yes, and this :
==6094==ERROR: AddressSanitizer: heap-use-after-free on address
0x6020000e6751 at pc 0x562a8dc492b8 bp 0x7f6805d2fa10 sp 0x7f6805d2fa00
READ of size 1 at 0x6020000e6751 thread T21
#0 0x562a8dc492b7 in local_open_nofollow hw/9pfs/9p-local.c:59
#1 0x562a8dc49361 in local_opendir_nofollow hw/9pfs/9p-local.c:92
#2 0x562a8dc4bd6e in local_mknod hw/9pfs/9p-local.c:662
#3 0x562a8dc521de in v9fs_co_mknod hw/9pfs/cofs.c:200
#4 0x562a8dc4413e in v9fs_mknod hw/9pfs/9p.c:3044
#5 0x562a8e600976 in coroutine_trampoline util/coroutine-ucontext.c:116
#6 0x7f68713635ff in __correctly_grouped_prefixwc
(/lib64/libc.so.6+0x4c5ff)
0x6020000e6751 is located 1 bytes inside of 2-byte region
[0x6020000e6750,0x6020000e6752)
freed by thread T0 here:
#0 0x7f687cdb9880 in __interceptor_free (/lib64/libasan.so.5+0xee880)
#1 0x7f687c1494d1 in g_free (/lib64/libglib-2.0.so.0+0x524d1)
#2 0x562a8dc30ce4 in v9fs_path_copy hw/9pfs/9p.c:195
#3 0x562a8dc3f0f3 in v9fs_create hw/9pfs/9p.c:2286
#4 0x562a8e600976 in coroutine_trampoline util/coroutine-ucontext.c:116
#5 0x7f68713635ff in __correctly_grouped_prefixwc
(/lib64/libc.so.6+0x4c5ff)
previously allocated by thread T5 here:
#0 0x7f687cdb9c48 in malloc (/lib64/libasan.so.5+0xeec48)
#1 0x7f6871421c37 in __GI___vasprintf_chk (/lib64/libc.so.6+0x10ac37)
Thread T21 created by T0 here:
#0 0x7f687cd16443 in pthread_create (/lib64/libasan.so.5+0x4b443)
#1 0x562a8e5bf61e in qemu_thread_create util/qemu-thread-posix.c:534
#2 0x562a8e5adbe4 in do_spawn_thread util/thread-pool.c:135
#3 0x562a8e5adc73 in spawn_thread_bh_fn util/thread-pool.c:143
#4 0x562a8e5aa4d0 in aio_bh_call util/async.c:90
#5 0x562a8e5aa787 in aio_bh_poll util/async.c:118
#6 0x562a8e5b65bd in aio_dispatch util/aio-posix.c:436
#7 0x562a8e5ab26f in aio_ctx_dispatch util/async.c:261
#8 0x7f687c1438ac in g_main_context_dispatch
(/lib64/libglib-2.0.so.0+0x4c8ac)
Thread T5 created by T0 here:
#0 0x7f687cd16443 in pthread_create (/lib64/libasan.so.5+0x4b443)
#1 0x562a8e5bf61e in qemu_thread_create util/qemu-thread-posix.c:534
#2 0x562a8d7a2258 in qemu_kvm_start_vcpu /root/qemu-3.0.0/cpus.c:1935
#3 0x562a8d7a2a0b in qemu_init_vcpu /root/qemu-3.0.0/cpus.c:2001
#4 0x562a8da3ef0c in x86_cpu_realizefn
/root/qemu-3.0.0/target/i386/cpu.c:4996
#5 0x562a8dd3a1e8 in device_set_realized hw/core/qdev.c:826
#6 0x562a8e2a1e62 in property_set_bool qom/object.c:1984
#7 0x562a8e29db0e in object_property_set qom/object.c:1176
#8 0x562a8e2a4b00 in object_property_set_qobject qom/qom-qobject.c:27
#9 0x562a8e29de2b in object_property_set_bool qom/object.c:1242
#10 0x562a8d9ad452 in pc_new_cpu /root/qemu-3.0.0/hw/i386/pc.c:1107
#11 0x562a8d9ad993 in pc_cpus_init /root/qemu-3.0.0/hw/i386/pc.c:1155
#12 0x562a8d9b79cb in pc_init1 /root/qemu-3.0.0/hw/i386/pc_piix.c:153
#13 0x562a8d9b981d in pc_init_v3_0
/root/qemu-3.0.0/hw/i386/pc_piix.c:438
#14 0x562a8dd4bf29 in machine_run_board_init hw/core/machine.c:830
#15 0x562a8db8d46e in main /root/qemu-3.0.0/vl.c:4516
