[Qemu-commits] [qemu/qemu] ff0507: block/iscsi:fix heap-buffer-overflow in iscsi_aio_...

[Kuhn-Chen]

  Branch: refs/heads/master
  Home:   https://github.com/qemu/qemu
  Commit: ff0507c239a246fd7215b31c5658fc6a3ee1e4c5
      
https://github.com/qemu/qemu/commit/ff0507c239a246fd7215b31c5658fc6a3ee1e4c5
  Author: Chen Qun <address@hidden>
  Date:   2020-04-20 (Mon, 20 Apr 2020)

  Changed paths:
    M block/iscsi.c

  Log Message:
  -----------
  block/iscsi:fix heap-buffer-overflow in iscsi_aio_ioctl_cb

There is an overflow, the source 'datain.data[2]' is 100 bytes,
 but the 'ss' is 252 bytes.This may cause a security issue because
 we can access a lot of unrelated memory data.

The len for sbp copy data should take the minimum of mx_sb_len and
 sb_len_wr, not the maximum.

If we use iscsi device for VM backend storage, ASAN show stack:

READ of size 252 at 0xfffd149dcfc4 thread T0
    #0 0xaaad433d0d34 in __asan_memcpy 
(aarch64-softmmu/qemu-system-aarch64+0x2cb0d34)
    #1 0xaaad45f9d6d0 in iscsi_aio_ioctl_cb /qemu/block/iscsi.c:996:9
    #2 0xfffd1af0e2dc  (/usr/lib64/iscsi/libiscsi.so.8+0xe2dc)
    #3 0xfffd1af0d174  (/usr/lib64/iscsi/libiscsi.so.8+0xd174)
    #4 0xfffd1af19fac  (/usr/lib64/iscsi/libiscsi.so.8+0x19fac)
    #5 0xaaad45f9acc8 in iscsi_process_read /qemu/block/iscsi.c:403:5
    #6 0xaaad4623733c in aio_dispatch_handler /qemu/util/aio-posix.c:467:9
    #7 0xaaad4622f350 in aio_dispatch_handlers /qemu/util/aio-posix.c:510:20
    #8 0xaaad4622f350 in aio_dispatch /qemu/util/aio-posix.c:520
    #9 0xaaad46215944 in aio_ctx_dispatch /qemu/util/async.c:298:5
    #10 0xfffd1bed12f4 in g_main_context_dispatch 
(/lib64/libglib-2.0.so.0+0x512f4)
    #11 0xaaad46227de0 in glib_pollfds_poll /qemu/util/main-loop.c:219:9
    #12 0xaaad46227de0 in os_host_main_loop_wait /qemu/util/main-loop.c:242
    #13 0xaaad46227de0 in main_loop_wait /qemu/util/main-loop.c:518
    #14 0xaaad43d9d60c in qemu_main_loop /qemu/softmmu/vl.c:1662:9
    #15 0xaaad4607a5b0 in main /qemu/softmmu/main.c:49:5
    #16 0xfffd1a460b9c in __libc_start_main (/lib64/libc.so.6+0x20b9c)
    #17 0xaaad43320740 in _start (aarch64-softmmu/qemu-system-aarch64+0x2c00740)

0xfffd149dcfc4 is located 0 bytes to the right of 100-byte region 
[0xfffd149dcf60,0xfffd149dcfc4)
allocated by thread T0 here:
    #0 0xaaad433d1e70 in __interceptor_malloc 
(aarch64-softmmu/qemu-system-aarch64+0x2cb1e70)
    #1 0xfffd1af0e254  (/usr/lib64/iscsi/libiscsi.so.8+0xe254)
    #2 0xfffd1af0d174  (/usr/lib64/iscsi/libiscsi.so.8+0xd174)
    #3 0xfffd1af19fac  (/usr/lib64/iscsi/libiscsi.so.8+0x19fac)
    #4 0xaaad45f9acc8 in iscsi_process_read /qemu/block/iscsi.c:403:5
    #5 0xaaad4623733c in aio_dispatch_handler /qemu/util/aio-posix.c:467:9
    #6 0xaaad4622f350 in aio_dispatch_handlers /qemu/util/aio-posix.c:510:20
    #7 0xaaad4622f350 in aio_dispatch /qemu/util/aio-posix.c:520
    #8 0xaaad46215944 in aio_ctx_dispatch /qemu/util/async.c:298:5
    #9 0xfffd1bed12f4 in g_main_context_dispatch 
(/lib64/libglib-2.0.so.0+0x512f4)
    #10 0xaaad46227de0 in glib_pollfds_poll /qemu/util/main-loop.c:219:9
    #11 0xaaad46227de0 in os_host_main_loop_wait /qemu/util/main-loop.c:242
    #12 0xaaad46227de0 in main_loop_wait /qemu/util/main-loop.c:518
    #13 0xaaad43d9d60c in qemu_main_loop /qemu/softmmu/vl.c:1662:9
    #14 0xaaad4607a5b0 in main /qemu/softmmu/main.c:49:5
    #15 0xfffd1a460b9c in __libc_start_main (/lib64/libc.so.6+0x20b9c)
    #16 0xaaad43320740 in _start (aarch64-softmmu/qemu-system-aarch64+0x2c00740)

Reported-by: Euler Robot <address@hidden>
Signed-off-by: Chen Qun <address@hidden>
Reviewed-by: Stefan Hajnoczi <address@hidden>
Message-id: address@hidden
Reviewed-by: Daniel P. Berrangé <address@hidden>
Signed-off-by: Peter Maydell <address@hidden>