xhci: Don't add a virt_dev to the devs array before it's fully allocated
Avoid null pointer dereference if some function is walking through the devs array accessing members of a new virt_dev that is mid allocation. Add the virt_dev to xhci->devs[i] _after_ the virt_device and all its members are properly allocated. issue found by KASAN: null-ptr-deref in xhci_find_slot_id_by_port "Quick analysis suggests that xhci_alloc_virt_device() is not mutex protected. If so, there is a time frame where xhci->devs[slot_id] is set but not fully initialized. Specifically, xhci->devs[i]->udev can be NULL." Cc: stable <stable@vger.kernel.org> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -971,10 +971,9 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
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return 0;
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}
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xhci->devs[slot_id] = kzalloc(sizeof(*xhci->devs[slot_id]), flags);
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if (!xhci->devs[slot_id])
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dev = kzalloc(sizeof(*dev), flags);
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if (!dev)
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return 0;
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dev = xhci->devs[slot_id];
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/* Allocate the (output) device context that will be used in the HC. */
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dev->out_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_DEVICE, flags);
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@ -1015,9 +1014,17 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
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trace_xhci_alloc_virt_device(dev);
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xhci->devs[slot_id] = dev;
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return 1;
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fail:
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xhci_free_virt_device(xhci, slot_id);
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if (dev->in_ctx)
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xhci_free_container_ctx(xhci, dev->in_ctx);
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if (dev->out_ctx)
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xhci_free_container_ctx(xhci, dev->out_ctx);
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kfree(dev);
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return 0;
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}
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