Re: [PATCH v2] hw/smbios: fix field corruption in type 4 table

[Ani Sinha]

On Thu, Feb 23, 2023 at 6:27 PM Julia Suvorova <jusual@redhat.com> wrote:
>
> Since table type 4 of SMBIOS version 2.6 is shorter than 3.0, the
> strings which follow immediately after the struct fields have been
> overwritten by unconditional filling of later fields such as core_count2.
> Make these fields dependent on the SMBIOS version.
>
> Fixes: 05e27d74c7 ("hw/smbios: add core_count2 to smbios table type 4")
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=2169904
>
> Signed-off-by: Julia Suvorova <jusual@redhat.com>

Reviewed-by: Ani Sinha <ani@anisinha.ca>

> ---
> v2:
>     * add fixes tag
>     * check tbl_len instead of ep_type
>
>  hw/smbios/smbios.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/hw/smbios/smbios.c b/hw/smbios/smbios.c
> index 4869566cf5..d2007e70fb 100644
> --- a/hw/smbios/smbios.c
> +++ b/hw/smbios/smbios.c
> @@ -750,14 +750,16 @@ static void smbios_build_type_4_table(MachineState *ms, 
> unsigned instance)
>      t->core_count = (ms->smp.cores > 255) ? 0xFF : ms->smp.cores;
>      t->core_enabled = t->core_count;
>
> -    t->core_count2 = t->core_enabled2 = cpu_to_le16(ms->smp.cores);
> -
>      t->thread_count = (ms->smp.threads > 255) ? 0xFF : ms->smp.threads;
> -    t->thread_count2 = cpu_to_le16(ms->smp.threads);
>
>      t->processor_characteristics = cpu_to_le16(0x02); /* Unknown */
>      t->processor_family2 = cpu_to_le16(0x01); /* Other */
>
> +    if (tbl_len == SMBIOS_TYPE_4_LEN_V30) {
> +        t->core_count2 = t->core_enabled2 = cpu_to_le16(ms->smp.cores);
> +        t->thread_count2 = cpu_to_le16(ms->smp.threads);
> +    }
> +
>      SMBIOS_BUILD_TABLE_POST;
>      smbios_type4_count++;
>  }
> --
> 2.38.1
>