#16 0x7f687133a11a in __libc_start_main (/lib64/libc.so.6+0x2311a)
SUMMARY: AddressSanitizer: heap-use-after-free hw/9pfs/9p-local.c:59 in
local_open_nofollow
Shadow bytes around the buggy address:
0x0c0480014c90: fa fa fd fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0480014ca0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0480014cb0: fa fa fa fa fa fa fd fd fa fa fd fa fa fa fd fa
0x0c0480014cc0: fa fa fa fa fa fa fa fa fa fa fd fd fa fa fd fa
0x0c0480014cd0: fa fa fa fa fa fa fa fa fa fa fd fa fa fa fd fd
=>0x0c0480014ce0: fa fa fa fa fa fa fd fa fa fa[fd]fa fa fa fa fa
0x0c0480014cf0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fd fd
0x0c0480014d00: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c0480014d10: fa fa fd fa fa fa fd fd fa fa fa fa fa fa fa fa
0x0c0480014d20: fa fa fa fa fa fa fd fa fa fa fa fa fa fa fd fa
0x0c0480014d30: fa fa fa fa fa fa fd fd fa fa fa fa fa fa fa fa
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
==6094==ABORTING
thanks.
On Mon, Nov 12, 2018 at 6:00 PM Greg Kurz <gr...@kaod.org> wrote:
> On Mon, 12 Nov 2018 16:28:28 +0800
> zhibin hu <noirf...@gmail.com> wrote:
>
> > hi,
> >
> > i use this patch with qemu 3.0.0 and it seems not fix completely.
> >
> > [root@localhost ~]# ./qemu-system-x86_64 -snapshot -m 1024 -smp 2
> > -enable-kvm -net nic,model=e1000 -net
> > tap,helper=/usr/libexec/qemu-bridge-helper -hda
> > /var/lib/libvirt/images/test.qcow2 -fsdev
> > local,id=test_dev,path=/tmp,security_model=none -device
> > virtio-9p-pci,fsdev=test_dev,mount_tag=test_mount -vnc 0.0.0.0:1
> > ==5014==WARNING: ASan doesn't fully support makecontext/swapcontext
> > functions and may produce false positives in some cases!
> > =================================================================
> > ==5014==ERROR: AddressSanitizer: heap-use-after-free on address
> > 0x60200014fc50 at pc 0x7f90c908697d bp 0x7f9053444970 sp 0x7f9053444118
> > READ of size 2 at 0x60200014fc50 thread T17
> > #0 0x7f90c908697c (/lib64/libasan.so.5+0x9997c)
> > #1 0x7f90c8452693 in g_path_get_basename
> > (/lib64/libglib-2.0.so.0+0x39693)
> > #2 0x559c1b78eb56 in local_lstat hw/9pfs/9p-local.c:182
> > #3 0x559c1b799628 in v9fs_co_lstat hw/9pfs/cofile.c:53
> > #4 0x559c1b777ee1 in fid_to_qid hw/9pfs/9p.c:598
> > #5 0x559c1b77aeae in v9fs_attach hw/9pfs/9p.c:1017
> > #6 0x559c1c145976 in coroutine_trampoline
> util/coroutine-ucontext.c:116
> > #7 0x7f90bd6855ff in __correctly_grouped_prefixwc
> > (/lib64/libc.so.6+0x4c5ff)
> >
> > 0x60200014fc50 is located 0 bytes inside of 2-byte region
> > [0x60200014fc50,0x60200014fc52)
> > freed by thread T0 here:
> > #0 0x7f90c90db880 in __interceptor_free (/lib64/libasan.so.5+0xee880)
> > #1 0x7f90c846b4d1 in g_free (/lib64/libglib-2.0.so.0+0x524d1)
> > #2 0x559c1b775ce4 in v9fs_path_copy hw/9pfs/9p.c:195
> > #3 0x559c1b78425d in v9fs_create hw/9pfs/9p.c:2297
>
> Ah, so we have a similar issue when creating files with the older
> 9p2000 and 9p2000.u protocols... I'll try to come up with a fix.
