* [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
@ 2022-05-09 0:51 Zhengchao Shao
2022-05-09 9:46 ` Toke Høiland-Jørgensen
0 siblings, 1 reply; 6+ messages in thread
From: Zhengchao Shao @ 2022-05-09 0:51 UTC (permalink / raw)
To: bpf, netdev, linux-kernel, ast, daniel, davem, kuba, hawk,
john.fastabend, andrii, kafai, songliubraving, yhs, kpsingh
Cc: weiyongjun1, shaozhengchao, yuehaibing
Before detach the prog, we should check detach prog exist or not.
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
---
samples/bpf/xdp_fwd_user.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/samples/bpf/xdp_fwd_user.c b/samples/bpf/xdp_fwd_user.c
index 1828487bae9a..a273ede3fd73 100644
--- a/samples/bpf/xdp_fwd_user.c
+++ b/samples/bpf/xdp_fwd_user.c
@@ -49,7 +49,18 @@ static int do_attach(int idx, int prog_fd, int map_fd, const char *name)
static int do_detach(int idx, const char *name)
{
- int err;
+ int err = 1;
+ __u32 curr_prog_id;
+
+ if (bpf_xdp_query_id(idx, xdp_flags, &curr_prog_id)) {
+ printf("ERROR: bpf_xdp_query_id failed\n");
+ return err;
+ }
+
+ if (!curr_prog_id) {
+ printf("ERROR: flags(0x%x) xdp prog is not attached to %s\n", xdp_flags, name);
+ return err;
+ }
err = bpf_xdp_detach(idx, xdp_flags, NULL);
if (err < 0)
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
2022-05-09 0:51 [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd Zhengchao Shao
@ 2022-05-09 9:46 ` Toke Høiland-Jørgensen
2022-05-09 10:27 ` 答复: " shaozhengchao
0 siblings, 1 reply; 6+ messages in thread
From: Toke Høiland-Jørgensen @ 2022-05-09 9:46 UTC (permalink / raw)
To: Zhengchao Shao, bpf, netdev, linux-kernel, ast, daniel, davem,
kuba, hawk, john.fastabend, andrii, kafai, songliubraving, yhs,
kpsingh
Cc: weiyongjun1, shaozhengchao, yuehaibing
Zhengchao Shao <shaozhengchao@huawei.com> writes:
> Before detach the prog, we should check detach prog exist or not.
If we're adding such a check we should also check that it's the *right*
program. I.e., query the ID for the program name and check that it
matches what the program attached, then obtain an fd and pass that as
XDP_EXPECTED_FD on detach to make sure it wasn't swapped out in the
meantime...
-Toke
^ permalink raw reply [flat|nested] 6+ messages in thread
* 答复: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
2022-05-09 9:46 ` Toke Høiland-Jørgensen
@ 2022-05-09 10:27 ` shaozhengchao
2022-05-09 10:55 ` Toke Høiland-Jørgensen
0 siblings, 1 reply; 6+ messages in thread
From: shaozhengchao @ 2022-05-09 10:27 UTC (permalink / raw)
To: Toke Høiland-Jørgensen, bpf, netdev, linux-kernel, ast,
daniel, davem, kuba, hawk, john.fastabend, andrii, kafai,
songliubraving, yhs, kpsingh
Cc: weiyongjun (A), yuehaibing
-----邮件原件-----
发件人: Toke Høiland-Jørgensen [mailto:toke@kernel.org]
发送时间: 2022年5月9日 17:46
收件人: shaozhengchao <shaozhengchao@huawei.com>; bpf@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; ast@kernel.org; daniel@iogearbox.net; davem@davemloft.net; kuba@kernel.org; hawk@kernel.org; john.fastabend@gmail.com; andrii@kernel.org; kafai@fb.com; songliubraving@fb.com; yhs@fb.com; kpsingh@kernel.org
抄送: weiyongjun (A) <weiyongjun1@huawei.com>; shaozhengchao <shaozhengchao@huawei.com>; yuehaibing <yuehaibing@huawei.com>
主题: Re: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
Zhengchao Shao <shaozhengchao@huawei.com> writes:
> Before detach the prog, we should check detach prog exist or not.
