4.9-stable review patch. If anyone has any objections, please let me know.
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From: Takashi Iwai tiwai@suse.de
commit 60bb83b81169820c691fbfa33a6a4aef32aa4b0b upstream.
We've got a bug report indicating a kernel panic at booting on an x86-32 system, and it turned out to be the invalid PCI resource assigned after reallocation. __find_resource() first aligns the resource start address and resets the end address with start+size-1 accordingly, then checks whether it's contained. Here the end address may overflow the integer, although resource_contains() still returns true because the function validates only start and end address. So this ends up with returning an invalid resource (start > end).
There was already an attempt to cover such a problem in the commit 47ea91b4052d ("Resource: fix wrong resource window calculation"), but this case is an overseen one.
This patch adds the validity check of the newly calculated resource for avoiding the integer overflow problem.
Bugzilla: http://bugzilla.opensuse.org/show_bug.cgi?id=1086739 Link: http://lkml.kernel.org/r/s5hpo37d5l8.wl-tiwai@suse.de Fixes: 23c570a67448 ("resource: ability to resize an allocated resource") Signed-off-by: Takashi Iwai tiwai@suse.de Reported-by: Michael Henders hendersm@shaw.ca Tested-by: Michael Henders hendersm@shaw.ca Reviewed-by: Andrew Morton akpm@linux-foundation.org Cc: Ram Pai linuxram@us.ibm.com Cc: Bjorn Helgaas bhelgaas@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/resource.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/kernel/resource.c +++ b/kernel/resource.c @@ -633,7 +633,8 @@ static int __find_resource(struct resour alloc.start = constraint->alignf(constraint->alignf_data, &avail, size, constraint->align); alloc.end = alloc.start + size - 1; - if (resource_contains(&avail, &alloc)) { + if (alloc.start <= alloc.end && + resource_contains(&avail, &alloc)) { new->start = alloc.start; new->end = alloc.end; return 0;