>
> Cheers,
>
> --
> Greg
>
> > #4 0x559c1c145976 in coroutine_trampoline
> util/coroutine-ucontext.c:116
> > #5 0x7f90bd6855ff in __correctly_grouped_prefixwc
> > (/lib64/libc.so.6+0x4c5ff)
> >
> > previously allocated by thread T4 here:
> > #0 0x7f90c90dbc48 in malloc (/lib64/libasan.so.5+0xeec48)
> > #1 0x7f90bd743c37 in __GI___vasprintf_chk (/lib64/libc.so.6+0x10ac37)
> >
> > Thread T17 created by T16 here:
> > #0 0x7f90c9038443 in pthread_create (/lib64/libasan.so.5+0x4b443)
> > #1 0x559c1c10461e in qemu_thread_create util/qemu-thread-posix.c:534
> > #2 0x559c1c0f2be4 in do_spawn_thread util/thread-pool.c:135
> > #3 0x559c1c0f2498 in worker_thread util/thread-pool.c:83
> > #4 0x559c1c1043e0 in qemu_thread_start util/qemu-thread-posix.c:504
> > #5 0x7f90bd9ff593 in start_thread (/lib64/libpthread.so.0+0x7593)
> >
> > Thread T16 created by T0 here:
> > #0 0x7f90c9038443 in pthread_create (/lib64/libasan.so.5+0x4b443)
> > #1 0x559c1c10461e in qemu_thread_create util/qemu-thread-posix.c:534
> > #2 0x559c1c0f2be4 in do_spawn_thread util/thread-pool.c:135
> > #3 0x559c1c0f2c73 in spawn_thread_bh_fn util/thread-pool.c:143
> > #4 0x559c1c0ef4d0 in aio_bh_call util/async.c:90
> > #5 0x559c1c0ef787 in aio_bh_poll util/async.c:118
> > #6 0x559c1c0fb5bd in aio_dispatch util/aio-posix.c:436
> > #7 0x559c1c0f026f in aio_ctx_dispatch util/async.c:261
> > #8 0x7f90c84658ac in g_main_context_dispatch
> > (/lib64/libglib-2.0.so.0+0x4c8ac)
> >
> > Thread T4 created by T0 here:
> > #0 0x7f90c9038443 in pthread_create (/lib64/libasan.so.5+0x4b443)
> > #1 0x559c1c10461e in qemu_thread_create util/qemu-thread-posix.c:534
> > #2 0x559c1b2e7258 in qemu_kvm_start_vcpu /root/qemu-3.0.0/cpus.c:1935
> > #3 0x559c1b2e7a0b in qemu_init_vcpu /root/qemu-3.0.0/cpus.c:2001
> > #4 0x559c1b583f0c in x86_cpu_realizefn
> > /root/qemu-3.0.0/target/i386/cpu.c:4996
> > #5 0x559c1b87f1e8 in device_set_realized hw/core/qdev.c:826
> > #6 0x559c1bde6e62 in property_set_bool qom/object.c:1984
> > #7 0x559c1bde2b0e in object_property_set qom/object.c:1176
> > #8 0x559c1bde9b00 in object_property_set_qobject qom/qom-qobject.c:27
> > #9 0x559c1bde2e2b in object_property_set_bool qom/object.c:1242
> > #10 0x559c1b4f2452 in pc_new_cpu /root/qemu-3.0.0/hw/i386/pc.c:1107
> > #11 0x559c1b4f2993 in pc_cpus_init /root/qemu-3.0.0/hw/i386/pc.c:1155
> > #12 0x559c1b4fc9cb in pc_init1 /root/qemu-3.0.0/hw/i386/pc_piix.c:153
> > #13 0x559c1b4fe81d in pc_init_v3_0
> > /root/qemu-3.0.0/hw/i386/pc_piix.c:438
> > #14 0x559c1b890f29 in machine_run_board_init hw/core/machine.c:830
> > #15 0x559c1b6d246e in main /root/qemu-3.0.0/vl.c:4516
> > #16 0x7f90bd65c11a in __libc_start_main (/lib64/libc.so.6+0x2311a)
> >
> > SUMMARY: AddressSanitizer: heap-use-after-free
