Christian, On Wed, Feb 02, 2022 at 05:55:45PM +0100, Christian Schoenebeck wrote: > On Freitag, 28. Januar 2022 23:33:26 CET Vitaly Chikunov wrote: > > `struct dirent' returned from readdir(3) could be shorter than > > `sizeof(struct dirent)', thus memcpy of sizeof length will overread > > into unallocated page causing SIGSEGV. Example stack trace: > > > > #0 0x00005555559ebeed v9fs_co_readdir_many (/usr/bin/qemu-system-x86_64 + > > 0x497eed) #1 0x00005555559ec2e9 v9fs_readdir (/usr/bin/qemu-system-x86_64 > > + 0x4982e9) #2 0x0000555555eb7983 coroutine_trampoline > > (/usr/bin/qemu-system-x86_64 + 0x963983) #3 0x00007ffff73e0be0 n/a (n/a + > > 0x0) > > > > While fixing, provide a helper for any future `struct dirent' cloning. > > > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/841 > > Cc: qemu-sta...@nongnu.org > > Co-authored-by: Christian Schoenebeck <qemu_...@crudebyte.com> > > Signed-off-by: Vitaly Chikunov <v...@altlinux.org> > > --- > > Tested on x86-64 Linux. > > I was too optimistic. Looks like this needs more work. With this patch applied > the 9p test cases [1] are crashing now: > > $ gdb --args tests/qtest/qos-test -m slow > ... > # Start of flush tests > ok 50 > /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-9p-pci/virtio-9p/virtio-9p-tests/synth/flush/success > ok 51 > /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-9p-pci/virtio-9p/virtio-9p-tests/synth/flush/ignored > # End of flush tests > # Start of readdir tests
I changed implementation from the one using dent->d_reclen to the one using strlen(dent->d_name) and it's passed readdir tests, but failed later: # Start of readdir tests ok 53 /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-9p-pci/virtio-9p/virtio-9p-tests/synth/readdir/basic ok 54 /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-9p-pci/virtio-9p/virtio-9p-tests/synth/readdir/split_512 ok 55 /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-9p-pci/virtio-9p/virtio-9p-tests/synth/readdir/split_256 ok 56 /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-9p-pci/virtio-9p/virtio-9p-tests/synth/readdir/split_128 # End of readdir tests # End of synth tests # Start of local tests # starting QEMU: exec x86_64-softmmu/qemu-system-x86_64 -qtest unix:/tmp/qtest-2822967.sock -qtest-log /dev/null -chardev socket,path=/tmp/qtest-2822967.qmp,id=char0 -mon chardev=char0,mode=control -display none -M pc -fsdev local,id=fsdev0,path='/usr/src/RPM/BUILD/qemu-6.2.0/build-dynamic/qtest-9p-local-NpcZCR',security_model=mapped-xattr -device virtio-9p-pci,fsdev=fsdev0,addr=04.0,mount_tag=qtest -accel qtest # GLib-DEBUG: setenv()/putenv() are not thread-safe and should not be used after threads are created ok 57 /x86_64/pc/i440FX-pcihost/pci-bus-pc/pci-bus/virtio-9p-pci/virtio-9p/virtio-9p-tests/local/config Received response 7 (RLERROR) instead of 73 (RMKDIR) Rlerror has errno 95 (Operation not supported) ** ERROR:../tests/qtest/virtio-9p-test.c:305:v9fs_req_recv: assertion failed (hdr.id == id): (7 == 73) Bail out! ERROR:../tests/qtest/virtio-9p-test.c:305:v9fs_req_recv: assertion failed (hdr.id == id): (7 == 73) Aborted Thanks, > Broken pipe > > Thread 1 "qos-test" received signal SIGABRT, Aborted. > __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50 > 50 ../sysdeps/unix/sysv/linux/raise.c: No such file or directory. > (gdb) bt > #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50 > #1 0x00007ffff7b7d537 in __GI_abort () at abort.c:79 > #2 0x00005555555ba495 in qtest_client_socket_recv_line (s=0x5555557663c0) at > ../tests/qtest/libqtest.c:503 > #3 0x00005555555ba5b3 in qtest_rsp_args (s=0x5555557663c0, expected_args=2) > at ../tests/qtest/libqtest.c:523 > #4 0x00005555555bbdb4 in qtest_clock_rsp (s=0x5555557663c0) at > ../tests/qtest/libqtest.c:970 > #5 0x00005555555bbe55 in qtest_clock_step (s=0x5555557663c0, step=100) at > ../tests/qtest/libqtest.c:985 > #6 0x00005555555cdc21 in qvirtio_wait_used_elem (qts=0x5555557663c0, > d=0x555555779b48, vq=0x5555557b0480, desc_idx=8, len=0x0, timeout_us=10000000) > at ../tests/qtest/libqos/virtio.c:220 > #7 0x00005555555ae79f in v9fs_req_wait_for_reply (req=0x5555557899a0, > len=0x0) at ../tests/qtest/virtio-9p-test.c:278 > #8 0x00005555555b03bf in fs_readdir (obj=0x555555779bb0, data=0x0, > t_alloc=0x5555557448b8) at ../tests/qtest/virtio-9p-test.c:851 > #9 0x00005555555990c4 in run_one_test (arg=0x5555557ac600) at > ../tests/qtest/qos-test.c:182 > #10 0x00007ffff7f02b9e in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #11 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #12 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #13 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #14 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #15 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #16 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #17 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #18 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #19 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #20 0x00007ffff7f0299b in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #21 0x00007ffff7f0308a in g_test_run_suite () from > /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #22 0x00007ffff7f030a1 in g_test_run () from > /lib/x86_64-linux-gnu/libglib-2.0.so.0 > #23 0x00005555555995a3 in main (argc=1, argv=0x7fffffffe508, > envp=0x7fffffffe528) at ../tests/qtest/qos-test.c:338 > (gdb) > > [1] https://wiki.qemu.org/Documentation/9p#Test_Cases > > Best regards, > Christian Schoenebeck > >
