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| author | Ian Jackson <ian.jackson@eu.citrix.com> | 2013-06-14 16:43:19 +0100 |
|---|---|---|
| committer | Ian Jackson <Ian.Jackson@eu.citrix.com> | 2013-06-14 16:43:19 +0100 |
| commit | d21d36e84354c04638b60a739a5f7c3d9f8adaf8 (patch) | |
| tree | 3623b58883ff2009a18200729816dc110392a405 | |
| parent | 2a548e22915535ac13694eb38222903bca7245e3 (diff) | |
| download | xen-d21d36e84354c04638b60a739a5f7c3d9f8adaf8.tar.gz xen-d21d36e84354c04638b60a739a5f7c3d9f8adaf8.tar.bz2 xen-d21d36e84354c04638b60a739a5f7c3d9f8adaf8.zip | |
libxc: Better range check in xc_dom_alloc_segment
If seg->pfn is too large, the arithmetic in the range check might
overflow, defeating the range check.
This is part of the fix to a security issue, XSA-55.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
| -rw-r--r-- | tools/libxc/xc_dom_core.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/tools/libxc/xc_dom_core.c b/tools/libxc/xc_dom_core.c index f8d1b08ba8..e79e38d513 100644 --- a/tools/libxc/xc_dom_core.c +++ b/tools/libxc/xc_dom_core.c @@ -509,7 +509,8 @@ int xc_dom_alloc_segment(struct xc_dom_image *dom, seg->vstart = start; seg->pfn = (seg->vstart - dom->parms.virt_base) / page_size; - if ( pages > dom->total_pages || /* double test avoids overflow probs */ + if ( pages > dom->total_pages || /* multiple test avoids overflow probs */ + seg->pfn > dom->total_pages || pages > dom->total_pages - seg->pfn) { xc_dom_panic(dom->xch, XC_OUT_OF_MEMORY, |