I found a bug in this and am posting the following
update. If a connection's alloc_msg() method sets
the skip flag, it will return with con->in_msg being
a null pointer. The original version of this would
dereference that pointer without checking, which
causes a crash. This version checks first.
(This and the updated patches that follow it are
available in the "review/wip-3761-4" branch of the
ceph-client git repository.)
-Alex
We know the length of our message buffers. If we get a message
that's too long, just dump it and ignore it. If skip was set
then con->in_msg won't be valid, so be careful not to dereference
a null pointer in the process.
This resolves:
http://tracker.ceph.com/issues/4664
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
v2: make sure con->in_msg is valid before dereferencing it
net/ceph/messenger.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 994192b..cb5b4e6 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2207,10 +2207,18 @@ static int read_partial_message(struct
ceph_connection *con)
ret = ceph_con_in_msg_alloc(con, &skip);
if (ret < 0)
return ret;
+
+ BUG_ON(!con->in_msg ^ skip);
+ if (con->in_msg && data_len > con->in_msg->data_length) {
+ pr_warning("%s skipping long message (%u > %zd)\n",
+ __func__, data_len, con->in_msg->data_length);
+ ceph_msg_put(con->in_msg);
+ con->in_msg = NULL;
+ skip = 1;
+ }
if (skip) {
/* skip this message */
dout("alloc_msg said skip message\n");
- BUG_ON(con->in_msg);
con->in_base_pos = -front_len - middle_len - data_len -
sizeof(m->footer);
con->in_tag = CEPH_MSGR_TAG_READY;
--
1.7.9.5
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