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68 lines
2.4 KiB
Diff
68 lines
2.4 KiB
Diff
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From fad6f73dc4367adb852ce6953f93f12cbb97b894 Mon Sep 17 00:00:00 2001
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From: Camelia Groza <camelia.groza@nxp.com>
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Date: Fri, 18 May 2018 10:33:37 +0300
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Subject: [PATCH] sdk_dpaa: ceetm: avoid use-after-free scenarios
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Once the pfiofo qdiscs are grafted to the netdev queues, they are destroyed
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by the kernel when required. Remove references to the pfifo qdiscs after
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grafting, in order to avoid double free scenarios.
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Signed-off-by: Camelia Groza <camelia.groza@nxp.com>
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---
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.../ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c | 23 +++++++++++++++++++---
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1 file changed, 20 insertions(+), 3 deletions(-)
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--- a/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c
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+++ b/drivers/net/ethernet/freescale/sdk_dpaa/dpaa_eth_ceetm.c
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@@ -477,7 +477,9 @@ static void ceetm_destroy(struct Qdisc *
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if (!priv->root.qdiscs)
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break;
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- /* Remove the pfifo qdiscs */
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+ /* Destroy the pfifo qdiscs in case they haven't been attached
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+ * to the netdev queues yet.
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+ */
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for (ntx = 0; ntx < dev->num_tx_queues; ntx++)
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if (priv->root.qdiscs[ntx])
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qdisc_destroy(priv->root.qdiscs[ntx]);
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@@ -608,7 +610,16 @@ static int ceetm_init_root(struct Qdisc
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goto err_init_root;
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}
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- /* pre-allocate underlying pfifo qdiscs */
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+ /* Pre-allocate underlying pfifo qdiscs.
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+ *
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+ * We want to offload shaping and scheduling decisions to the hardware.
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+ * The pfifo qdiscs will be attached to the netdev queues and will
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+ * guide the traffic from the IP stack down to the driver with minimum
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+ * interference.
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+ *
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+ * The CEETM qdiscs and classes will be crossed when the traffic
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+ * reaches the driver.
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+ */
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priv->root.qdiscs = kcalloc(dev->num_tx_queues,
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sizeof(priv->root.qdiscs[0]),
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GFP_KERNEL);
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@@ -1280,7 +1291,10 @@ static int ceetm_change(struct Qdisc *sc
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return ret;
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}
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-/* Attach the underlying pfifo qdiscs */
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+/* Graft the underlying pfifo qdiscs to the netdev queues.
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+ * It's safe to remove our references at this point, since the kernel will
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+ * destroy the qdiscs on its own and no cleanup from our part is required.
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+ */
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static void ceetm_attach(struct Qdisc *sch)
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{
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struct net_device *dev = qdisc_dev(sch);
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@@ -1296,6 +1310,9 @@ static void ceetm_attach(struct Qdisc *s
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if (old_qdisc)
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qdisc_destroy(old_qdisc);
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}
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+
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+ kfree(priv->root.qdiscs);
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+ priv->root.qdiscs = NULL;
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}
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static unsigned long ceetm_cls_search(struct Qdisc *sch, u32 handle)
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