1. Patchew
  2. QEMU
  3. View series

[Qemu-devel] [PATCH] spapr: fix buffer-overflow

Marc-André Lureau posted 1 patch 7 years, 1 month ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20170323100455.26821-1-marcandre.lureau@redhat.com
Test checkpatch passed
Test docker passed
Test s390x passed
hw/ppc/spapr.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
[Qemu-devel] [PATCH] spapr: fix buffer-overflow
Posted by Marc-André Lureau 7 years, 1 month ago 
Running postcopy-test with ASAN produces the following error:

QTEST_QEMU_BINARY=ppc64-softmmu/qemu-system-ppc64  tests/postcopy-test
...
=================================================================
==23641==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f1556600000 at pc 0x55b8e9d28208 bp 0x7f1555f4d3c0 sp 0x7f1555f4d3b0
READ of size 8 at 0x7f1556600000 thread T6
    #0 0x55b8e9d28207 in htab_save_first_pass /home/elmarco/src/qq/hw/ppc/spapr.c:1528
    #1 0x55b8e9d2939c in htab_save_iterate /home/elmarco/src/qq/hw/ppc/spapr.c:1665
    #2 0x55b8e9beae3a in qemu_savevm_state_iterate /home/elmarco/src/qq/migration/savevm.c:1044
    #3 0x55b8ea677733 in migration_thread /home/elmarco/src/qq/migration/migration.c:1976
    #4 0x7f15845f46c9 in start_thread (/lib64/libpthread.so.0+0x76c9)
    #5 0x7f157d9d0f7e in clone (/lib64/libc.so.6+0x107f7e)

0x7f1556600000 is located 0 bytes to the right of 2097152-byte region [0x7f1556400000,0x7f1556600000)
allocated by thread T0 here:
    #0 0x7f159bb76980 in posix_memalign (/lib64/libasan.so.3+0xc7980)
    #1 0x55b8eab185b2 in qemu_try_memalign /home/elmarco/src/qq/util/oslib-posix.c:106
    #2 0x55b8eab186c8 in qemu_memalign /home/elmarco/src/qq/util/oslib-posix.c:122
    #3 0x55b8e9d268a8 in spapr_reallocate_hpt /home/elmarco/src/qq/hw/ppc/spapr.c:1214
    #4 0x55b8e9d26e04 in ppc_spapr_reset /home/elmarco/src/qq/hw/ppc/spapr.c:1261
    #5 0x55b8ea12e913 in qemu_system_reset /home/elmarco/src/qq/vl.c:1697
    #6 0x55b8ea13fa40 in main /home/elmarco/src/qq/vl.c:4679
    #7 0x7f157d8e9400 in __libc_start_main (/lib64/libc.so.6+0x20400)

Thread T6 created by T0 here:
    #0 0x7f159bae0488 in __interceptor_pthread_create (/lib64/libasan.so.3+0x31488)
    #1 0x55b8eab1d9cb in qemu_thread_create /home/elmarco/src/qq/util/qemu-thread-posix.c:465
    #2 0x55b8ea67874c in migrate_fd_connect /home/elmarco/src/qq/migration/migration.c:2096
    #3 0x55b8ea66cbb0 in migration_channel_connect /home/elmarco/src/qq/migration/migration.c:500
    #4 0x55b8ea678f38 in socket_outgoing_migration /home/elmarco/src/qq/migration/socket.c:87
    #5 0x55b8eaa5a03a in qio_task_complete /home/elmarco/src/qq/io/task.c:142
    #6 0x55b8eaa599cc in gio_task_thread_result /home/elmarco/src/qq/io/task.c:88
    #7 0x7f15823e38e6  (/lib64/libglib-2.0.so.0+0x468e6)
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/elmarco/src/qq/hw/ppc/spapr.c:1528 in htab_save_first_pass

index seems to be wrongly incremented, unless I miss something that
would be worth a comment.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/ppc/spapr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 6ee566d658..63439811d5 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1524,16 +1524,16 @@ static void htab_save_first_pass(QEMUFile *f, sPAPRMachineState *spapr,
         /* Consume invalid HPTEs */
         while ((index < htabslots)
                && !HPTE_VALID(HPTE(spapr->htab, index))) {
-            index++;
             CLEAN_HPTE(HPTE(spapr->htab, index));
+            index++;
         }
 
