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resource: fix integer overflow at reallocation

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commit 60bb83b811 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
47ea91b405 ("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: 23c570a674 ("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>
This commit is contained in:
Takashi Iwai 2018-04-13 15:35:13 -07:00 committed by Greg Kroah-Hartman
parent f659e7e79f
commit c25ef6220f
1 changed files with 2 additions and 1 deletions
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3
kernel/resource.c
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@ -633,7 +633,8 @@ 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;