If we're adding such a check we should also check that it's the *right* program. I.e., query the ID for the program name and check that it matches what the program attached, then obtain an fd and pass that as XDP_EXPECTED_FD on detach to make sure it wasn't swapped out in the meantime...
-Toke
Thank you for your reply. When finish running xdp_fwd to attatch prog, the program will exit and can't store fd as XDP_EXPECTED_FD.
I think the sample xdp_fwd -d is just detach prog and don't care if the fd is expected.
-zhengchao shao
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: 答复: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
2022-05-09 10:27 ` 答复: " shaozhengchao
@ 2022-05-09 10:55 ` Toke Høiland-Jørgensen
2022-05-17 2:00 ` 答复: " shaozhengchao
0 siblings, 1 reply; 6+ messages in thread
From: Toke Høiland-Jørgensen @ 2022-05-09 10:55 UTC (permalink / raw)
To: shaozhengchao, bpf, netdev, linux-kernel, ast, daniel, davem,
kuba, hawk, john.fastabend, andrii, kafai, songliubraving, yhs,
kpsingh
Cc: weiyongjun (A), yuehaibing
shaozhengchao <shaozhengchao@huawei.com> writes:
> -----邮件原件-----
> 发件人: Toke Høiland-Jørgensen [mailto:toke@kernel.org]
> 发送时间: 2022年5月9日 17:46
> 收件人: shaozhengchao <shaozhengchao@huawei.com>; bpf@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; ast@kernel.org; daniel@iogearbox.net; davem@davemloft.net; kuba@kernel.org; hawk@kernel.org; john.fastabend@gmail.com; andrii@kernel.org; kafai@fb.com; songliubraving@fb.com; yhs@fb.com; kpsingh@kernel.org
> 抄送: weiyongjun (A) <weiyongjun1@huawei.com>; shaozhengchao <shaozhengchao@huawei.com>; yuehaibing <yuehaibing@huawei.com>
> 主题: Re: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
>
> Zhengchao Shao <shaozhengchao@huawei.com> writes:
>
>> Before detach the prog, we should check detach prog exist or not.
>
> If we're adding such a check we should also check that it's the *right* program. I.e., query the ID for the program name and check that it matches what the program attached, then obtain an fd and pass that as XDP_EXPECTED_FD on detach to make sure it wasn't swapped out in the meantime...
>
> -Toke
>
> Thank you for your reply. When finish running xdp_fwd to attatch prog,
> the program will exit and can't store fd as XDP_EXPECTED_FD.
>
> I think the sample xdp_fwd -d is just detach prog and don't care if
> the fd is expected.
So why are you adding the check? Either keep it the way it is, or add a
proper check that examines the program type; you're right that it
doesn't store the prog FD, but you can still check the program name and
see if it matches to get some idea that it's not a totally separate
program that's loaded. I think doing so would be an improvement to the
sample, but just adding a check if a program is loaded is not, really...
