From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhang Yanfei , Ghennadi Procopciuc , Daniel Baluta , David Rientjes , Minchan Kim , KOSAKI Motohiro , Andrew Morton , Linus Torvalds , Anatoly Muliarski 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 Message-Id: <20131109065117.964902801@linuxfoundation.org> In-Reply-To: <20131109065113.502217951@linuxfoundation.org> References: <20131109065113.502217951@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zhang Yanfei 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 Reported-by: Ghennadi Procopciuc Tested-by: Daniel Baluta Cc: David Rientjes Cc: Minchan Kim Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Cc: Anatoly Muliarski Signed-off-by: Greg Kroah-Hartman --- 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))