On 12/1/15 1:35 PM, Konrad Rzeszutek Wilk wrote: > On Tue, Dec 01, 2015 at 11:47:17AM -0500, Konrad Rzeszutek Wilk wrote: >> On Thu, Nov 26, 2015 at 02:32:39PM -0600, Doug Goldstein wrote: >>> When allocating a pciback device fails, avoid the possibility of a >>> use after free. >> >> Reviewed-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> >> >> Ugh, and it looks like xen-blkfront has the same issue. > > <whew> Nope. No problems there. > > The ->probe if it fails (so xenbus_dev_probe returns the error) > ends up in the 'probe_failed' label in really_probe which takes care by doing: > > dev_set_drvdata(dev, NULL); > > Wheew! > > either way the patch should go in, but the 'possibility' should > be perhaps removed? Unless there is some other path I missed?
I put 'possibility' in there because it will only happen when the function returns failure. I was also trying to not make it sound panicky I guess. I can resubmit the patch with that word dropped if that's desirable. > >> >>> >>> Reported-by: Jonathan Creekmore <jonathan.creekm...@gmail.com> >>> Signed-off-by: Doug Goldstein <car...@cardoe.com> >>> --- >>> drivers/xen/xen-pciback/xenbus.c | 4 +++- >>> 1 file changed, 3 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/xen/xen-pciback/xenbus.c >>> b/drivers/xen/xen-pciback/xenbus.c >>> index 98bc345..4843741 100644 >>> --- a/drivers/xen/xen-pciback/xenbus.c >>> +++ b/drivers/xen/xen-pciback/xenbus.c >>> @@ -44,7 +44,6 @@ static struct xen_pcibk_device *alloc_pdev(struct >>> xenbus_device *xdev) >>> dev_dbg(&xdev->dev, "allocated pdev @ 0x%p\n", pdev); >>> >>> pdev->xdev = xdev; >>> - dev_set_drvdata(&xdev->dev, pdev); >>> >>> mutex_init(&pdev->dev_lock); >>> >>> @@ -58,6 +57,9 @@ static struct xen_pcibk_device *alloc_pdev(struct >>> xenbus_device *xdev) >>> kfree(pdev); >>> pdev = NULL; >>> } >>> + >>> + dev_set_drvdata(&xdev->dev, pdev); >>> + >>> out: >>> return pdev; >>> } >>> -- >>> 2.4.10 >>> -- Doug Goldstein
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