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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2017-12-08 19:10:05 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-20 12:10:19 +0300 |
| commit | 2b3ff282dff3a42a081bef0f8249a99f64d7669f (patch) | |
| tree | cbbd276dbb687a4c152f5df0058f41a732cd20dc /drivers | |
| parent | 912fe79116f2456a00cf4a9b2ad3ef207ba3e162 (diff) | |
| download | linux-2b3ff282dff3a42a081bef0f8249a99f64d7669f.tar.xz | |
xhci: Don't add a virt_dev to the devs array before it's fully allocated
commit 5d9b70f7d52eb14bb37861c663bae44de9521c35 upstream.
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."
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/host/xhci-mem.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 97f30eb7dac0..ccdc971283d0 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -983,10 +983,9 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id, return 0; } - xhci->devs[slot_id] = kzalloc(sizeof(*xhci->devs[slot_id]), flags); - if (!xhci->devs[slot_id]) + dev = kzalloc(sizeof(*dev), flags); + if (!dev) return 0; - dev = xhci->devs[slot_id]; /* Allocate the (output) device context that will be used in the HC. */ dev->out_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_DEVICE, flags); @@ -1027,9 +1026,17 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id, trace_xhci_alloc_virt_device(dev); + xhci->devs[slot_id] = dev; + return 1; fail: - xhci_free_virt_device(xhci, slot_id); + + if (dev->in_ctx) + xhci_free_container_ctx(xhci, dev->in_ctx); + if (dev->out_ctx) + xhci_free_container_ctx(xhci, dev->out_ctx); + kfree(dev); + return 0; } |