[PATCH 04/14] mwifiex: pcie: don't allow cmd buffer reuse after reset

Brian Norris
2017-05-25T00:11:49Z

In rogue cases (due to other bugs) it's possible we try to process an
old command response *after* resetting the device. This could trigger a
double-free (or the SKB can get reallocated elsewhere...causing other
memory corruptions) in mwifiex_pcie_process_cmd_complete().

For safety (and symmetry) let's always NULL out the command buffer as we
free it up. We're already doing this for the command response buffer.

Signed-off-by: Brian Norris <briannorris@chromium.org>
---
drivers/net/wireless/marvell/mwifiex/pcie.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index ea75315bf19d..3d5c29d79609 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -1060,12 +1060,14 @@ static int mwifiex_pcie_delete_cmdrsp_buf(struct mwifiex_adapter *adapter)
mwifiex_unmap_pci_memory(adapter, card->cmdrsp_buf,
PCI_DMA_FROMDEVICE);
dev_kfree_skb_any(card->cmdrsp_buf);
+ card->cmdrsp_buf = NULL;
}

if (card && card->cmd_buf) {
mwifiex_unmap_pci_memory(adapter, card->cmd_buf,
PCI_DMA_TODEVICE);
dev_kfree_skb_any(card->cmd_buf);
+ card->cmd_buf = NULL;
}
return 0;
}
@@ -2946,7 +2948,6 @@ static void mwifiex_pcie_free_buffers(struct mwifiex_adapter *adapter)
mwifiex_pcie_delete_evtbd_ring(adapter);
mwifiex_pcie_delete_rxbd_ring(adapter);
mwifiex_pcie_delete_txbd_ring(adapter);
- card->cmdrsp_buf = NULL;
}

/*
--
2.13.0.219.gdb65acc882-goog