Re: [PATCH] hw/dma/xlnx_csu_dma: Set TYPE_XLNX_CSU_DMA class_size

[Alistair Francis]

On Wed, Mar 9, 2022 at 1:07 AM Peter Maydell <peter.maydell@linaro.org> wrote:
>
> In commit 00f05c02f9e7342f we gave the TYPE_XLNX_CSU_DMA object its
> own class struct, but forgot to update the TypeInfo::class_size
> accordingly.  This meant that not enough memory was allocated for the
> class struct, and the initialization of xcdc->read in the class init
> function wrote off the end of the memory. Add the missing line.
>
> Found by running 'check-qtest-aarch64' with a clang
> address-sanitizer build, which complains:
>
> ==2542634==ERROR: AddressSanitizer: heap-buffer-overflow on address 
> 0x61000000ab00 at pc 0x559a20aebc29 bp 0x7fff97df74d0 sp 0x7fff97df74c8
> WRITE of size 8 at 0x61000000ab00 thread T0
>     #0 0x559a20aebc28 in xlnx_csu_dma_class_init 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../hw/dma/xlnx_csu_dma.c:722:16
>     #1 0x559a21bf297c in type_initialize 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../qom/object.c:365:9
>     #2 0x559a21bf3442 in object_class_foreach_tramp 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../qom/object.c:1070:5
>     #3 0x7f09bcb641b7 in g_hash_table_foreach 
> (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x401b7)
>     #4 0x559a21bf3c27 in object_class_foreach 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../qom/object.c:1092:5
>     #5 0x559a21bf3c27 in object_class_get_list 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../qom/object.c:1149:5
>     #6 0x559a2081a2fd in select_machine 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../softmmu/vl.c:1661:24
>     #7 0x559a2081a2fd in qemu_create_machine 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../softmmu/vl.c:2146:35
>     #8 0x559a2081a2fd in qemu_init 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../softmmu/vl.c:3706:5
>     #9 0x559a20720ed5 in main 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../softmmu/main.c:49:5
>     #10 0x7f09baec00b2 in __libc_start_main 
> /build/glibc-sMfBJT/glibc-2.31/csu/../csu/libc-start.c:308:16
>     #11 0x559a2067673d in _start 
> (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/qemu-system-aarch64+0xf4b73d)
>
> 0x61000000ab00 is located 0 bytes to the right of 192-byte region 
> [0x61000000aa40,0x61000000ab00)
> allocated by thread T0 here:
>     #0 0x559a206eeff2 in calloc 
> (/mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/qemu-system-aarch64+0xfc3ff2)
>     #1 0x7f09bcb7bef0 in g_malloc0 
> (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x57ef0)
>     #2 0x559a21bf3442 in object_class_foreach_tramp 
> /mnt/nvmedisk/linaro/qemu-from-laptop/qemu/build/san/../../qom/object.c:1070:5
>
> Fixes: 00f05c02f9e7342f ("hw/dma/xlnx_csu_dma: Support starting a read 
> transfer through a class method")
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  hw/dma/xlnx_csu_dma.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/hw/dma/xlnx_csu_dma.c b/hw/dma/xlnx_csu_dma.c
> index 84f782fcdc0..60ada3286b4 100644
> --- a/hw/dma/xlnx_csu_dma.c
> +++ b/hw/dma/xlnx_csu_dma.c
> @@ -744,6 +744,7 @@ static const TypeInfo xlnx_csu_dma_info = {
>      .parent        = TYPE_SYS_BUS_DEVICE,
>      .instance_size = sizeof(XlnxCSUDMA),
>      .class_init    = xlnx_csu_dma_class_init,
> +    .class_size    = sizeof(XlnxCSUDMAClass),
>      .instance_init = xlnx_csu_dma_init,
>      .interfaces = (InterfaceInfo[]) {
>          { TYPE_STREAM_SINK },
> --
> 2.25.1
>
>