         /* Consume valid HPTEs */
         chunkstart = index;
         while ((index < htabslots) && (index - chunkstart < USHRT_MAX)
                && HPTE_VALID(HPTE(spapr->htab, index))) {
-            index++;
             CLEAN_HPTE(HPTE(spapr->htab, index));
+            index++;
         }
 
         if (index > chunkstart) {
-- 
2.12.0.191.gc5d8de91d
Re: [Qemu-devel] [PATCH] spapr: fix buffer-overflow
Posted by David Gibson 7 years, 1 month ago 
On Thu, Mar 23, 2017 at 02:04:55PM +0400, Marc-André Lureau wrote:
> Running postcopy-test with ASAN produces the following error:
> 
> QTEST_QEMU_BINARY=ppc64-softmmu/qemu-system-ppc64  tests/postcopy-test
> ...
> =================================================================
> ==23641==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f1556600000 at pc 0x55b8e9d28208 bp 0x7f1555f4d3c0 sp 0x7f1555f4d3b0
> READ of size 8 at 0x7f1556600000 thread T6
>     #0 0x55b8e9d28207 in htab_save_first_pass /home/elmarco/src/qq/hw/ppc/spapr.c:1528
>     #1 0x55b8e9d2939c in htab_save_iterate /home/elmarco/src/qq/hw/ppc/spapr.c:1665
>     #2 0x55b8e9beae3a in qemu_savevm_state_iterate /home/elmarco/src/qq/migration/savevm.c:1044
>     #3 0x55b8ea677733 in migration_thread /home/elmarco/src/qq/migration/migration.c:1976
>     #4 0x7f15845f46c9 in start_thread (/lib64/libpthread.so.0+0x76c9)
>     #5 0x7f157d9d0f7e in clone (/lib64/libc.so.6+0x107f7e)
> 
> 0x7f1556600000 is located 0 bytes to the right of 2097152-byte region [0x7f1556400000,0x7f1556600000)
> allocated by thread T0 here:
>     #0 0x7f159bb76980 in posix_memalign (/lib64/libasan.so.3+0xc7980)
>     #1 0x55b8eab185b2 in qemu_try_memalign /home/elmarco/src/qq/util/oslib-posix.c:106
>     #2 0x55b8eab186c8 in qemu_memalign /home/elmarco/src/qq/util/oslib-posix.c:122
>     #3 0x55b8e9d268a8 in spapr_reallocate_hpt /home/elmarco/src/qq/hw/ppc/spapr.c:1214
>     #4 0x55b8e9d26e04 in ppc_spapr_reset /home/elmarco/src/qq/hw/ppc/spapr.c:1261
>     #5 0x55b8ea12e913 in qemu_system_reset /home/elmarco/src/qq/vl.c:1697
>     #6 0x55b8ea13fa40 in main /home/elmarco/src/qq/vl.c:4679
>     #7 0x7f157d8e9400 in __libc_start_main (/lib64/libc.so.6+0x20400)
> 
> Thread T6 created by T0 here:
>     #0 0x7f159bae0488 in __interceptor_pthread_create (/lib64/libasan.so.3+0x31488)
>     #1 0x55b8eab1d9cb in qemu_thread_create /home/elmarco/src/qq/util/qemu-thread-posix.c:465
>     #2 0x55b8ea67874c in migrate_fd_connect /home/elmarco/src/qq/migration/migration.c:2096
>     #3 0x55b8ea66cbb0 in migration_channel_connect /home/elmarco/src/qq/migration/migration.c:500
>     #4 0x55b8ea678f38 in socket_outgoing_migration /home/elmarco/src/qq/migration/socket.c:87
>     #5 0x55b8eaa5a03a in qio_task_complete /home/elmarco/src/qq/io/task.c:142
>     #6 0x55b8eaa599cc in gio_task_thread_result /home/elmarco/src/qq/io/task.c:88
>     #7 0x7f15823e38e6  (/lib64/libglib-2.0.so.0+0x468e6)
> SUMMARY: AddressSanitizer: heap-buffer-overflow /home/elmarco/src/qq/hw/ppc/spapr.c:1528 in htab_save_first_pass
> 
> index seems to be wrongly incremented, unless I miss something that
> would be worth a comment.
> 
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Oh my.  That's an impressively embarrassing bug.  As well as the
overrun itself, we're marking the wrong HPTEs clean.  I'm kind of
surprised we haven't seen this bite already.  Anyway, I've applied to
ppc-for-2.9, and I'll send a pull request ASAP.

> ---
>  hw/ppc/spapr.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 6ee566d658..63439811d5 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -1524,16 +1524,16 @@ static void htab_save_first_pass(QEMUFile *f, sPAPRMachineState *spapr,
>          /* Consume invalid HPTEs */
>          while ((index < htabslots)
>                 && !HPTE_VALID(HPTE(spapr->htab, index))) {
> -            index++;
>              CLEAN_HPTE(HPTE(spapr->htab, index));
> +            index++;
>          }
>  
>          /* Consume valid HPTEs */
>          chunkstart = index;
>          while ((index < htabslots) && (index - chunkstart < USHRT_MAX)
>                 && HPTE_VALID(HPTE(spapr->htab, index))) {
> -            index++;
>              CLEAN_HPTE(HPTE(spapr->htab, index));
> +            index++;
>          }
>  
>          if (index > chunkstart) {

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Patchew 2.1-devel-0870f84

© 2016 - 2024 Red Hat, Inc.