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| author | Mathias Nyman <mathias.nyman@linux.intel.com> | 2017-12-08 18:10:05 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-20 10:07:17 +0100 |
| commit | 3bdb508d686e4943bfb761d78dc915dd825f811f (patch) | |
| tree | c6323bc112a65daecd019e599b68b068dd28e3e4 /drivers | |
| parent | 7336f5481f6cf913a2d29d98c6e11f4bbe19d3b2 (diff) | |
| download | linux-stable-3bdb508d686e4943bfb761d78dc915dd825f811f.tar.gz linux-stable-3bdb508d686e4943bfb761d78dc915dd825f811f.tar.bz2 linux-stable-3bdb508d686e4943bfb761d78dc915dd825f811f.zip | |
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 a3ecd8bd5324..82eea55a7b5c 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1032,10 +1032,9 @@ 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); @@ -1083,9 +1082,17 @@ int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id, &xhci->dcbaa->dev_context_ptrs[slot_id], le64_to_cpu(xhci->dcbaa->dev_context_ptrs[slot_id])); + 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; } |