Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.10 64/74] mm/vmalloc.c: fix an overflow bug in alloc_vmap_area() | Date | Fri, 8 Nov 2013 22:52:09 -0800 |
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3.10-stable review patch. If anyone has any objections, please let me know.
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From: Zhang Yanfei <zhangyanfei.yes@gmail.com>
commit bcb615a81b1765864c71c50afb56631e7a1e5283 upstream.
When searching a vmap area in the vmalloc space, we use (addr + size - 1) to check if the value is less than addr, which is an overflow. But we assign (addr + size) to vmap_area->va_end.
So if we come across the below case:
(addr + size - 1) : not overflow (addr + size) : overflow
we will assign an overflow value (e.g 0) to vmap_area->va_end, And this will trigger BUG in __insert_vmap_area, causing system panic.
So using (addr + size) to check the overflow should be the correct behaviour, not (addr + size - 1).
Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Reported-by: Ghennadi Procopciuc <unix140@gmail.com> Tested-by: Daniel Baluta <dbaluta@ixiacom.com> Cc: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Anatoly Muliarski <x86ever@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- mm/vmalloc.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -388,12 +388,12 @@ nocache: addr = ALIGN(first->va_end, align); if (addr < vstart) goto nocache; - if (addr + size - 1 < addr) + if (addr + size < addr) goto overflow; } else { addr = ALIGN(vstart, align); - if (addr + size - 1 < addr) + if (addr + size < addr) goto overflow; n = vmap_area_root.rb_node; @@ -420,7 +420,7 @@ nocache: if (addr + cached_hole_size < first->va_start) cached_hole_size = first->va_start - addr; addr = ALIGN(first->va_end, align); - if (addr + size - 1 < addr) + if (addr + size < addr) goto overflow; if (list_is_last(&first->list, &vmap_area_list))
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