On 04/25/2011 05:53 PM, Tim Gardner wrote:
On 04/25/2011 01:29 PM, Brad Figg wrote:
From: Sean Hefty<sean.hefty@intel.com>
CVE-2011-0695
BugLink: http://bugs.launchpad.net/bugs/770369
When processing a SIDR REQ, the ib_cm allocates a new cm_id. The
refcount of the cm_id is initialized to 1. However, cm_process_work
will decrement the refcount after invoking all callbacks. The result
is that the cm_id will end up with refcount set to 0 by the end of the
sidr req handler.
If a user tries to destroy the cm_id, the destruction will proceed,
under the incorrect assumption that no other threads are referencing
the cm_id. This can lead to a crash when the cm callback thread tries
to access the cm_id.
This problem was noticed as part of a larger investigation with kernel
crashes in the rdma_cm when running on a real time OS.
Signed-off-by: Sean Hefty<sean.hefty@intel.com>
Acked-by: Doug Ledford<dledford@redhat.com>
Cc:<stable@kernel.org>
Signed-off-by: Roland Dreier<roland@purestorage.com>
(cherry-picked from commit 29963437a48475036353b95ab142bf199adb909e)
Signed-off-by: Brad Figg<brad.figg@canonical.com>
---
drivers/infiniband/core/cm.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 64e0903..1d9616b 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -2989,6 +2989,7 @@ static int cm_sidr_req_handler(struct cm_work *work)
goto out; /* No match. */
}
atomic_inc(&cur_cm_id_priv->refcount);
+ atomic_inc(&cm_id_priv->refcount);
spin_unlock_irq(&cm.lock);
cm_id_priv->id.cm_handler = cur_cm_id_priv->id.cm_handler;
I'm a bit curious how you got these 2 patches to apply 'cause they were released with 2.6.35-29.51. Did you start with master instead of master-next ?
rtg
That's a really good question. I patched an old local repo. I got distracted
working on these and thought I'd updated my repo but had not. Thanks for
catching this and sorry to waste everyone's time.
Brad
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IB/cm: Bump reference count on cm_id before invoking callback, CVE-2011-0695