-Toke
^ permalink raw reply [flat|nested] 6+ messages in thread
* 答复: 答复: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
2022-05-09 10:55 ` Toke Høiland-Jørgensen
@ 2022-05-17 2:00 ` shaozhengchao
2022-05-17 9:42 ` Toke Høiland-Jørgensen
0 siblings, 1 reply; 6+ messages in thread
From: shaozhengchao @ 2022-05-17 2:00 UTC (permalink / raw)
To: Toke Høiland-Jørgensen, bpf, netdev, linux-kernel, ast,
daniel, davem, kuba, hawk, john.fastabend, andrii, kafai,
songliubraving, yhs, kpsingh
Cc: weiyongjun (A), yuehaibing
-----邮件原件-----
发件人: Toke Høiland-Jørgensen [mailto:toke@kernel.org]
发送时间: 2022年5月9日 18:55
收件人: shaozhengchao <shaozhengchao@huawei.com>; bpf@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; ast@kernel.org; daniel@iogearbox.net; davem@davemloft.net; kuba@kernel.org; hawk@kernel.org; john.fastabend@gmail.com; andrii@kernel.org; kafai@fb.com; songliubraving@fb.com; yhs@fb.com; kpsingh@kernel.org
抄送: weiyongjun (A) <weiyongjun1@huawei.com>; yuehaibing <yuehaibing@huawei.com>
主题: Re: 答复: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
shaozhengchao <shaozhengchao@huawei.com> writes:
> -----邮件原件-----
> 发件人: Toke Høiland-Jørgensen [mailto:toke@kernel.org]
> 发送时间: 2022年5月9日 17:46
> 收件人: shaozhengchao <shaozhengchao@huawei.com>; bpf@vger.kernel.org;
> netdev@vger.kernel.org; linux-kernel@vger.kernel.org; ast@kernel.org;
> daniel@iogearbox.net; davem@davemloft.net; kuba@kernel.org;
> hawk@kernel.org; john.fastabend@gmail.com; andrii@kernel.org;
> kafai@fb.com; songliubraving@fb.com; yhs@fb.com; kpsingh@kernel.org
> 抄送: weiyongjun (A) <weiyongjun1@huawei.com>; shaozhengchao
> <shaozhengchao@huawei.com>; yuehaibing <yuehaibing@huawei.com>
> 主题: Re: [PATCH bpf-next] samples/bpf: check detach prog exist or not
> in xdp_fwd
>
> Zhengchao Shao <shaozhengchao@huawei.com> writes:
>
>> Before detach the prog, we should check detach prog exist or not.
>
> If we're adding such a check we should also check that it's the *right* program. I.e., query the ID for the program name and check that it matches what the program attached, then obtain an fd and pass that as XDP_EXPECTED_FD on detach to make sure it wasn't swapped out in the meantime...
>
> -Toke
>
> Thank you for your reply. When finish running xdp_fwd to attatch prog,
> the program will exit and can't store fd as XDP_EXPECTED_FD.
>
> I think the sample xdp_fwd -d is just detach prog and don't care if
> the fd is expected.
So why are you adding the check? Either keep it the way it is, or add a proper check that examines the program type; you're right that it doesn't store the prog FD, but you can still check the program name and see if it matches to get some idea that it's not a totally separate program that's loaded. I think doing so would be an improvement to the sample, but just adding a check if a program is loaded is not, really...
-Toke
Could I add helper function to implement this function which can check the program name and see if it attach to the device.
-Zhengchao Shao
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: 答复: 答复: [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd
2022-05-17 2:00 ` 答复: " shaozhengchao
@ 2022-05-17 9:42 ` Toke Høiland-Jørgensen
0 siblings, 0 replies; 6+ messages in thread
From: Toke Høiland-Jørgensen @ 2022-05-17 9:42 UTC (permalink / raw)
To: shaozhengchao, bpf, netdev, linux-kernel, ast, daniel, davem,
kuba, hawk, john.fastabend, andrii, kafai, songliubraving, yhs,
kpsingh
Cc: weiyongjun (A), yuehaibing
> Could I add helper function to implement this function which can check
> the program name and see if it attach to the device.
You just need to call bpf_prog_get_fd_by_id() followed by
bpf_obj_get_info_by_fd(), and the program name will be in info.name.
Here's an example in libxdp where we pull out the prog name:
https://github.com/xdp-project/xdp-tools/blob/master/lib/libxdp/libxdp.c#L1165
-Toke
^ permalink raw reply [flat|nested] 6+ messages in thread
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2022-05-09 0:51 [PATCH bpf-next] samples/bpf: check detach prog exist or not in xdp_fwd Zhengchao Shao
2022-05-09 9:46 ` Toke Høiland-Jørgensen
2022-05-09 10:27 ` 答复: " shaozhengchao
2022-05-09 10:55 ` Toke Høiland-Jørgensen
2022-05-17 2:00 ` 答复: " shaozhengchao
2022-05-17 9:42 ` Toke Høiland-Jørgensen
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