[ovs-dev] [PATCH] ofproto: fix stack-buffer-overflow

Numan Siddique numans at ovn.org
Fri Nov 29 10:45:59 UTC 2019


On Fri, Nov 29, 2019 at 11:44 AM Linhaifeng <haifeng.lin at huawei.com> wrote:
>
> Should use flow->actions not &flow->actions.
>
> here is ASAN report:
> =================================================================
> ==57189==ERROR: AddressSanitizer: stack-buffer-overflow on address 0xffff428fa0e8 at pc 0xffff7f61a520 bp 0xffff428f9420 sp 0xffff428f9498 READ of size 196 at 0xffff428fa0e8 thread T150 (revalidator22)
>     #0 0xffff7f61a51f in __interceptor_memcpy (/lib64/libasan.so.4+0xa251f)
>     #1 0xaaaad26a3b2b in ofpbuf_put lib/ofpbuf.c:426
>     #2 0xaaaad26a30cb in ofpbuf_clone_data_with_headroom lib/ofpbuf.c:248
>     #3 0xaaaad26a2e77 in ofpbuf_clone_with_headroom lib/ofpbuf.c:218
>     #4 0xaaaad26a2dc3 in ofpbuf_clone lib/ofpbuf.c:208
>     #5 0xaaaad23e3993 in ukey_set_actions ofproto/ofproto-dpif-upcall.c:1640
>     #6 0xaaaad23e3f03 in ukey_create__ ofproto/ofproto-dpif-upcall.c:1696
>     #7 0xaaaad23e553f in ukey_create_from_dpif_flow ofproto/ofproto-dpif-upcall.c:1806
>     #8 0xaaaad23e65fb in ukey_acquire ofproto/ofproto-dpif-upcall.c:1984
>     #9 0xaaaad23eb583 in revalidate ofproto/ofproto-dpif-upcall.c:2625
>     #10 0xaaaad23dee5f in udpif_revalidator ofproto/ofproto-dpif-upcall.c:1076
>     #11 0xaaaad26b84ef in ovsthread_wrapper lib/ovs-thread.c:708
>     #12 0xffff7e74a8bb in start_thread (/lib64/libpthread.so.0+0x78bb)
>     #13 0xffff7e0665cb in thread_start (/lib64/libc.so.6+0xd55cb)
>
> Address 0xffff428fa0e8 is located in stack of thread T150 (revalidator22) at offset 328 in frame
>     #0 0xaaaad23e4cab in ukey_create_from_dpif_flow ofproto/ofproto-dpif-upcall.c:1762
>
>   This frame has 4 object(s):
>     [32, 96) 'actions'
>     [128, 192) 'buf'
>     [224, 328) 'full_flow'
>     [384, 2432) 'stub' <== Memory access at offset 328 partially underflows this variable
> HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
>       (longjmp and C++ exceptions *are* supported) Thread T150 (revalidator22) created by T0 here:
>     #0 0xffff7f5b0f7f in __interceptor_pthread_create (/lib64/libasan.so.4+0x38f7f)
>     #1 0xaaaad26b891f in ovs_thread_create lib/ovs-thread.c:792
>     #2 0xaaaad23dc62f in udpif_start_threads ofproto/ofproto-dpif-upcall.c:639
>     #3 0xaaaad23daf87 in ofproto_set_flow_table ofproto/ofproto-dpif-upcall.c:446
>     #4 0xaaaad230ff7f in dpdk_evs_cfg_set vswitchd/bridge.c:1134
>     #5 0xaaaad2310097 in bridge_reconfigure vswitchd/bridge.c:1148
>     #6 0xaaaad23279d7 in bridge_run vswitchd/bridge.c:3944
>     #7 0xaaaad23365a3 in main vswitchd/ovs-vswitchd.c:240
>     #8 0xffff7dfb1adf in __libc_start_main (/lib64/libc.so.6+0x20adf)
>     #9 0xaaaad230a3d3  (/usr/sbin/ovs-vswitchd-2.7.0-1.1.RC5.001.asan+0x26f3d3)
>
> SUMMARY: AddressSanitizer: stack-buffer-overflow (/lib64/libasan.so.4+0xa251f) in __interceptor_memcpy Shadow bytes around the buggy address:
>   0x200fe851f3c0: 00 00 00 00 f1 f1 f1 f1 f8 f2 f2 f2 00 00 00 00
>   0x200fe851f3d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x200fe851f3e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x200fe851f3f0: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 00
>   0x200fe851f400: f2 f2 f2 f2 f8 f8 f8 f8 f8 f8 f8 f8 f2 f2 f2 f2
> =>0x200fe851f410: 00 00 00 00 00 00 00 00 00 00 00 00 00[f2]f2 f2
>   0x200fe851f420: f2 f2 f2 f2 00 00 00 00 00 00 00 00 00 00 00 00
>   0x200fe851f430: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x200fe851f440: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x200fe851f450: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x200fe851f460: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Shadow byte legend (one shadow byte represents 8 application bytes):
>   Addressable:           00
>   Partially addressable: 01 02 03 04 05 06 07
>   Heap left redzone:       fa
>   Freed heap region:       fd
>   Stack left redzone:      f1
>   Stack mid redzone:       f2
>   Stack right redzone:     f3
>   Stack after return:      f5
>   Stack use after scope:   f8
>   Global redzone:          f9
>   Global init order:       f6
>   Poisoned by user:        f7
>   Container overflow:      fc
>   Array cookie:            ac
>   Intra object redzone:    bb
>   ASan internal:           fe
>   Left alloca redzone:     ca
>   Right alloca redzone:    cb
> ==57189==ABORTING
>
> Signed-off-by: Linhaifeng <haifeng.lin at huawei.com>

Acked-by: Numan Siddique <numans at ovn.org>

Numan

> ---
>  ofproto/ofproto-dpif-upcall.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/ofproto/ofproto-dpif-upcall.c b/ofproto/ofproto-dpif-upcall.c index dc30824771..c2fc527a31 100644
> --- a/ofproto/ofproto-dpif-upcall.c
> +++ b/ofproto/ofproto-dpif-upcall.c
> @@ -1796,7 +1796,7 @@ ukey_create_from_dpif_flow(const struct udpif *udpif,
>      }
>
>      reval_seq = seq_read(udpif->reval_seq) - 1; /* Ensure revalidation. */
> -    ofpbuf_use_const(&actions, &flow->actions, flow->actions_len);
> +    ofpbuf_use_const(&actions, flow->actions, flow->actions_len);
>      *ukey = ukey_create__(flow->key, flow->key_len,
>                            flow->mask, flow->mask_len, flow->ufid_present,
>                            &flow->ufid, flow->pmd_id, &actions,
> --
> 2.19.1
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