Re: [Qemu-devel] [PATCH] xilinx: fix buffer overflow on realize

[Peter Maydell]

On 18 October 2016 at 12:50, Marc-André Lureau
<address@hidden> wrote:
> ASAN complains about buffer overflow when running:
> aarch64-softmmu/qemu-system-aarch64 -machine xilinx-zynq-a9
>
> ==476==ERROR: AddressSanitizer: heap-buffer-overflow on address 
> 0x602000035e38 at pc 0x000000f75253 bp 0x7ffc597e0ec0 sp 0x7ffc597e0eb0
> READ of size 8 at 0x602000035e38 thread T0
>     #0 0xf75252 in xilinx_spips_realize hw/ssi/xilinx_spips.c:623
>     #1 0xb9ef6c in device_set_realized hw/core/qdev.c:918
>     #2 0x129ae01 in property_set_bool qom/object.c:1854
>     #3 0x1296e70 in object_property_set qom/object.c:1088
>     #4 0x129dd1b in object_property_set_qobject qom/qom-qobject.c:27
>     #5 0x1297168 in object_property_set_bool qom/object.c:1157
>     #6 0xb9aeac in qdev_init_nofail hw/core/qdev.c:358
>     #7 0x78a5bf in zynq_init_spi_flashes 
> /home/elmarco/src/qemu/hw/arm/xilinx_zynq.c:125
>     #8 0x78af60 in zynq_init /home/elmarco/src/qemu/hw/arm/xilinx_zynq.c:238
>     #9 0x998eac in main /home/elmarco/src/qemu/vl.c:4534
>     #10 0x7f96ed692730 in __libc_start_main (/lib64/libc.so.6+0x20730)
>     #11 0x41d0a8 in _start 
> (/home/elmarco/src/qemu/aarch64-softmmu/qemu-system-aarch64+0x41d0a8)
>
> 0x602000035e38 is located 0 bytes to the right of 8-byte region 
> [0x602000035e30,0x602000035e38)
> allocated by thread T0 here:
>     #0 0x7f970b014e60 in malloc (/lib64/libasan.so.3+0xc6e60)
>     #1 0x7f96f15b0e18 in g_malloc (/lib64/libglib-2.0.so.0+0x4ee18)
>     #2 0xb9ef6c in device_set_realized hw/core/qdev.c:918
>     #3 0x129ae01 in property_set_bool qom/object.c:1854
>     #4 0x1296e70 in object_property_set qom/object.c:1088
>     #5 0x129dd1b in object_property_set_qobject qom/qom-qobject.c:27
>     #6 0x1297168 in object_property_set_bool qom/object.c:1157
>     #7 0xb9aeac in qdev_init_nofail hw/core/qdev.c:358
>     #8 0x78a5bf in zynq_init_spi_flashes 
> /home/elmarco/src/qemu/hw/arm/xilinx_zynq.c:125
>     #9 0x78af60 in zynq_init /home/elmarco/src/qemu/hw/arm/xilinx_zynq.c:238
>     #10 0x998eac in main /home/elmarco/src/qemu/vl.c:4534
>     #11 0x7f96ed692730 in __libc_start_main (/lib64/libc.so.6+0x20730)
>
> s->spi is allocated with the size of num_busses which may be 1 (by
> default).
>
> It looks like ssi_auto_connect_slaves() connects all devices children to
> a s->spi bus. Since there can be only one parent bus, remove the second call.
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  hw/ssi/xilinx_spips.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
> index e2b77dc..ab7fa6f 100644
> --- a/hw/ssi/xilinx_spips.c
> +++ b/hw/ssi/xilinx_spips.c
> @@ -620,7 +620,7 @@ static void xilinx_spips_realize(DeviceState *dev, Error 
> **errp)
>
>      s->cs_lines = g_new0(qemu_irq, s->num_cs * s->num_busses);
>      ssi_auto_connect_slaves(DEVICE(s), s->cs_lines, s->spi[0]);
> -    ssi_auto_connect_slaves(DEVICE(s), s->cs_lines, s->spi[1]);

As Paolo said this should really be a loop. I'm assuming Paolo's
going to take this patch and fix that up.

thanks
-- PMM