[PATCH 5.18 852/879] ceph: fix decoding of client session messages flags

Greg Kroah-Hartman
2022-06-08T02:03:22Z

From: Luís Henriques <lhenriques@suse.de>

commit ea16567f11018e2f58e72b667b0c803ff92b8153 upstream.

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.

Cc: stable@vger.kernel.org
Fixes: e1c9788cb397 ("ceph: don't rely on error_string to validate blocklisted session.")
Signed-off-by: Luís Henriques <lhenriques@suse.de>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/ceph/mds_client.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -3375,13 +3375,17 @@ static void handle_session(struct ceph_m
}

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;
}
}