> > (/lib64/libasan.so.5+0x9997c)
> > Shadow bytes around the buggy address:
> > 0x0c0480021f30: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
> > 0x0c0480021f40: fa fa fd fa fa fa fd fd fa fa fa fa fa fa fa fa
> > 0x0c0480021f50: fa fa fa fa fa fa fa fa fa fa fd fa fa fa fd fd
> > 0x0c0480021f60: fa fa fd fa fa fa fa fa fa fa fd fa fa fa fa fa
> > 0x0c0480021f70: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fd fa
> > =>0x0c0480021f80: fa fa fa fa fa fa fd fa fa fa[fd]fa fa fa fd fa
> > 0x0c0480021f90: fa fa fd fd fa fa fd fa fa fa fa fa fa fa fd fa
> > 0x0c0480021fa0: fa fa fd fa fa fa fd fa fa fa fd fa fa fa fa fa
> > 0x0c0480021fb0: fa fa fd fa fa fa fa fa fa fa fa fa fa fa fd fd
> > 0x0c0480021fc0: fa fa fd fa fa fa fa fa fa fa fa fa fa fa fd fa
> > 0x0c0480021fd0: fa fa fd fa fa fa fd fa fa fa fa fa fa fa fd fa
> > 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
> > ==5014==ABORTING
> >
> > thanks.
> >
> > On Wed, Nov 7, 2018 at 8:21 AM Greg Kurz <gr...@kaod.org> wrote:
> >
> > > The assumption that the fid cannot be used by any other operation is
> > > wrong. At least, nothing prevents a misbehaving client to create a
> > > file with a given fid, and to pass this fid to some other operation
> > > at the same time (ie, without waiting for the response to the creation
> > > request). The call to v9fs_path_copy() performed by the worker thread
> > > after the file was created can race with any access to the fid path
> > > performed by some other thread. This causes use-after-free issues that
> > > can be detected by ASAN with a custom 9p client.
> > >
> > > Unlike other operations that only read the fid path, v9fs_co_open2()
> > > does modify it. It should hence take the write lock.
> > >
> > > Cc: P J P <ppan...@redhat.com>
> > > Reported-by: zhibin hu <noirf...@gmail.com>
> > > Signed-off-by: Greg Kurz <gr...@kaod.org>
> > > ---
> > > hw/9pfs/cofile.c | 6 +++---
> > > 1 file changed, 3 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/hw/9pfs/cofile.c b/hw/9pfs/cofile.c
> > > index 88791bc327ac..9c22837cda32 100644
> > > --- a/hw/9pfs/cofile.c
> > > +++ b/hw/9pfs/cofile.c
> > > @@ -140,10 +140,10 @@ int coroutine_fn v9fs_co_open2(V9fsPDU *pdu,
> > > V9fsFidState *fidp,
> > > cred.fc_gid = gid;
> > > /*
> > > * Hold the directory fid lock so that directory path name
> > > - * don't change. Read lock is fine because this fid cannot
> > > - * be used by any other operation.
> > > + * don't change. Take the write lock to be sure this fid
> > > + * cannot be used by another operation.
> > > */
> > > - v9fs_path_read_lock(s);
> > > + v9fs_path_write_lock(s);
> > > v9fs_co_run_in_worker(
> > > {
> > > err = s->ops->open2(&s->ctx, &fidp->path,
> > >
> > >
>
>
