2022-05-23 16:09:40

by Luis Henriques

Subject: [PATCH] ceph: fix decoding of client session messages flags

The cephfs kernel client started to show the message:

ceph: mds0 session blocklisted

when mounting a filesystem. This is due to the fact that the session
messages are being incorrectly decoded: the skip needs to take into
account the 'len'.

While there, fixed some whitespaces too.

Fixes: e1c9788cb397 ("ceph: don't rely on error_string to validate blocklisted session.")
Signed-off-by: Luís Henriques <[email protected]>
---
fs/ceph/mds_client.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 00c3de177dd6..1bd3e1bb0fdf 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3375,13 +3375,17 @@ static void handle_session(struct ceph_mds_session *session,
}

if (msg_version >= 5) {
- u32 flags;
- /* version >= 4, struct_v, struct_cv, len, metric_spec */
- ceph_decode_skip_n(&p, end, 2 + sizeof(u32) * 2, bad);
+ u32 flags, len;
+
+ /* version >= 4 */
+ ceph_decode_skip_16(&p, end, bad); /* struct_v, struct_cv */
+ ceph_decode_32_safe(&p, end, len, bad); /* len */
+ ceph_decode_skip_n(&p, end, len, bad); /* metric_spec */
+
/* version >= 5, flags */
- ceph_decode_32_safe(&p, end, flags, bad);
+ ceph_decode_32_safe(&p, end, flags, bad);
if (flags & CEPH_SESSION_BLOCKLISTED) {
- pr_warn("mds%d session blocklisted\n", session->s_mds);
+ pr_warn("mds%d session blocklisted\n", session->s_mds);
blocklisted = true;
}
}

2022-05-23 16:19:51

by Jeff Layton

Subject: Re: [PATCH] ceph: fix decoding of client session messages flags

On Mon, 2022-05-23 at 17:09 +0100, Lu?s Henriques wrote:
> The cephfs kernel client started to show the message:
>
> ceph: mds0 session blocklisted
>
> when mounting a filesystem. This is due to the fact that the session
> messages are being incorrectly decoded: the skip needs to take into
> account the 'len'.
>
> While there, fixed some whitespaces too.
>
> Fixes: e1c9788cb397 ("ceph: don't rely on error_string to validate blocklisted session.")
> Signed-off-by: Lu?s Henriques <[email protected]>
> ---
> fs/ceph/mds_client.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 00c3de177dd6..1bd3e1bb0fdf 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -3375,13 +3375,17 @@ static void handle_session(struct ceph_mds_session *session,
> }
>
> if (msg_version >= 5) {
> - u32 flags;
> - /* version >= 4, struct_v, struct_cv, len, metric_spec */
> - ceph_decode_skip_n(&p, end, 2 + sizeof(u32) * 2, bad);
> + u32 flags, len;
> +
> + /* version >= 4 */
> + ceph_decode_skip_16(&p, end, bad); /* struct_v, struct_cv */
> + ceph_decode_32_safe(&p, end, len, bad); /* len */
> + ceph_decode_skip_n(&p, end, len, bad); /* metric_spec */
> +
> /* version >= 5, flags */
> - ceph_decode_32_safe(&p, end, flags, bad);
> + ceph_decode_32_safe(&p, end, flags, bad);
> if (flags & CEPH_SESSION_BLOCKLISTED) {
> - pr_warn("mds%d session blocklisted\n", session->s_mds);
> + pr_warn("mds%d session blocklisted\n", session->s_mds);
> blocklisted = true;
> }
> }

Good catch! Should we send this to stable too?

Reviewed-by: Jeff Layton <[email protected]>

2022-05-23 16:34:12

by Luis Henriques

Subject: Re: [PATCH] ceph: fix decoding of client session messages flags

Jeff Layton <[email protected]> writes:

> On Mon, 2022-05-23 at 17:09 +0100, Luís Henriques wrote:
>> The cephfs kernel client started to show the message:
>>
>> ceph: mds0 session blocklisted
>>
>> when mounting a filesystem. This is due to the fact that the session
>> messages are being incorrectly decoded: the skip needs to take into
>> account the 'len'.
>>
>> While there, fixed some whitespaces too.
>>
>> Fixes: e1c9788cb397 ("ceph: don't rely on error_string to validate blocklisted session.")
>> Signed-off-by: Luís Henriques <[email protected]>
>> ---
>> fs/ceph/mds_client.c | 14 +++++++++-----
>> 1 file changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
>> index 00c3de177dd6..1bd3e1bb0fdf 100644
>> --- a/fs/ceph/mds_client.c
>> +++ b/fs/ceph/mds_client.c
>> @@ -3375,13 +3375,17 @@ static void handle_session(struct ceph_mds_session *session,
>> }
>>
>> if (msg_version >= 5) {
>> - u32 flags;
>> - /* version >= 4, struct_v, struct_cv, len, metric_spec */
>> - ceph_decode_skip_n(&p, end, 2 + sizeof(u32) * 2, bad);
>> + u32 flags, len;
>> +
>> + /* version >= 4 */
>> + ceph_decode_skip_16(&p, end, bad); /* struct_v, struct_cv */
>> + ceph_decode_32_safe(&p, end, len, bad); /* len */
>> + ceph_decode_skip_n(&p, end, len, bad); /* metric_spec */
>> +
>> /* version >= 5, flags */
>> - ceph_decode_32_safe(&p, end, flags, bad);
>> + ceph_decode_32_safe(&p, end, flags, bad);
>> if (flags & CEPH_SESSION_BLOCKLISTED) {
>> - pr_warn("mds%d session blocklisted\n", session->s_mds);
>> + pr_warn("mds%d session blocklisted\n", session->s_mds);
>> blocklisted = true;
>> }
>> }
>
> Good catch! Should we send this to stable too?

Ah, yeah. I didn't explicitly tagged it as I assumed the 'Fixes:' would
be enough for that. But it's probably better to do add the 'Cc: stable'
too.

> Reviewed-by: Jeff Layton <[email protected]>

Cheers,
--
Luís

2022-05-24 03:30:17

by Xiubo Li

Subject: Re: [PATCH] ceph: fix decoding of client session messages flags

On 5/24/22 12:34 AM, Luís Henriques wrote:
> Jeff Layton <[email protected]> writes:
>
>> On Mon, 2022-05-23 at 17:09 +0100, Luís Henriques wrote:
>>> The cephfs kernel client started to show the message:
>>>
>>> ceph: mds0 session blocklisted
>>>
>>> when mounting a filesystem. This is due to the fact that the session
>>> messages are being incorrectly decoded: the skip needs to take into
>>> account the 'len'.
>>>
>>> While there, fixed some whitespaces too.
>>>
>>> Fixes: e1c9788cb397 ("ceph: don't rely on error_string to validate blocklisted session.")
>>> Signed-off-by: Luís Henriques <[email protected]>
>>> ---
>>> fs/ceph/mds_client.c | 14 +++++++++-----
>>> 1 file changed, 9 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
>>> index 00c3de177dd6..1bd3e1bb0fdf 100644
>>> --- a/fs/ceph/mds_client.c
>>> +++ b/fs/ceph/mds_client.c
>>> @@ -3375,13 +3375,17 @@ static void handle_session(struct ceph_mds_session *session,
>>> }
>>>
>>> if (msg_version >= 5) {
>>> - u32 flags;
>>> - /* version >= 4, struct_v, struct_cv, len, metric_spec */
>>> - ceph_decode_skip_n(&p, end, 2 + sizeof(u32) * 2, bad);
>>> + u32 flags, len;
>>> +
>>> + /* version >= 4 */
>>> + ceph_decode_skip_16(&p, end, bad); /* struct_v, struct_cv */
>>> + ceph_decode_32_safe(&p, end, len, bad); /* len */
>>> + ceph_decode_skip_n(&p, end, len, bad); /* metric_spec */
>>> +
>>> /* version >= 5, flags */
>>> - ceph_decode_32_safe(&p, end, flags, bad);
>>> + ceph_decode_32_safe(&p, end, flags, bad);
>>> if (flags & CEPH_SESSION_BLOCKLISTED) {
>>> - pr_warn("mds%d session blocklisted\n", session->s_mds);
>>> + pr_warn("mds%d session blocklisted\n", session->s_mds);
>>> blocklisted = true;
>>> }
>>> }
>> Good catch! Should we send this to stable too?
> Ah, yeah. I didn't explicitly tagged it as I assumed the 'Fixes:' would
> be enough for that. But it's probably better to do add the 'Cc: stable'
> too.

Good catch! Merged into the testing branch and added the 'Cc: stable'.

Thanks Luis.

-- Xiubo


>> Reviewed-by: Jeff Layton <[email protected]>
> Cheers,