mirror of https://gitee.com/openkylin/linux.git
USB: EHCI: fix NULL pointer dererence in HCDs that use HCD_LOCAL_MEM
If we use the HCD_LOCAL_MEM flag and dma_declare_coherent_memory() to enforce the host controller's local memory utilization we also need to disable native scatter-gather support, otherwise hcd_alloc_coherent() in map_urb_for_dma() is called with urb->transfer_buffer == NULL, that triggers a NULL pointer dereference. We can also consider to add a WARN_ON() and return an error code to better catch this problem in the future. At the moment no driver seems to hit this bug, so I should consider this a low-priority fix. Signed-off-by: Andrea Righi <arighi@develer.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -1218,6 +1218,11 @@ static int hcd_alloc_coherent(struct usb_bus *bus,
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{
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{
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unsigned char *vaddr;
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unsigned char *vaddr;
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if (*vaddr_handle == NULL) {
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WARN_ON_ONCE(1);
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return -EFAULT;
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}
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vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
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vaddr = hcd_buffer_alloc(bus, size + sizeof(vaddr),
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mem_flags, dma_handle);
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mem_flags, dma_handle);
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if (!vaddr)
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if (!vaddr)
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@ -629,7 +629,8 @@ static int ehci_init(struct usb_hcd *hcd)
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ehci->command = temp;
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ehci->command = temp;
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/* Accept arbitrarily long scatter-gather lists */
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/* Accept arbitrarily long scatter-gather lists */
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hcd->self.sg_tablesize = ~0;
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if (!(hcd->driver->flags & HCD_LOCAL_MEM))
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hcd->self.sg_tablesize = ~0;
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return 0;
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return 0;
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}
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}
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