diff options
authorTakashi Iwai <tiwai@suse.de>2018-04-13 15:35:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-13 17:10:27 -0700
commit60bb83b81169820c691fbfa33a6a4aef32aa4b0b (patch)
parent16e205cf42da1f497b10a4a24f563e6c0d574eec (diff)
resource: fix integer overflow at reallocation
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>
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/resource.c b/kernel/resource.c
index e270b5048988..2af6c03858b9 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -651,7 +651,8 @@ static int __find_resource(struct resource *root, struct resource *old,
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;

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