.brauner@ubuntu.com> (raw)
In-Reply-To: <20191009160907.10981-1-christian.brauner@ubuntu.com>
In v5.4-rc2 we added a new helper (cf. [1]) check_zeroed_user() which
does what bpf_check_uarg_tail_zero() is doing generically. We're slowly
switching such codepaths over to use check_zeroed_user() instead of
using their own hand-rolled version.
[1]: f5a1a536fa14 ("lib: introduce copy_struct_from_user() helper")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
kernel/bpf/syscall.c | 22 +++++++---------------
1 file changed, 7 insertions(+), 15 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 82eabd4e38ad..78790778f101 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -63,30 +63,22 @@ 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;
+ size_t size = min(expected_size, actual_size);
+ size_t rest = max(expected_size, actual_size) - size;
int err;
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;
+ err = check_zeroed_user(uaddr + expected_size, rest);
+ if (err < 0)
+ return err;
- for (; addr < end; addr++) {
- err = get_user(val, addr);
- if (err)
- return err;
- if (val)
- return -E2BIG;
- }
+ if (err)
+ return -E2BIG;
return 0;
}
--
2.23.0
next prev parent reply other threads:[~2019-10-09 16:09 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-09 16:09 [PATCH 0/3] bpf: switch to new usercopy helpers Christian Brauner
2019-10-09 16:09 ` Christian Brauner [this message]
2019-10-10 10:50 ` [PATCH 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Aleksa Sarai
2019-10-09 16:09 ` [PATCH 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-10 10:51 ` Aleksa Sarai
2019-10-09 16:09 ` [PATCH 3/3] bpf: use copy_struct_from_user() in bpf() syscall Christian Brauner
2019-10-10 10:51 ` Aleksa Sarai
2019-10-09 23:06 ` [PATCH 0/3] bpf: switch to new usercopy helpers Alexei Starovoitov
2019-10-10 9:26 ` Christian Brauner
2019-10-15 22:45 ` Alexei Starovoitov
2019-10-15 22:55 ` Christian Brauner
2019-10-15 23:02 ` Alexei Starovoitov
2019-10-15 23:08 ` Christian Brauner
2019-10-16 0:41 ` [PATCH v2 " Christian Brauner
2019-10-16 0:41 ` [PATCH v2 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Christian Brauner
2019-10-16 0:41 ` [PATCH v2 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 0:41 ` [PATCH v2 3/3] bpf: use copy_struct_from_user() in bpf() syscall Christian Brauner
2019-10-16 0:48 ` [PATCH v2 0/3] bpf: switch to new usercopy helpers Christian Brauner
2019-10-16 2:14 ` Alexei Starovoitov
2019-10-16 3:31 ` Christian Brauner
2019-10-16 3:44 ` [PATCH v3 " Christian Brauner
2019-10-16 3:44 ` [PATCH v3 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Christian Brauner
2019-10-16 5:23 ` Alexei Starovoitov
2019-10-16 3:44 ` [PATCH v3 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 5:25 ` Alexei Starovoitov
2019-10-16 7:30 ` [PATCH v3 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd()y Christian Brauner
2019-10-16 7:43 ` [PATCH v3 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 3:44 ` [PATCH v3 3/3] bpf: use copy_struct_from_user() in bpf() syscall Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 0/3] bpf: switch to new usercopy helpers Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 1/3] bpf: use check_zeroed_user() in bpf_check_uarg_tail_zero() Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 2/3] bpf: use copy_struct_from_user() in bpf_prog_get_info_by_fd() Christian Brauner
2019-10-16 11:18 ` [PATCH bpf-next v4 3/3] bpf: use copy_struct_from_user() in bpf() syscall Christian Brauner
2019-10-16 18:31 ` [PATCH bpf-next v4 0/3] bpf: switch to new usercopy helpers Alexei Starovoitov
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