+ resource-fix-integer-overflow-at-reallocation.patch added to -mm tree

+ resource-fix-integer-overflow-at-reallocation.patch added to -mm tree

[akpm]

The patch titled
     Subject: resource: fix integer overflow at reallocation
has been added to the -mm tree.  Its filename is
     resource-fix-integer-overflow-at-reallocation.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/resource-fix-integer-overflow-at-reallocation.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/resource-fix-integer-overflow-at-reallocation.patch

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------------------------------------------------------
From: Takashi Iwai <tiwai@suse.de>
Subject: 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 resource assigned after PCI
resource 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 in resource_contains() to see whether
the given resource has a valid range for avoiding the integer overflow
problem.

Bugzilla: http://bugzilla.opensuse.org/show_bug.cgi?id=1086739
Link: http://lkml.kernel.org/r/20180408072026.27365-1-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: 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>
---


diff -puN include/linux/ioport.h~resource-fix-integer-overflow-at-reallocation include/linux/ioport.h
--- a/include/linux/ioport.h~resource-fix-integer-overflow-at-reallocation
+++ a/include/linux/ioport.h
@@ -212,6 +212,9 @@ static inline bool resource_contains(str
 		return false;
 	if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET)
 		return false;
+	/* sanity check whether it's a valid resource range */
+	if (r2->end < r2->start)
+		return false;
 	return r1->start <= r2->start && r1->end >= r2->end;
 }
 
_

Patches currently in -mm which might be from tiwai@suse.de are

resource-fix-integer-overflow-at-reallocation.patch